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Sample records for laser applications milan

  1. [Public food service in Milan city and Hinterland: GMP application (Part 1)].

    PubMed

    Pontello, M; Dal Vecchio, A; Bertini, I; Valerio, E

    2005-01-01

    Food service establishments are recognized as a critical sector concerning foodborne diseases occurrence, that is associated to contributing factors such as the anticipated preparation of meals that are often highly handled, and long-time distributed. A survey has been planned to evaluate the application of HACCP plan, in order to select a statistically representative sample of food services (restaurant, pizza-shop, bar, ..) in two Milan area' Public Health Units (PHU). During the inspections a proper check-list has been filled up in order to give a conformity evaluation about the global situation and about three specific sections: hygiene of food-handlers, procedures control, temperatures management. The food services have been found satisfactory in 9/106 and 5/54 cases in Milan City and in hinterland, respectively; among the two areas, highly significant differences have been revealed about temperatures management (68% and 28% unsatisfactory, respectively). In Milan City restaurants provided with HACCP plan scores are significantly different from unprovided restaurants scores (global and the three sections' evaluation); in Milan hinterland differences between provided and unprovided HACCP plan restaurants regard temperature management scores only. Useful suggestions to improve the quality of surveillance activity come from complex and heterogeneous findings shown in this study. PMID:16041926

  2. Mobile Applications as Tool for Exploiting Cultural Heritage in the Region of Turin and Milan

    NASA Astrophysics Data System (ADS)

    Rolando, A.; Scandiffio, A.

    2013-07-01

    visualization of data flows. In the current research, the field of investigation refers both to the territorial scale of Turin - Milan axis, and to the local scale of small cities localized in the territories in between. The research has been applied to Turin - Milan infrastructural axis, with the aim to represent the relationships that can be established between mobility infrastructure and cultural heritage. Such relationships should be intended in terms of accessibility from mobility infrastructure (motorway exit, service areas, railways stations) to cultural heritage localized in the surrounding landscape. The richness of cultural heritage and landscape along the chosen infrastructural bundle represent a great opportunity for territorial development in terms of attractiveness, both for local inhabitants and for tourists. Nowadays, the use of tracking technologies can be applied to investigate tourist flows, behaviors of local inhabitants in the historic city centre, number of visitors in the city and so on. In this sense it is possible to apply these technologies, which are particularly relevant in urban studies, extending them to the territorial scale of the Turin - Milan region. The large amount of available geo-referenced data can be used in different ways and it is very potential for different kind of analysis: it is possible to show tourist flows in the territory, receive information about more visited places, obtain interaction from users and cultural heritage in terms of visitors opinion about the places, give information to tourists about cultural places, monitor the accessibility to the places, understand the use of means of transport and keep under control the impacts of tourism (social, cultural, environmental) on territory. Applications based on smartphones can be considered a powerful device for visitors but also for institutions that are involved in tourism and cultural heritage management. In fact, the use of mobile applications it can produce a real time data

  3. The Milan photooxidant plume

    NASA Astrophysics Data System (ADS)

    PréVôT, André S. H.; Staehelin, Johannes; Kok, Gregory L.; Schillawski, Richard D.; Neininger, Bruno; Staffelbach, Thomas; Neftel, Albrecht; Wernli, Heini; Dommen, Josef

    1997-10-01

    In Switzerland, measurement campaigns including aircraft measurements were carried out in the summers of 1992 and 1993 as part of the Pollution and Meteorology (POLLUMET) study. Ozone (O3) concentrations, up to 185 ppb, with a large spatial variability were found south of the Alps in the afternoon. Comparison to measurements north of the Alps shows that these concentration levels are extraordinarily high for central Europe. Backward trajectories reveal that the highest O3 levels were found 4-5 hours downwind of Milan, Italy. The measurements suggest a reactive organic gas (ROG) sensitive O3 production regime 1-3 hours downwind in the plume, and a NOx (sum of nitrogen oxide (NO) and nitrogen dioxide (NO2)) limitation in air masses not affected by the Milan plume. Air masses originating north of Milan are probably close to the transition zone between the two photochemical regimes. This was found by using measurements of total odd nitrogen (NOy,), NO, NO2, formaldehyde (HCHO), and hydrogen peroxide (H2O2) yielding indicators for ROG and NOx sensitive O3 production. The slope of ozone versus NOz (=NOy-NOx: photochemical products of NOx) were markedly higher in NOx limited conditions (ΔO3/ΔNOz=13.6) than in air masses close to the transition zone (ΔO3/ΔNOz=4.2).

  4. Laser Applications in Orthodontics

    PubMed Central

    Heidari, Somayeh; Torkan, Sepideh

    2013-01-01

    A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field. PMID:25606324

  5. Laser applications in phlebology

    NASA Astrophysics Data System (ADS)

    Longo, Leonardo; Mancini, S.; Postiglione, Marco; Postiglione, M. G.

    2001-06-01

    PURPOSE: review of laser used in phlebology METHOD: critical analysis of scientific data taken from the literature and based on 25 years personal experience. RESULTS: we have three groups of laser applications in phlebology: for the diagnosis, as physical therapy and as surgical therapy. DISCUSSION AND CONCLUSION: the laser-doppler studies the microcirculations, the no-surgical therapy shown positive results in the treatment of venous ulcers and for the wound healing. It could be indicate also as antiphlogistic and anti-edema therapy, in superficial thrombophlebitis. The surgical laser is useful for the surgical cleaning of ulcers, for haemorroids, angiomas and telangiectases.

  6. Seasonal behavior of PM2.5 deliquescence, crystallization, and hygroscopic growth in the Po Valley (Milan): Implications for remote sensing applications

    NASA Astrophysics Data System (ADS)

    D'Angelo, Luca; Rovelli, Grazia; Casati, Marco; Sangiorgi, Giorgia; Perrone, Maria Grazia; Bolzacchini, Ezio; Ferrero, Luca

    2016-07-01

    Atmospheric aerosols deliquescence and crystallization relative humidity (DRH and CRH) are rarely measured compared to the worldwide number of hygroscopicity measurements; this feature comes from the lack of an efficient method able to capture the whole complexity of chemical composition of aerosols. Despite this, the knowledge of both DRH and CRH are crucial for a correct parameterization of the aerosol hygroscopic growth used in different applications, among which the remote sensing is very important. In this paper, a newly developed technique (direct current conductance method) was applied in an aerosol chamber to Milan PM2.5 samples, to identify aerosol DRH and CRH both during winter and summer. These results were compared with those independently obtained by gravimetric measurements conducted in the chamber using a microbalance. Microbalance data allowed also the determination of the mass hygroscopic growth factor on the collected PM2.5 samples. Results evidenced first a good agreement between the two methods (RMSE = 2.7% and 2.3% for DRH and CRH, respectively). Collected data evidenced the hysteresis behavior of ambient particles and variability in both DRH and CRH between the two seasons. Summer samples showed higher DRH and CRH (on average 71.4 ± 1.0% RH and 62.6 ± 1.2% RH, respectively) than the winter ones (on average 55.2 ± 0.7% RH and 46.9 ± 0.6% RH). This behavior was related to the higher content of sulfates during the summer season. Conversely, the mass hygroscopic growth factor at 90% RH was higher for winter samples (2.76 ± 0.06) with respect to the summer ones (1.91 ± 0.11). Since hysteresis behavior affects optical properties of aerosols, when RH conditions are within the loop, the hygroscopic growth factor could be assigned in a wrong way. Thus, the growth factor was calculated within the hysteresis loop for both upper and lower branches: results showed that difference in hygroscopic growth factor could reach up the 24%.

  7. Laser applications in neurosurgery

    NASA Astrophysics Data System (ADS)

    Cerullo, Leonard J.

    1985-09-01

    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  8. The water footprint of Milan.

    PubMed

    Vanham, D; Bidoglio, G

    2014-01-01

    This study quantifies the water footprint of consumption (WFcons) and production (WFprod) of Milan. The current WFcons amounts to 6,139 l/cap/d (a volume of 2.93 km(3) annually), of which 52 l/cap/d (1%) is attributed to domestic water, 448 l/cap/d (7%) to the consumption of industrial products and 5,639 l/cap/d (92%) to the consumption of agricultural products. The WFprod is 52 l/cap/d. Milan is thus a net virtual water importer, predominantly through the import of agricultural products. These are produced outside city borders, both in Italy and abroad. This shows the dependency of city dwellers on water resources from other river basins. In addition, the WFcons for a healthy diet (based on Mediterranean Food-Based Dietary Guidelines) and a vegetarian diet are analysed. The current Milanese diet consists of too much sugar, crop oils, meat, animal fats, milk and milk products and not enough cereals, rice, potatoes, vegetables and fruit. The latter two diets result in substantial WFcons reductions: -29% (to 4,339 l/cap/d) for a healthy diet and -41% (to 3,631 l/cap/d) for a vegetarian diet. Indeed, a lot of water could be saved by Milan citizens through a change in their diet. A sustainable city should account for its impacts beyond its borders. PMID:24569278

  9. ): laser processing and applications

    NASA Astrophysics Data System (ADS)

    Fricke-Begemann, T.; Meinertz, J.; Weichenhain-Schriever, R.; Ihlemann, J.

    2014-10-01

    Substoichiometric silicon oxide SiOx with x < 2 in form of evaporated or sputtered thin films offers a versatile material basis for laser ablation techniques such as film patterning, laser-induced forward transfer, or laser-induced backside dry etching. Applications in the field of (micro-) optics are favoured strongly by the fact that SiOx can be oxidised to UV-transparent SiO2 by thermal treatment (furnace or laser annealing). On the other hand, with x ≈ 1, SiOx exhibits an absorption coefficient of >105 cm-1 in the deep UV below 250 nm, comparable to strongly absorbing polymers such as polyimide. This enables precise ablation with, e.g., excimer lasers at moderate fluences. For example, UV-transparent diffractive elements or phase masks are made by laser patterning of an appropriate SiOx film and subsequent oxidation to SiO2. Modifications of the basic film ablation process lead to novel surface topographies such as blister or cup arrays with potential non-optical applications, e.g., in micro-/nanofluidics.

  10. Novel oral laser applications

    NASA Astrophysics Data System (ADS)

    Yousif, A.; Strassl, M.; Beer, F.; Verhagen, L.; Wittschier, M.; Wintner, E.

    2007-03-01

    In dental hard tissue ablation, ultra-short laser pulses have proven sufficiently their potential for material ablation with negligible collateral damage providing many advantages. The absence of micro-cracks and the possibility to avoid overheating of the pulp during dental cavity preparation may be among the most important issues, the latter opening up an avenue for potential painless treatment. Beside the evident short interaction time of laser radiation with the irradiated tissue, scanning of the ultra-short pulse trains turned out to be crucial for ablating cavities of required quality and shape. Additionally, long-pulsed laser systems have demonstrated successfully their suitability for decontamination purposes. In this paper, an overview of different indications for laser application in dental therapies in both pulse regimes is presented. A special focus is set on the decontamination of dental implants in periimplantitis therapy. Having employed commercially available long pulse systems for dental applications and ultra-short 330 fs pulses, we present first results for temperature development and corresponding ablation thresholds for dental implants, as in the future more gentle implant cleaning by ultra-short laser pulses could become of interest.

  11. Laser applications in criminalistics

    NASA Astrophysics Data System (ADS)

    Menzel, E. R.

    1990-10-01

    Lasers find application in numerous areas of criminalistics such as fiber analysis document examination and serology. Their widest use however is in detection of latent finger prints. Several routine procedures for obtaining laserexcited fingerprint fluorescence on a range of surfaces have been devel oped. However many surfaces fluoresce so strongly themselves that they are not amenable to these procedures. Timeresolved luminescence imaging is being investigated to permit detection of fingerprints on such surfaces.

  12. Diode laser applications in urology

    NASA Astrophysics Data System (ADS)

    Sam, Richard C.; Esch, Victor C.

    1995-05-01

    Diode lasers are air-cooled, efficient, compact devices which have the potential of very low cost when produced in quantity. The characteristics of diode lasers are discussed. Their applications in interstitial thermal treatment of the prostate, and laser ablation of prostate tissues, will be presented.

  13. Novel fiber lasers and applications

    NASA Astrophysics Data System (ADS)

    Zenteno, Luis A.; Walton, Donnell T.

    2003-07-01

    Glass fiber lasers were invented in the 60's by Elias Snitzer at Americal Optical, soon after the invention of the first solid-state glass laser. However, it was not until the 80's when these waveguide devices were deployed in industrial applications, driven largely by the technological success of the semiconductor laser diode, which provided practical and efficient pumps, and by the advent of low loss rare-earth-doped optical fiber.

  14. Application of lasers in endodontics

    NASA Astrophysics Data System (ADS)

    Ertl, Thomas P.; Benthin, Hartmut; Majaron, Boris; Mueller, Gerhard J.

    1997-12-01

    Root canal treatment is still a problem in dentistry. Very often the conventional treatment fails and several treatment sessions are necessary to save the tooth from root resection or extraction. Application of lasers may help in this situation. Bacteria reduction has been demonstrated both in vitro and clinically and is either based on laser induced thermal effects or by using an ultraviolet light source. Root canal cleansing is possible by Er:YAG/YSGG-Lasers, using the hydrodynamic motion of a fluid filled in the canals. However root canal shaping using lasers is still a problem. Via falsas and fiber breakage are points of research.

  15. Some emerging applications of lasers

    NASA Astrophysics Data System (ADS)

    Christensen, C. P.

    1982-10-01

    Applications of lasers in photochemistry, advanced instrumentation, and information storage are discussed. Laser microchemistry offers a number of new methods for altering the morphology of a solid surface with high spatial resolution. Recent experiments in material deposition, material removal, and alloying and doping are reviewed. A basic optical disk storage system is described and the problems faced by this application are discussed, in particular those pertaining to recording media. An advanced erasable system based on the magnetooptic effect is described. Applications of lasers for remote sensing are discussed, including various lidar systems, the use of laser-induced fluorescence for oil spill characterization and uranium exploration, and the use of differential absorption for detection of atmospheric constituents, temperature, and humidity.

  16. Laser applications in integrated circuit packaging

    NASA Astrophysics Data System (ADS)

    Lu, Yongfeng; Song, Wen D.; Ren, ZhongMin; An, Chengwu; Ye, Kaidong D.; Liu, DaMing; Wang, Weijie; Hong, Ming Hui; Chong, Tow Chong

    2002-06-01

    Laser processing has large potential in the packaging of integrated circuits (IC). It can be used in many applications such as laser cleaning of IC mold tools, laser deflash to remove mold flash form heat sinks and lead wires of IC packages, laser singulation of BGA and CSP, laser reflow of solder ball on GBA, laser marking on packages and on SI wafers. During the implementation of all these applications, laser parameters, material issues, throughput, yield, reliability and monitoring techniques have to b taken into account. Monitoring of laser-induced plasma and laser induced acoustic wave has been used to understand and to control the processes involved in these applications.

  17. Energy engineering analysis study report, Milan Army Ammunition Plant, Milan, Tennessee: Executive summary. Final report

    SciTech Connect

    1982-09-01

    This report is a summary of the Energy Engineering Analysis for the Milan Army Ammunition Plant (MAAP) in Milan, Tennessee. It includes the recommendations for the development of a Basewide Energy Plan consisting of energy conservation projects and other recommendations for reduction of the installation`s 1985 source energy consumption. Milan Army Ammunition Plant, containing 22,541 acres, is situated in both Gibson and Carroll Counties, Tennessee, and is approximately equally divided longitudinally into the two counties. The Milan area experiences typically short mild winters and long warm summers. With the exception of a few modernized facilities, the overwhelming majority of buildings at MAAP were constructed for World War II ammunition production.

  18. Laser applications. Final report

    SciTech Connect

    Horn, R.T.

    1980-07-01

    Processes were developed that use lasers as manufacturing tools. These processes were stripping of insulation from cables and wires, machining of quartz, microdrilling and welding of reflective metals, and precision alignment of curved surfaces before machining. A technological basis also was formed which resulted in a process for automatic surface inspection of parts and aided development of machining processes for Kevlar parts.

  19. Quality in Public Spaces: Monitoring Green Areas in Milan

    NASA Astrophysics Data System (ADS)

    Guzzetti, F.; Pasquinelli, A.; Privitera, A.

    2013-05-01

    The city of Milan gained a lot of experience in management and conservation of urban green spaces: the set goal is to come to a high quality standard of the green areas, to be realized not only downtown, but all over the city. All the activities related to this issue has been outsourced to a specific Consortium through three-yearly contracts based on a Global Service model and the management structure implemented since 2004 has been set up on GIS technologies and open source applications: this structure has evolved over the years following an increasingly integration of the different operative phases and paying close attention to the update of the geographical data. With the contribution of the academic world and the support of technical experts in webGIS applications field, Milan today can count on a management system in which cartographical aspects are perfectly integrated with maintenance activities executed by operators on site and check inspections carried out by municipal controllers, ensuring a high level of the geo-database updating. The focus now is on the arrangement of a performance monitoring system, aimed to control the achievement of the quality standard fixed by contract with the Consortium. In the research here introduced we want to describe how the unification of the workflows - related to the upkeep schedules on the one hand and to the control activities on the other hand- together with the use of GPS technologies contributed in improving efficiency in practical intervention in case of warnings sent by controllers, in daily works and data update, producing as a consequence an enhancement of the maintenance service provided. In this way the "Green GIS" can now be used for further qualitative upgrade in management of green areas in Milan, with new challenges related to the concept of "smart city".

  20. Argon laser application to endodontics

    NASA Astrophysics Data System (ADS)

    Blankenau, Richard J.; Ludlow, Marvin; Anderson, David

    1993-07-01

    The application of laser technology to endodontics has been studied for some time. At the present time several major problems are being investigated: (1) removal of infected tissues, (2) sterilization of canals, (3) obturation of canals, and (4) preservation of the vitality of supporting tissues. This list is not intended to imply other problems do not exist or have been solved, but it is a starting point. This paper reviews some of the literature that relates to laser applications to endodontics and concludes with some of the findings from our investigation.

  1. Semiconductor laser applications in rheumatology

    NASA Astrophysics Data System (ADS)

    Pascu, Mihail-Lucian; Suteanu, S.

    1996-01-01

    Two types of laser diode (LD) based equipment for rheumatology are introduced. The first is a portable device which contains single LD emitting at 890 nm laser pulses (time full width 100 nsec) of reprate tunable within (0.5 - 1.5) kHz; the laser beam average power is 0.7 mW at 1 kHz reprate. The second is computer controlled, contains one HeNe laser and 5 LD allowing 6 modes of patient irradiation (placebo effect evaluation included). HeNe laser works in cw at 632.8 nm; the LD works each as described for the portable equipment. HeNe and LD beams are superposed so that HeNe laser spot in the irradiation plane has a 60 mm diameter and the LD spots covers a 50 mm diameter disc centered on the HeNe laser spot. Clinical applications using the second type of equipment are reported; 1287 patients were treated between October 1991 and October 1994. Female/male ratio was 4:1 and their age distribution was between 18 and 85 years. The average number of exposures was 10 and the mean exposure time was 7 minutes. Studies were made on the treatment of rheumatoid arthritis, seronegative arthritis, degenerative joint diseases, abarticular rheumatism, osteoporosis pain and pains and edema after fractures.

  2. Laser Applications: Implications for Vocational Education.

    ERIC Educational Resources Information Center

    Fraser, Jeannette L.

    Recent and projected advances in and commercial applications of lasers and laser technology were examined in order to assist vocational planners in responding to skill needs that will be created by lasers in the next few years. Until recently, most laser applications were in research and development settings; however, in the last several years…

  3. Industrial applications of laser micromachining.

    PubMed

    Gower, M C

    2000-07-17

    The use of pulsed lasers for microprocessing material in several manufacturing industries is presented. Microvia, ink jet printer nozzle and biomedical catheter hole drilling, thin-film scribing and micro-electro-mechanical system (MEMS) fabrication applications are reviewed. PMID:19404370

  4. The New Epistemology and the Milan Approach: Feminist and Sociopolitical Considerations.

    ERIC Educational Resources Information Center

    MacKinnon, Laurie Katherine; Miller, Dusty

    1987-01-01

    Explores the sociopolitical implications of the new epistemology and the Milan approach, concluding that, while second order cybernetics has greater potential to incorporate a radical social analysis, it has, nevertheless, failed to do so. The application of second order cybernetics in family therapy appears to be constrained by the sociopolitical…

  5. [The application of laser in endodontics].

    PubMed

    He, W X; Liu, N N; Wang, X L; He, X Y

    2016-08-01

    Since laser was introduced in the field of medicine in 1970's, its application range has continuously expanded. The application of laser in endodontics also increased due to its safety and effectiveness in dental treatments. The majority of the laser application researches in dentistry focused on dentin hypersensitivity, removal of carious tissues, tooth preparations, pulp capping or pulpotomy, and root canal treatment. In this article, we reviewed literature on the effects of laser in the treatments of dental and pulp diseases. PMID:27511037

  6. [Applications of lasers in dental implantology].

    PubMed

    Mu, Yue; Li, Qian; Zhao, Ji-zhi

    2014-10-01

    With the constant progress of laser physics, medical laser technology has been widely applied in clinical practices and basic researches. In this article, we reviewed the relevant articles on the laser applications in dental implantology and concluded that lasers provides promising solutions in the treatment technology of dental implants and in the treatment of soft and hard tissue conditions. PMID:25360659

  7. NASA Goddard's Application of Lasers in Space

    NASA Technical Reports Server (NTRS)

    Abshire, James B.; Krainak, Michael A.; Degnan, John J.

    2007-01-01

    Researchers at NASA Goddard have been applying lasers for space measurements for over 4 decades, starting with satellite laser ranging in the mid 1960s. This talk will briefly review the history of Goddard's application to lasers to the scientific exploration of space, provide an overview of its ongoing laser-related programs, and give some possibilities for the future.

  8. Laser remanufacturing technology and its applications

    NASA Astrophysics Data System (ADS)

    Dong, Shiyun; Xu, Binshi; Wang, Zhijian; Ma, Yunzhe; Liu, Weihong

    2008-03-01

    Remanufacture engineering, which has become an important way to sustainable society progress, and its recent development were introduced. Laser remanufacturing technology utilizes high energy density laser beam to remanufacture the worn or failed components. As laser processing is important and advanced technology for remanufacturing, laser remanufacturing was introduced on connotation, characteristics and technical sorts. Research and application status of laser remanufacturing was reviewed, and two laser remanufacturing examples were described to show that laser remanufacturing can solve the difficult problems in equipment maintenance and remanufacturing. It pointed out that the main problems of laser remanufacturing technology for further developing lies in high power laser system, laser remanufacturing technique or processing, supports from government and enterprises. It stated out the developing trends of laser remanufacturing technology, and showed that laser remanufacturing can bring great economic and social benefits.

  9. Tailored Ceramics for Laser Applications

    SciTech Connect

    Hollingsworth, Joel

    2007-12-10

    Transparent ceramics match or exceed the performance of single-crystal materials in laser applications, with a more-robust fabrication process. Controlling the distribution of optical dopants in transparent ceramics would allow qualitative improvements in amplifier slab design by allowing gain and loss to be varied within the material. My work aims to achieve a controlled pattern or gradient of dopant prior to sintering, in order to produce tailored ceramics.

  10. The clinical application of laser in otorhinolaryngology

    NASA Astrophysics Data System (ADS)

    Meng, Guo Zhen; Meng, Zhao-He; Zhang, Zhi Hua

    2005-07-01

    Objective: The paper presented the current application of laser in Otolaryngology in our hospital. Methods: We have applied the carbon dioxide, the YAG, the He-Ne and the Ho:YAG lasers to coagulate or vaporize treated Otolaryngology disease. Results: After treatment, we have a satisfying result. Conclusion: The paper presented the current application of laser respectively in otology, rhinology and pharynolaryngology and some representative of the treated diseases. It also demonstrated that long-term effectiveness of some diseases, such as allergic rhinitis and laryngeal stenosis treated by laser was not satisfying and further studies were expected, laser excision of tonsile was only used in the cases which traditional tonsillectomy was not available. Therefore, to improve clinical laser application greatly, further more research works and cooprations between investors of laser instrument and surgeons of oto-laryngology were necessary. Theory and Clinics of laser application should be improved also.

  11. Applications of soft x-ray lasers

    SciTech Connect

    Skinner, C.H.

    1993-08-01

    The high brightness and short pulse duration of soft x-ray lasers provide unique advantages for novel applications. Imaging of biological specimens using x-ray lasers has been demonstrated by several groups. Other applications to fields such as chemistry, material science, plasma diagnostics, and lithography are beginning to emerge. We review the current status of soft x-ray lasers from the perspective of applications, and present an overview of the applications currently being developed.

  12. Optical coatings for laser fusion applications

    SciTech Connect

    Lowdermilk, W.H.; Milam, D.; Rainer, F.

    1980-04-24

    Lasers for fusion experiments use thin-film dielectric coatings for reflecting, antireflecting and polarizing surface elements. Coatings are most important to the Nd:glass laser application. The most important requirements of these coatings are accuracy of the average value of reflectance and transmission, uniformity of amplitude and phase front of the reflected or transmitted light, and laser damage threshold. Damage resistance strongly affects the laser's design and performance. The success of advanced lasers for future experiments and for reactor applications requires significant developments in damage resistant coatings for ultraviolet laser radiation.

  13. Oceanographic applications of laser technology

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.

    1988-01-01

    Oceanographic activities with the Airborne Oceanographic Lidar (AOL) for the past several years have primarily been focussed on using active (laser induced pigment fluorescence) and concurrent passive ocean color spectra to improve existing ocean color algorithms for estimating primary production in the world's oceans. The most significant results were the development of a technique for selecting optimal passive wavelengths for recovering phytoplankton photopigment concentration and the application of this technique, termed active-passive correlation spectroscopy (APCS), to various forms of passive ocean color algorithms. Included in this activity is use of airborne laser and passive ocean color for development of advanced satellite ocean color sensors. Promising on-wavelength subsurface scattering layer measurements were recently obtained. A partial summary of these results are shown.

  14. Oceanographic applications of laser technology

    NASA Astrophysics Data System (ADS)

    Hoge, F. E.

    Oceanographic activities with the Airborne Oceanographic Lidar (AOL) for the past several years have primarily been focussed on using active (laser induced pigment fluorescence) and concurrent passive ocean color spectra to improve existing ocean color algorithms for estimating primary production in the world's oceans. The most significant results were the development of a technique for selecting optimal passive wavelengths for recovering phytoplankton photopigment concentration and the application of this technique, termed active-passive correlation spectroscopy (APCS), to various forms of passive ocean color algorithms. Included in this activity is use of airborne laser and passive ocean color for development of advanced satellite ocean color sensors. Promising on-wavelength subsurface scattering layer measurements were recently obtained. A partial summary of these results are shown.

  15. Applications analysis of high energy lasers

    NASA Technical Reports Server (NTRS)

    Arno, R. D.; Mackay, J. S.; Nishioka, K.

    1972-01-01

    An analysis and comparison of laser technology with competing technologies were made to determine possible laser applications. The analysis was undertaken as follows: (1) possible applications were listed and categorized; (2) required components were enumerated and the characteristics of these components were extrapolated; (3) complete system characteristics were calculated parametrically for selected applications using the postulated component characteristics; and (4) where possible and appropriate, comparisons were made with competing systems. It was found that any large scale replacement of existing systems and methods by lasers requires many technological advances in laser and associated systems. However, several applications appear feasible, such as low orbit drag make-up, orbit changing, communications, and illumination applications.

  16. Lasers.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1981-01-01

    Examines the nature of laser light. Topics include: (1) production and characteristics of laser light; (2) nine types of lasers; (3) five laser techniques including holography; (4) laser spectroscopy; and (5) laser fusion and other applications. (SK)

  17. Current new applications of laser plasmas

    SciTech Connect

    Hauer, A.A.; Forslund, D.W.; McKinstrie, C.J.; Wark, J.S.; Hargis, P.J. Jr.; Hamil, R.A.; Kindel, J.M.

    1988-09-01

    This report describes several new applications of laser-produced plasmas that have arisen in the last few years. Most of the applications have been an outgrowth of the active research in laser/matter interaction inspired by the pursuit of laser fusion. Unusual characteristics of high-intensity laser/matter interaction, such as intense x-ray and particle emission, were noticed early in the field and are now being employed in a significant variety of applications outside the fusion filed. Applications range from biology to materials science to pulsed-power control and particle accelerators. 92 refs., 23 figs., 4 tabs.

  18. Laser Marked Codes For Paperless Tracking Applications

    NASA Astrophysics Data System (ADS)

    Crater, David

    1987-01-01

    The application of laser markers for marking machine readable codes is described. Use of such codes for automatic tracking and considerations for marker performance and features are discussed. Available laser marker types are reviewed. Compatibility of laser/material combinations and material/code/reader systems are reviewed.

  19. Application of laser in obstetrics and gynecology

    NASA Astrophysics Data System (ADS)

    Ding, Ai-Hua

    1998-11-01

    Mainman developed the first ruby laser in 1960 and after 13 Kaplan successfully reported the use of CO2 laser in the treatment of cervicitis. Soon after, Chinese gynecologists started to use the laser for diagnosis and therapy. It had been proved that more than 30 kinds of gynecological diseases could be treated effectively by laser. The remarkable laser treatment technique partially replaced with conventional methods used in that century. However, the application of laser had shown a broad prospect along with its further investigation.

  20. Selection of patients of hepatocellular carcinoma beyond the Milan criteria for liver transplantation.

    PubMed

    Chan, See Ching; Fan, Sheung Tat

    2013-04-01

    The Milan criteria have been proven to be reliable and easily applicable in selection of patients with small unresectable hepatocellular carcinomas for liver transplantation. It has been repeatedly shown that patients who met these criteria had a 5-year survival of over 70% after transplantation. Such a result is remarkably good for an otherwise incurable malignancy. The main disadvantage of this set of criteria is that it is rather restrictive. Following it religiously denies transplantation to many patients who have tumor stage slightly more advanced. There have been many attempts to extend the criteria to include tumors with larger sizes (as in the UCSF criteria) or with a larger number (as in the Kyoto criteria). Alpha-fetoprotein and PIVKA-II, two biological markers in more aggressive tumors, have also been employed in the selection of patients, and biopsies have been used by the University of Toronto to determine tumor aggressiveness before deciding on transplantation. Patients with tumors beyond the Milan criteria yet not of a high grade have been accepted for transplantation and their survival is comparable to that of transplant recipients who were within the Milan criteria. Preoperative dual-tracer ((11)C-acetate and FDG) positron emission tomography has been used to determine tumor grade, and transarterial chemoembolization has been used to downstage tumors, rendering them meeting the Milan criteria. Patients with downstaged tumors have excellent survival after transplantation. Partial response to chemical treatment is a reflection of less aggressive tumor behavior. Careful selection of patients beyond the Milan criteria with the aid of serum tumor marker assay, positron emission tomography or tumor biopsy allows transplanting more patients without compromising survival. The use of liver grafts either from the deceased or from living donors could thus be justified. PMID:24570921

  1. Laser techniques for ground to air applications

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove

    1989-02-01

    Laser techniques used in air defense for rangefinding, tracking, beamriding, and for ground to air applications are examined. Of special interest are the coherent systems which will add classical radar functions at optical wavelengths and allow imaging systems and Doppler functions. Besides target acquisition, future laser systems will also offer a possibility of atmospheric wind sounding and slant path measurements. Lasers can be used for jamming and destruction of optical sensors. Ordnance information about tactical laser weapons is included.

  2. Cascade laser applications: trends and challenges

    NASA Astrophysics Data System (ADS)

    d'Humières, B.; Margoto, Éric; Fazilleau, Yves

    2016-03-01

    When analyses need rapid measurements, cost effective monitoring and miniaturization, tunable semiconductor lasers can be very good sources. Indeed, applications like on-field environmental gas analysis or in-line industrial process control are becoming available thanks to the advantage of tunable semiconductor lasers. Advances in cascade lasers (CL) are revolutionizing Mid-IR spectroscopy with two alternatives: interband cascade lasers (ICL) in the 3-6μm spectrum and quantum cascade lasers (QCL), with more power from 3 to 300μm. The market is getting mature with strong players for driving applications like industry, environment, life science or transports. CL are not the only Mid-IR laser source. In fact, a strong competition is now taking place with other technologies like: OPO, VCSEL, Solid State lasers, Gas, SC Infrared or fiber lasers. In other words, CL have to conquer a share of the Mid-IR application market. Our study is a market analysis of CL technologies and their applications. It shows that improvements of components performance, along with the progress of infrared laser spectroscopy will drive the CL market growth. We compare CL technologies with other Mid-IR sources and estimate their share in each application market.

  3. Fiber lasers and their applications [Invited].

    PubMed

    Shi, Wei; Fang, Qiang; Zhu, Xiushan; Norwood, R A; Peyghambarian, N

    2014-10-01

    Fiber lasers have seen progressive developments in terms of spectral coverage and linewidth, output power, pulse energy, and ultrashort pulse width since the first demonstration of a glass fiber laser in 1964. Their applications have extended into a variety of fields accordingly. In this paper, the milestones of glass fiber laser development are briefly reviewed and recent advances of high-power continuous wave, Q-switched, mode-locked, and single-frequency fiber lasers in the 1, 1.5, 2, and 3 μm regions and their applications in such areas as industry, medicine, research, defense, and security are addressed in detail. PMID:25322245

  4. Laser Scanning Applications in Fluvial Geomorphology

    NASA Astrophysics Data System (ADS)

    Alho, P.

    2014-12-01

    During recent decades, the use of high-resolution laser scanning data in fluvial studies has rapidly increased. Airborne laser scanning (ALS) can be used to extensively map riverine topography. Laser scanning data have great potential to improve the effectiveness of topographical data acquisition and the accuracy and resolution of DTMs (Digital Terrain Models) needed in fluvial geomorphology. Airborne Laser Scanning (ALS) is applicable for mapping areas varying from reach to catchment scale and these data are, therefore, particularly suitable, especially for hydraulic modelling, mapping of flood inundation, and the detection of macro-scale fluvial geomorphology. With Terrestrial Laser Scanning (TLS) a spatial resolution of less than 1 mm and a range accuracy of few millimetres can be achieved. Mobile Laser Scanning (MLS) enables a remarkably faster survey approach compared to the conventional TLS method. One of the newest applications of MLS approaches involves a boat/cart/backpack -based mobile mapping system. This set-up includes laser scanning and imaging from a platform moving along a river course or floodplain and may be used to expand the spatial extent of terrestrial scanning. Detailed DTMs derived from laser scanning data can be used to improve the recognition of fluvial landforms, the geometric data of hydraulic modelling, and the estimation of flood inundation extents and the associated fluvial processes. Fluvial environments also offer challenges for the application of laser scanning techniques. Factors such as vegetation cover, terrain undulation, coarse surface materials and water surfaces may distort a laser scanning survey.

  5. Current status of laser applications in urology

    NASA Astrophysics Data System (ADS)

    Knipper, Ansgar; Thomas, Stephen; Durek, C.; Jocham, Dieter

    1993-05-01

    The overall development of laser use in urology is recessing. The reasons are the refinement of methods of radical surgery and the continuing development of alternative technologies involving electric current. Taking the cost factor into account, are lasers still opportune in medicine? The answer is definitely yes. Cost reduction in medical practice without quality loss is only possible with effective methods of minimally invasive surgery. Continuing investigation of cutting, welding, coagulating and ablating instruments is justified. Competition of lasers to other technologies can only be beneficial to the cause. But where are the highlights of laser applications? The unsurpassed utilization of optical properties of lasers lie in the concept of photodynamic therapies and in optical feedback mechanisms for laser applications. The combination of lasers with three dimensional visualization of the treatment area by ultrasound (TULIP-procedure for benign prostatic hyperplasia) is a novel approach in laser application. The further development of these treatment modalities will reveal the true benefit of laser technology in urological applications.

  6. Pathophysiological aspects of laser application

    NASA Astrophysics Data System (ADS)

    Egorova, Alla B.; Stavitskaya, Ekaterina Y.; Salmin, Vladimir V.; Fedyukovich, Lyudmila V.; Mikhutkina, S. V.; Shapran, M. V.; Ivanov, V. V.; Provorov, Alexander S.

    1996-04-01

    The rapid growth of electrooptics and laser technology has increased the possibility of human exposure to optical radiation and concern about health effects. The much attention has to be focused on the creation of the safety program that assures the safe use of lasers taking into account the possible side effects of laser therapy. In order to investigate the imunotropic effect of lasers the experimental model which was close to the therapeutic modes has been used for IR laser (the wavelength 890 nm) and He-Ne laser (the wavelength 633 nm). The immune system underwent changes testifying about the breaches in the processes of maturation and migration of the lymphoid cells, also the alteration of receptors as a sign of the membrane damaging effect of lasers was seen.

  7. Deformable mirror for high power laser applications

    NASA Astrophysics Data System (ADS)

    Mrň; a, Libor; Sarbort, Martin; Hola, Miroslava

    2015-01-01

    The modern trend in high power laser applications such as welding, cutting and surface hardening lies in the use of solid-state lasers. The output beam of these lasers is characterized by a Gaussian intensity distribution. However, the laser beams with different intensity distributions, e.g. top-hat, are preferable in various applications. In this paper we present a new type of deformable mirror suitable for the corresponding laser beam shaping. The deformation of the mirror is achieved by an underlying array of actuators and a pressurized coolant that also provides the necessary cooling. We describe the results of the surface shape measurement using a 3D scanner for different settings of actuators. Further, we show the achieved intensity distributions measured by a beam profiler for a low power laser beam reflected from the mirror.

  8. Liver transplantation for hepatocellular carcinoma beyond the Milan criteria

    PubMed Central

    Xu, Xiao; Lu, Di; Ling, Qi; Wei, Xuyong; Wu, Jian; Zhou, Lin; Yan, Sheng; Wu, Liming; Geng, Lei; Ke, Qinghong; Gao, Feng; Tu, Zhenhua; Wang, Weilin; Zhang, Min; Shen, Yan; Xie, Haiyang; Jiang, Wenshi; Wang, Haibo; Zheng, Shusen

    2016-01-01

    Objective Liver transplantation is an optimal radical therapy for selected patients with hepatocellular carcinoma. The stringent organ allocation system driven by the Milan criteria has been challenged by alternative sets of expanded criteria. Careful analysis is needed to prove that the Milan criteria can be expanded safely and effectively. Design This study collectively reviewed 6012 patients of hepatocellular carcinoma from the China Liver Transplant Registry. Expanded criteria were evaluated to characterise an optimised expansion with acceptable outcomes beyond the Milan criteria. Results Compared with the Milan criteria, Valencia, University of California, San Francisco, University Clinic of Navarra and Hangzhou criteria provided an expansion of 12.4%, 16.3%, 19.6%, and 51.5%, respectively. The post-transplant survivals of patients fulfilling the expanded criteria were comparable to that of the Milan criteria. The analysis of net reclassification improvement and area under the receiver operating characteristic curves showed an excellent efficiency in recurrence prediction for the expanded criteria compared with the Milan criteria. In patients exceeding Milan but fulfilling the Hangzhou criteria (N=1352), α-fetoprotein (AFP) >100 ng/mL and tumour burden>8 cm were the only two independent prognostic factors (p<0.001). Accordingly, the Hangzhou criteria were stratified as type A (tumour burden ≤8 cm, or tumour burden >8 cm but AFP≤100 ng/mL) and type B (tumour burden >8 cm but AFP between 100 and 400 ng/mL). Type A showed significantly higher 5-year tumour-free survival rates compared with type B (p<0.001). Conclusions The Milan criteria can be expanded safely and effectively. The prognostic stratification system based on the Hangzhou criteria serves as a hierarchy of transplant candidates for hepatocellular carcinoma. PMID:25804634

  9. Fiber optic applications for laser polarized targets

    SciTech Connect

    Cummings, W.J.; Kowalczyk, R.S.

    1997-10-01

    For the past two years, the laser polarized target group at Argonne has been used multi-mode fiber optic patch cords for a variety of applications. In this paper, the authors describe the design for transporting high power laser beams with optical fibers currently in use at IUCF.

  10. Physics and applications of laser diode chaos

    NASA Astrophysics Data System (ADS)

    Sciamanna, M.; Shore, K. A.

    2015-03-01

    This Review Article provides an overview of chaos in laser diodes by surveying experimental achievements in the area and explaining the theory behind the phenomenon. The fundamental physics underpinning laser diode chaos and also the opportunities for harnessing it for potential applications are discussed. The availability and ease of operation of laser diodes, in a wide range of configurations, make them a convenient testbed for exploring basic aspects of nonlinear and chaotic dynamics. It also makes them attractive for practical tasks, such as chaos-based secure communications and random number generation. Avenues for future research and development of chaotic laser diodes are also identified.

  11. GAS LASERS FOR STRONG-FIELD APPLICATIONS.

    SciTech Connect

    POGORELSKY,I.V.

    2004-09-15

    Atomic-, molecular- and excimer-gas lasers employ variety of pumping schemes including electric discharge, optical, or chemical reactions and cover a broad spectral range from UV to far-IR. Several types of gas lasers can produce multi-kilojoule pulses and kilowatts of average power. Among them, excimer- and high-pressure molecular lasers have sufficient bandwidth for generating pico- and femtosecond pulses. Projects are underway and prospects are opening up to bring ultrafast gas laser technology to the front lines of advanced accelerator applications.

  12. Alkali metal vapors - Laser spectroscopy and applications

    NASA Technical Reports Server (NTRS)

    Stwalley, W. C.; Koch, M. E.

    1980-01-01

    The paper examines the rapidly expanding use of lasers for spectroscopic studies of alkali metal vapors. Since the alkali metals (lithium, sodium, potassium, rubidium and cesium) are theoretically simple ('visible hydrogen'), readily ionized, and strongly interacting with laser light, they represent ideal systems for quantitative understanding of microscopic interconversion mechanisms between photon (e.g., solar or laser), chemical, electrical and thermal energy. The possible implications of such understanding for a wide variety of practical applications (sodium lamps, thermionic converters, magnetohydrodynamic devices, new lasers, 'lithium waterfall' inertial confinement fusion reactors, etc.) are also discussed.

  13. Laser Application In Photobiology And Photomedicine

    NASA Astrophysics Data System (ADS)

    Anders, Angelika

    1981-05-01

    Applications of lasers in photobiology and photomedicine will be reviewed; for example, genetic processes, photosynthesis, vision, spectroscopy of skin, phototherapy and photochemotherapy of dermatosis and tumors are considered. New results and future possibilities are discussed.

  14. Applications of ultrafast lasers in ophthalmology

    NASA Astrophysics Data System (ADS)

    Heisterkamp, Alexander; Ripken, Tammo; Oberheide, Uwe; Kermani, Omid; Mamom, Thanongsak; Drommer, Wolfgang; Ertmer, Wolfgang; Lubatschowski, Holger

    2003-10-01

    Ultrafast lasers are suitable for different surgical procedures in the eye: As a main goal in our group, the application of fs-lasers in refractive surgery is studied. Therefore,experiments in living rabbits were conducted, with wound healing studies up to 120 ays after surgery. Moreover,highly precise cuts inside the cornea were used to do keratoplasty an lamellar keratoplasty. Further applications like a new technique to overcome presbyopia are shown.

  15. Coherent x-ray lasers for applications

    SciTech Connect

    London, R.A.; Amendt, P.; Rosen, M.D.; Feit, M.D.; Fleck, J.A. ); Strauss, M. )

    1990-12-01

    Many of the projected applications of x-ray lasers require high quality output radiation with properties such as short wavelength, high power, good focusability, short pulse, and high degree of coherence. We discuss the requirements of an x-ray laser for the application of holography of biological samples. We present ideas for achieving these properties. Given that population inversions can be established to provide laser gain, we discuss how the propagation and amplification of x-rays within the lasing medium affect the quality of the output radiation. Particular attention is given toward the development of transverse coherence. Results are presented from several methods for calculating the coherence, including a modal analysis and a numerical-wave propagation code. Calculations of the expected degree of coherence of standard x-ray lasers are given, as well as designs for more coherent lasers. 9 refs., 6 figs., 1 tab.

  16. Laser power beaming for satellite applications

    SciTech Connect

    Friedman, H.W.

    1993-09-22

    A serious consideration of laser power beaming for satellite applications appears to have grown out of a NASA mission analysis for transmitting power to lunar bases during the two week dark period. System analyses showed that laser power beaming to the moon in conjunction with efficient, large area solar cell collection panels, were an attractive alternative to other schemes such as battery storage and nuclear generators, largely because of the high space transportation costs. The primary difficulty with this scheme is the need for very high average power visible lasers. One system study indicated that lasers in excess of 10 MW at a wavelength of approximately 850 nm were required. Although such lasers systems have received much attention for military applications, their realization is still a long term goal.

  17. Lasers '92; Proceedings of the International Conference on Lasers and Applications, 15th, Houston, TX, Dec. 7-10, 1992

    NASA Technical Reports Server (NTRS)

    Wang, Charles P. (Editor)

    1993-01-01

    Papers from the conference are presented, and the topics covered include the following: x-ray lasers, excimer lasers, chemical lasers, high power lasers, blue-green lasers, dye lasers, solid state lasers, semiconductor lasers, gas and discharge lasers, carbon dioxide lasers, ultrafast phenomena, nonlinear optics, quantum optics, dynamic gratings and wave mixing, laser radar, lasers in medicine, optical filters and laser communication, optical techniques and instruments, laser material interaction, and industrial and manufacturing applications.

  18. Applications of spaceborne laser ranger on EOS

    NASA Technical Reports Server (NTRS)

    Degnan, John J.; Cohen, Steven C.

    1988-01-01

    An account is given of the design concept and potential applications in science and engineering of the spaceborne laser ranging and altimeter apparatus employed by the Geodynamics Laser Ranging System; this is scheduled for 1997 launch as part of the multiple-satellite Earth Observing System. In the retrograding mode for geodynamics, the system will use a Nd:YAG laser's green and UV output for distance determination to ground retroreflectors. Engineering applications encompass land management and long-term ground stability studies relevant to nuclear power plant, pipeline, and aqueduct locations.

  19. Lasers and their therapeutic application in chiropractic

    PubMed Central

    Fitz-Ritson, Don

    2001-01-01

    The purpose of this paper is to review some of the applications of laser therapy and its reported effects on tissue healing, pain relief and other effects. Several musculoskeletal and low back pain studies are highlighted to show the efficacy of laser therapy and its' applicability as an adjunct to chiropractic treatment. Information is also presented which highlights the necessary information the clinician should be aware of in order to develop specific protocols for musculoskeletal pathologies. The parameters, which are now available on lasers, include power, frequency, duty cycle and cadence. When these are manipulated, different effects are achieved on tissues, which may enhance chiropractic treatment. Imagesp34-a

  20. ESO Council Visits First VLT Unit Telescope Structure in Milan

    NASA Astrophysics Data System (ADS)

    1995-12-01

    As the ESO Very Large Telescope (VLT) rapidly takes on shape, Europe has just come one step closer to the realisation of its 556 million DEM astronomical showcase project. Last week, the ESO Council held its semi-annual meeting in Milan (Italy) [1]. During a break in the long agenda list, Council members had the opportunity to visit the Ansaldo factory in the outskirts of this city and to see for the first time the assembled mechanical structure of one of the four 8.2-metre VLT Unit telescopes. This Press Release is accompanied by a photo that shows the ESO Council delegates in front of the giant telescope. After a long climb up the steep staircase to the large Nasmyth platform at the side of the telescope where the astronomical instruments will later be placed, Dr. Peter Creola (Switzerland) , President of the ESO Council and a mechanics expert, grabbed the handrail and surveyed the structure with a professional eye: `I knew it was going to be big, but not that enormous!', he said. Other delegates experienced similar feelings, especially when they watched the 430 tonnes of steel in the 24-metre tall and squat structure turn smoothly and silently around the vertical axis. The Chairman of the ESO Scientific Technical Committee (STC), Dr. Johannes Andersen (Denmark) , summarized his first, close encounter with the VLT by `This is great fun!' and several of his colleague astronomers were soon seen in various corners of the vast structure, engaged in elated discussions about the first scientific investigations to be done with the VLT in two years' time. The VLT Main Structures The visit by Council took place at the invitation of Ansaldo Energia S.p.A. (Genova), EIE-European Industrial Engineering S.r.I. (Venice) and SOIMI-Societa Impianti Industriale S.p.A. (Milan), the three Italian enterprises responsible for the construction of the main structures of the VLT 8.2-metre Unit telescopes. Short speeches were given on this occasion by Drs. Ferruccio Bressani (Ansaldo

  1. Laser application for hypertrophic rhinitis

    NASA Astrophysics Data System (ADS)

    Inouye, Tetsuzo; Tanabe, Tetsuya; Nakanoboh, Manabu; Ogura, Masami

    1995-05-01

    The CO2 and KTP/532 lasers have been used in the treatment of an allergic and hypertrophic rhinitis for the past several years. As we know, the laser enables a surgeon to perform the operation with minimum hemorrhage and minimized pain, during and after the procedure. Additionally many of these operations can be performed under local anesthesia instead of general anesthesia, on an outpatient basis. The laser is used to irradiate the mucous membranes of the inferior turbinates. Vaporization and cutting is easily done. Post operative management of the local operated area is easy. The advantages of laser surgery over regular surgical techniques are supreme for intranasal operations when performed under local anesthesia.

  2. Application of lasers in neurosurgery

    SciTech Connect

    Cerullo, L.J. )

    1988-01-01

    This book contains 13 chapters. Some of the titles are: Laser Safety; Photoradiation Therapy of Malignant Brian Tumors; Photochemotherapy: Anesthesiologic Considerations; Power; From Instrument to Tissue; and Theoretical Neurosurgery.

  3. Laser scatter in clinical applications

    NASA Astrophysics Data System (ADS)

    Luther, Ed; Geddie, William

    2008-02-01

    Brightfield Laser Scanning Imaging (BLSI) is available on Laser Scanning Cytometers (LSCs) from CompuCyte Corporation. Briefly, digitation of photodetector outputs is coordinated with the combined motions of a small diameter (typically 2 to 10 microns) laser beam scanning a specimen in the Y direction (directed by a galvanometer-driven scanning mirror) and the microscope stage motion in the X direction. The output measurements are assembled into a two-dimensional array to provide a "non-real" digital image, where each pixel value reports the amount of laser-scattered light that is obtained when the laser beam is centered on that location. Depending on the detector positions, these images are analogous to Differential Interference Contrast or Phase Contrast microscopy. We report the incorporation of the new laser scattering capabilities into the workflow of a high-volume clinical cytology laboratory at University Health Network, Toronto, Canada. The laboratory has been employing LSC technology since 2003 for immunophenotypic fluorescence analysis of approximately 1200 cytological specimens per year, using the Clatch methodology. The new BLSI component allows visualization of cellular morphology at higher resolution levels than is possible with standard brightfield microscopic evaluation of unstained cells. BLSI is incorporated into the triage phase, where evaluation of unstained samples is combined with fluorescence evaluation to obtain specimen background levels. Technical details of the imaging methodology will be presented, as well as illustrative examples from current studies and comparisons to detailed, but obscure, historical studies of cytology specimens based on phase contrast microscopy.

  4. Biomedical applications of laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Svanberg, Sune

    1999-07-01

    Very soon after the invention of the laser, the use of the thermal effects of the radiation was introduced. Such techniques have been refined and the laser is now routinely used for treatment in many specialities. Photodynamic therapy (PDT) is a non-thermal modality employing the combination of a tumor-seeking agent and activating laser light. During the last 15 years laser spectroscopic techniques have also been developed providing powerful means for non-intrusive medical diagnostics of tissue in real time. At the beginning only few groups were involved in exploratory work, but successively the field has developed now to occupy a large number of research teams, which meet at large specialized conferences. We will here consider three aspects of laser diagnostics: fluorescence, Raman and near-IR, and elastic scattering spectroscopy, and we will also briefly discuss PDT. The activity in the field is very extensive, and rather than trying to give a full overview, illustrations from work performed at the Lund University Medical Laser Center will be given.

  5. Laser beam application with high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Beyer, Eckhard; Brenner, Berndt; Morgenthal, Lothar

    2007-05-01

    With the new industrial high power fiber lasers we have already stepped into a new generation of laser applications. These lasers are smaller, better, more cost-effective, and offer a processing "on the fly." Of utmost importance is their excellent beam quality which enables us to reduce the size of the focussing head including the scanning mirrors. With the reduced mass of the mirrors we can reach scanning frequencies up to 1.5 kHz and in special configurations up to 4 kHz. Using such mirrors with this high beam quality we can shape the key hole geometry, and thus it is possible to decrease the keyhole spiking, which always occur in the case of deep penetration welding. We can generate very thin and deep welding seams, which we have only experienced with electron beam welding. The excellent beam quality of the fiber lasers offers us a lot of new applications from deep penetration welding to high speed welding. By using beam scanning we are able to easily change the beam and the seam geometry. Furthermore, it is possible to work with this kind of laser from a distance of some meters between focussing/scanning head and the work piece. This technique is called remote processing or processing "on the fly." The excellent beam quality also enables us to cut very precisely, and due to the small cutting widths with a very high speed. In this case the main problem is that the roughness of the cutting edge increases a little bit. One reason for this is that we cannot blow out the mold as easily as we can do it with higher cutting widths. There are also polarized fiber lasers on the market where we can use the Brewster effect for different applications. The presentation will cover some physical basics including different industrial applications.

  6. Anti-tank missile system MILAN: optronic sensors for the new generation firing post MILAN ADT/ER

    NASA Astrophysics Data System (ADS)

    Barth, Jochen; Fendt, Alfred; Kuffner, Herbert; Pröls, Rudolf; Rüger, Roderich; Schmid, Christian

    2007-04-01

    The European anti-tank missile system MILAN has found wide-spread use in numerous countries. Introduced in 1974 it has since undergone several technological upgrades. We report here on the newly developed firing post MILAN ADT ("Advanced Technology") which improves the MILAN system performance substantially while maintaining all operational features to which MILAN operators are accustomed. An even further advanced version of this firing post is now under development in the frame of a range extension of the missile system dubbed MILAN ADT/ER. Being a command-to-line-of-sight system, the new MILAN ADT firing post is equipped with a missile tracking sensor which captures the missile's signature with a wide field-of-view optics and a large CMOS detector covering both gathering and guidance phase. Using adaptive windowing and sub-sampling functions combined with differential imaging modes this sensor tracks the signatures of all MILAN missile types with optimum precision, high resistance against IRCM, and improved signal-to-noise ratio over the entire flight path. An integrated thermal imager replaces the earlier ancillary TIs, MIRA and MILIS. The TI image is displayed on an internal micromonitor and projected into the eyepiece. Optimum axis harmonization between both missile tracking and sighting channels is ensured by projection of reference marks into each optical sensor path from an integrated multispectral projector. An extended range version will also be offered which takes advantage of the missile tracking sensor's enhanced responsivity and the oustanding precision of axis alignment. An integrated color TV sensor is substituted for the bulky direct view telescope, and both TI-/TV-sensor will provide two fields-of-view on the internal micromonitor for surveillance and target identification, respectively.

  7. Laser applications in pediatric airway surgery

    NASA Astrophysics Data System (ADS)

    Karamzadeh, Amir M.; Ahuja, Gurpreet S.; Nguyen, John D.; Crumley, Roger

    2003-06-01

    The smaller anatomy and limited access to instrumentation pose a challenge to the pediatric airway surgeon. The enhanced precision and ability to photocoagulate tissue while operating with the laser enhances the surgeon"s ability to successfully treat unique pediatric conditions such subglottic hemangiomas, congenital cysts, respiratory papillomatosis, and laryngeal or tracheal stenosis. Due to its shallow tissue penetration and thermal effect, the carbon dioxide (CO2) laser is generally considered the laser of choice for pediatric airway applications. The potential for increased scarring and damage to underlying tissue caused by the greater penetration depth and thermal effect of the Nd:YAG and KTP lasers preclude their use in this population. In this review, we will describe the specific advantages of using lasers in airway surgery, the current technology and where the current technology is deficient.

  8. Solid state laser systems for space application

    NASA Technical Reports Server (NTRS)

    Kay, Richard B.

    1994-01-01

    Since the last report several things have happened to effect the research effort. In laser metrology, measurements using Michelson type interferometers with an FM modulated diode laser source have been performed. The discrete Fourier transform technique has been implemented. Problems associated with this technique as well as the overall FM scheme were identified. The accuracy of the technique is not at the level we would expect at this point. We are now investigating the effect of various types of noise on the accuracy as well as making changes to the system. One problem can be addressed by modifying the original optical layout. Our research effort was also expanded to include the assembly and testing of a diode pumped\\Nd:YAG laser pumped\\Ti sapphire laser for possible use in sounding rocket applications. At this stage, the diode pumped Nd:YAG laser has been assembled and made operational.

  9. Metal Vapour Lasers: Physics, Engineering and Applications

    NASA Astrophysics Data System (ADS)

    Little, Christopher E.

    1999-03-01

    Metal Vapour Lasers Christopher E. Little University of St Andrews, St Andrews, Scotland Since the first successful demonstration of a metal vapour laser (MVL) in 1962, this class of laser has become widely used in a broad range of fields including precision materials processing, isotope separation and medicine. The MVLs that are used today have a range of impressive characteristics that are not readily available using other technologies. In particular, the combination of high average output powers, pulse recurrence frequencies and beam quality available from green/yellow Cu vapour lasers (CVLs) and Cu bromide lasers, coupled with the high-quality, multiwatt ultraviolet (265-289 nm) radiation that can be produced using simple nonlinear optical techniques, means that Cu lasers will continue to be important for many years. Metal Vapour Lasers covers all the most commercially important and scientifically interesting pulsed and continuous wave (CW) gas-discharge MVLs, and includes device histories, operating characteristics, engineering, kinetics, commercial exploitation and applications. Short descriptions of gas discharges and excitation techniques make this volume self-consistent. A comprehensive bibliography is also provided. The greater part of this book is devoted to CVLs and their variants, including new sealed-off, high-power 'kinetically enhanced' CVLs and Cu bromide lasers. However, many other self-terminating MVLs are also discussed, including the red AuVL, green/infrared MnVL and infrared BaVL. Pulsed, high-gain, high average power lasers in the UV/violet (373.7, 430.5 nm) spectral regions are represented by Sr¯+ and Ca¯+ discharge-afterglow recombination lasers. The most commercially successful of the MVLs - the CW, UV/blue cataphoretic He-Cd¯+ ion laser - is described. Hollow cathode lasers are represented in two guises: 'white light' (blue/green/red) He-Cd¯+ ion lasers and UV/infrared Ne/He-Cu¯+ ion lasers. This unique volume is an

  10. High power disk lasers: advances and applications

    NASA Astrophysics Data System (ADS)

    Havrilla, David; Holzer, Marco

    2011-02-01

    Though the genesis of the disk laser concept dates to the early 90's, the disk laser continues to demonstrate the flexibility and the certain future of a breakthrough technology. On-going increases in power per disk, and improvements in beam quality and efficiency continue to validate the genius of the disk laser concept. As of today, the disk principle has not reached any fundamental limits regarding output power per disk or beam quality, and offers numerous advantages over other high power resonator concepts, especially over monolithic architectures. With well over 1000 high power disk lasers installations, the disk laser has proven to be a robust and reliable industrial tool. With advancements in running cost, investment cost and footprint, manufacturers continue to implement disk laser technology with more vigor than ever. This paper will explain important details of the TruDisk laser series and process relevant features of the system, like pump diode arrangement, resonator design and integrated beam guidance. In addition, advances in applications in the thick sheet area and very cost efficient high productivity applications like remote welding, remote cutting and cutting of thin sheets will be discussed.

  11. Laser nanostructuring of polymers: Ripples and applications

    NASA Astrophysics Data System (ADS)

    Castillejo, Marta; Ezquerra, Tiberio A.; Martín, Margarita; Oujja, Mohamed; Pérez, Susana; Rebollar, Esther

    2012-07-01

    Polymer nanostructures and nanopatterns are being profusely used for developing next-generation organic devices with analytical and biological functions and photonic applications. Laser based strategies constitute an advantageous approach for the assembly and control of this type of soft matter nanostructures as they afford the sought versatility and reliability. Recent and on-going research on laser nanostructuring of thin films of synthetic polymers and natural biopolymers will be exemplified by studies on the generation of laser induced periodic surface structures (LIPSS) and their use for surface enhanced Raman spectroscopy (SERS) based sensors.

  12. Supercontinuum fiber lasers: new developments and applications

    NASA Astrophysics Data System (ADS)

    Devine, Adam; Hooper, Lucy; Clowes, John

    2016-05-01

    In this talk we give an overview of recent advances in the development of high power supercontinuum fiber lasers with powers exceeding 50W and spectral brightness of tens of mW/nm. We also discuss the fundamental limitations of power scaling and spectral broadening and review the existing and emerging applications of this unique light source which combines the broadband properties of a light bulb with the spatial properties of a laser.

  13. Space Applications Industrial Laser System (SAILS)

    NASA Astrophysics Data System (ADS)

    McCay, T. D.; Bible, J. B.; Mueller, R. E.

    1993-10-01

    A program is underway to develop a YAG laser based materials processing workstation to fly in the cargo bay of the Space Shuttle. This workstation, called Space Applications Industrial Laser System (SAILS), will be capable of cutting and welding steel, aluminum, and Inconel alloys of the type planned for use in constructing the Space Station Freedom. As well as demonstrating the ability of a YAG laser to perform remote (fiber-optic delivered) repair and fabrication operations in space, fundamental data will be collected on these interactions for comparison with terrestrial data and models. The flight system, scheduled to fly in 1996, will be constructed as three modules using standard Get-Away-Special (GAS) canisters. The first module holds the laser head and cooling system, while the second contains a high peak power electrical supply. The third module houses the materials processing workstation and the command and data acquisition subsystems. The laser head and workstation cansisters are linked by a fiber-optic cable to transmit the laser light. The team assembled to carry out this project includes Lumonics Industrial Products (laser), Tennessee Technological University (structural analysis and fabrication), Auburn University Center for Space Power (electrical engineering), University of Waterloo (low-g laser process consulting), and CSTAR/UTSI (data acquisition, control, software, integration, experiment design). This report describes the SAILS program and highlights recent activities undertaken at CSTAR.

  14. Resonant laser ablation: Mechanisms and applications

    SciTech Connect

    Anderson, J.E.; Bodla, R.; Eiden, G.C.; Nogar, N.S.; Smith, C.H.

    1994-06-01

    Ever since the first report of laser action, it has been recognized that laser ablation (evaporation/volatilization) may provide a useful sampling mechanism for chemical analysis. In particular, laser ablation is rapidly gaining popularity as a method of sample introduction for mass spectrometry. While most laser ablation/mass spectrometry has been performed with fixed frequency lasers operating at relatively high intensities/fluences ({ge}10{sup 8} W/cm{sup 2}, {ge}1 J/cm{sup 2}), there has been some recent interest in the use of tunable lasers to enhance the ionization yield of selected components in an analytical sample. This process has been termed resonant laser ablation (RLA), and typically relies on irradiation of a sample in a mass spectrometer with modest intensity laser pulses tuned to a one- or two-photon resonant transition in the analyte of interest. Potential advantages of RLA include: (1) simplification of the mass spectrum, by enhancement of signal from the analyte of interest; (2) improvement of the absolute detection limits by improving the ionization efficiency, and (3) improvement in relative sensitivity. The sensitivity enhancement results from reduction of spurious signal, and accompanying noise, in the detection channel. This spurious signal may be due to bleed through from adjacent mass channels, or from isobaric interferences. RLA tends to produce higher mass resolution because of minimal spatial spread in the ion source and small space charge effects. In this manuscript we present a survey of RLA attributes and applications.

  15. Space Applications Industrial Laser System (SAILS)

    NASA Technical Reports Server (NTRS)

    Mccay, T. D.; Bible, J. B.; Mueller, R. E.

    1993-01-01

    A program is underway to develop a YAG laser based materials processing workstation to fly in the cargo bay of the Space Shuttle. This workstation, called Space Applications Industrial Laser System (SAILS), will be capable of cutting and welding steel, aluminum, and Inconel alloys of the type planned for use in constructing the Space Station Freedom. As well as demonstrating the ability of a YAG laser to perform remote (fiber-optic delivered) repair and fabrication operations in space, fundamental data will be collected on these interactions for comparison with terrestrial data and models. The flight system, scheduled to fly in 1996, will be constructed as three modules using standard Get-Away-Special (GAS) canisters. The first module holds the laser head and cooling system, while the second contains a high peak power electrical supply. The third module houses the materials processing workstation and the command and data acquisition subsystems. The laser head and workstation cansisters are linked by a fiber-optic cable to transmit the laser light. The team assembled to carry out this project includes Lumonics Industrial Products (laser), Tennessee Technological University (structural analysis and fabrication), Auburn University Center for Space Power (electrical engineering), University of Waterloo (low-g laser process consulting), and CSTAR/UTSI (data acquisition, control, software, integration, experiment design). This report describes the SAILS program and highlights recent activities undertaken at CSTAR.

  16. Solar pumped lasers and their applications

    NASA Astrophysics Data System (ADS)

    Lee, Ja H.

    Since 1980, NASA has been pursuing high power solar lasers as part of the space power beaming program. Materials in liquid, solid, and gas phases have been evaluated against the requirements for solar pumping. Two basic characteristics of solar insolation, namely its diffuse irradiance and 5800 K blackbody-like spectrum, impose rather stringent requirements for laser excitation. However, meeting these requirements is not insurmountable as solar thermal energy technology has progressed today, and taking advantage of solar pumping lasers is becoming increasingly attractive. The high density photons of concentrated solar energy have been used for mainly electric power generation and thermal processing of materials by the DOE Solar Thermal Technologies Program. However, the photons can interact with materials through many other direct kinetic paths, and applications of the concentrated photons could be extended to processes requiring photolysis, photosynthesis, and photoexcitation. The use of solar pumped lasers on Earth seems constrained by economics and sociopolitics. Therefore, prospective applications may be limited to those that require use of quantum effects and coherency of the laser in order to generate extremely high value products and services when conventional and inexpensive means are ineffective or impossible. The new applications already proposed for concentrated solar photons, such as destruction of hazardous waste, production of renewable fuel, production of fertilizer, and air/water pollution controls, may benefit from the use of inexpensive solar pumped laser matched with the photochemical kinetics of these processes.

  17. Biomedical applications of laser photoionization

    NASA Astrophysics Data System (ADS)

    Xiong, Xiaoxiong; Moore, Larry J.; Fassett, John R.; O'Haver, Thomas C.

    1991-07-01

    Trace elements are important for many essential metabolic functions. Zinc is a structural/functional component in more than 200 enzymes active in the biochemistry of cell division and tissue growth, neurology and endocrine control. Calcium is involved in intracellular control mechanisms and in skeletal bone building and resorption processes related to osteoporosis. Sensitive and selective laser photoionization is being developed to understand mechanisms in smaller samples and biological units approaching the cellular domain. Zinc has an ionization potential of 9.4 eV, or 75766.8 cm-1. Several processes are being explored, including two-photon resonant, three- photon ionization utilizing sequential UV transitions, e.g., 4s2 1S0 yields 4s4p 3P1 and 4s4p 3P1 yields 4s5d 3D1. Preliminary zinc stable isotope ratio data obtained by thermal atomization and laser photoionization agree with accepted values within 2 to 5%, except for anomalous 67Zn. Photoionization of calcium is being studied for isotope enrichment and ratio measurement using narrow and medium bandwidth lasers. Several ionization pathways, e.g., 4s2 1S0 - 2hv1 yields 4s10s - hv2 yields Ca+ (4s2S), are being investigated for isotopically selective ionization. Auto-ionization pathways are explored for greater efficiency in isotopic analysis. All studies have utilized a Nd:YAG- pumped laser system with one or two frequency-doubled tunable dye lasers coupled either to a magnetic sector or time-of-flight mass spectrometer.

  18. Atmospheric applications of high-energy lasers

    NASA Astrophysics Data System (ADS)

    Cook, Joung R.

    2005-03-01

    It has been over forty years since the invention of the laser, which has inspired the imagination of scientists and science fiction writers alike. Many ideas have been realized, many still remain as dreams, and new ones are still being conceived. The High Energy Laser (HEL) has been associated with weapon applications during the past three decades. Much of the same technology can be directly applied to power beaming, laser propulsion, and other potential remote energy and power transfer applications. Economically, these application areas are becoming increasingly more viable. This paper reviews the evolutionarey history of the HEL device technologies. It points out the basic system components and layouts with associated key technologies that drive the effectiveness and efficiency of the system level performance. It describes the fundamental properties and wavelength dependencies of atmospheric propagation that in turn have become the prescription for wavelength properties that are desired from the device.

  19. Optical resonator and laser applications

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  20. Laser application in tracheobronchial tumors

    NASA Astrophysics Data System (ADS)

    Rau, B. Krishna; Krishna, Sharon

    2004-09-01

    Ninety three patients with obstructing tracheobronchial tumors were treated with Neodymium: Yttrium - Aluminum - Garnet (Nd:YAG) laser photocoagulation over a period of six years. There were sixty seven Males and 26 Females with a mean age of 44.3 years (range 6- 79 years). 21 benign and 72 malignant lesions were treated with a total 212 sessions of laser photocoagulation (mean 2.4 sessions). The anatomical distribution of lesions were as follows; larynx 9 (three benign and 6 malignant) trachea 39 (27 benign and 12 malignant) left main bronchus 27 (14 malignant) right main bronchus 24 (14 malignant) and vocal cords - 9 (three malignant). There were 21 patients with squamous cell carcinoma, two adenocarcinomas, one adenoid cystic carcinoma, 7 cases of locally infiltrating tumors from thyroid and esophagus, 6 cases of carcinoid tumor and 16 benign lesions. Twenty one patients had a tracheostomy tube in place when treatment was started. Eighteen of the 21 patients with tracheostomy were weaned off the tube in a mean of 5.5 days from the start of treatment. Lumen was restored in 31 (79.4%) patients. In the other eight (20.6%), lumen was achieved, but not sustained. Complications included bleeding in three cases which were managed conservatively, two cases of pneumothorax, and four cases of bronchospasm. There were six deaths during the follow up but none attributable to the procedure. Laser photocoagulation offered effective treatment in the majority of patients with obstructing tracheobronchial tumors, with acceptable morbidity.

  1. Analytical Applications Of Laser Powered Pyrolysis

    NASA Astrophysics Data System (ADS)

    Woodin, R. L.; Kajkowski, K. A.

    1984-05-01

    The ability to rapidly heat samples using infrared laser radiation without the complicating effects of hot surfaces offers new opportunities for pyrolysis techniques in materials characterization and process control. By using pulsed radiation, timescales on the order of microseconds are achieved, restricting the chemistry primarily to initial reactions. The homogeneous nature of laser powered heating minimizes wall reactions and improves reproducibility by eliminating effects of surface contamination in the pyrolysis reactor. In Laser Powered Homogeneous Pyrolysis (LPHP), a pulsed CO2 laser (10μm) is used to rapidly heat a gas mixture to be pyrolyzed. If the mixture does not absorb 10um radiation, a chemically inert sensitizer such as SF6 or SiF4 must be added to couple energy into the mixture. Temperatures up to 1200K can be reached, with reaction times ranging from lOpsec to lOmsec. Product analysis is by gas chromatography after a sufficient number of laser pulses to generate detectable amounts of products. Applications of LPHP to hydrocarbon mixture analysis will be presented, as well as potential applications to process control. The short reaction times in LPHP will be illustrated by methane and ethane pyrolysis, which also provide information on the details of the temperature profile during laser powered pyrolysis.

  2. Laser-material interactions; fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Bloembergen, N.

    1993-10-01

    The interaction of light with matter leads to electronic excitation by the absorption of photons. A large fraction of the high excitation energy of the electrons is transformed into heat on a time scale of about one picosecond in many circumstances. With lasers, power flux densities or intensities exceeding a terawatt/cm2 are readily achieved and any material may be converted into a high temperature plasma. The material response has been investigated over a wide range of intensities and irradiation times. Applications include heat treatment and ablation of surfaces, cutting, drilling, and welding of a wide variety of materials, laser recording and printing, and laser surgery. Phase transitions induced by ultrashort femtosecond laser pulses enlarge our understanding of materials under extreme conditions of pressure and temperature.

  3. Lasers: invention to application. Final report

    SciTech Connect

    Ausubel, J.H.; Langford, H.D.

    1987-08-01

    Contents include: The laser--still young at 25; Lasers in modern industries; Lasers in communications and information processing; Lasers in medicine; Lasers in science; Interactions between the science and technology of lasers; Glossary.

  4. Tailored ceramics for laser applications

    NASA Astrophysics Data System (ADS)

    Hollingsworth, Joel Philip

    Transparent ceramics have many features that recommend them over single crystals for use as laser amplifiers. Some features, such as greater mechanical toughness and an absence of extended crystalline defects, are intrinsic to polycrystalline materials. Other advantages accrue from ceramic processing: ceramics sinter more rapidly than crystals grow from a melt, at lower temperatures. Ceramic processes are more readily scaled than Czochralski growth, facilitating larger apertures. Unlike a uniform melt, a ceramic green structure can have controlled concentration gradients, resulting in a multifunctional device upon sintering. Identifying diffusion mechanisms in a suitable host material and quantifying diffusion for a dopant with appropriate energy levels are key steps toward tailoring laser ceramics to the specifications of device designers. Toward that end, this study was the first to identify the mechanism and rate of Nd diffusion in YAG. Grain boundary diffusion was shown to dominate Nd transport under conditions relevant to laser ceramics fabrication. Based on a definition of grain boundary width as 1 A, this process occurs at a rate of DGB = 6.4 x 105 +/- 2.0 x 105 exp(-491 +/- 64 kJ/(mol K))m 2/s. Mechanism identification and the first published kinetics measurement were made possible by the introduction of a heat treatment method that isolates microstructural change from dopant diffusion: the concentration of grain boundaries was kept great enough to allow rapid diffusion, but low enough to limit the driving force for coarsening. Sintering of fine-grained and phase-pure precursor powder for 4 min at 1700 °C produced 0.8 mum grains; subsequent diffusion heat treatments at up to 1650 °C for up to 64 h caused negligible coarsening, while achieving diffusion distances of up to 23 mum.

  5. Innovations in high power fiber laser applications

    NASA Astrophysics Data System (ADS)

    Beyer, Eckhard; Mahrle, Achim; Lütke, Matthias; Standfuss, Jens; Brückner, Frank

    2012-02-01

    Diffraction-limited high power lasers represent a new generation of lasers for materials processing, characteristic traits of which are: smaller, cost-effective and processing "on the fly". Of utmost importance is the high beam quality of fiber lasers which enables us to reduce the size of the focusing head incl. scanning mirrors. The excellent beam quality of the fiber laser offers a lot of new applications. In the field of remote cutting and welding the beam quality is the key parameter. By reducing the size of the focusing head including the scanning mirrors we can reach scanning frequencies up to 1.5 kHz and in special configurations up to 4 kHz. By using these frequencies very thin and deep welding seams can be generated experienced so far with electron beam welding only. The excellent beam quality of the fiber laser offers a high potential for developing new applications from deep penetration welding to high speed cutting. Highly dynamic cutting systems with maximum speeds up to 300 m/min and accelerations up to 4 g reduce the cutting time for cutting complex 2D parts. However, due to the inertia of such systems the effective cutting speed is reduced in real applications. This is especially true if complex shapes or contours are cut. With the introduction of scanner-based remote cutting systems in the kilowatt range, the effective cutting speed on the contour can be dramatically increased. The presentation explains remote cutting of metal foils and sheets using high brightness single mode fiber lasers. The presentation will also show the effect of optical feedback during cutting and welding with the fiber laser, how those feedbacks could be reduced and how they have to be used to optimize the cutting or welding process.

  6. New Medical Applications Of Metal Vapor Lasers

    NASA Astrophysics Data System (ADS)

    Anderson, Robert S.; McIntosh, Alexander I.

    1989-06-01

    The first medical application for metal vapor lasers has been granted marketing approval by the FDA. This represents a major milestone for this technology. Metalaser Technologies recently received this approval for its Vasculase unit in the treatment of vascular lesions such as port wine stains, facial telangiectasia and strawberry hemangiomas.

  7. Applications for Energy Recovering Free Electron Lasers

    SciTech Connect

    George Neil

    2007-08-01

    The availability of high-power, high-brilliance sources of tunable photons from energy-recovered Free Electron Lasers is opening up whole new fields of application of accelerators in industry. This talk will review some of the ideas that are already being put into production, and some of the newer ideas that are still under development.

  8. Advances in laser diodes for pyrotechnic applications

    NASA Technical Reports Server (NTRS)

    Craig, Richard R.

    1993-01-01

    Background information concerning the use of laser diodes in pyrotechnic applications is provided in viewgraph form. The following topics are discussed: damage limits, temperature stability, fiber coupling issues, and small (100 micron) and large (400 micron) fiber results. The discussions concerning fiber results concentrate on the areas of package geometry and electro-optical properties.

  9. Geometrical Detector Considerations in Laser Sensing Applications

    NASA Technical Reports Server (NTRS)

    Killinger, Dennis

    2000-01-01

    We have studied the influence of the geometrical interaction of different detectors with the impinging optical/laser received beam for a wide range of laser sensing applications. Although different techniques apply, it is found that similar aspects of geometrical physics plays a role in direct detection of a range-resolved large M(sup 2) OPO atmospheric Lidar, heterodyne multi-detector reception of atmospheric turbulence distorted coherent lidar type laser sensing, and the distribution and summation of laser induced fluorescence signals after being spectrally resolved with a spectrometer and detected by a column summing CCD detector. In each of these systems, the focused received light is spatially and spectrally distributed due to several factors including Field-of-View considerations, laser beam quality/divergence, multi-detector aspects, and hardware and software summation (coherent and non-coherent) of multi-element or spatially integrated signals. This invited talk will present some of our recent results in these areas and show the similarities in the detector spatial and temporal summation techniques of these different laser sensing systems.

  10. Laser weld jig. [Patent application

    DOEpatents

    Van Blarigan, P.; Haupt, D.L.

    1980-12-05

    A system is provided for welding a workpiece along a predetermined weld line that may be of irregular shape, which includes the step of forming a lip on the workpiece to extend parallel to the weld line, and moving the workpiece by engaging the lip between a pair of rotatable members. Rotation of one of the members at a constant speed, causes the workpiece to move so that all points on the weld line sequentially pass a fixed point in space at a constant speed, so that a laser welding beam can be directed at that fixed point to form a weld along the weld line. The workpiece can include a reusable jig forming the lip, and with the jig constructed to detachably hold parts to be welded at a position wherein the weld line of the parts extends parallel to the lip on the jig.

  11. High power gas laser - Applications and future developments

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1977-01-01

    Fast flow can be used to create the population inversion required for lasing action, or can be used to improve laser operation, for example by the removal of waste heat. It is pointed out that at the present time all lasers which are capable of continuous high-average power employ flow as an indispensable aspect of operation. High power laser systems are discussed, taking into account the gasdynamic laser, the HF supersonic diffusion laser, and electric discharge lasers. Aerodynamics and high power lasers are considered, giving attention to flow effects in high-power gas lasers, aerodynamic windows and beam manipulation, and the Venus machine. Applications of high-power laser technology reported are related to laser material working, the employment of the laser in controlled fusion machines, laser isotope separation and photochemistry, and laser power transmission.

  12. Laser applications to atmospheric sciences: A bibliography

    NASA Technical Reports Server (NTRS)

    Harris, F. S., Jr.

    1975-01-01

    A bibliography is given of 1460 references of the applications of lasers to atmospheric sciences. The subjects covered include: aerosols; clouds; the distribution and motion of atmospheric natural and man-made constituents; winds; temperature; turbulence; scintillation; elastic, Raman and resonance scattering; fluorescence; absorption and transmission; the application of the Doppler effect and visibility. Instrumentation, in particular lidar, is included, also data handling, and interpretation of the data for meteorological processes. Communications, geodesy and rangefinding are not included as distinct areas. The application to the atmosphere is covered, but not the ocean or its surface.

  13. Excimer Laser Application For Cataract Surgery

    NASA Astrophysics Data System (ADS)

    Bath, Patricia E.; Mueller, Gerhard; Apple, David J.; Stolzenburg, Norbert M.

    1988-06-01

    The ablation threshold of bovine lenses was determined for excimer laser radiatiF at 308 nanreters. The ablation th5eshold for bovine lenses was approximately 0.6J/cm +/-0.1J/cm , for cortex and 1J/cm for nucleus. The threshold for bovine nucleus was higher than the threshold for cortex and difference was statistically significant at the 0.05 level. The relatively low ablation threshold for bovine lenses demonstrates the potential effectiveness of excimer laser radiation at 308 nm for cataract surgery. An experimental prototype has been developed and results of its application demonstrated. Further experiments to demonstrate safety for the retina and adjacent ocular structures are necessary because of the well known hazards of ultraviolet radiation. The potential of theleymir laser for keratorefractive surgery is currently under intensive investigation. In preliminary studies the ablation behavior of bovine lenses was investigated. The objective of this study was to quantify ablation rates as the first step in determining the specification for a laser system which would be practical in the clinical setting. Although excimer laser systems are available at 193 nm (ArF), 248 (KrF) and 351 (xeF) we selected 308 nm because of the availability of fiberoptics for the transmission of 308 nm as well as the known absorbance of human lenses in the 280 nm region.

  14. Review - 40 years of laser-marking - industrial applications

    NASA Astrophysics Data System (ADS)

    Gu, Bo

    2006-02-01

    One of the early applications of lasers was marking electronics components. Today laser marking has found its way into a wide range of applications, from wafer marking at the chip scale package level to beer bottles and food package identifications, and to marking of the cloth buttons. In many cases, laser marking has become a standard manufacturing process. We will review the laser marking technology over the last four decades. This would include the review on evolution of the different laser technologies and beam delivery systems used in various laser-marking systems for the past 40 years. Finally, the latest laser marking technologies will be presented and future directions be discussed.

  15. Advances in solid state laser technology for space and medical applications

    NASA Technical Reports Server (NTRS)

    Byvik, C. E.; Buoncristiani, A. M.

    1988-01-01

    Recent developments in laser technology and their potential for medical applications are discussed. Gas discharge lasers, dye lasers, excimer lasers, Nd:YAG lasers, HF and DF lasers, and other commonly used lasers are briefly addressed. Emerging laser technology is examined, including diode-pumped lasers and other solid state lasers.

  16. Semiconductor Lasers and Their Application in Optical Fiber Communication.

    ERIC Educational Resources Information Center

    Agrawal, Govind P.

    1985-01-01

    Working principles and operating characteristics of the extremely compact and highly efficient semiconductor lasers are explained. Topics include: the p-n junction; Fabry-Perot cavity; heterostructure semiconductor lasers; materials; emission characteristics; and single-frequency semiconductor lasers. Applications for semiconductor lasers include…

  17. Lasers '86; Proceedings of the Ninth International Conference on Lasers and Applications, Orlando, FL, Nov. 3-7, 1986

    SciTech Connect

    Mcmillan, R.W.

    1987-01-01

    Laser physics, technology, and applications are examined in reviews and reports. Topics addressed include VUV and X-ray lasers, vibrational energy transfer and kinetics, medical applications, ultrashort lasers and spectroscopy, surface and material interactions, lasers in atmospheric physics, and fiber-optic systems. Consideration is given to alexandrite lasers, four-wave mixing and nonlinear optics, chemical lasers, semiconductor lasers, photothermal and photoacoustic spectroscopy, dye lasers, optical phase conjugation and SBS, excimer lasers, SDI laser applications, remote-sensing with lasers, FELs, and applications in chemistry. Diagrams, drawings, graphs, and photographs are provided.

  18. Laser scanners: from industrial to biomedical applications

    NASA Astrophysics Data System (ADS)

    Duma, Virgil-Florin

    2013-11-01

    We present a brief overview of our contributions in the field of laser scanning technologies, applied for a variety of applications, from industrial, dimensional measurements to high-end biomedical imaging, such as Optical Coherence Tomography (OCT). Polygon Mirror (PM) scanners are presented, as applied from optical micrometers to laser sources scanned in frequency for Swept Sources (SSs) OCT. Galvanometer-based scanners (GSs) are approached to determine the optimal scanning function in order to obtain the highest possible duty cycle. We demonstrated that this optimal scanning function is linear plus parabolic, and not linear plus sinusoidal, as it has been previously considered in the literature. Risley prisms (rotational double wedges) scanners are pointed out, with our exact approach to determine and simulate their scan patterns in order to optimize their use in several types of applications, including OCT. A discussion on the perspectives of scanning in biomedical imaging, with a focus on OCT concludes the study.

  19. Resonant laser ablation: Mechanisms and applications

    SciTech Connect

    Anderson, J.E.; Allen, T.M.; Garrett, A.W.; Gill, C.G.; Hemberger, P.H.; Kelly, P.B.; Nogar, N.S.

    1997-01-01

    We will report on aspects of resonant laser ablation (RLA) behavior for a number of sample types: metals, alloys, thin films, zeolites and soil. The versatility of RLA is demonstrated, with results on a variety of samples and in several mass spectrometers. In addition, the application to depth profiling of thin films is described; absolute removal rates and detection limits are also displayed. A discussion of possible mechanisms for low-power ablation are presented. {copyright} {ital 1997 American Institute of Physics.}

  20. Laser beamed power: Satellite demonstration applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Westerlund, Larry H.

    1992-01-01

    It is possible to use a ground-based laser to beam light to the solar arrays of orbiting satellites, to a level sufficient to provide all or some of the operating power required. Near-term applications of this technology for providing supplemental power to existing satellites are discussed. Two missions with significant commercial pay-off are supplementing solar power for radiation-degraded arrays and providing satellite power during eclipse for satellites with failed batteries.

  1. Applications of laser techniques in fluid mechanics

    NASA Astrophysics Data System (ADS)

    Chan, W. K.; Liu, C. Y.; Wong, Y. W.

    1991-03-01

    Three examples of different applications of laser techniques in experimental fluid mechanics are described including flow field around a proposed heart prostheses, flow field around a model motor vehicle, and flow visualization of the vortex shedding from a delta wing. Velocity measurements of flow around the heart valve prosthesis indicate that the new design is capable of delaying flow separation. Velocity measurements of flow around a model motor vehicle show that separation occurs above the bonnet and at the rear of the vehicle.

  2. Medical laser application: translation into the clinics

    NASA Astrophysics Data System (ADS)

    Sroka, Ronald; Stepp, Herbert; Hennig, Georg; Brittenham, Gary M.; Rühm, Adrian; Lilge, Lothar

    2015-06-01

    Medical laser applications based on widespread research and development is a very dynamic and increasingly popular field from an ecological as well as an economic point of view. Conferences and personal communication are necessary to identify specific requests and potential unmet needs in this multi- and interdisciplinary discipline. Precise gathering of all information on innovative, new, or renewed techniques is necessary to design medical devices for introduction into clinical applications and finally to become established for routine treatment or diagnosis. Five examples of successfully addressed clinical requests are described to show the long-term endurance in developing light-based innovative clinical concepts and devices. Starting from laboratory medicine, a noninvasive approach to detect signals related to iron deficiency is shown. Based upon photosensitization, fluorescence-guided resection had been discovered, opening the door for photodynamic approaches for the treatment of brain cancer. Thermal laser application in the nasal cavity obtained clinical acceptance by the introduction of new laser wavelengths in clinical consciousness. Varicose veins can be treated by innovative endoluminal treatment methods, thus reducing side effects and saving time. Techniques and developments are presented with potential for diagnosis and treatment to improve the clinical situation for the benefit of the patient.

  3. Applications for reactor-pumped lasers

    SciTech Connect

    Lipinski, R.J.; McArthur, D.A.

    1994-10-01

    Nuclear reactor-pumped lasers (RPLs) have been developed in the US by the Department of Energy for over two decades, with the primary research occurring at Sandia National Laboratories and Idaho National Engineering Laboratory. The US program has experimentally demonstrated reactor-pumped lasing in various mixtures of xenon, argon, neon, and helium at wavelengths of 585, 703, 725, 1,271, 1,733, 1,792, 2,032, 2,630, 2,650, and 3,370 nm with intrinsic efficiency as high as 2.5%. The major strengths of a reactor-pumped laser are continuous high-power operation, modular construction, self-contained power, compact size, and a variety of wavelengths (from visible to infrared). These characteristics suggest numerous applications not easily accessible to other laser types. The continuous high power of an RPL opens many potential manufacturing applications such as deep-penetration welding and cutting of thick structures, wide-area hardening of metal surfaces by heat treatment or cladding application, wide-area vapor deposition of ceramics onto metal surfaces, production of sub-micron sized particles for manufacturing of ceramics, and 3-D ceramic lithography. In addition, a ground-based RPL could beam its power to space for such activities as illuminating geosynchronous communication satellites in the earth`s shadow to extend their lives, beaming power to orbital transfer vehicles, removing space debris, and providing power (from earth) to a lunar base during the long lunar night.

  4. Expanded mode lasers for telecommunications applications

    NASA Astrophysics Data System (ADS)

    Lealman, Ian F.

    This thesis describes the development of a long wavelength (1.55 μm) expanded mode semiconductor laser. The increased spot size of the laser improves both the coupling efficiency to cleaved fibre and fibre alignment tolerances and reduces packaging cost. In this type of device the strength of the waveguide is gradually reduced towards the front facet allowing the mode to adiabatically expand so that the laser mode is better matched in size to that of a cleaved fibre. This can be achieved by either reducing the refractive index of the guide or reducing the amount of material in the core. The structure chosen was a buried heterostructure laser that utilised a twin guide consisting of an upper higher refractive index guide (the active region of the laser) above a weak passive guide. The width of the active region was reduced along part of the device allowing the mode to expand into the weak underlying guide. The guide structure was optimised using a variable grid finite difference mode solver, and the taper length calculated by an approximation to Love's method. Detailed results are presented for the measured light-current characteristic, farfield and coupling loss to cleaved fibre. These coupling losses were compared to the calculated data thus allowing the waveguide design to be optimised. Several iterations in the design of the device were undertaken, with the aim of reducing the coupling loss to cleaved single mode fibre without significantly compromising the laser performance. The final device design had extremely low coupling losses as low as 1.2 dB to cleaved fibre. Finally, the positive impact this device had on passive alignment using a silicon motherboard is examined, and the application this technology to a range of other optoelectronic components is discussed.

  5. Current applications of lasers in heart disease

    NASA Astrophysics Data System (ADS)

    Lee, Garrett; Chan, Ming C.; Mason, Dean T.

    1993-03-01

    Although the laser has been in existence for abut 30 years, its application in heart disease has only been examined in the past decade. Much attention has been given its exciting potential in treating coronary artery disease. Transmitted through a catheter comprised of one or more thin optical fibers which can be threaded nonsurgically into the coronary artery, the laser can ablate atherosclerotic plaque that obstructs the artery and diminishes blood flow to the myocardium. In clinical studies, the laser can treat some obstructive lesions that are not suitable for balloon angioplasty (i.e., long and diffuse lesions, very tight stenoses, ostial lesions, calcified lesions). In patients who failed balloon angioplasty due to severe dissection or abrupt closure, the laser may seal up the dissections and restore antegrade blood flow. In addition, the laser may have other applications and treatment modalities that are still under investigation. It may ablate ectopic ventricular foci, or terminate supraventricular tachyrhythmia by destroying the heart's abnormal conduction pathways. It can cut the hypertrophied septum that is associated with left ventricular outflow tract obstruction, or create a channel in the atrial septum as a palliative procedure in newborns with transposition of the great vessels. It may provide a wider orifice for blood flow within the heart in infants with pulmonary outflow obstruction and in adults with aortic valvular stenosis. It is also capable of fusing small thin-walled blood vessels together. Further, a more intriguing possibility is its use to bore several tiny channels in the myocardium to allow oxygenated blood from within the ventricular chamber to perfuse the ischemic heart tissue.

  6. Application of Low level Lasers in Dentistry (Endodontic)

    PubMed Central

    Asnaashari, Mohammad; Safavi, Nassimeh

    2013-01-01

    Low level lasers, cold or soft lasers: These lasers do not produce thermal effects on tissues and induce photoreactions in cells through light stimulation which is called photobiostimulation. Power of these lasers is usually under 250mW. The main point differentiating low level lasers and high power ones is the activation of photochemical reactions without heat formation. The most important factor to achieve this light characteristic in lasers is not their power, but their power density for each surfa ceunit (i.e cm2). Density lower than 670mW/cm2, can induce the stimulatory effects of low level lasers without thermal effects. Low level lasers (therapeutic) used today as treatment adjunctive devices in medicine and dentistry. Numerous studies have been performed on the applications of low level lasers in patient pain reduction. Mechanisms of pain reduction with therapeutic lasers and their application are expressed, and the studies realized in this field are presented. PMID:25606308

  7. Ultrafast pulse lasers jump to macro applications

    NASA Astrophysics Data System (ADS)

    Griebel, Martin; Lutze, Walter; Scheller, Torsten

    2016-03-01

    Ultrafast Lasers have been proven for several micro applications, e.g. stent cutting, for many years. Within its development of applications Jenoptik has started to use ultrafast lasers in macro applications in the automotive industry. The JenLas D2.fs-lasers with power output control via AOM is an ideal tool for closed loop controlled material processing. Jenoptik enhanced his well established sensor controlled laser weakening process for airbag covers to a new level. The patented process enables new materials using this kind of technology. One of the most sensitive cover materials is genuine leather. As a natural product it is extremely inhomogeneous and sensitive for any type of thermal load. The combination of femtosecond pulse ablation and closed loop control by multiple sensor array opens the door to a new quality level of defined weakening. Due to the fact, that the beam is directed by scanning equipment the process can be split in multiple cycles additionally reducing the local energy input. The development used the 5W model as well as the latest 10W release of JenLas D2.fs and achieved amazing processing speeds which directly fulfilled the requirements of the automotive industry. Having in mind that the average cycle time of automotive processes is about 60s, trials had been done of processing weakening lines in genuine leather of 1.2mm thickness. Parameters had been about 15 cycles with 300mm/s respectively resulting in an average speed of 20mm/s and a cycle time even below 60s. First samples had already given into functional and aging tests and passed successfully.

  8. Technology and applications of ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Lang, Marion; Hellerer, Thomas; Stuhler, Juergen

    2011-11-01

    We briefly review the key technology of modern fiber based femtosecond laser sources summarizing advantages and disadvantages of different mode-locking solutions. A description of possible extensions of a FemtoFiber-type modelocked Er-doped fiber laser oscillator (1560 nm) reveals the flexibility with respect to wavelength coverage (488 nm .. 2200 nm) and pulse duration (10 fs .. 10 ps). The resulting FemtoFiber family and its versions for instrument integration allow one to use these state-of-the-art light sources in many important applications, e.g. THz spectroscopy and microscopy. We show that, depending on the fiber laser model and the THz emitter, THz radiation can be produced with 4-10 THz bandwidth and detected with up to 60 dB signal-to-noise ratio (SNR). Electronically controlled optical scanning (ECOPS) - a unique method for fast, precise and comfortable sampling of the THz pulse or other pump-probe experiments - is described and recommended for efficient data acquisition. As examples for modern microscopy with ultrafast fiber lasers we present results of two-photon fluorescence, coherent microscopy techniques (SHG/THG/CARS) and fluorescence lifetime imaging (FLIM).

  9. Technology and applications of ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Lang, Marion; Hellerer, Thomas; Stuhler, Juergen

    2012-03-01

    We briefly review the key technology of modern fiber based femtosecond laser sources summarizing advantages and disadvantages of different mode-locking solutions. A description of possible extensions of a FemtoFiber-type modelocked Er-doped fiber laser oscillator (1560 nm) reveals the flexibility with respect to wavelength coverage (488 nm .. 2200 nm) and pulse duration (10 fs .. 10 ps). The resulting FemtoFiber family and its versions for instrument integration allow one to use these state-of-the-art light sources in many important applications, e.g. THz spectroscopy and microscopy. We show that, depending on the fiber laser model and the THz emitter, THz radiation can be produced with 4-10 THz bandwidth and detected with up to 60 dB signal-to-noise ratio (SNR). Electronically controlled optical scanning (ECOPS) - a unique method for fast, precise and comfortable sampling of the THz pulse or other pump-probe experiments - is described and recommended for efficient data acquisition. As examples for modern microscopy with ultrafast fiber lasers we present results of two-photon fluorescence, coherent microscopy techniques (SHG/THG/CARS) and fluorescence lifetime imaging (FLIM).

  10. Catadioptric Optics for laser Doppler velocimeter applications

    NASA Technical Reports Server (NTRS)

    Dunagan, Stephen E.

    1989-01-01

    In the design of a laser velocimeter system, attention must be given to the performance of the optical elements in their two principal tasks: focusing laser radiation into the probe volume, and collecting the scattered light. For large aperture applications, custom lens design and fabrication costs, long optical path requirements, and chromatic aberration (for two color operation) can be problematic. The adaptation of low cost Schmidt-Cassegrain astronomical telescopes to perform these laser beam manipulation and scattered light collection tasks is examined. A generic telescope design is analyzed using ray tracing and Gaussian beam propagation theory, and a simple modification procedure for converting from infinite to near unity conjugate ratio operation with image quality near the diffraction limit was identified. Modification requirements and performance are predicted for a range of geometries. Finally, a 200-mm-aperture telescope was modified for f/10 operation; performance data for this modified optic for both laser beam focusing and scattered light collection tasks agree well with predictions.

  11. High Power Fiber Lasers and Applications to Manufacturing

    NASA Astrophysics Data System (ADS)

    Richardson, Martin; McComb, Timothy; Sudesh, Vikas

    2008-09-01

    We summarize recent developments in high power fiber laser technologies and discuss future trends, particularly in their current and future use in manufacturing technologies. We will also describe our current research programs in fiber laser development, ultra-fast and new lasers, and will mention the expectations in these areas for the new Townes Laser Institute. It will focus on new core laser technologies and their applications in medical technologies, advanced manufacturing technologies and defense applications. We will describe a program on large mode area fiber development that includes results with the new gain-guiding approach, as well as high power infra-red fiber lasers. We will review the opportunities for high power fiber lasers in various manufacturing technologies and illustrate this with applications we are pursuing in the areas of femtosecond laser applications, advanced lithographies, and mid-IR technologies.

  12. Spaceborne laser development for future remote sensing applications

    NASA Astrophysics Data System (ADS)

    Stephen, Mark A.; Yu, Anthony W.; Krainak, Michael A.; Abshire, James B.; Harding, David J.; Riris, Haris; Li, Steven X.; Chen, Jeffrey; Numata, Kenji; Wu, Stewart; Camp, Jordan

    2011-09-01

    At NASA's Goddard Space Flight Center, we are developing the next generation laser transmitters for future remote sensing applications including a micropulse altimeter for ice-sheet monitoring, laser spectroscopic measurements and high resolution mapping of the Earth's surface as well as potential missions to other planets for trace gas measurement and mapping. In this paper we will present an overview of the spaceborne laser programs and offer insights into future spaceborne lasers for remote sensing applications.

  13. Laser microprocessing unit and its application

    NASA Astrophysics Data System (ADS)

    Fukumitsu, Kenshi; Oie, Tomonori

    2000-11-01

    This is the report for compact laser micro processing unit excimer laser employed featuring a very fine process with high accuracy. This unit consists of objective lens, of which magnification is 10 to 80, used for both processing and observation. It makes possible high energy density resulting 0.5micrometers resolution at 248nm, accurate positioning and compact size. Applications 1) Removing upper metal layer of LSI in order to inspect pattern of the bottom layer. 2) Creating fine geometrical pattern on PET fiber cloth in order to apply new function such as better dyeing and adhesiveness. 3) Creating 100micrometers dia. Hole to artificial blood vessel made of polyurethane tube with 2mm inner dia. In order to have similar mechanical property to real blood vessel.

  14. Tunable infrared laser sources and applications

    NASA Astrophysics Data System (ADS)

    Libatique, Nathaniel Joseph C.

    Fiber lasers are emerging as attractive alternative technologies for wavelength-selectable WDM sources because of a number of reasons which include: (1) their direct compatibility with the fiber-optic transmission medium, (2) the excellent amplifying properties of rare-earth doped fibers and the rapidly continuing progress in novel fiber gain media (i.e. L-Band, S-band, and Raman fiber amplifiers), (3) the potential for order-of-magnitude power scalability via the use of double-clad geometries, (4) the maturity and robustness of the laser diode pumps used, and (5) the ready availability of fiber-based components and fiber-pigtailed devices (i.e. fused couplers, Bragg gratings, polarization controllers, etalons). The tunable laser applications of interest to this work have two distinct performance requirements, the need for either continuous tunability (the ability to tune the lasing emission through a continuous range of wavelengths) or discrete tunability (the ability to switch the lasing emission to an arbitrarily-fixed set of wavelengths). The latter class of "push-button" switchability to pre-set wavelength channels is especially critical for WDM optical communications. In this Thesis, I will discuss experimental achievements and key issues related to the design and demonstration of these two classes of tunable lasers, with a special emphasis on channel-selectable sources for optical communications. In particular I will discuss: (1) Novel FBG-based rapidly wavelength-selectable WDM sources, the scaling of such FBG-string-based tunable sources to intermediate channel counts, and the demonstration of single frequency tunable WDM sources based on line-narrowed tunable FBGs. (2) The first demonstration of a potentially all-fiber wavelength-selectable WDM laser source based on a fiber Sagnac loop filter. (3) Wavelength-selectable WDM laser sources based on the novel use of a current-tunable (semiconductor Fabry-Perot) grid filter. (4) The first demonstration of a

  15. Progress of Power Laser and its Application to Space

    NASA Astrophysics Data System (ADS)

    Nakai, Sadao

    2004-03-01

    The progress of power laser is now opening new applications in science and industry. The laser for the inertial fusion requires the most advanced and heavy specifications, typically a few MJ in 10 ns pulse with 10Hz repetitive operation with the efficiency higher than 10%. The challenge to develop such a laser include basic and generic laser and photonics technologies as power diode laser, solid state laser material, nonlinear optical material, high efficiency energy conversion between the light and electricity, high power optical beam propagation and control, heat treatment of optical components. The power laser application to space is supported by these common technologies and gives us new dreams such as laser propulsion, laser energy network in space, energy supply to the ground energy system such as electricity and/or hydrogen fuel. The technical perspectives are reviewed.

  16. Applications Of Laser Processing For Automotive Manufacturing In Japan

    NASA Astrophysics Data System (ADS)

    Ito, Masashi; Ueda, Katsuhiko; Takagi, Soya

    1986-11-01

    Recently in Japan, laser processing is increasingly being employed for production, so that laser cutting, laser welding and other laser material processing have begun to be used in various industries. As a result, the number of lasers sold has been increasing year by year in Japan. In the Japanese automotive industry, a number applications have been introduced in laboratories and production lines. In this paper, several current instances of such laser applications will be introduced. In the case of welding, studies have been conducted on applying laser welding to automatic transmission components, in place of electron beam welding. Another example of application, the combination of lasers and robots to form highly flexible manufacturing systems, has been adopted for trimming steel panel and plastic components.

  17. Applications of laser printing for organic electronics

    NASA Astrophysics Data System (ADS)

    Delaporte, Ph.; Ainsebaa, A.; Alloncle, A.-P.; Benetti, M.; Boutopoulos, C.; Cannata, D.; Di Pietrantonio, F.; Dinca, V.; Dinescu, M.; Dutroncy, J.; Eason, R.; Feinaugle, M.; Fernández-Pradas, J.-M.; Grisel, A.; Kaur, K.; Lehmann, U.; Lippert, T.; Loussert, C.; Makrygianni, M.; Manfredonia, I.; Mattle, T.; Morenza, J.-L.; Nagel, M.; Nüesch, F.; Palla-Papavlu, A.; Rapp, L.; Rizvi, N.; Rodio, G.; Sanaur, S.; Serra, P.; Shaw-Stewart, J.; Sones, C. L.; Verona, E.; Zergioti, I.

    2013-03-01

    The development of organic electronic requires a non contact digital printing process. The European funded e-LIFT project investigated the possibility of using the Laser Induced Forward Transfer (LIFT) technique to address this field of applications. This process has been optimized for the deposition of functional organic and inorganic materials in liquid and solid phase, and a set of polymer dynamic release layer (DRL) has been developed to allow a safe transfer of a large range of thin films. Then, some specific applications related to the development of heterogeneous integration in organic electronics have been addressed. We demonstrated the ability of LIFT process to print thin film of organic semiconductor and to realize Organic Thin Film Transistors (OTFT) with mobilities as high as 4 10-2 cm2.V-1.s-1 and Ion/Ioff ratio of 2.8 105. Polymer Light Emitting Diodes (PLED) have been laser printed by transferring in a single step process a stack of thin films, leading to the fabrication of red, blue green PLEDs with luminance ranging from 145 cd.m-2 to 540 cd.m-2. Then, chemical sensors and biosensors have been fabricated by printing polymers and proteins on Surface Acoustic Wave (SAW) devices. The ability of LIFT to transfer several sensing elements on a same device with high resolution allows improving the selectivity of these sensors and biosensors. Gas sensors based on the deposition of semiconducting oxide (SnO2) and biosensors for the detection of herbicides relying on the printing of proteins have also been realized and their performances overcome those of commercial devices. At last, we successfully laser-printed thermoelectric materials and realized microgenerators for energy harvesting applications.

  18. Future scientific applications for high-energy lasers

    SciTech Connect

    Lee, R.W.

    1994-08-01

    This report discusses future applications for high-energy lasers in the areas of astrophysics and space physics; hydrodynamics; material properties; plasma physics; radiation sources; and radiative properties.

  19. Applications of semiconductor lasers to secure communications

    NASA Astrophysics Data System (ADS)

    Mirasso, Claudio R.

    2000-12-01

    We numerically study the synchronization of two chaotic semiconductor lasers in a master-slave configuration. To synchronize the lasers a small amount of the output power from the master laser is injected into the slave laser. We show that the output of the master laser can be used as a chaotic carrier to encode a digital message which can be recovered at the receiver. We also check the quality of the synchronization diagram when the two lasers are slightly different.

  20. Eye safe lasers and their military applications in Germany

    NASA Astrophysics Data System (ADS)

    Ruger, James F.

    1988-01-01

    A laser system with a Nominal Optical Hazard Distance requirement of 0 meters for intrabeam viewing with 10 x 50 binoculars is described. The performance of the system, which is used in military applications, is discussed. The laser system meets the Class IIIa NOHD requirements in the Standard NATO Agreement 3606 and outperforms the Nd:YAG laser. The eye-safe laser system makes it possible to conduct real system training, eliminating the need for laser simulation. Consideration is given to the performance of semiconductor, Raman-shifted Nd:YAG, and CO2 TEA lasers operating at 0.9, 1.54, and 10.6 microns, respectively.

  1. Application of Laser Ablation Processing in Electric Power System Industries

    NASA Astrophysics Data System (ADS)

    Konagai, Chikara; Sano, Yuji; Nittoh, Koichi; Kuwako, Akira

    The present status of laser ablation processing applied in electric power system industries is reviewed. High average power LD-pumped Nd:YAG lasers with Q-switch have been developed and currently introduced into various applications. Optical fiber based laser beam delivery systems for Q-switched pulse laser are also being developed these years. Based on such laser and beam delivery technology, laser ablation processes are gradually introduced in maintenance of nuclear power plant, thermal power plant and electrical power distribution system. Cost effectiveness, robustness and reliability of the process is highly required for wide utilization in these fields.

  2. Lasers '90; Proceedings of the 13th International Conference on Lasers and Applications, San Diego, CA, Dec. 10-14, 1990

    NASA Astrophysics Data System (ADS)

    Harris, Dennis G.; Herbelin, John

    Various papers on lasers are presented. The general topics considered are: X-ray lasers; FELs, solid state lasers; techniques and phenomena of ultrafast lasers; optical filters and free space laser communications, discharge lasers; tunable lasers; application of lasers in medicine and surgery; lasers in materials processing; high power lasers; dynamic gratings, wave mixing, and holography; up-conversion lasers; lidar and laser radar; laser resonators; excimer lasers; laser propagation; nonlinear and quantum optics; blue-green technology; imaging; laser spectroscopy; chemical lasers; dye lasers; lasers in chemistry.

  3. Diode pumped solid-state laser oscillators for spectroscopic applications

    NASA Technical Reports Server (NTRS)

    Byer, R. L.; Basu, S.; Fan, T. Y.; Kozlovsky, W. J.; Nabors, C. D.; Nilsson, A.; Huber, G.

    1987-01-01

    The rapid improvement in diode laser pump sources has led to the recent progress in diode laser pumped solid state lasers. To date, electrical efficiencies of greater than 10 percent were demonstrated. As diode laser costs decrease with increased production volume, diode laser and diode laser array pumped solid state lasers will replace the traditional flashlamp pumped Nd:YAG laser sources. The use of laser diode array pumping of slab geometry lasers will allow efficient, high peak and average power solid state laser sources to be developed. Perhaps the greatest impact of diode laser pumped solid state lasers will be in spectroscopic applications of miniature, monolithic devices. Single-stripe diode-pumped operation of a continuous-wave 946 nm Nd:YAG laser with less than 10 m/w threshold was demonstrated. A slope efficiency of 16 percent near threshold was shown with a projected slope efficiency well above a threshold of 34 percent based on results under Rhodamine 6G dye-laser pumping. Nonlinear crystals for second-harmonic generation of this source were evaluated. The KNbO3 and periodically poled LiNbO3 appear to be the most promising.

  4. High power semiconductor laser beam combining technology and its applications

    NASA Astrophysics Data System (ADS)

    Wang, Lijun; Tong, Cunzhu; Peng, Hangyu; Zhang, Jun

    2013-05-01

    With the rapid development of laser applications, single elements of diode lasers are not able to meet the increasing requirements on power and beam quality in the material processing and defense filed, whether are used as pumping sources or directly laser sources. The coupling source with high power and high beam quality, multiplexed by many single elements, has been proven to be a promising technical solution. In this paper, the authors review the development tendency of efficiency, power, and lifetime of laser elements firstly, and then introduce the progress of laser beam combining technology. The authors also present their recent progress on the high power diode laser sources developed by beam combining technology, including the 2600W beam combining direct laser source, 1000W fiber coupled semiconductor lasers and the 1000W continuous wave (CW) semiconductor laser sources with beam quality of 12.5×14[mm. mrad]2.

  5. Optofluidic lasers and their applications in bioanalysis (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Fan, Xudong

    2016-03-01

    The optofluidic laser is an emerging technology that integrates microfluidics, miniaturized laser cavity, and laser gain medium in liquid. It is unique due to its biocompatibility, thus can be used for unconventional bioanalysis, in which biointeraction or process takes place within the optical cavity mode volume. Rather than using fluorescence, the optofluidic laser based detection employs laser emission, i.e., stimulated emission, as the sensing signal, which takes advantage of optical amplification provided by the laser cavity to achieve much higher sensitivity. In this presentation, I will first introduce the concept of optofluidic laser based bioanalysis. Then I will discuss each of the three components (cavity, gain medium, and fluidics) of the optofluidic laser and describe how to use the optofluidic laser in bioanalysis at the molecular, cellular, and tissue level. Finally, I will discuss future research and application directions.

  6. Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Thomas, Matt; Bossard, John; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

    2001-01-01

    This viewgraph presentation gives an overview of laser ignition technology for bipropellant rocket engines applications. The objectives of this project include: (1) the selection test chambers and flows; (2) definition of the laser ignition setup; (3) pulse format optimization; (4) fiber optic coupled laser ignition system analysis; and (5) chamber integration issues definition. The testing concludes that rocket combustion chamber laser ignition is imminent. Support technologies (multiplexing, window durability/cleaning, and fiber optic durability) are feasible.

  7. High-power laser applications in Nippon Steel Corporation

    NASA Astrophysics Data System (ADS)

    Minamida, Katsuhiro

    2000-02-01

    The laser, which was invented in 1960, has been developed using various substances of solids, liquids, gases and semiconductors as laser active media. Applications of laser utilizing the coherent properties of laser light and the high power density light abound in many industries and in heavy industries respectively. The full-scale use of lasers in the steel industry began nearly 23 years ago with their applications as controllable light sources. Its contribution to the increase in efficiency and quality of the steel making process has been important and brought us the saving of the energy, the resource and the labor. Laser applications in the steel making process generally require high input energy, so it is essential to consider the interaction between the laser beam and the irradiated material. In particular, the reflectivity of the laser beam on the surface of material and the quantity of the laser-induced plasma are critical parameters for high efficient processes with low energy losses. We have developed plenty of new laser systems for the steel making process with their considerations in mind. A review of the following high-power-laser applications is given in the present paper: (1) Use of plasma as a secondary heat source in CO2 laser welding for connecting steel sheets of various grades. (2) Laser-assisted electric resistance welding of pipes. (3) New type all-laser-welded honeycomb panels for high-speed transport. (4) Laser flying welder for continuous hot rolling mill using two 45 kW CO2 lasers.

  8. Laser application to occlusive vascular disease

    SciTech Connect

    Berns, M.W.; Mirhoseini, M.

    1985-01-01

    This book contains 13 selections. Some of the titles are: Effect of laser radiation on tissue during laser angioplasty; Optical properties of human blood vessel wall and plaque; Modeling of coronary laser-angioplasty; and Absence of distal emboli during in vivo laser recanalization.

  9. Laser applications in integrated circuits and photonics packaging

    NASA Astrophysics Data System (ADS)

    Lu, Yong Feng; Li, L. P.; Mendu, K.; Shi, J.

    2004-07-01

    Laser processing has large potential in the packaging of integrated circuits (IC). It can be used in many applications such as laser cleaning of IC mold tools, laser deflash to remove mold flash from heat sinks and lead wires of IC packages, laser singulation of BGA (ball grid array) and CSP (chip scale packages), laser reflow of solder ball on GBA, laser peeling for CSP, laser marking on packages and on Si wafers. Laser nanoimprinting of self-assembled nanoparticles has been recently developed to fabricate hemispherical cavity arrays on semiconductor surfaces. This process has the potential applications in fabrication and packaging of photonic devices such as waveguides and optical interconnections. During the implementation of all these applications, laser parameters, material issues, throughput, yield, reliability and monitoring techniques have to be taken into account. Monitoring of laser-induced plasma and laser induced acoustic wave has been used to understand and to control the processes involved in these applications. Numerical simulations can provide useful information on process analysis and optimization.

  10. Laser wakefield accelerator based light sources: potential applications and requirements

    SciTech Connect

    Albert, F.; Thomas, A. G.; Mangles, S. P.D.; Banerjee, S.; Corde, S.; Flacco, A.; Litos, M.; Neely, D.; Viera, J.; Najmudin, Z.; Bingham, R.; Joshi, C.; Katsouleas, T.

    2015-01-15

    In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose as a result of discussions held at the 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, X-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted as potential applications for laser-plasma based light sources. We discuss ongoing and future efforts to improve the properties of radiation from plasma betatron emission and Compton scattering using laser wakefield accelerators for these specific applications.

  11. Tenth Biennial Coherent Laser Radar Technology and Applications Conference

    NASA Technical Reports Server (NTRS)

    Kavaya, Michael J. (Compiler)

    1999-01-01

    The tenth conference on coherent laser radar technology and applications is the latest in a series beginning in 1980 which provides a forum for exchange of information on recent events current status, and future directions of coherent laser radar (or lidar or lader) technology and applications. This conference emphasizes the latest advancement in the coherent laser radar field, including theory, modeling, components, systems, instrumentation, measurements, calibration, data processing techniques, operational uses, and comparisons with other remote sensing technologies.

  12. MARE-l in Milan: Status and Perspectives

    NASA Technical Reports Server (NTRS)

    Ferri, E.; Arnaboldi, C.; Ceruti, G.; Faverzani, M.; Gatti, C.; Giachero, A.; Gotti, C.; Kilbourne, C.; Kraft-Bermuth, S.; Nucciotti, A.; Pessini, G.; Schaeffer, D.; Sisti, M.

    2012-01-01

    The international project MARE (Microcalorimeter Array for a Rhenium Experiment) aims at the direct and calorimetric measurement of the electron neutrino mass with sub-eV sensitivity. Although the baseline of the MARE project consists in a large array of rhenium based thermal detectors, a different option for the isotope is also being considered. The different option is Ho-163. The potential of using Re-187 for a calorimetric neutrino mass experiment has been already demonstrated. On the contrary, no calorimetric spectrum of Ho-163 has been so far measured with the precision required to set a useful limit on the neutrino mass. The first phase of the project (MARE-1) is a collection of activities with the aim of sorting out both the best isotope and the most suited detector technology to be used for the final experiment. One of the MARE-1 activities is carried out in Milan by the group of Milano-Bicocca in collaboration with NASA/GSFC and Wisconsin groups. The Milan MARE-l arrays are based on semiconductor thermistors, provided by the NASA/GSFC group, with dielectric silver perrhenate absorbers, AgReO4. The experiment, which is presently being assembled, is designed to host up to 8 arrays.

  13. Early Greek Typography in Milan: A Historical Note on a New Greek Typeface.

    ERIC Educational Resources Information Center

    Wallraff, Martin

    1997-01-01

    Discusses the history of Greek typography, focusing on the first book to be entirely printed in Greek in 1476 and the series of new typefaces that resulted. Cites Milan as a center of Greek printing in the early history of Greek typography. Describes a revival of one of these typefaces created under the name of Milan Greek. (PA)

  14. Latest developments of ultrafast fiber laser and its material applications

    NASA Astrophysics Data System (ADS)

    Cho, G. C.; Liu, B.; Shah, L.; Liu, Z.; Che, Y.; Xu, J.

    2009-02-01

    We address recent fiber-based femtosecond laser technology. Specifically, fiber-chirped pulse amplifier is discussed for the enabling the concept of real-world applications. We review recent selected material applications demonstrating advantages of ultrafast dynamics of highly repetitive pulse train in nanoparticle generation in pulsed-laser deposition and reliable Si wafer singulation.

  15. Application of repumping laser in optical switching

    NASA Astrophysics Data System (ADS)

    Ray, Ayan; Ali, Md. Sabir; Chakrabarti, Alok

    2014-08-01

    The application of electromagnetically induced transparency (EIT) in high speed optical switching has remained as a key topic in research related to all optical switching. Demonstration of optical switching through EIT realized under ladder (Ξ) level coupling has been reported earlier. Due to narrow linewidth (ГEIT) and low coherent dephasing rate (γ) the EIT needs to be prepared only once to demonstrate such switching action. However, in a Ξ system the EIT is accompanied with double resonance optical pumping (DROP) signal, which is limited by spontaneous decay (Г) rates. It has been shown by our group that the simultaneous presence of DROP-EIT combination paves the way for executing a kind of slow-fast switching action. However the focus always remain on improving the modulation depth in such type of coherence assisted switch. Here we report a possible way to improve modulation depth by using an additional (named 'repumping' after convention used in laser cooling experiments) laser in the Ξ system. The 5S1/2→5P3/2→5D5/2 level coupling scheme of 87Rb atom is used in the current experiment.

  16. Diode Laser Application in Soft Tissue Oral Surgery

    PubMed Central

    Azma, Ehsan; Safavi, Nassimeh

    2013-01-01

    Introduction: Diode laser with wavelengths ranging from 810 to 980 nm in a continuous or pulsed mode was used as a possible instrument for soft tissue surgery in the oral cavity. Discussion: Diode laser is one of laser systems in which photons are produced by electric current with wavelengths of 810, 940 and 980nm. The application of diode laser in soft tissue oral surgery has been evaluated from a safety point of view, for facial pigmentation and vascular lesions and in oral surgery excision; for example frenectomy, epulis fissuratum and fibroma. The advantages of laser application are that it provides relatively bloodless surgical and post surgical courses with minimal swelling and scarring. We used diode laser for excisional biopsy of pyogenic granuloma and gingival pigmentation. Conclusion: The diode laser can be used as a modality for oral soft tissue surgery PMID:25606331

  17. Tunable lasers and their application in analytical chemistry

    NASA Technical Reports Server (NTRS)

    Steinfeld, J. I.

    1975-01-01

    The impact that laser techniques might have in chemical analysis is examined. Absorption, scattering, and heterodyne detection is considered. Particular emphasis is placed on the advantages of using frequency-tunable sources, and dye solution lasers are regarded as the outstanding example of this type of laser. Types of spectroscopy that can be carried out with lasers are discussed along with the ultimate sensitivity or minimum detectable concentration of molecules that can be achieved with each method. Analytical applications include laser microprobe analysis, remote sensing and instrumental methods such as laser-Raman spectroscopy, atomic absorption/fluorescence spectrometry, fluorescence assay techniques, optoacoustic spectroscopy, and polarization measurements. The application of lasers to spectroscopic methods of analysis would seem to be a rewarding field both for research in analytical chemistry and for investments in instrument manufacturing.

  18. Polymers designed for laser applications: fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Lippert, Thomas; Hauer, Marc; Phipps, Claude R.; Wokaun, Alexander J.

    2002-09-01

    The ablation characteristics of various polymers were studied at low and high fluences. The polymers can be divided into three groups, i.e. polymers containing triazene groups, designed ester groups, and reference polymers, such as polyimide. The polymers containing the photochemically most active group (triazene) exhibit the lowest threshold of ablation (as low as 25 mJ cm-2) and the highest etch rates (e.g. 250 nm/pulse at 100 mJ cm-2), followed by the designed polyesters and then polyimide. Neither the linear nor the effective absorption coefficients reveal a clear influence on the ablation characteristics. The different behavior of polyimide might be explained by a pronounced thermal part in the ablation mechanism. The laser-induced decomposition of the designed polymers was studied by nanosecond interferometry and shadowgraphy. The etching of the triazene polymer starts and ends with a laser pulse, clearly indicating photochemical etching. Shadowgraphy reveals mainly gaseous products and a pronounced shockwave in air. The designed polymers were tested for applications ranging from microoptical elements to polymer fuel for laser plasma thrusters.

  19. Reliability of Semiconductor Laser Packaging in Space Applications

    NASA Technical Reports Server (NTRS)

    Gontijo, Ivair; Qiu, Yueming; Shapiro, Andrew A.

    2008-01-01

    A typical set up used to perform lifetime tests of packaged, fiber pigtailed semiconductor lasers is described, as well as tests performed on a set of four pump lasers. It was found that two lasers failed after 3200, and 6100 hours under device specified bias conditions at elevated temperatures. Failure analysis of the lasers indicates imperfections and carbon contamination of the laser metallization, possibly from improperly cleaned photo resist. SEM imaging of the front facet of one of the lasers, although of poor quality due to the optical fiber charging effects, shows evidence of catastrophic damage at the facet. More stringent manufacturing controls with 100% visual inspection of laser chips are needed to prevent imperfect lasers from proceeding to packaging and ending up in space applications, where failure can result in the loss of a space flight mission.

  20. Medical Applications of Laser Induced Breakdown Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pathak, A. K.; Rai, N. K.; Singh, Ankita; Rai, A. K.; Rai, Pradeep K.; Rai, Pramod K.

    2014-11-01

    Sedentary lifestyle of human beings has resulted in various diseases and in turn we require a potential tool that can be used to address various issues related to human health. Laser Induced Breakdown Spectroscopy (LIBS) is one such potential optical analytical tool that has become quite popular because of its distinctive features that include applicability to any type/phase of samples with almost no sample preparation. Several reports are available that discusses the capabilities of LIBS, suitable for various applications in different branches of science which cannot be addressed by traditional analytical methods but only few reports are available for the medical applications of LIBS. In the present work, LIBS has been implemented to understand the role of various elements in the formation of gallstones (formed under the empyema and mucocele state of gallbladder) samples along with patient history that were collected from Purvancal region of Uttar Pradesh, India. The occurrence statistics of gallstones under the present study reveal higher occurrence of gallstones in female patients. The gallstone occurrence was found more prevalent for those male patients who were having the habit of either tobacco chewing, smoking or drinking alcohols. This work further reports in-situ LIBS study of deciduous tooth and in-vivo LIBS study of human nail.

  1. Biophysics applications of free-electron lasers

    NASA Astrophysics Data System (ADS)

    Austin, Robert H.

    1993-07-01

    There has been a significant financial effort poured into the technology of the Free Electron Laser (FEL) over the last 15 years or so. Much of that money was spent in the hopes that the FEL would be a key element in the Strategic Defense Initiative, but a small fraction of money was allocated for the Medical FEL program. The Medical FELs program was aimed at exploring how the unique capabilities of the FEL could be utilized in medical applications. Part of the Medical FEl effort has been in clinical applications, but some of the effort has also been put into exploring applications of the FEL for fundamental biological physics. It is the purpose of this brief text to outline some of the fundamental biophysics I have done, and some plans we have for the future. Since the FEL is (still) considered to be an avant garde device, the reader should not be surprised to find that much of the work proposed here is also rather radical and avant garde.

  2. Laser ignition application in a space experiment

    NASA Technical Reports Server (NTRS)

    Liou, Larry C.; Culley, Dennis E.

    1993-01-01

    A laser ignition system is proposed for the Combustion Experiment Module on an orbiting spacecraft. The results of a design study are given using the scheduled 'Flame Ball Experiment' as the design guidelines. Three laser ignition mechanisms and wavelengths are evaluated. A prototype laser is chosen and its specifications are given, followed by consideration of the beam optical arrangement, the ignition power requirement, the laser ignition system weight, size, reliability, and laser cooling and power consumption. Electromagnetic interference to the onboard electronics caused by the laser ignition process is discussed. Finally, ground tests are suggested.

  3. Manufacturing applications of lasers; Proceedings of the Meeting, Los Angeles, CA, Jan. 23, 24, 1986

    NASA Astrophysics Data System (ADS)

    Cheo, Peter K.

    1986-01-01

    The present conference encompasses topics in laser material processing for industrial applications, laser applications in microelectronics, laser inspection and quality control, and laser diagnostics and measurements. Attention is given to the laser welding of cylinders, production laser hardfacing of jet engine turbine blades, production laser welding of gears, electric arc augmentation for laser cutting of mild steel, laser-assisted etching for microelectronics, and laser fabrication of interconnect structures on CMOS gate arrays. Also discussed are angle-scanning laser interferometry for film thickness measurements, the application of heterodyne interferometry to disk drive technology, and CARS applications to combustion diagnostics.

  4. CO2 laser oscillators for laser radar applications

    NASA Technical Reports Server (NTRS)

    Freed, C.

    1990-01-01

    This paper reviews the spectral purity, frequency stability, and long-term stabilization of newly developed CO2 isotope lasers. Extremely high spectral purity, and short-term stability of less than 1.5 x 10 to the -13th have been achieved. A brief description on using CO2 isotope lasers as secondary frequency standards and in optical radar is given. The design and output characteristics of a single frequency, TEM00q mode, variable pulse width, hybrid TE CO2 laser system is also described. The frequency chirp in the output has been measured and almost completely eliminated by means of a novel technique.

  5. Process and quality control for automotive laser welding applications

    SciTech Connect

    Toenshoff, H.K.; Overmeyer, L.; Schumacher, J.

    1996-12-31

    Laser welding applications using CO{sub 2} and Nd:YAG-Lasers are of growing importance for the production of car bodies. Especially for parts influencing the safety of the product, it would be advantageous to control the welding result which is, in practical applications, influenced by many process parameters. In this paper, an innovative process monitoring and quality control system with a closed loop control of the laser output power will be described, which is based on monitoring and evaluating the light emission from the welding process. In contrast to systems which have been developed in the past, the sensors which detect the light emission were integrated into the beam guidance system for CO{sub 2} lasers, and into the laser source for Nd:YAG lasers. The optical set-up of this system, together with the automatic detection of welding failures, will be described, and the results of the system for industrial applications will be evaluated.

  6. Spectroscopic and Dynamic Applications of Laser - Interactions.

    NASA Astrophysics Data System (ADS)

    Quesada, Mark Alejandro

    1987-05-01

    Five different studies of laser-molecule interactions are conducted in this thesis. In part one, the first observation of Autler-Townes splitting of molecules is discussed and used to measure vibronic transition moments between excited electronic states. The effect was observed in the two-color, four -photon ionization of hydrogen via the resonant levels E,F(v = 6, J = 1) and D(v = 2, J = 2). Calculations gave good fits to the observed spectra yielding a vibronic transition moment of 2.0 +/- 0.5 a.u. between the above excited states. In part two, a method for extracting the alignment parameters of a molecular angular momentum distribution using laser-induced fluorescence is presented. The treatment is applicable to the common case of cylindrically symmetric orientation distributions in the high J-limit. Four different combinations of rotational branches in the LIF absorption emission process are examined. Computer algebra programs are used to generate simple analytical expressions which account for the influence of saturation on determining alignment parameters. In part three, the application of MPI-optogalvanic spectroscopy to the molecule 1,4-diazabicyclo (2.2.2) octane (DABCO) at various levels in a methane/air flame environment is described. The method employs a burner design that permits access to preheated and primary reaction zones of the flame for laser probing. Hot bands arising from two-photon resonant (X_1 ' to A_1') transitions are measured and the intramolecular vibrational potentials for the ground and first excited state are determined. In part four, DABCO's nu_ {13} torsional mode relaxation in a helium -DABCO and argon-DABCO supersonic jet, under low expansion conditions, is discussed. Modeling of the relaxation using the linear Landau-Teller relaxation equation is undertaken with various attempts to incorporate the effects of velocity slip. The relaxation rate is found to be independent of slip and the cross section dependent on the inverse of

  7. Patient and tumour biology predict survival beyond the Milan criteria in liver transplantation for hepatocellular carcinoma

    PubMed Central

    Andreou, Andreas; Gül, Safak; Pascher, Andreas; Schöning, Wenzel; Al-Abadi, Hussein; Bahra, Marcus; Klein, Fritz; Denecke, Timm; Strücker, Benjamin; Puhl, Gero; Pratschke, Johann; Seehofer, Daniel

    2015-01-01

    Background Patients with hepatocellular carcinoma (HCC) beyond the Milan criteria are not considered for liver transplantation (LT) in many centres; however, LT may be the only treatment able to achieve long-term survival in patients with unresectable HCC. The aim of this study was to assess the role of recipient age and tumour biology expressed by the DNA index in the selection of HCC patients for LT. Patients Clinicopathological data of 364 patients with HCC who underwent LT between 1989 and 2010 were evaluated. Overall survival (OS) was analysed by patient age, tumour burden based on Milan criteria and the DNA index. Results After a median follow-up time of 78 months, the median survival was 100 months. Factors associated with OS on univariate analysis included Milan criteria, patient age, hepatitis C infection, alpha-fetoprotein (AFP) level, the DNA index, number of HCC, diameter of HCC, bilobar HCC, microvascular tumour invasion and tumour grading. On multivariate analysis, HCC beyond Milan criteria and the DNA index >1.5 independently predicted a worse OS. When stratifying patients by both age and Milan criteria, patients ≤60 years with HCC beyond Milan criteria had an OS comparable to that of patients >60 years within Milan criteria (10-year OS: 33% versus 37%, P = 0.08). Patients ≤60 years with HCC beyond Milan criteria but a favourable DNA index ≤1.5 achieved excellent long-term outcomes, comparable with those of patients within Milan criteria. Conclusions Patients ≤60 years may undergo LT for HCC with favourable outcomes independently of their tumour burden. Additional assessment of tumour biology, e.g. using the DNA index, especially in this subgroup of patients can support the selection of LT candidates who may derive the most long-term survival benefit, even if Milan criteria are not fulfilled. PMID:25263399

  8. Novel applications of sub-surface laser machining

    NASA Astrophysics Data System (ADS)

    Campbell, B. R.; Forster, L. A.; Bernot, D. M.

    2011-03-01

    Lasers can uniquely be used to create physical changes inside a bulk material. Traditional manufacturing processes are limited to surface modifications, but a laser can be focused at any location inside a material transparent to that wavelength. Using sub surface machining methods with ultrashort pulse lasers two practical applications are demonstrated. First, a laser is used to sever short-circuited wires embedded deep inside a thick piece of glass, effectively repairing a defective wire network. Second, subsurface bar-coding was shown to produce readable markings. Surface laser markings were shown to weaken the glass, but subsurface marking had virtually no effect on strength.

  9. LASER APPLICATIONS: Thermographic system with a laser scanning device

    NASA Astrophysics Data System (ADS)

    Skvortsov, L. A.; Kirillov, V. M.

    2007-11-01

    It is shown that laser photothermal radiometry (LPTR) in combination with laser beam scanning within the instantaneous field of view of a single-element photodetector can be used to develop a scanning thermal emission microscope. An expression is derived for estimating its temperature resolution. The results of calculations are presented and the factors influencing the spatial lateral resolution of the technique and the time of image formation with the help of an acousto-optical deflector are analysed.

  10. Ultra-intense Laser Applications to the Industries at GPI

    SciTech Connect

    Kitagawa, Yoneyoshi; Mori, Yoshitaka; Ootsuka, Shuji; Makino, Takahiro; Ohta, Mari; Suzuki, Tetsuya; Kuwabara, Hajime

    2009-01-22

    The laser accelerator provides us not only ultra high field, but also extremely short pulse radiation sources, the laser-produced X-rays. Using a 1.2 TW table-top Ti:sap laser, we are pursuing the activities for the industrial application. First we proposed a new injection acceleration scheme using the ultra short beat-wave accelerator for the economical radiation source. Then we proposed two applications both on the backward see-through vision of distant objects using the laser X-rays, and on the X-ray illumination on Aspergillus awamori spores, which is 100 times effective of the current X-ray tube cases.

  11. High-power lasers for directed-energy applications.

    PubMed

    Sprangle, Phillip; Hafizi, Bahman; Ting, Antonio; Fischer, Richard

    2015-11-01

    In this article, we review and discuss the research programs at the Naval Research Laboratory (NRL) on high-power lasers for directed-energy (DE) applications in the atmosphere. Physical processes affecting propagation include absorption/scattering, turbulence, and thermal blooming. The power levels needed for DE applications require combining a number of lasers. In atmospheric turbulence, there is a maximum intensity that can be placed on a target that is independent of the initial beam spot size and laser beam quality. By combining a number of kW-class fiber lasers, scientists at the NRL have successfully demonstrated high-power laser propagation in a turbulent atmosphere and wireless recharging. In the NRL experiments, four incoherently combined fiber lasers having a total power of 5 kW were propagated to a target 3.2 km away. These successful high-power experiments in a realistic atmosphere formed the basis of the Navy's Laser Weapon System. We compare the propagation characteristics of coherently and incoherently combined beams without adaptive optics. There is little difference in the energy on target between coherently and incoherently combined laser beams for multi-km propagation ranges and moderate to high levels of turbulence. Unlike incoherent combining, coherent combining places severe constraints on the individual lasers. These include the requirement of narrow power spectral linewidths in order to have long coherence times as well as polarization alignment of all the lasers. These requirements are extremely difficult for high-power lasers. PMID:26560609

  12. Do Open Geodata Actually have the Quality they Declare? the Case Study of Milan, Italy

    NASA Astrophysics Data System (ADS)

    Brovelli, M. A.; Minghini, M.; Molinari, M. E.; Molteni, M.

    2016-06-01

    In the past number of years there has been an amazing flourishing of spatial data products released with open licenses. Researchers and professionals are extensively exploiting open geodata for many applications, which, in turn, include decision-making results and other (derived) geospatial datasets among their outputs. Despite the traditional availability of metadata, a question arises about the actual quality of open geodata, as their declared quality is typically given for granted without any systematic assessment. The present work investigates the case study of Milan Municipality (Northern Italy). A wide set of open geodata are available for this area which are released by national, regional and local authoritative entities. A comprehensive cataloguing operation is first performed, with 1061 geospatial open datasets from Italian providers found which highly differ in terms of license, format, scale, content, and release date. Among the many quality parameters for geospatial data, the work focuses on positional accuracy. An example of positional accuracy assessment is described for an openly-licensed orthophoto through comparison with the official, up-to-date, and large-scale vector cartography of Milan. The comparison is run according to the guidelines provided by ISO and shows that the positional accuracy declared by the orthophoto provider does not correspond to the reality. Similar results are found from analyses on other datasets (not presented here). Implications are twofold: raising the awareness on the risks of using open geodata by taking their quality for granted; and highlighting the need for open geodata providers to introduce or refine mechanisms for data quality control.

  13. Applications of Adaptive Optics Scanning Laser Ophthalmoscopy

    PubMed Central

    Roorda, Austin

    2010-01-01

    Adaptive optics (AO) describes a set of tools to correct or control aberrations in any optical system. In the eye, AO allows for precise control of the ocular aberrations. If used to correct aberrations over a large pupil, for example, cellular level resolution in retinal images can be achieved. AO systems have been demonstrated for advanced ophthalmoscopy as well as for testing and/or improving vision. In fact, AO can be integrated to any ophthalmic instrument where the optics of the eye is involved, with a scope of applications ranging from phoropters to optical coherence tomography systems. In this paper, I discuss the applications and advantages of using AO in a specific system, the adaptive optics scanning laser ophthalmoscope, or AOSLO. Since the Borish award was, in part, awarded to me because of this effort, I felt it appropriate to select this as the topic for this paper. Furthermore, users of AOSLO continue to appreciate the benefits of the technology, some of which were not anticipated at the time of development, and so it is time to revisit this topic and summarize them in a single paper. PMID:20160657

  14. Laser polishing of niobium for SRF applications

    SciTech Connect

    Zhao, Liang; Klopf, J. Michael; Reece, Charles E.; Kelley, Michael

    2013-09-01

    Smooth interior surfaces are desired for niobium SRF cavities, now obtained by buffered chemical polish (BCP) and/or electropolish (EP). Laser polishing is a potential alternative, having advantages of speed, freedom from chemistry and in-process inspection. Here we show that laser polishing can produce smooth topography with Power Spectral Density (PSD) measurements similar to that obtained by EP. We studied the influence of the laser power density and laser beam raster rate on the surface topography. These two factors need to be combined carefully to smooth the surface without damaging it. Computational modeling was used to simulate the surface temperature and explain the mechanism of laser polishing.

  15. Semiconductor lasers for space sensor applications

    NASA Technical Reports Server (NTRS)

    Katz, Joseph

    1988-01-01

    Despite their intrinsic power limitations, semiconductor laser diodes are essential for laser-based spaceborne sensor systems covering a wide spectral range, fulfilling such roles as pumping and injection-locking. They may also be used as direct sources in shorter-range operations. AlGaAs laser arrays have been developed for 810-nm band pumping in Nd:YAG lasers otherwise emitting at 1.064 nm. Additional roles include their use as low-power injection seeds, locking a solid-state laser into a specific desired wavelength.

  16. High power laser applications in Nippon Steel Corporation

    NASA Astrophysics Data System (ADS)

    Minamida, Katsuhiro

    2003-03-01

    The full-scale use of lasers in the steel industry began 25 years ago with their applications as controllable light sources. The laser systems contribute to increase efficiency and quality of the steel making processes, and also save energy of resources and labor. Laser applications in the steel making process generally require high input energy, however, it is essential to consider the interaction between the laser beam and materials. In particular, the reflectivity of the laser beam on the surface of material and the quantity of the laser-induced plasma are critical parameters for high efficient processes. We newly developed methods and systems of high power 45 kW CO2 laser welding of hot steel specimens with their applications as welding characteristics of hot steel specimens that temperature is about 1000 degree C, have been examined. Using laser induced plasma as a secondary heat source, the penetration depth improves about 30% compared to that at room temperature. The bead width is also enlarged by 10%. The maximum depth is 38 mm at 1m/min welding velocity at 40 kW. A beam weaving method is adopted for further enlargement of bead width without degrading fusion efficiency. It is also effective for suppressing the bead depth deviation. Additionally, several new applications, for example, new type all-laser-welded honeycomb panels for high- speed civil transport, will be talked.

  17. Quantum Cascade Lasers Modulation and Applications

    NASA Astrophysics Data System (ADS)

    Luzhansky, Edward

    The mid-wave IR (MWIR) spectral band, extending from 3 to 5 microns, is considered to be a low loss atmospheric window. There are several spectral sub-bands with relatively low atmospheric attenuation in this region making it popular for various commercial and military applications. Relatively low thermal and solar background emissions, effective penetration through the natural and anthropogenic obscurants and eye safety add to the long list of advantages of MWIR wavelengths. Quantum Cascade Lasers are compact semiconductor devices capable of operating in MWIR spectrum. They are based on inter-subband transitions in a multiple-quantum-well (QW) hetero-structure, designed by means of band-structure engineering. The inter-subband nature of the optical transition has several key advantages. First, the emission wavelength is primarily a function of the QW thickness. This characteristic allows choosing well-understood and reliable semiconductors for the generation of light in a wavelength range of interest. Second, a cascade process in which tens of photons are generated per injected electron. This cascading process is behind the intrinsic high-power capabilities of QCLs. This dissertation is focused on modulation properties of Quantum Cascade Lasers. Both amplitude and phase/frequency modulations were studied including modulation bandwidth, modulation efficiency and chirp linearity. Research was consisted of the two major parts. In the first part we describe the theory of frequency modulation (FM) response of Distributed Feedback Quantum Cascade Lasers (DFB QCL). It includes cascading effect on the QCL's maximum modulation frequency. The "gain levering" effect for the maximum FM response of the two section QCLs was studied as well. In the second part of research we concentrated on the Pulse Position Amplitude Modulation of a single section QCL. The low complexity, low size, weight and power Mid-Wavelength Infra-Red optical communications transceiver concept is

  18. Laser applications in machining slab materials

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoping

    1990-10-01

    Since the invention of the laser back in 1960, laser technology has been extensively applied in many fields of science and technology. These has been a history of nearly two decades of using lasers as an energy source in machining materials, such as cutting, welding, ruling and boring, among other operations. With the development of flexible automation in production, the advantages of laser machining have has grown more and more obvious. The combination of laser technology and computer science further promotes the enhancement and upgrading of laser machining and related equipment. At present, many countries are building high quality laser equipment for machining slab materials, such as the Coherent and Spectra Physics corporations in the United States, the Trumpf Corporation in West Germany, the Amada Corporation in Japan, and the Bystronic Corporation in Switzerland, among other companies.

  19. Archaeometric study of fictile tubes from three churches in Milan

    NASA Astrophysics Data System (ADS)

    Galli, A.; Bonizzoni, L.; Martini, M.; Sibilia, E.

    2008-07-01

    Fictile tubes (or vaulting tubes) are architectural elements that sustain and underline the shapes of cupolas and vaults. Several of these, sampled in three churches of Milan (S. Ambrogio, S. Lorenzo and Duomo) have been recently dated at the Archaeometry Laboratory of Milano Bicocca University. These architectural elements, differently shaped, styled and sampled from different structures, were all produced, according to thermoluminescence (TL), in the period 970 1080 AD. Energy dispersive X-rays fluorescence (EDXRF) measurements were performed to obtain the elemental composition of the clays and to attempt a classification of the samples. Multivariate PCA (principal components analysis) analyses and HCA (hierarchical clusters analysis) did not show any grouping of similarity. On the basis of the results, a tentative historical interpretation could be proposed.

  20. Properties and Applications of Laser Generated X-Ray Sources

    SciTech Connect

    Smith, R F; Key, M H

    2002-02-25

    The rapid development of laser technology and related progress in research using lasers is shifting the boundaries where laser based sources are preferred over other light sources particularly in the XUV and x-ray spectral region. Laser based sources have exceptional capability for short pulse and high brightness and with improvements in high repetition rate pulsed operation, such sources are also becoming more interesting for their average power capability. This study presents an evaluation of the current capabilities and near term future potential of laser based light sources and summarizes, for the purpose of comparison, the characteristics and near term prospects of sources based on synchrotron radiation and free electron lasers. Conclusions are drawn on areas where the development of laser based sources is most promising and competitive in terms of applications potential.

  1. Injection seeded single mode alexandrite ring laser for lidar applications

    NASA Technical Reports Server (NTRS)

    Lee, H. Sang; Notari, Anthony

    1992-01-01

    Along with many spectroscopic applications, atmospheric lidar measurements require a tunable, narrow band laser with a very high degree of spectral purity. A standing wave pulsed alexandrite laser tuned by injection seeding with an AlGaAs laser diode has demonstrated high stability. The standing wave cavity, however, poses several difficulties in light of the single mode operation and efficient seeding beam into the cavity. In order to overcome these problems and to operate the high power alexandrite laser in a single axial mode with a high spectral purity, a new ring laser system is being developed. The design features of the ring laser and some measurements of the laser characteristics are presented.

  2. Application of laser Doppler velocimeter to chemical vapor laser system

    NASA Technical Reports Server (NTRS)

    Gartrell, Luther R.; Hunter, William W., Jr.; Lee, Ja H.; Fletcher, Mark T.; Tabibi, Bagher M.

    1993-01-01

    A laser Doppler velocimeter (LDV) system was used to measure iodide vapor flow fields inside two different-sized tubes. Typical velocity profiles across the laser tubes were obtained with an estimated +/-1 percent bias and +/-0.3 to 0.5 percent random uncertainty in the mean values and +/-2.5 percent random uncertainty in the turbulence-intensity values. Centerline velocities and turbulence intensities for various longitudinal locations ranged from 13 to 17.5 m/sec and 6 to 20 percent, respectively. In view of these findings, the effects of turbulence should be considered for flow field modeling. The LDV system provided calibration data for pressure and mass flow systems used routinely to monitor the research laser gas flow velocity.

  3. The NASA high power carbon dioxide laser: A versatile tool for laser applications

    NASA Technical Reports Server (NTRS)

    Lancashire, R. B.; Alger, D. L.; Manista, E. J.; Slaby, J. G.; Dunning, J. W.; Stubbs, R. M.

    1976-01-01

    A closed-cycle, continuous wave, carbon dioxide high power laser has been designed and fabricated to support research for the identification and evaluation of possible high power laser applications. The device is designed to generate up to 70 kW of laser power in annular shape beams from 1 to 9 cm in diameter. Electric discharge, either self sustained or electron beam sustained, is used for excitation. This laser facility provides a versatile tool on which research can be performed to advance the state-of-the-art technology of high power CO2 lasers in such areas as electric excitation, laser chemistry, and quality of output beams. The facility provides a well defined, continuous wave beam for various application experiments, such as propulsion, power conversion, and materials processing.

  4. Micro-scanning mirrors for high-power laser applications in laser surgery

    NASA Astrophysics Data System (ADS)

    Sandner, Thilo; Kimme, Simon; Grasshoff, Thomas; Todt, Ulrich; Graf, Alexander; Tulea, Cristian; Lenenbach, Achim; Schenk, Harald

    2014-03-01

    We present two novel micro scanning mirrors with large aperture and HR dielectric coatings suitable for high power laser applications in a miniaturized laser-surgical instrument for neurosurgery to cut skull tissue. An electrostatic driven 2D-raster scanning mirror with 5x7.1mm aperture is used for dynamic steering of a ps-laser beam of the laser cutting process. A second magnetic 2D-beam steering mirror enables a static beam correction of a hand guided laser instrument. Optimizations of a magnetic gimbal micro mirror with 6 mm x 8 mm mirror plate are presented; here static deflections of 3° were reached. Both MEMS devices were successfully tested with a high power ps-laser at 532nm up to 20W average laser power.

  5. Diagnostic and therapeutic applications of diode lasers and solid state lasers in medicine. Progress report

    SciTech Connect

    Jacques, S.L.; Welch, A.J.; Motamedi, M.; Rastegar, S.; Tittel, F.; Esterowitz, L.

    1993-05-01

    The Texas Medical Center in Houston and the nearby UT Medical Branch at Galveston together constitute a major center of medical research activities. Laser applications in medicine are under development with the engineering assistance of the collaborating engineering enters at Rice University, UT-Austin, Texas A&M Univ. In addition, this collective is collaborating with the naval Research Laboratory, where new developments in laser design are underway, in order to transfer promising new laser technology rapidly into the medical environment.

  6. Diagnostic and therapeutic applications of diode lasers and solid state lasers in medicine. Progress report

    SciTech Connect

    Jacques, S.L.; Welch, A.J.; Motamedi, M.; Rastegar, S.; Tittel, F.; Esterowitz, L.

    1992-05-01

    The Texas Medical Center in Houston and the nearby UT Medical Branch at Galveston together constitute a major center of medical research activities. Laser applications in medicine are under development with the engineering assistance of the colloborating engineering centers at Rice University, UT-Austin, and Texas A&M Univ. In addition, this collective is collaborating with the Naval Research Laboratory, where new developments in laser design are underway, in order to transfer promising new laser technology rapidly into the medical environment.

  7. Diagnostic and therapeutic applications of diode lasers and solid state lasers in medicine

    SciTech Connect

    Jacques, S.L. . Cancer Center); Welch, A.J. ); Motamedi, M. . Medical Branch); Rastegar, S. ); Tittel, F. ); Esterowitz, L. )

    1992-05-01

    The Texas Medical Center in Houston and the nearby UT Medical Branch at Galveston together constitute a major center of medical research activities. Laser applications in medicine are under development with the engineering assistance of the colloborating engineering centers at Rice University, UT-Austin, and Texas A M Univ. In addition, this collective is collaborating with the Naval Research Laboratory, where new developments in laser design are underway, in order to transfer promising new laser technology rapidly into the medical environment.

  8. Scientific applications of frequency-stabilized laser technology in space

    NASA Technical Reports Server (NTRS)

    Schumaker, Bonny L.

    1990-01-01

    A synoptic investigation of the uses of frequency-stabilized lasers for scientific applications in space is presented. It begins by summarizing properties of lasers, characterizing their frequency stability, and describing limitations and techniques to achieve certain levels of frequency stability. Limits to precision set by laser frequency stability for various kinds of measurements are investigated and compared with other sources of error. These other sources include photon-counting statistics, scattered laser light, fluctuations in laser power, and intensity distribution across the beam, propagation effects, mechanical and thermal noise, and radiation pressure. Methods are explored to improve the sensitivity of laser-based interferometric and range-rate measurements. Several specific types of science experiments that rely on highly precise measurements made with lasers are analyzed, and anticipated errors and overall performance are discussed. Qualitative descriptions are given of a number of other possible science applications involving frequency-stabilized lasers and related laser technology in space. These applications will warrant more careful analysis as technology develops.

  9. Industrial Applications of High Power CO2 Lasers - System Descriptions

    NASA Astrophysics Data System (ADS)

    Gukelberger, Armin

    1986-10-01

    The laser as a cutting tool for sheet metal cutting has beenl well accepted in industry for many years. Several hundreds of units are used for contour cutting of small and medium-sized series on plane metal sheets up to 6 mm thick. Within the last three years, cutting systems have been expanded in three ways: thicker material up to 12 mm can now be cut by using higher powered lasers (1500 W); with the introduction of flying optic systems which cover sheet dimensions up to 4 m x 3 m, the cutting of larger sized metal sheets is possible. In addition, the use of five or six axis systems allows cutting of three-dimensional plastic and metal material. Besides laser cutting, the acceptance of systems for laser welding applications is increa sing. Several systems have been running in production for a couple of years and laser wel ding will probably become the fastest growing market in laser material processing within the next five years. The laser technology is regarded as a beneficial tool for welding, whenever low heat input and, consequently, low heat distortion is requested. To day's main welding application areas are: components of car engines and transmissions, window spacer and stainless steel tube welding, and also car body welding with laser robots or five axis gantry type systems. The output power of CO2-lasers for welding applications is between 1 and 5 kw in most cases.

  10. Solid state dye laser for medical applications

    NASA Astrophysics Data System (ADS)

    Aldag, Henry R.

    1994-06-01

    The development of solid state dye lasers could lead to a major breakthrough in the cost and compactness of a medical device. Advantages include: elimination of the flow system for the gain medium; ease with which to implement wavelength agility or the replacement of a degraded rod or sheet; and toxicity and flammability become a non-issue. Dye lasers have played a role in cardiology, dermatology, and urology. Of these cardiology is of interest to Palomar. The Palomar Model 3010 flashlamp-pumped dye laser medical device was used during phase 1 FDA clinical trials to break-up blood clots that cause heart attacks, a process known as coronary laser thrombolysis. It is the objective of this research and development effort to produce solid matrix lasers that will replace liquid dye lasers in these medical specialties.

  11. Laser Material Processing for Microengineering Applications

    NASA Technical Reports Server (NTRS)

    Helvajian, H.

    1995-01-01

    The processing of materials via laser irradiation is presented in a brief survey. Various techniques currently used in laser processing are outlined and the significance to the development of space qualified microinstrumentation are identified. In general the laser processing technique permits the transferring of patterns (i.e. lithography), machining (i.e. with nanometer precision), material deposition (e.g., metals, dielectrics), the removal of contaminants/debris/passivation layers and the ability to provide process control through spectroscopy.

  12. National funding initiatives for laser technology in Germany: projects on brilliant laser sources and their applications

    NASA Astrophysics Data System (ADS)

    Bachmann, Friedrich

    2010-09-01

    Germany's leading role in laser technology is not least a consequence of successful national precompetitive joint development projects between industry and science: Funding of laser technology in Germany is strongly performed by the German Federal Ministry of Education and Research (BMBF) and has already been started in the second half of the eighties of last century. Since then several programs matched to the actual technological status and the future requirements of the market have been run: whilst activities have been focused on gas lasers in the beginning, today - in the actual research funding program "optical technologies" - semiconductor lasers and diode pumped lasers are in the center of interest. More than ever before relevance of the development to applications must be integrated into the projects. Consequently, in most projects lasers source development and application of novel brilliant laser sources are combined. This has been successfully performed in the BRIOLAS (Brilliant Diode Lasers) initiative, which has been launched in 2004 and will come to an end in 2010. Based on the knowledge and experience gained in the 13 projects of the BRIOLAS initiative, two new initiatives have been launched in 2008, namely INLAS (Integrated Optical Components for High Power Laser Beam Sources) and MABRILAS (Material Processing with Brilliant Laser Beam Sources).

  13. National funding initiatives for laser technology in Germany: projects on brilliant laser sources and their applications

    NASA Astrophysics Data System (ADS)

    Bachmann, Friedrich

    2011-02-01

    Germany's leading role in laser technology is not least a consequence of successful national precompetitive joint development projects between industry and science: Funding of laser technology in Germany is strongly performed by the German Federal Ministry of Education and Research (BMBF) and has already been started in the second half of the eighties of last century. Since then several programs matched to the actual technological status and the future requirements of the market have been run: whilst activities have been focused on gas lasers in the beginning, today - in the actual research funding program "optical technologies" - semiconductor lasers and diode pumped lasers are in the center of interest. More than ever before relevance of the development to applications must be integrated into the projects. Consequently, in most projects lasers source development and application of novel brilliant laser sources are combined. This has been successfully performed in the BRIOLAS (Brilliant Diode Lasers) initiative, which has been launched in 2004 and will come to an end in 2010. Based on the knowledge and experience gained in the 13 projects of the BRIOLAS initiative, two new initiatives have been launched in 2008, namely INLAS (Integrated Optical Components for High Power Laser Beam Sources) and MABRILAS (Material Processing with Brilliant Laser Beam Sources).

  14. Diode Lasers used in Plastic Welding and Selective Laser Soldering - Applications and Products

    NASA Astrophysics Data System (ADS)

    Reinl, S.

    Aside from conventional welding methods, laser welding of plastics has established itself as a proven bonding method. The component-conserving and clean process offers numerous advantages and enables welding of sensitive assemblies in automotive, electronic, medical, human care, food packaging and consumer electronics markets. Diode lasers are established since years within plastic welding applications. Also, soft soldering using laser radiation is becoming more and more significant in the field of direct diode laser applications. Fast power controllability combined with a contactless temperature measurement to minimize thermal damage make the diode laser an ideal tool for this application. These advantages come in to full effect when soldering of increasingly small parts in temperature sensitive environments is necessary.

  15. Industrial applications of high-power copper vapor lasers

    SciTech Connect

    Warner, B.E.; Boley, C.D.; Chang, J.J.; Dragon, E.P.; Havstad, M.A.; Martinez, M.; McLean, W. II

    1995-08-01

    A growing appreciation has developed in the last several years for the copper vapor laser because of its utility in ablating difficult materials at high rates. Laser ablation at high rates shows promise for numerous industrial applications such as thin film deposition, precision hole drilling, and machining of ceramics and other refractories.

  16. Laser Printing for a Variety of Library Applications.

    ERIC Educational Resources Information Center

    Kelly, Glen J.

    1988-01-01

    Summarizes the current status of laser printers in terms of cost, hardware and software requirements, measurement and operational considerations, ease of use, and maintenance. The cost effectiveness of laser printing in libraries for applications such as spine labels, purchase orders, and reports, is explored. (9 notes with references) (CLB)

  17. Mode-Locked Laser Arrays for WDM Applications

    NASA Technical Reports Server (NTRS)

    Forouhar, S.

    1997-01-01

    Colliding pulse mode-locked laser arrays are being developed at 20 GHz for WDM applications. Arrays with 5 wavelengths in the EDFA gain bandwidth have already been demonstrated, with the final goal being a packaged, 10 wavelength mode-locked laser array.

  18. Surgical application of lasers. 2nd edition

    SciTech Connect

    Dixon, J.A.

    1987-01-01

    Lasers have been successfully used in several new clinical areas such as cardiovascular, orthopedic, and pulmonary surgery as well as in specialties covered in the first edition including otorhinolaryngology, dermatology and plastic surgery, gastroenterology, and urology. These advances are all discussed in this text. Introductory chapters cover the background of laser surgery, techniques and instrumentation and safety procedures. The remaining chapters cover lasers in specific fields such as endoscopic surgery, gynecology, neurosurgery and many more. The final chapters provide an overview of photodynamic therapy and the future of laser surgery.

  19. Ophthalmic applications of ultrashort pulsed lasers

    NASA Astrophysics Data System (ADS)

    Juhasz, Tibor; Spooner, Greg; Sacks, Zachary S.; Suarez, Carlos G.; Raksi, Ferenc; Zadoyan, Ruben; Sarayba, Melvin; Kurtz, Ronald M.

    2004-06-01

    Ultrashort laser pulses can be used to create high precision incision in transparent and translucent tissue with minimal damage to adjacent tissue. These performance characteristics meet important surgical requirements in ophthalmology, where femtosecond laser flap creation is becoming a widely used refractive surgery procedure. We summarize clinical findings with femtosecond laser flaps as well as early experiments with other corneal surgical procedures such as corneal transplants. We also review laser-tissue interaction studies in the human sclera and their consequences for the treatment of glaucoma.

  20. [Use of the thermal laser effect of laser irradiation for cardiovascular applications exemplified by the Nd:YAG laser].

    PubMed

    Ischinger, T; Coppenrath, K; Weber, H; Enders, S; Unsöld, E; Hessel, S

    1989-11-01

    Techniques of percutaneous transluminal application of laser energy for vessel recanalization have been used clinically since 1983. The commonly used Nd:YAG and argon lasers achieve ablation of atherosclerotic plaques by thermal action (vaporization). In order to reduce undesirable thermal damage in the neighborhood of the target tissue and to avoid vessel perforation, optimal irradiation parameters, modified (atraumatic) fiber tips (hot tips, sapphires), and steerable catheter systems needed to be implemented. Favorable results from peripheral application have encouraged use in the coronary circulation. More recently, coagulative tissue effects of circumferential irradiation of the vessel wall during balloon dilatation have been used for stabilization of acute and late results after mechanical balloon angioplasty. Enhancement of the differential light absorption of atherosclerotic plaque by use of biological dyes may further improve selective intravascular laser application. Intraoperative ECG-guided laser coagulation of arrhythmogenic areas of myocardium is a method for treatment of malignant arrhythmias. Transluminal non-operative application of myocardial laser photocoagulation has now been tested experimentally and shown to be safe and effective. There was no arrhythmogenicity or thermal damage of coronary arteries associated with this method. Innovative techniques such as nanosecond pulsed excimer lasers (athermal action) and development of "intelligent" lasers--which are equipped with spectroscopy-guided feedback systems for plaque recognition--have opened new perspectives and will further improve safety and efficacy of clinical laser application. However, according to current experience, the thermally acting Nd:YAG laser is an effective and versatile mode of laser therapy for selected cardiovascular indications. PMID:2532812

  1. Review of soft x-ray lasers and their applications

    SciTech Connect

    Skinner, C.H.

    1991-03-01

    The emerging technology of soft x-ray lasers is in a transition phase between the first laboratory demonstrations of gain and the acceptance of soft x-ray lasers as practical tools for novel applications. Current research is focused on several fronts. The operational wavelength range has been extended to the water window'', important for applications in the life sciences. Gain has also been generated with substantially simpler technology (such as a 6J laser) and this augurs well for the commercially availability in the near future of soft x-ray lasers for a variety of applications. Advanced soft x-ray laser concepts are being developed from investigations into ultra-high intensity laser/matter interactions. The first paper a brief historical perspective of x-ray microscopy and holography have begun. In this paper a brief historical perspective of x-ray laser development will be followed by a review of recent advances in recombination, collisional and photo-pumped systems and applications. A summary of current gain-length performance achieved in laboratories worldwide is presented. Near term prospects for applications to novel fields are discussed. 81 refs., 9 figs., 1 tab.

  2. Laser crystallization and localized growth of nanomaterials for solar applications

    NASA Astrophysics Data System (ADS)

    In, Jungbin; Ryu, Sang-Gil; Lee, Daeho; Ahn, Sanghoon; Zheng, Andy Cheng; Hwang, David Jae-Seok; Grigoropoulos, Costas P.

    2013-09-01

    Laser-assisted localized growth of semiconducting nanostructures is reported. As is the case of conventional crystal growth, localized laser enables three kinds of crystal growth: (1) melt growth (recrystallization) of amorphous silicon nanopillars by pulsed laser; (2) vapor growth (chemical vapor deposition) of germanium nanowires; (3) solution growth (hydrothermal growth) of zinc oxide nanowires. The results not only demonstrate programmable and digital fabrication of laser-assisted crystal growth, but also reveal unusual growth chacracteristics (grain morphologies, growth kinetics). Related to solar applications, it is suggested that these structures can act as epitaxial seeds for growth of coarse grains and as multi-spectral centers for enhanced and engineered light absorption.

  3. Application of Laser in Oral Surgery

    PubMed Central

    Asnaashari, Mohammad; Zadsirjan, Saeede

    2014-01-01

    In this review collected from the literature on usage of laser in oral minor surgery based on a Medline search in the time period between the years: 2008 and 2013, the most current evidence on laser-assisted oral minor surgery is going to be surveyed. PMID:25653807

  4. Laser radar for spacecraft guidance applications

    NASA Technical Reports Server (NTRS)

    Liebe, C. C.; Abramovici, A.; Bartman, R. K.; Bunker, R. L.; Chapsky, J.; Chu, C. C.; Clouse, D.; Dillon, J. W.; Hausmann, B.; Hemmati, H.; Kornfeld, R. P.; Kwa, C.; Mobasser, S.; Newell, M.; Padgett, C.; Roberts, W. T.; Spiers, G.; Warfield, Z.; Wright, M.

    2003-01-01

    A flight qualified laser radar called LAMP (LAser MaPper) is under development at JPL. LAMP is a guidance and control sensor that can form 3 dimensional images of its field of regard. This paper describes the detailed design of the LAMP sensor.

  5. Laser radar technology and applications; Proceedings of the Meeting, Quebec, Canada, June 3-5, 1986

    NASA Astrophysics Data System (ADS)

    Cruickshank, James M.; Harney, Robert C.

    1986-01-01

    Various papers on laser radar technology and applications are presented. The topics considered include: eye-safe solid lasers for lidar applications, practical DF laser for ranging applications, ultrafast surface barrier photodetectors, performance analyses for peak-detecting laser radars, multiple scattering for laser beams propagating in a layered atmosphere, laser radar cross section of objects immersed in the earth's atmosphere, measurements of pulse coherence in mode-locked TEA-CO2 lasers, and single longitudinal mode operation of a continuously tunable high pressure TE-CO2. Also discussed are: amplitude-modulated laser system for distance and displacement measurement, minilaser rangefinder, laser docking system radar flight experiment, improved optical resonator for laser radars, design of frequency-stable TEA-CO2 lasers, HgCdTe photodiodes for heterodyne applications, acoustooptic spectrum analyzer for laser radar applications, laser cloud mapper and its applications, scanning lidar bathymeter for water depth measurement, and fluorescence lidar for land and sea remote sensing.

  6. Advanced laser diodes for sensing applications

    SciTech Connect

    VAWTER,GREGORY A.; MAR,ALAN; CHOW,WENG W.; ALLERMAN,ANDREW A.

    2000-01-01

    The authors have developed diode lasers for short pulse duration and high peak pulse power in the 0.01--100.0 m pulsewidth regime. A primary goal of the program was producing up to 10 W while maintaining good far-field beam quality and ease of manufacturability for low cost. High peak power, 17 W, picosecond pulses have been achieved by gain switching of flared geometry waveguide lasers and amplifiers. Such high powers area world record for this type of diode laser. The light emission pattern from diode lasers is of critical importance for sensing systems such as range finding and chemical detection. They have developed a new integrated optical beam transformer producing rib-waveguide diode lasers with a symmetric, low divergence, output beam and increased upper power limits for irreversible facet damage.

  7. Scientific applications for high-energy lasers

    SciTech Connect

    Lee, R.W.

    1994-03-01

    The convergence of numerous factors makes the time ripe for the development of a community of researchers to use the high-energy laser for scientific investigations. This document attempts to outline the steps necessary to access high-energy laser systems and create a realistic plan to implement usage. Since an academic/scientific user community does not exist in the USA to any viable extent, we include information on present capabilities at the Nova laser. This will briefly cover laser performance and diagnostics and a sampling of some current experimental projects. Further, to make the future possibilities clearer, we will describe the proposed next- generation high-energy laser, named for its inertial fusion confinement (ICF) goal, the multi-megaJoule, 500-teraWatt National Facility, or NIF.

  8. Clarinet laser: Semiconductor laser design for high-brightness applications

    NASA Astrophysics Data System (ADS)

    Borruel, Luis; Esquivias, Ignacio; Moreno, Pablo; Krakowski, Michel; Auzanneau, Sophie Charlotte; Calligaro, Michel; Parillaud, Olivier; Lecomte, Michel; Sujecki, Slawomir; Wykes, Jim; Larkins, Eric C.

    2005-09-01

    High-power and high-brightness continuous-wave (cw) operation has been achieved with an optimized design of fully index-guided tapered laser emitting at 975 nm. The device achieves simultaneously negligible astigmatism and stable low divergence in the lateral axis at high-power operation. By using a quasi-three-dimensional simulation model, the different mechanisms modifying the slow axis beam divergence at high power have been carefully balanced in the clarinet design, easing the use of collective optics in laser bars. The devices consist of a relatively long ridge-waveguide filtering section coupled to a relatively short tapered section with an aperture angle of 2°. InGaAs /InGaAsP lasers were fabricated with this design, demonstrating an output power of 1 W cw, a maximum wall-plug efficiency of 50%, negligible astigmatism, a slow-axis far-field divergence (measured at 1/e2) of 5° at 1 W and beam quality parameter M2<3.

  9. High-power disk lasers: advances and applications

    NASA Astrophysics Data System (ADS)

    Havrilla, David; Ryba, Tracey; Holzer, Marco

    2012-03-01

    Though the genesis of the disk laser concept dates to the early 90's, the disk laser continues to demonstrate the flexibility and the certain future of a breakthrough technology. On-going increases in power per disk, and improvements in beam quality and efficiency continue to validate the genius of the disk laser concept. As of today, the disk principle has not reached any fundamental limits regarding output power per disk or beam quality, and offers numerous advantages over other high power resonator concepts, especially over monolithic architectures. With about 2,000 high power disk lasers installations, and a demand upwards of 1,000 lasers per year, the disk laser has proven to be a robust and reliable industrial tool. With advancements in running cost, investment cost and footprint, manufacturers continue to implement disk laser technology with more vigor than ever. This paper will explain recent advances in disk laser technology and process relevant features of the laser, like pump diode arrangement, resonator design and integrated beam guidance. In addition, advances in applications in the thick sheet area and very cost efficient high productivity applications like remote welding, remote cutting and cutting of thin sheets will be discussed.

  10. Excimer laser ceramic and metal surface alloying applications

    NASA Astrophysics Data System (ADS)

    Hontzopoulos, E.; Zervaki, A.; Zergioti, Y.; Hourdakis, G.; Raptakis, E.; Giannacopoulos, A.; Fotakis, C.

    1991-02-01

    Recent excimer laser based deposition and surface modification techniques for ceramic and metallurgical engineering applications are reported. These include the improvement of the anti-corrosion and erosion properties and wear resistance of metal alloys and the formation of surface conducting patterns on ceramic materials. Excimer laser chemical vapour deposition (LCVD) applications B, AI and Hf or multielement combinations are discussed together with studies which aim at a better understanding of the fundamental processes governing the deposition process.

  11. Femtosecond lasers in ophthalmology: clinical applications in anterior segment surgery

    NASA Astrophysics Data System (ADS)

    Juhasz, Tibor; Nagy, Zoltan; Sarayba, Melvin; Kurtz, Ronald M.

    2010-02-01

    The human eye is a favored target for laser surgery due to its accessibility via the optically transparent ocular tissue. Femtosecond lasers with confined tissue effects and minimized collateral tissue damage are primary candidates for high precision intraocular surgery. The advent of compact diode-pumped femtosecond lasers, coupled with computer controlled beam delivery devices, enabled the development of high precision femtosecond laser for ophthalmic surgery. In this article, anterior segment femtosecond laser applications currently in clinical practice and investigation are reviewed. Corneal procedures evolved first and remain dominant due to easy targeting referenced from a contact surface, such as applanation lenses placed on the eye. Adding a high precision imaging technique, such as optical coherence tomography (OCT), can enable accurate targeting of tissue beyond the cornea, such as the crystalline lens. Initial clinical results of femtosecond laser cataract surgery are discussed in detail in the latter portion part of the article.

  12. Spaceflight laser development for future remote sensing applications

    NASA Astrophysics Data System (ADS)

    Yu, Anthony W.; Krainak, Michael A.; Stephen, Mark A.; Abshire, James B.; Harding, David J.; Riris, Haris; Li, Steven X.; Chen, Jeffrey R.; Allan, Graham R.; Numata, Kenji; Wu, Stewart T.; Camp, Jordan B.

    2011-11-01

    At NASA's Goddard Space Flight Center we are developing next generation laser transmitters for future spaceflight, remote instruments including a micropulse altimeter for ice-sheet and sea ice monitoring, laser spectroscopic measurements of atmospheric CO2 and an imaging lidar for high resolution mapping of the Earth's surface. These laser transmitters also have applicability to potential missions to other solar-system bodies for trace gas measurements and surface mapping. In this paper we review NASA spaceflight laser transmitters used to acquire measurements in orbit around Mars, Mercury, Earth and the Moon. We then present an overview of our current spaceflight laser programs and describe their intended uses for remote sensing science and exploration applications.

  13. DOE Center of Excellence in Medical Laser Applications. Final report

    SciTech Connect

    Jacques, S.L. )

    1998-01-01

    An engineering network of collaborating medical laser laboratories are developing laser and optical technologies for medical diagnosis and therapy and are translating the engineering into medical centers in Portland, OR, Houston, TX, and Galveston, TX. The Center includes the University of Texas M.D. Anderson Cancer Center, the University of Texas-Austin, Texas A and M University, Rice University, the University Texas Medical Branch-Galveston, Oregon Medical Laser Center (Providence St. Vincent Medical Center, Oregon Health Sciences University, and Oregon Graduate Institute, Portland, OR), and the University of Oregon. Diagnostics include reflectance, fluorescence, Raman IR, laser photoacoustics, optical coherence tomography, and several new video techniques for spectroscopy and imaging. Therapies include photocoagulation therapy, laser welding, pulsed laser ablation, and light-activated chemotherapy of cancer (photodynamic therapy, or PDT). Medical applications reaching the clinic include optical monitoring of hyperbilirubinemia in newborns, fluorescence detection of cervical dysplasia, laser thrombolysis of blood clots in heart attack and brain stroke, photothermal coagulation of benign prostate hyperplasia, and PDT for both veterinary and human cancer. New technologies include laser optoacoustic imaging of breast tumors and hemorrhage in head trauma and brain stroke, quality control monitoring of dosimetry during PDT for esophageal and lung cancer, polarization video reflectometry of skin cancer, laser welding of artificial tissue replacements, and feedback control of laser welding.

  14. Theoretical investigations of the processes of laser interaction with ocular tissues for laser applications in ophthalmology

    NASA Astrophysics Data System (ADS)

    Pustovalov, V. K.; Jean, B.

    2006-08-01

    Theoretical investigations and the results of computer modeling of the optical, thermophysical, and thermochemical processes during laser interaction with ocular tissues are reviewed in this paper. Physical-mathematical models and results of numerical simulation of the processes are presented. The computer modeling was applied for investigations of laser heating and coagulation of ocular tissues for treatment of retina diseases and intraocular tumors, cyclophotocoagulation of the ciliary body for treatment of glaucoma, and laser thermal keratoplasty of the cornea. The influence of radiation parameters on the selectivity of laser coagulation of laminated ocular tissues is considered. The results obtained are of essential interest for laser applications in ophthalmology and can be used for investigation of heating and coagulation of tissues in different fields of laser medicine.

  15. Laser-Induced Underwater Plasma And Its Spectroscopic Applications

    SciTech Connect

    Lazic, Violeta

    2008-09-23

    Applications of Laser Induced Breakdown Spectroscopy (LIBS) for analysis of immersed solid and soft materials, and for liquid impurities are described. A method for improving the LIBS signal underwater and for obtaining quantitative analyses in presence of strong shot-to-shot variations of the plasma properties is proposed. Dynamic of the gas bubble formed by the laser pulse is also discussed, together with its importance in Double-Pulse (DP) laser excitation. Results of the studies relative to an application of multi-pulse sequence and its effects on the plasma and gas bubble formation are also presented.

  16. Enabling laser applications in microelectronics manufacturing

    NASA Astrophysics Data System (ADS)

    Delmdahl, Ralph; Brune, Jan; Fechner, Burkhard; Senczuk, Rolf

    2016-02-01

    In this experimental study, we report on high-pulse-energy excimer laser drilling into high-performance build-up films which are pivotal in microelectronics manufacturing. Build-up materials ABF-GX13 from Ajinomoto as well as ZS-100 from Zeon Corporation are evaluated with respect to their viability for economic excimer laser-based micro-via formation. Excimer laser mask imaging projection at laser wavelengths of 193, 248 and 308 nm is employed to generate matrices of smaller micro-vias with different diameters and via pitches. High drilling quality is achievable for all excimer laser wavelengths with the fastest ablation rates measured in the case of 248 and 308 nm wavelengths. The presence of glass fillers in build-up films as in the ABF-GX13 material poses some limitations to the minimum achievable via diameter. However, surprisingly good drilling results are obtainable as long as the filler dimensions are well below the diameter of the micro-vias. Sidewall angles of vias are controllable by adjusting the laser energy density and pulse number. In this work, the structuring capabilities of excimer lasers in build-up films as to taper angle variations, attainable via diameters, edge-stop behavior and ablation rates will be elucidated.

  17. Speciation of PM10 and PM2.5 in the urban atmosphere of Milan

    NASA Astrophysics Data System (ADS)

    Bolzacchini, E.; Gianelle, V.; Perrone, G.; Pozzoli, L.; Rindone, B.; Mognaschi, G.; Avella, F.; Faedo, D.

    2003-04-01

    A new project (Urban Particulate in Milan, PUMI) is started since last February 2002 to study the air pollution in the Milan urban area which during last winter reached a critical dimension, not only for the city of Milan (Italy) but also for all the Region Lombardia. A project involve the collection and elaboration of all the data about fine particles (PM10, PM2.5) in the Milan urban area to study their spatial and temporal distribution and their correlation with meteorological parameters and other pollutants. Monitoring campaigns for the emissions from primary representative sources (mobile sources, household heating, power plants and incinerators). Speciation of the samples collected from the principal sources and speciation of the fine particulate samples. Compounds of particular interest for the health (e.g. elements, PAH, nitro-PHA) will be analysed to identify the impact of the different sources.

  18. Aero-optics overview. [laser applications

    NASA Technical Reports Server (NTRS)

    Gilbert, K. G.

    1980-01-01

    Various aero-optical phenomena are discussed with reference to their effect on airborne high energy lasers. Major emphasis is placed on: compressibility effects induced in the surrounding flow field; viscous effects which manifests themselves as aircraft boundary layers or shear layers; inviscid flow fields surrounding the aircraft due to airflow around protuberance such as laser turret assemblies; and shocks, established whenever local flow exceeds Mach one. The significant physical parameters affecting the interaction of a laser beam with a turbulent boundary layer are also described.

  19. Screening submersed plant species for phytoremediation of explosives-contaminated groundwater from the Milan Army Ammunition Plant, Milan, Tennessee. Final report

    SciTech Connect

    Best, E.P.; Sprecher, S.L.; Fredrickson, H.L.; Zappi, M.E.; Larson, S.L.

    1997-11-01

    As an alternative to other groundwater extraction and surface treatment techniques, phytoremediation systems are currently being evaluated by civilian and military administrators for their ability to enhance removal of potentially toxic or mutagenic munitions materiel such as 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5- trinitro-1,3,5-triazine (RDX), and their degradation products. To guide selection of aquatic plants for use in demonstration phytoremediation lagoons at the Milan Army Ammunition Plant (MAAP), Milan, TN, this study evaluated the relative ability of ten species to decrease levels of TNT and RDX explosives and related nitrobodies in contaminated MAAP groundwater.

  20. Possible application of laser isotope separation

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1975-01-01

    The laser isotope separation process is described and its special economic features discussed. These features are its low cost electric power operation, capital investment costs, and the costs of process materials.

  1. [The application of laser rays in gastroenterology].

    PubMed

    Platteborse, R

    1990-01-01

    After reminding the difference between the surface electro-coagulation-section and the photo-coagulation "at distance" by Laser-ray, the author underlines that the most interesting indications of the Laser-ray introduced into the digestive endoscopes are the destruction of esophageal and colonic tumors for inoperable patients or patients with operative risks. The palliative destructions avoid mutilating operations which won't increase the survival time of the patients. PMID:1701104

  2. Managing the maintainance and conservation of the built heritage: a web-gis approach for the Richini courtyard in Milan

    NASA Astrophysics Data System (ADS)

    Toniolo, L.; Gulotta, D.; Bertoldi, M.; Bortolotto, S.

    2012-04-01

    The Richini courtyard is a masterpiece of northern Italy baroque and it is part of the complex that currently hosts the "Università degli Studi" of Milan. Its four internal façades are based on a double arcade structure with granitic columns along a rectangular plan. The architectural elements are enriched by an outstanding sculpted decoration made of Angera stone (a typical Lombard dolostone) with bas-relief panels, high-relief figures, mouldings and voussoirs. The courtyard suffers the consequences of a troubled conservation history: the Second World War bombardment caused devastating damages to both the structure and the sculpted surfaces, so that an extensive restoration was carried out during the early fifties. Moreover, a further and massive conservative intervention was required during the nineties due to the increasing degradation rate of the Angera stone subjected to severely polluted environmental conditions. The overall durability of this last intervention, as well as the long-term compatibility of the restoration materials, has been evaluated almost twenty years later, in 2011. A thorough study of representative areas of the courtyard has been conducted by a multi-disciplinary research group. The aim of the study was the evaluation of the state of conservation of the ancient and restoration materials, as well as the identification of the decay phenomena. A high-accurate 3D laser scanner survey of the courtyard has been performed as well. The results of the diagnostic activity has been summarised in the present work. The wide range of different type of data (analytical and geometrical data, historical records, photographic documentation) have been managed by the latest release of a web-GIS software specifically designed for the application in the built heritage conservation. A new data structure has been purposely designed in order to maximize the efficiency for what concerning data entry, data query and data updating. The enhanced web-GIS software has

  3. Applications of microlens-conditioned laser diode arrays

    SciTech Connect

    Beach, R.J.; Emanuel, M.A.; Freitas, B.L.

    1995-01-01

    The ability to condition the radiance of laser diodes using shaped-fiber cylindrical-microlens technology has dramatically increased the number of applications that can be practically engaged by diode laser arrays. Lawrence Livermore National Laboratory (LLNL) has actively pursued optical efficiency and engineering improvements in this technology in an effort to supply large radiance-conditioned laser diode array sources for its own internal programs. This effort has centered on the development of a modular integrated laser diode packaging technology with the goal of enabling the simple and flexible construction of high average power, high density, two-dimensional arrays with integrated cylindrical microlenses. Within LLNL, the principal applications of microlens-conditioned laser diode arrays are as high intensity pump sources for diode pumped solid state lasers (DPSSLs). A simple end-pumping architecture has been developed and demonstrated that allows the radiation from microlens-conditioned, two-dimensional diode array apertures to be efficiently delivered to the end of rod lasers. To date, pump powers as high as 2.5 kW have been delivered to 3 mm diameter laser rods. Such high power levels are critical for pumping solid state lasers in which the terminal laser level is a Stark level lying in the ground state manifold. Previously, such systems have often required operation of the solid state gain medium at low temperature to freeze out the terminal laser Stark level population. The authors recently developed high intensity pump sources overcome this difficulty by effectively pumping to much higher inversion levels, allowing efficient operation at or near room temperature. Because the end-pumping technology is scalable in absolute power, the number of rare-earth ions and transitions that can be effectively accessed for use in practical DPSSL systems has grown tremendously.

  4. A High Energy 2-microns Laser for Multiple Lidar Applications

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Singh, Upendra N.; Barnes, James C.; Barnes, Norman P.; Petros, Mulugeta

    2000-01-01

    Solid-state 2-microns laser has been receiving considerable interest because of its eye-safe property and efficient diode pump operation, It has potential for multiple lidar applications to detect water vapor. carbon dioxide and winds. In this paper, we describe a 2-microns double pulsed Ho:Tm:YLF laser and end-pumped amplifier system. A comprehensive theoretical model has been developed to aid the design and optimization of the laser performance. In a single Q-switched pulse operation the residual energy stored in the Tm atoms will be wasted. However, in a double pulses operation mode, the residual energy stored in the Tm atoms will repopulate the Ho atoms that were depleted by the extraction of the first Q-switched pulse. Thus. the Tin sensitized Ho:YLF laser provides a unique advantage in applications that require double pulse operation, such as Differential Absorption Lidar (DIAL). A total output energy of 146 mJ per pulse pair under Q-switch operation is achieved with as high as 4.8% optical to optical efficiency. Compared to a single pulse laser, 70% higher laser efficiency is realized. To obtain high energy while maintaining the high beam quality, a master-oscillator-power-amplifier 2-microns system is designed. We developed an end-pumped Ho:Tm:YLF disk amplifier. This amplifier uses two diode arrays as pump source. A non-imaging lens duct is used to couple the radiation from the laser diode arrays to the laser disk. Preliminary result shows that the efficiency of this laser can be as high as 3%, a factor of three increases over side-pump configuration. This high energy, highly efficient and high beam quality laser is a promising candidate for use in an efficient, multiple lidar applications.

  5. Preliminary experience of shared clinical management between Milan and Pointe Noire using the INteractive TeleConsultation Network for Worldwide HealthcAre Services (INCAS): telemedicine between Milan and Africa.

    PubMed

    Malacarne, Mara; Lesma, Alessandro; Madera, Angelo; Malfatti, Eugenio; Castelli, Alberto; Lucini, Daniela; Pizzinelli, Paolo; Pagani, Massimo

    2004-01-01

    This paper describes preliminary experience in shared clinical management of patients located in Pointe Noire, Africa, and a referral center, Sacco University Hospital, located in Milan, Italy. The employed infrastructure INteractive TeleConsultation Network for Worldwide HealthcAre Services (INCAS) jointly developed by CEFRIEL (Center of Excellence For Research, Innovation, Education & Industrial Labs partnership) and ENI (Ente Nazionale Idrocarburi) is based on commercial off-the-shelf technology. This minimizes maintenance problems, while permitting a simple and friendly sharing of data using the telephone and e-mail for store-and-forward applications. The critical aspect of the flow of events comprising the exchange of information is discussed. In 60% of cases, only one telemedicine consultation was required. In the remainder 40%, a number of telemedicine consultations were required for appropriate management of clinical cases. The project demonstrated flexibility as documented by the wide range of pathologies that can be dealt with it. Finally the possibility of using shared clinical management as a learning tool is highlighted by the steep and rising learning curve. We conclude, however, that the patient, although handled in a "virtual" manner, should be viewed as very "real," as some of them elected to close the gap physically between Pointe Noire and Milan, and chose to be treated at the referral site. PMID:15689647

  6. Applications and mechanisms of laser tissue welding in 1995: review

    NASA Astrophysics Data System (ADS)

    Godlewski, Guilhem; Prudhomme, Michel; Tang, Jing

    1996-01-01

    For several years laser tissue welding has appeared as a new alternative technique for tissue repair instead of manual sutures. It has been evaluated in different experimental models including blood vessels, skin, nerve, intestine, bile ducts, vas and fallopian tube. Different types of lasers with different sets of parameters have been used: carbon dioxide laser, Nd:YAG laser, argon and KTP laser and diode laser. Recent trends in tissue fusion promote near infrared lasers at low irradiance with intraoperative enhancement of light absorption by specific chromophores. As far as microvascular reconstruction is concerned, successful clinical applications are currently published. Although the molecular mechanism involved in welding is not completely understood, the tissular fusion is considered as a thermal phenomena. In laser assisted microvascular anastomosis, the best experimental model, the ultrastructural examination of arteries anastomosed with Nd:YAG, argon or diode laser revealed interdigitation of collagen fibers which appeared swollen, with modified striation and organized in irregular network. The mechanism of welding involving the formation of non covalent bands between collagen strands, is generally induced by a temperature of 60 - 63 degrees Celsius well adapted to collagen denaturation.

  7. Application of reactor-pumped lasers to power beaming

    SciTech Connect

    Repetti, T.E.

    1991-10-01

    Power beaming is the concept of centralized power generation and distribution to remote users via energy beams such as microwaves or laser beams. The power beaming community is presently performing technical evaluations of available lasers as part of the design process for developing terrestrial and space-based power beaming systems. This report describes the suitability of employing a nuclear reactor-pumped laser in a power beaming system. Although there are several technical issues to be resolved, the power beaming community currently believes that the AlGaAs solid-state laser is the primary candidate for power beaming because that laser meets the many design criteria for such a system and integrates well with the GaAs photodiode receiver array. After reviewing the history and physics of reactor-pumped lasers, the advantages of these lasers for power beaming are discussed, along with several technical issues which are currently facing reactor-pumped laser research. The overriding conclusion is that reactor-pumped laser technology is not presently developed to the point of being technially or economically competitive with more mature solid-state technologies for application to power beaming. 58 refs.

  8. Application of reactor-pumped lasers to power beaming

    NASA Astrophysics Data System (ADS)

    Repetti, T. E.

    1991-10-01

    Power beaming is the concept of centralized power generation and distribution to remote users via energy beams such as microwaves or laser beams. The power beaming community is presently performing technical evaluations of available lasers as part of the design process for developing terrestrial and space-based power beaming systems. This report describes the suitability of employing a nuclear reactor-pumped laser in a power beaming system. Although there are several technical issues to be resolved, the power beaming community currently believes that the AlGaAs solid-state laser is the primary candidate for power beaming because that laser meets the many design criteria for such a system and integrates well with the GaAs photodiode receiver array. After reviewing the history and physics of reactor-pumped lasers, the advantages of these lasers for power beaming are discussed, along with several technical issues which are currently facing reactor-pumped laser research. The overriding conclusion is that reactor-pumped laser technology is not presently developed to the point of being technically or economically competitive with more mature solid-state technologies for application to power beaming.

  9. Laser production and heating of plasma for MHD application

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1988-01-01

    Experiments have been made on the production and heating of plasmas by the absorption of laser radiation. These experiments were performed to ascertain the feasibility of using laser-produced or laser-heated plasmas as the input for a magnetohydrodynamic (MHD) generator. Such a system would have a broad application as a laser-to-electricity energy converter for space power transmission. Experiments with a 100-J-pulsed CO2 laser were conducted to investigate the breakdown of argon gas by a high-intensity laser beam, the parameters (electron density and temperature) of the plasma produced, and the formation and propagation of laser-supported detonation (LSD) waves. Experiments were also carried out using a 1-J-pulsed CO2 laser to heat the plasma produced in a shock tube. The shock-tube hydrogen plasma reached electron densities of approximately 10 to the 17th/cu cm and electron temperatures of approximately 1 eV. Absorption of the CO2 laser beam by the plasma was measured, and up to approximately 100 percent absorption was observed. Measurements with a small MHD generator showed that the energy extraction efficiency could be very large with values up to 56 percent being measured.

  10. The soundscape quality in some urban parks in Milan, Italy.

    PubMed

    Brambilla, Giovanni; Gallo, Veronica; Zambon, Giovanni

    2013-06-01

    Urban parks play an important role in preserving and promoting the health of citizens who are often exposed to noise pollution and the stress of daily life. The present study describes the main results obtained from a survey performed in five urban parks in Milan. Measurements of the acoustic environment were carried out in 29 sites together with interviews with 231 users on certain aspects of the parks not limited to merely sound. Acoustic data show that the surveyed parks mostly do not comply with the noise limit issued by the Italian legislation on protected areas. The unweighted 1/3-octave spectrum centre of gravity G and LA50 perform satisfactorily in discriminating among the acoustic environments. Such clear distinction was not observed in the subjective ratings on the perceived quality of the soundscape, likely due to the influence by non-acoustic factors that act as mediators in the assessment. This hypothesis is supported by the collected data on the perceived quality of quietness, which was rated worse than that of the soundscape. Comparing acoustic data with ratings, the perceived quality of the total environment was found to be less dependent on LAeq than soundscape and quietness. PMID:23743795

  11. Hepatocellular carcinoma beyond Milan criteria: Management and transplant selection criteria.

    PubMed

    Elshamy, Mohammed; Aucejo, Federico; Menon, K V Narayanan; Eghtesad, Bijan

    2016-07-28

    Liver transplantation (LT) for hepatocellular carcinoma (HCC) has been established as a standard treatment in selected patients for the last two and a half decades. After initially dismal outcomes, the Milan criteria (MC) (single HCC ≤ 5 cm or up to 3 HCCs ≤ 3 cm) have been adopted worldwide to select HCC patients for LT, however cumulative experience has shown that MC can be too strict. This has led to the development of numerous expanded criteria worldwide. Morphometric expansions on MC as well as various criteria which incorporate biomarkers as surrogates of tumor biology have been described. HCC that presents beyond MC initially can be downstaged with locoregional therapy (LRT). Post-LRT monitoring aims to identify candidates with favorable tumor behavior. Similarly, tumor marker levels as response to LRT has been utilized as surrogate of tumor biology. Molecular signatures of HCC have also been correlated to outcomes; these have yet to be incorporated into HCC-LT selection criteria formally. The ongoing discrepancy between organ demand and supply makes patient selection the most challenging element of organ allocation. Further validation of extended HCC-LT criteria models and pre-LT treatment strategies are required. PMID:27478537

  12. Hepatocellular carcinoma beyond Milan criteria: Management and transplant selection criteria

    PubMed Central

    Elshamy, Mohammed; Aucejo, Federico; Menon, K V Narayanan; Eghtesad, Bijan

    2016-01-01

    Liver transplantation (LT) for hepatocellular carcinoma (HCC) has been established as a standard treatment in selected patients for the last two and a half decades. After initially dismal outcomes, the Milan criteria (MC) (single HCC ≤ 5 cm or up to 3 HCCs ≤ 3 cm) have been adopted worldwide to select HCC patients for LT, however cumulative experience has shown that MC can be too strict. This has led to the development of numerous expanded criteria worldwide. Morphometric expansions on MC as well as various criteria which incorporate biomarkers as surrogates of tumor biology have been described. HCC that presents beyond MC initially can be downstaged with locoregional therapy (LRT). Post-LRT monitoring aims to identify candidates with favorable tumor behavior. Similarly, tumor marker levels as response to LRT has been utilized as surrogate of tumor biology. Molecular signatures of HCC have also been correlated to outcomes; these have yet to be incorporated into HCC-LT selection criteria formally. The ongoing discrepancy between organ demand and supply makes patient selection the most challenging element of organ allocation. Further validation of extended HCC-LT criteria models and pre-LT treatment strategies are required. PMID:27478537

  13. The Soundscape Quality in Some Urban Parks in Milan, Italy

    PubMed Central

    Brambilla, Giovanni; Gallo, Veronica; Zambon, Giovanni

    2013-01-01

    Urban parks play an important role in preserving and promoting the health of citizens who are often exposed to noise pollution and the stress of daily life. The present study describes the main results obtained from a survey performed in five urban parks in Milan. Measurements of the acoustic environment were carried out in 29 sites together with interviews with 231 users on certain aspects of the parks not limited to merely sound. Acoustic data show that the surveyed parks mostly do not comply with the noise limit issued by the Italian legislation on protected areas. The unweighted 1/3-octave spectrum centre of gravity G and LA50 perform satisfactorily in discriminating among the acoustic environments. Such clear distinction was not observed in the subjective ratings on the perceived quality of the soundscape, likely due to the influence by non-acoustic factors that act as mediators in the assessment. This hypothesis is supported by the collected data on the perceived quality of quietness, which was rated worse than that of the soundscape. Comparing acoustic data with ratings, the perceived quality of the total environment was found to be less dependent on LAeq than soundscape and quietness. PMID:23743795

  14. The NASA high-power carbon dioxide laser - A versatile tool for laser applications

    NASA Technical Reports Server (NTRS)

    Lancashire, R. B.; Alger, D. L.; Manista, E. J.; Slaby, J. G.; Dunning, J. W.; Stubbs, R. M.

    1977-01-01

    The NASA Lewis Research Center has designed and fabricated a closed-cycle, continuous wave (CW), carbon dioxide (CO2) high-power laser to support research for the identification and evaluation of possible high-power laser applications. The device is designed to generate up to 70 kW of laser power in annular-shape beams from 1 to 9 cm in diameter. Electric discharge, either self-sustained or electron-beam-sustained, is used for excitation. This laser facility can be used in two ways. First, it provides a versatile tool on which research can be performed to advance the state-of-the-art technology of high-power CO2 lasers in such areas as electric excitation, laser chemistry, and quality of output beams, all of which are important whether the laser application is government or industry oriented. Second, the facility provides a well-defined, continuous wave beam for various application experiments, such as propulsion, power conversion, and materials processing.

  15. The development of novel Ytterbium fiber lasers and their applications

    NASA Astrophysics Data System (ADS)

    Nie, Bai

    The aim of my Ph.D. research is to push the fundamental limits holding back the development of novel Yb fiber lasers with high pulse energy and short pulse duration. The purpose of developing these lasers is to use them for important applications such as multiphoton microscopy and laser-induced breakdown spectroscopy. My first project was to develop a short-pulse high-energy ultrafast fiber laser for multiphoton microscopy. To achieve high multiphoton efficiency and depth resolved tissue imaging, ultrashort pulse duration and high pulse energy are required. In order to achieve this, an all-normal dispersion cavity design was adopted. Output performances of the built lasers were investigated by varying several cavity parameters, such as pump laser power, fiber length and intra-cavity spectral filter bandwidth. It was found that the length of the fiber preceding the gain fiber is critical to the laser performance. Generally, the shorter the fiber is, the broader the output spectrum is. The more interesting parameter is the intra-cavity spectral filter bandwidth. Counter intuitively, laser cavities using narrower bandwidth spectral filters generated much broader spectra. It was also found that fiber lasers with very narrow spectral filters produced laser pulses with parabolic profile, which are referred to as self-similar pulses or similaritons. This type of pulse can avoid wave-breaking and is an optimal approach to generate pulses with high pulse energy and ultrashort pulse duration. With a 3nm intra-cavity spectral filter, output pulses with about 20 nJ pulse energy were produced and compressed to about 41 fs full-width-at-half-maximum (FWHM) pulse duration. Due to the loss in the compression device, the peak power of the compressed pulses is about 250 kW. It was the highest peak power generated from a fiber oscillator when this work was published. This laser was used for multiphoton microscopy on living tissues like Drosophila larva and fruit fly wings. Several

  16. Near-infrared laser diodes in monitoring applications

    NASA Astrophysics Data System (ADS)

    Patonay, Gabor; Zen, Jyh-Myng; Czuppon, Tibor

    1992-05-01

    Absorption and fluorescence spectroscopy has proven to be a valuable analytical tool for environmental and process monitoring. Several publications have addressed different spectroscopic applications related to process monitoring. Since most chemicals absorb in the UVIVis part of the spectrum, the majority of laser applications utilize this shorter wavelength region. Nevertheless, the utilization of the longer wavelength part of the electromagnetic spectrum may be advantageous due to its relatively low interference. The environmental and process monitoring applications of this spectral region may be especially advantageous if semiconductor lasers are utilized as light sources. Laser diodes have all the properties of other types of lasers with the added benefits of compactness, low power consumption, low cost and long lifetime. However, to utilize this spectral region for environmental or process monitoring applications, appropriate near-infrared (NIR) absorbing probe molecules need to be employed. These probes may be used to determine analytical properties important for environmental or process monitoring applications, e.g., pH, oxygen concentration, metal ion determinations, solvent hydrophobicity, just to mention a few. These NIR probes may be incorporated into polymers to form a stable probe arrangement for convenient monitoring using semiconductor lasers. The utility can be further enhanced using fiber optics. In this paper the use of MR absorption and fluorescence spectroscopy for monitoring applications will be demonstrated.

  17. Applications of absorption spectroscopy using quantum cascade lasers.

    PubMed

    Zhang, Lizhu; Tian, Guang; Li, Jingsong; Yu, Benli

    2014-01-01

    Infrared laser absorption spectroscopy (LAS) is a promising modern technique for sensing trace gases with high sensitivity, selectivity, and high time resolution. Mid-infrared quantum cascade lasers, operating in a pulsed or continuous wave mode, have potential as spectroscopic sources because of their narrow linewidths, single mode operation, tunability, high output power, reliability, low power consumption, and compactness. This paper reviews some important developments in modern laser absorption spectroscopy based on the use of quantum cascade laser (QCL) sources. Among the various laser spectroscopic methods, this review is focused on selected absorption spectroscopy applications of QCLs, with particular emphasis on molecular spectroscopy, industrial process control, combustion diagnostics, and medical breath analysis. PMID:25239063

  18. Pulsed mononode dye laser developed for a geophysical application

    NASA Technical Reports Server (NTRS)

    Jegou, J. P.; Pain, T.; Megie, G.

    1986-01-01

    Following the extension of the lidar technique in the study of the atmosphere, the necessity of having a high power pulsed laser beam with a narrowed bandwidth and the possibility of selecting a particular wavelength within a certain spectral region arises. With the collaboration of others, a laser cavity using the multiwave Fizeau wedge (MWFW) was developed. Using the classical method of beam amplification with the aid of different stages, a new pulsed dye laser device was designed. The originality resides in the use of reflecting properties of the MFWF. Locally a plan wave coming with a particular angular incidence is reflected with a greater than unity coefficient; this is the consequence of the wedge angle which doubles the participation of every ray in the interferometric process. This dye laser operation and advantages are discussed. The feasibility of different geophysical applications envisageable with this laser is discussed.

  19. Medical Applications Of CO2 Laser Fiber Optics

    NASA Astrophysics Data System (ADS)

    McCord, R. C.

    1981-07-01

    In 1978, Hughes Laboratories reported development of fiber optics that were capable of transmitting CO2 laser energy. These fibers are now being tested for medical applications. Wide ranging medical investigation with CO2 lasers has occurred during the twelve years since the first observations of laser hemostasis. Specialists in ophthalmology, neurosurgery, urology, gynecology, otolaryngology, maxillo-facial/plastic surgery, dermatology, and oncology among others, have explored its use. In principle, all these specialists use CO2 laser radiation at 10.6 microns to thermally destroy diseased tissues. As such, CO2 lasers compare and compete with electrosurgical devices. The fundamental difference between these modalities lies in how they generate heat in treated tissue.

  20. Optimized laser application in dermatology using infrared thermography

    NASA Astrophysics Data System (ADS)

    Thomas, Roderick A.; Donne, Kelvin E.; Clement, Marc; Kiernan, Michael N.

    2002-03-01

    Infrared thermography can be used to optimize the application of lasers in dermatology with particular reference to the treatment of certain skin disorders such as vascular lesions and depilation. The efficacy of treatment is dependent upon a number of factors including: Optimization and correct selection of laser parameters such as wavelength and spot size. Human factors, such as laser operator skill, patient's skin type and anatomical location. By observing the thermal effects of laser irradiation on the skins surface during treatment results in improved efficacy and minimizes the possible threshold to skin damage, reducing the possibility of burning and scarring. This is of particular significance for example, in the control of purpura for the treatment of vascular lesions. The optimization is validated with reference to a computer model that predicts various skin temperatures based on two different laser spot sizes.

  1. Laser-Induced Breakdown Spectroscopy (LIBS): specific applications

    NASA Astrophysics Data System (ADS)

    Trtica, M. S.; Savovic, J.; Stoiljkovic, M.; Kuzmanovic, M.; Momcilovic, M.; Ciganovic, J.; Zivkovic, S.

    2015-12-01

    A short overview of Laser Induced Breakdown Spectroscopy (LIBS) with emphasis on the new trends is presented. Nowadays, due to unique features of this technique, LIBS has found applications in a great variety of fields. Achievements in the application of LIBS in nuclear area, for hazardous materials detection and in geology were considered. Also, some results recently obtained at VINCA Institute, with LIBS system based on transversely excited atmospheric (TEA) CO2 laser, are presented. Future investigations of LIBS will be oriented toward further improvement of the analytical performance of this technique, as well as on finding new application fields.

  2. Optofluidic Bio-Lasers: Concept and Applications

    PubMed Central

    Fan, Xudong; Yun, Seok-Hyun

    2014-01-01

    An optofluidic bio-laser integrates biological materials into the gain medium while forming an optical cavity in the fluidic environment, either on a microfluidic chip or within a biological system. The laser emission has characteristics fundamentally different from conventional fluorescence emission. It can be highly sensitive to a specific molecular change in the gain medium as the light-matter interaction is amplified by the resonance in the cavity. The enhanced sensitivity can be used to probe and quantify the underlying biochemical and biological processes in vitro in a microfluidic device, in situ in a cell (cytosol), or in vivo in a live organism. Here we describe the principle of the optofluidic bio-laser, review its recent progress and provide an outlook of this emerging technology. PMID:24481219

  3. Adaptive Tunable Laser Spectrometer for Space Applications

    NASA Technical Reports Server (NTRS)

    Flesch, Gregory; Keymeulen, Didier

    2010-01-01

    An architecture and process for the rapid prototyping and subsequent development of an adaptive tunable laser absorption spectrometer (TLS) are described. Our digital hardware/firmware/software platform is both reconfigurable at design time as well as autonomously adaptive in real-time for both post-integration and post-launch situations. The design expands the range of viable target environments and enhances tunable laser spectrometer performance in extreme and even unpredictable environments. Through rapid prototyping with a commercial RTOS/FPGA platform, we have implemented a fully operational tunable laser spectrometer (using a highly sensitive second harmonic technique). With this prototype, we have demonstrated autonomous real-time adaptivity in the lab with simulated extreme environments.

  4. Application of Laser-Induced Bone Therapy by Carbon Dioxide Laser Irradiation in Implant Therapy

    PubMed Central

    Naka, Takahiro; Yokose, Satoshi

    2012-01-01

    This study evaluated the application of laser-induced bone therapy (LIBT) to reduce implant healing time in rat tibia. Twenty 10-week-old female Sprague-Dawlay rats were used. The rats received laser irradiation (laser group) or sham operation (control group) on either side of the tibia. Five days after invasion, titanium implants were inserted in proximal tibia. Five, 10, and 20 days after implant placement, tibiae were collected. After taking micro-CT and performing a torque test, the tibiae were decalcified and 8-μm-thick sections were prepared. Specimens were stained with hematoxylin and eosin. Results. Micro-CT images, removal torque values, and histomorphometric analysis data demonstrated a significantly accelerated bone formation in the laser group earlier in the healing process. Conclusion. The use of laser irradiation was effective in promoting bone formation and acquiring osseointegration of titanium implants inserted in rat tibia. LIBT may be suitable for use in implant therapy. PMID:22505900

  5. Applications of the 308-nm excimer laser in dermatology

    NASA Astrophysics Data System (ADS)

    Farkas, A.; Kemeny, L.

    2006-05-01

    Excimer lasers contain a mixture of a noble inert gas and a halogen, which form excited dimers only in the activated state. High-energy current is used to produce these dimers, which have a very short lifetime, and after their fast dissociation they release the excitation energy through ultraviolet photons. The application of these lasers proved to be successful in medicine, including the field of ophthalmology, cardiology, angiology, dentistry, orthopaedics, and, in recent years, dermatology. For medical purposes, the 193-nm argon fluoride, the 248-nm krypton fluoride, the 351-nm xenon fluoride, and the 308-nm xenon chloride lasers are used. Recently, the 308-nm xenon chloride laser has gained much attention as a very effective treatment modality in dermatological disorders. It was successfully utilized in psoriasis; later, it proved to be useful in handling other lightsensitive skin disorders and even in the treatment of allergic rhinitis. This review summarizes the possible applications of this promising tool in dermatology.

  6. Catadioptric optics for laser Doppler velocimeter applications

    NASA Technical Reports Server (NTRS)

    Dunagan, Stephen E.

    1989-01-01

    This paper examines the adaptation of low-cost Schmidt-Cassegrain astronomical telescopes to perform the laser-beam-focusing and scattered-light collection tasks associated with dual-beam laser Doppler velocimetry. A generic telescope design is analyzed using ray-tracing methods and Gaussian beam-propagation theory. A straightforward modification procedure to convert from infinite to near unity conjugate-ratio operation with very low residual aberration is identified and tested with a 200-mm-aperture telescope modified for f/10 operation. Performance data for this modified telescope configuration are near the diffraction limit and agree well with predictions.

  7. Advances in 193 nm excimer lasers for mass spectrometry applications

    NASA Astrophysics Data System (ADS)

    Delmdahl, Ralph; Esser, Hans-Gerd; Bonati, Guido

    2016-03-01

    Ongoing progress in mass analysis applications such as laser ablation inductively coupled mass spectrometry of solid samples and ultraviolet photoionization mediated sequencing of peptides and proteins is to a large extent driven by ultrashort wavelength excimer lasers at 193 nm. This paper will introduce the latest improvements achieved in the development of compact high repetition rate excimer lasers and elaborate on the impact on mass spectrometry instrumentation. Various performance and lifetime measurements obtained in a long-term endurance test over the course of 18 months will be shown and discussed in view of the laser source requirements of different mass spectrometry tasks. These sampling type applications are served by excimer lasers delivering pulsed 193 nm output of several mJ as well as fast repetition rates which are already approaching one Kilohertz. In order to open up the pathway from the laboratory to broader market industrial use, sufficient component lifetimes and long-term stable performance behavior have to be ensured. The obtained long-term results which will be presented are based on diverse 193 nm excimer laser tube improvements aiming at e.g. optimizing the gas flow dynamics and have extended the operational life the laser tube for the first time over several billion pulses even under high duty-cycle conditions.

  8. Near and medium infrared optical fiber lasers and emerging applications

    NASA Astrophysics Data System (ADS)

    Prudenzano, F.; Mescia, L.; Allegretti, L.; De Sario, M.; D'Orazio, A.; Di Tommaso, A.; Palmisano, T.; Petruzzelli, V.

    2010-02-01

    Laser cavities emitting in the near and medium infrared wavelength range, made of rare earth doped optical fibers and suitable pairs of integrated mirrors, are used in a large number of applications. Nowadays, the efficient employment of near and medium infrared laser beams is largely widespread in the field of m*aterial processing, surgery, directed energy, remote sensing, spectroscopy, imaging, and so on. In a lot of cases, the high conversion efficiency, the excellent beam quality, the compactness and, the good heat dissipation capability make fiber lasers competitive and attractive with respect to other light sources, such as ion-doped crystal and bulk glass lasers, optical parametric oscillators, semiconductor and gas lasers. The paper aims to recall and/or briefly illustrate a few among the numerous strategies recently followed by research laboratories and industries to obtain laser sources based on rare earth doped optical fibres. A recall on the host materials and the dopants employed for their construction, and the corresponding applications is given, too. Moreover, an example of near infrared (NIR) fiber optic laser development, by employing available on market components is illustrated by underlining the possibility to easily obtain high beam quality.

  9. Coherent Doppler Laser Radar: Technology Development and Applications

    NASA Technical Reports Server (NTRS)

    Kavaya, Michael J.; Arnold, James E. (Technical Monitor)

    2000-01-01

    NASA's Marshall Space Flight Center has been investigating, developing, and applying coherent Doppler laser radar technology for over 30 years. These efforts have included the first wind measurement in 1967, the first airborne flights in 1972, the first airborne wind field mapping in 1981, and the first measurement of hurricane eyewall winds in 1998. A parallel effort at MSFC since 1982 has been the study, modeling and technology development for a space-based global wind measurement system. These endeavors to date have resulted in compact, robust, eyesafe lidars at 2 micron wavelength based on solid-state laser technology; in a factor of 6 volume reduction in near diffraction limited, space-qualifiable telescopes; in sophisticated airborne scanners with full platform motion subtraction; in local oscillator lasers capable of rapid tuning of 25 GHz for removal of relative laser radar to target velocities over a 25 km/s range; in performance prediction theory and simulations that have been validated experimentally; and in extensive field campaign experience. We have also begun efforts to dramatically improve the fundamental photon efficiency of the laser radar, to demonstrate advanced lower mass laser radar telescopes and scanners; to develop laser and laser radar system alignment maintenance technologies; and to greatly improve the electrical efficiency, cooling technique, and robustness of the pulsed laser. This coherent Doppler laser radar technology is suitable for high resolution, high accuracy wind mapping; for aerosol and cloud measurement; for Differential Absorption Lidar (DIAL) measurements of atmospheric and trace gases; for hard target range and velocity measurement; and for hard target vibration spectra measurement. It is also suitable for a number of aircraft operations applications such as clear air turbulence (CAT) detection; dangerous wind shear (microburst) detection; airspeed, angle of attack, and sideslip measurement; and fuel savings through

  10. Shaping laser accelerated ions for future applications - The LIGHT collaboration

    NASA Astrophysics Data System (ADS)

    Busold, S.; Almomani, A.; Bagnoud, V.; Barth, W.; Bedacht, S.; Blažević, A.; Boine-Frankenheim, O.; Brabetz, C.; Burris-Mog, T.; Cowan, T. E.; Deppert, O.; Droba, M.; Eickhoff, H.; Eisenbarth, U.; Harres, K.; Hoffmeister, G.; Hofmann, I.; Jaeckel, O.; Jaeger, R.; Joost, M.; Kraft, S.; Kroll, F.; Kaluza, M.; Kester, O.; Lecz, Z.; Merz, T.; Nürnberg, F.; Al-Omari, H.; Orzhekhovskaya, A.; Paulus, G.; Polz, J.; Ratzinger, U.; Roth, M.; Schaumann, G.; Schmidt, P.; Schramm, U.; Schreiber, G.; Schumacher, D.; Stoehlker, T.; Tauschwitz, A.; Vinzenz, W.; Wagner, F.; Yaramyshev, S.; Zielbauer, B.

    2014-03-01

    The generation of intense ion beams from high-intensity laser-generated plasmas has been the focus of research for the last decade. In the LIGHT collaboration the expertise of heavy ion accelerator scientists and laser and plasma physicists has been combined to investigate the prospect of merging these ion beams with conventional accelerator technology and exploring the possibilities of future applications. We report about the goals and first results of the LIGHT collaboration to generate, handle and transport laser driven ion beams. This effort constitutes an important step in research for next generation accelerator technologies.

  11. Biological applications of ultraviolet free-electron lasers

    SciTech Connect

    Sutherland, J.C.

    1997-10-01

    This review examines the possibilities for biological research using the three ultraviolet free-electron lasers that are nearing operational status in the US. The projected operating characteristics of major interest in biological research of the free-electron lasers at Brookhaven National Laboratory, the Thomas Jefferson National Accelerator Facility, and Duke University are presented. Experimental applications in the areas of far- and vacuum ultraviolet photophysics and photochemistry, structural biology, environmental photobiology, and medical research are discussed and the prospects for advances in these areas, based upon the characteristics of the new ultraviolet free-electron lasers, are evaluated.

  12. Novel diode laser-based sensors for gas sensing applications

    NASA Technical Reports Server (NTRS)

    Tittel, F. K.; Lancaster, D. G.; Richter, D.

    2000-01-01

    The development of compact spectroscopic gas sensors and their applications to environmental sensing will be described. These sensors employ mid-infrared difference-frequency generation (DFG) in periodically poled lithium niobate (PPLN) crystals pumped by two single-frequency solid state lasers such as diode lasers, diode-pumped solid state, and fiber lasers. Ultrasensitive, highly selective, and real-time measurements of several important atmospheric trace gases, including carbon monoxide, nitrous oxide, carbon dioxide, formaldehyde [correction of formaldehye], and methane, have been demonstrated.

  13. Application of G criterion in metal vapor ion laser

    NASA Astrophysics Data System (ADS)

    Gang, Chen; Bailiang, Pan; Yi, Jin; Kun, Chen; Zhixin, Yao

    2003-09-01

    Application of G criterion to efficient operation of pulsed discharge-excited R-M transition metal vapor laser was successfully extended to univalent ionic lasing medium from neutral atomic lasing medium on the basis of analyzing the simulation results of 1.09 μm Sr + lasing process. All of the known 17 R-M transition laser lines of univalent ions follow the G criterion except one, to which an interpretation is given. Furthermore, we suggest that only 69 lines among 212 possible R-M transition laser lines predicted by S.V. Markova, which satisfy the G criterion, should be explored first.

  14. Laser-based Measurement Systems for Space Applications

    NASA Astrophysics Data System (ADS)

    Plattner, Markus

    2012-03-01

    Measurement systems based on laser technology are widely used in laboratories, metrology institutes and industry. Measurement applications like optical sensing and optical spectroscopy are state of the art. For space applications, however, laser systems are rarely used due to the sensitivity of optical components to the harsh environmental conditions. The focus of this work lies on further development of laser technologies for the applications optical frequency comb generation and fiber-optic sensing. In order to identify suitable laser technologies, the conditions for systems that shall be operated in space are analyzed thoroughly. The influences due to the space environment are considered and the radiation and temperature effects on laser optics are determined. Commercially available femtosecond fiber lasers based on mode-locking technologies non-linear polarization rotation and quasi-soliton generation are functionally tested in order to verify the theoretical analysis. Thermal-vacuum and Gamma radiation test series are carried out and the performance of the lasers is measured online. Evaluation of measurement data, assessment of laser setups in terms of robustness and their behaviors during tests allow concluding an optimized femtosecond laser design. This design serves as baseline for further development and will yield a system that can cope with the requirements for an application in space. In order to demonstrate the functionality of fiber-optic sensing based on a tunable laser diode, an interrogator system is built and tested in the frame of this work. This technology, based on a monolithic laser, enables an all-in-fiber setup without any free-space optics. The laser wavelength is tuned by feeding in three control currents. Thereby, the connected fiber Bragg grating temperature sensors are sampled spectrally. Newly developed algorithms enhance the measurement performance, evaluate the back reflected sensor responses and determine the measurement value. This

  15. Indium phosphide solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, Geoffrey A.

    1992-01-01

    Lasers can be used to transmit power to photovoltaic cells. Solar cell efficiencies are enhanced significantly under monochromatic light, and therefore a laser beam of proper wavelength could be a very effective source of illumination for a solar array operating at very high efficiencies. This work reviews the modeling studies made on indium phosphide solar cells for such an application. These cells are known to be very radiation resistant and have a potential for high efficiency. Effects of cell series resistance, laser intensity, and temperature on cell performance have been discussed.

  16. Laser Induced Breakdown Spectroscopy:. AN Application on Multilayered Archeological Ceramics

    NASA Astrophysics Data System (ADS)

    Ponterio, R.; Trusso, S.; Vasi, C.; Aragona, S.; Mavilia, L.

    2004-10-01

    In this work we show an example of application of Laser Induced Breakdown Spectroscopy (LIBS) in combination with another laser-based technique: Raman micro-spectroscopy for the identification of pigments and glaze on pottery found archaeological excavations in Amendolea castle site (south of Italy in Calabrian peninsula); the objects belong to medieval period. The spectral data indicates the qualitative elemental composition of the examined materials and, in addition, give us useful information on the stratigraphy of the paint layers.

  17. Diffraction Gratings for High-Intensity Laser Applications

    SciTech Connect

    Britten, J

    2008-01-23

    The scattering of light into wavelength-dependent discrete directions (orders) by a device exhibiting a periodic modulation of a physical attribute on a spatial scale similar to the wavelength of light has been the subject of study for over 200 years. Such a device is called a diffraction grating. Practical applications of diffraction gratings, mainly for spectroscopy, have been around for over 100 years. The importance of diffraction gratings in spectroscopy for the measurement of myriad properties of matter can hardly be overestimated. Since the advent of coherent light sources (lasers) in the 1960's, applications of diffraction gratings in spectroscopy have further exploded. Lasers have opened a vast application space for gratings, and apace, gratings have enabled entirely new classes of laser systems. Excellent reviews of the history, fundamental properties, applications and manufacturing techniques of diffraction gratings up to the time of their publication can be found in the books by Hutley (1) and more recently Loewen and Popov (2). The limited scope of this chapter can hardly do justice to such a comprehensive subject, so the focus here will be narrowly limited to characteristics required for gratings suitable for high-power laser applications, and methods to fabricate them. A particular area of emphasis will be on maximally-efficient large-aperture gratings for short-pulse laser generation.

  18. Laser dentistry: A new application of excimer laser in root canal therapy

    SciTech Connect

    Pini, R.; Salimbeni, R.; Vannini, M.; Barone, R.; Clauser, C.

    1989-01-01

    We report the first study of the application of excimer lasers in dentistry for the treatment of dental root canals. High-energy ultraviolet (UV) radiation emitted by an XeCl excimer laser (308 nm) and delivered through suitable optical fibers can be used to remove residual organic tissue from the canals. To this aim, UV ablation thresholds of dental tissues have been measured, showing a preferential etching of infiltrated dentin in respect to healthy dentin, at laser fluences of 0.5-1.5 J/cm{sup 2}. This technique has been tested on extracted tooth samples, simulating a clinical procedure. Fibers of decreasing core diameters have been used to treat different sections of the root canal down to its apical portion, resulting in an effective, easy, and fast cleaning action. Possible advantages of excimer laser clinical applications in respect to usual procedures are also discussed.

  19. Tailoring Laser Propulsion for Future Applications in Space

    SciTech Connect

    Eckel, Hans-Albert; Scharring, Stefan

    2010-10-08

    Pulsed laser propulsion may turn out as a low cost alternative for the transportation of small payloads in future. In recent years DLR investigated this technology with the goal of cheaply launching small satellites into low earth orbit (LEO) with payload masses on the order of 5 to 10 kg. Since the required high power pulsed laser sources are yet not at the horizon, DLR focused on new applications based on available laser technology. Space-borne, i.e. in weightlessness, there exist a wide range of missions requiring small thrusters that can be propelled by laser power. This covers space logistic and sample return missions as well as position keeping and attitude control of satellites.First, a report on the proof of concept of a remote controlled laser rocket with a thrust vector steering device integrated in a parabolic nozzle will be given. Second, the road from the previous ground-based flight experiments in earth's gravity using a 100-J class laser to flight experiments with a parabolic thruster in an artificial 2D-zero gravity on an air cushion table employing a 1-J class laser and, with even less energy, new investigations in the field of laser micro propulsion will be reviewed.

  20. Tailoring Laser Propulsion for Future Applications in Space

    NASA Astrophysics Data System (ADS)

    Eckel, Hans-Albert; Scharring, Stefan

    2010-10-01

    Pulsed laser propulsion may turn out as a low cost alternative for the transportation of small payloads in future. In recent years DLR investigated this technology with the goal of cheaply launching small satellites into low earth orbit (LEO) with payload masses on the order of 5 to 10 kg. Since the required high power pulsed laser sources are yet not at the horizon, DLR focused on new applications based on available laser technology. Space-borne, i.e. in weightlessness, there exist a wide range of missions requiring small thrusters that can be propelled by laser power. This covers space logistic and sample return missions as well as position keeping and attitude control of satellites. First, a report on the proof of concept of a remote controlled laser rocket with a thrust vector steering device integrated in a parabolic nozzle will be given. Second, the road from the previous ground-based flight experiments in earth's gravity using a 100-J class laser to flight experiments with a parabolic thruster in an artificial 2D-zero gravity on an air cushion table employing a 1-J class laser and, with even less energy, new investigations in the field of laser micro propulsion will be reviewed.

  1. Space Applications of Industrial Laser Systems (SAILS)

    NASA Technical Reports Server (NTRS)

    Mueller, Robert E.; McCay, T. Dwayne; McCay, Mary Helen; Bible, Brice

    1992-01-01

    A program is under way to develop a YAG laser based materials processing workstation to fly in the cargo bay of the Space Shuttle. The system will be capable of cutting and welding steel, aluminum and Inconel alloys of the type planned for use on the Space Station Freedom. As well as demonstrating the ability of a YAG laser to perform remote (fiber-optic delivered) repair and fabrication operations in space, fundamental data will be collected on these interactions for comparison with terrestrial data and models. The flight system, scheduled to fly in 1995, will be constructed as two modules to fit into standard Get Away Special (GAS) canisters. The first can holds the laser and its power supply, to be constructed by our industrial partner, Lumonics Industrial Processing Division. The second canister has the materials processing workstation and the command and data acquisition subsystems. These components will be provided by groups at UTSI and the University of Waterloo. The cans are linked by a fiber-optic cable which transmits the beam from the laser head to the workstation.

  2. Space Applications of Industrial Laser Systems (SAILS)

    NASA Technical Reports Server (NTRS)

    Mueller, Robert E.; McCay, T. Dwayne; McCay, Mary Helen; Bible, Brice

    1995-01-01

    A program is under way to develop a YAG laser based materials processing workstation to fly in the cargo bay of the Space Shuttle. The system will be capable of cutting and welding steel, aluminum, and Inconel alloys of the type planned for use on Space Station Freedom. As well as demonstrating the ability of a YAG laser to perform remote (fiber-optic delivered) repair and fabrication operations in space, fundamental data will be collected on these interactions for comparison with terrestrial data and models. The flight system, scheduled to fly in 1995, will be constructed as two modules to fit into the standard Get Away Special (GAS) canisters. The first can holds the laser and its power supply, to be constructed by our industrial partner, Lumonics Industrial Processing Division. The second canister has the materials processing workstation and the command and data acquisition subsystems. These components will be provided by groups at the University of Tennessee Space Institute (UTSI) and the University of Waterloo. The cans are linked by a fiber-optic cable which transmits the beam from the laser head to the workstation.

  3. Dye system for dye laser applications

    DOEpatents

    Hammond, Peter R.

    1991-01-01

    A dye of the DCM family, [2-methyl-6-[2-(1,2,3,4-tetrahydro-1-methyl-6-quinolinyl)ethenyl]-4H-pyran -4-ylidene]-propanedinitrile, dissolved in 2-phenoxyethanol, is non-mutagenic, stable and efficient, particularly in a pumped continuous wave laser system.

  4. Facet joint laser radiation: tissue effects of a new clinical laser application

    NASA Astrophysics Data System (ADS)

    Werkmann, Klaus; Thal, Dietmar R.

    1996-01-01

    Chronic unilateral and bilateral back pain with pseudoradicular symptoms, is a common clinical syndrome, which in many cases can be related to the facet joint syndrome. The pain is caused by mechanical affection of synovial and capsular nerve terminals. Therefore, current therapeutical attempts including physical therapy, intra-articular injection of local anesthetics and steroids and thermocoagulation of the facet joint with a thermocoagulator, are performed. We confirmed laser coagulation of the facet joint. Porcine cadaveric spines were treated immediately after death by intra-articular facet joint laser radiation. With the pulsed Nd:YAG laser (1064 nm) altogether 600 J were applied in three different places 4 mm apart at the top of the facet joint. The results showed that facet joint laser radiation leads to a small (about 1 - 2 mm diameter) lesion restricted to the facet joint cavity and its synovia. Histologically, we found a central carbonization zone and necrosis, including almost the whole cartilage and approximately 0.2 mm of the adjacent bone. These changes are similar to Nd:Yag-laser applications in other skeletal regions. It is suggested that these changes may lead to facet joint denervation by coagulation of the synovial nerve terminals. Cicatration of the laser lesion might cause ankylosis of this joint. In sum, facet joint laser radiation could be an alternative therapeutical tool for lower back pain of the facet joint syndrome type. Therefore, future clinical application of this technique seems to be very promising.

  5. Frequency stabilized lasers for space applications

    NASA Astrophysics Data System (ADS)

    Lieber, Mike; Adkins, Mike; Pierce, Robert; Warden, Robert; Wallace, Cynthia; Weimer, Carl

    2014-09-01

    metrology, spectroscopy, atomic clocks and geodesy. This technology will be a key enabler to several proposed NASA science missions. Although lasers such as Q-switched Nd-YAG are now commonly used in space, other types of lasers - especially those with narrow linewidth - are still few in number and more development is required to advance their technology readiness. In this paper we discuss a reconfigurable laser frequency stabilization testbed, and end-to-end modeling to support system development. Two important features enabling testbed flexibility are that the controller, signal processing and interfaces are hosted on a field programmable gate array (FPGA) which has spacequalified equivalent parts, and secondly, fiber optic relay of the beam paths. Given the nonlinear behavior of lasers, FPGA implementation is a key system reliability aspect allowing on-orbit retuning of the control system and initial frequency acquisition. The testbed features a dual sensor system, one based upon a high finesse resonator cavity which provides relative stability through Pound-Drever-Hall (PDH) modulation and secondly an absolute frequency reference by dither locking to an acetylene gas cell (GC). To provide for differences between ground and space implementation, we have developed an end-to-end Simulink/ Matlab®-based control system model of the testbed components including the important noise sources. This model is in the process of being correlated to the testbed data which then can be used for trade studies, and estimation of space-based performance and sensitivities. A 1530 nm wavelength semiconductor laser is used for this initial work.

  6. Atmospheric Propagation of High Energy Lasers and Applications

    NASA Astrophysics Data System (ADS)

    Cook, Joung R.

    2005-04-01

    It has been over forty years since the invention of the laser, which has inspired the imagination of scientists and science fiction writers alike. Many ideas have been realized, still many remain as dreams, and new ones are still being conceived. The High Energy Laser (HEL) has been associated with weapon applications during the past three decades. Much of the same technology can be directly applied to power beaming, laser propulsion, and other potential remote energy and power transfer applications. Economically, these application areas are becoming increasingly more viable. This paper reviews the evolutionary history of the HEL device technologies. It points out the basic system components and layouts with associated key technologies that drive the effectiveness and efficiency of the system level performance. It describes the fundamental properties and wavelength dependencies of atmospheric propagation that in turn have become the prescription for wavelength properties that are desired from the device.

  7. A laser application to nuclear astrophysics

    SciTech Connect

    Barbui, M.; Hagel, K.; Schmidt, K.; Zheng, H.; Burch, R.; Barbarino, M.; Natowitz, J. B.; Bang, W.; Dyer, G.; Quevedo, H. J.; Gaul, E.; Bernstein, A. C.; Donovan, M.; Bonasera, A.; Kimura, S.; Mazzocco, M.; Consoli, F.; De Angelis, R.; Andreoli, P.; Ditmire, T.

    2014-05-09

    In the last decade, the availability in high-intensity laser beams capable of producing plasmas with ion energies large enough to induce nuclear reactions has opened new research paths in nuclear physics. We studied the reactions {sup 3}He(d,p){sup 4}He and d(d,n){sup 3}He at temperatures of few keV in a plasma, generated by the interaction of intense ultrafast laser pulses with molecular deuterium or deuterated-methane clusters mixed with {sup 3}He atoms. The yield of 14.7 MeV protons from the {sup 3}He(d,p){sup 4}He reaction was used to extract the astrophysical S factor. Results of the experiment performed at the Center for High Energy Density Science at The University of Texas at Austin will be presented.

  8. Solid state laser systems for space application

    NASA Technical Reports Server (NTRS)

    Kay, Richard B.

    1993-01-01

    Work on the development of an interferometric system for the purpose of absolute length determination commenced in January of this year. Our goal is to develop a system capable of measurements on the order of one meter with an accuracy of 1 part in 10 or greater. A modified Michelson bread board with stabilized laser diode source was assembled. Some preliminary measurements began using the tunable Santek laser in an FM modulation scheme. During this same period a literature search yielded a paper by Suematsu and Takeda which discusses a promising fourier transform technique for real time data analysis. We are in the process of evaluating this technique while we continue to change and upgrade the system configuration.

  9. Quality evaluation of laser medical applications

    NASA Astrophysics Data System (ADS)

    Dal Maso, Maurizio

    2003-12-01

    Laser surgery is a standard operating procedure for many specialists. These innovative technologies have dramatically reduced the risk/benefit ratios of health care. These reductions have led to marked growths in health care utilization resulting in the spiraling increases in health care costs. With innovative technologies, the question regarding health care delivery has changed from "can it be done?" to "should it be done?" Physicians do not currently have enough the information necessary to answer this question.

  10. Laser micromachining of semiconductors for photonics applications

    NASA Astrophysics Data System (ADS)

    Nantel, Marc; Yashkir, Yuri; Lee, Seong K.; Mugford, Chas; Hockley, Bernard S.

    2001-10-01

    For decades, precisely machining silicon has been critical for the success of the semiconductor industry. This has traditionally been done through wet chemical etching, but in the pursuit of integrating photonics devices on a single chip, other techniques are worth exploring. This quest opens up interest in finding a non-wet, non-contact, arbitrary-shape milling technique for silicon. In this paper, we present our latest work in the laser micromachining of silicon. A kilohertz-repetition-rate diode-pumped Nd:YLF laser (in infrared, green or ultraviolet modes) is focused on the surface of silicon wafers in a chlorine atmosphere for an enhanced magnitude and control of the etching rate. In the chlorine atmosphere, much less debris is deposited on the surface around the cut, sub-damage threshold machining is achieved for a better control of the etching depth, and etching rates ranging from 20-300,000 micron-cube/s have been measured. In particular, the use of an infrared laser beam is singled out, along with the advantages that it holds. Results of simulations highlight the particular characteristics of the various wavelength chosen for the machining.

  11. Applications of laser annealing and laser-induced diffusion to photovoltaic conversion

    SciTech Connect

    Lowndes, D.H.; Young, R.T.; Wood, R.F.

    1981-01-01

    Over the past several years it has been demonstrated that a variety of techniques involving pulsed laser irradiation of both single crystal and polycrystalline silicon by pulsed lasers can result in the reproducible achievement of high efficiency silicon solar cells. Pulsed laser annealing (PLA) after an ion implantation (II) step results in melting (for a time of order 100 nsec) and essentially defect-free liquid phase epitaxial regrowth within approx. 0.5 ..mu..m of the surface. Complete electrical activation of a number of dopant ions, at concentrations exceeding ordinary solubility limits, has been demonstrated and crystalline (polycrystalline) silicon solar cell efficiencies of 16.6% (12.5%) have been obtained. Other p-n junction and solar cell fabrication techniques have been demonstrated. Pulsed laser processing has also been demonstrated to have several other unique and beneficial advantages in polycrystalline silicon substrates. For example, grain boundaries do not exist during laser melting, while dopant diffusion is taking place; the short melt durations involved further limit dopant diffusion; precipitates present after conventional high temperature dopant diffusion can be removed; and, certain types of electrically active grain boundaries can be made inactive by pulsed laser irradiation. Finally, grain growth in fine-grained polycrystalline silicon films, via pulsed laser melting and recrystallization, has been demonstrated. Because little is known about the application of similar pulsed laser processing techniques to compound semiconductors, particularly in connection with the formation of shallow p-n junctions, research has been devoted to studies of pulsed laser processing of GaAs and compound semiconductor solar cell fabrication techniques that are compatible with the use of pulsed lasers. Progress is reported. (WHK)

  12. Laser Application in Prevention of Demineralization in Orthodontic Treatment

    PubMed Central

    Sadr Haghighi, Hooman; Skandarinejad, Mahsa; Abdollahi, Amir Ardalan

    2013-01-01

    One common negative side effect of orthodontic treatment with fixed appliances is the development of incipient caries lesions around brackets, particularly in patients with poor oral hygiene. Different methods have been used to prevent demineralization such as fluoride therapy and application of sealant to prevent caries. The recent effort to improve the resistance against the demineralization is by the application of different types of lasers. The purpose of this review article is discussing the effects of laser in prevention of demineralization in orthodontic patients. PMID:25606317

  13. A NASA high-power space-based laser research and applications program

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.; Walberg, G. D.; Conway, E. J.; Jones, L. W.

    1983-01-01

    Applications of high power lasers are discussed which might fulfill the needs of NASA missions, and the technology characteristics of laser research programs are outlined. The status of the NASA programs or lasers, laser receivers, and laser propulsion is discussed, and recommendations are presented for a proposed expanded NASA program in these areas. Program elements that are critical are discussed in detail.

  14. Clinical application of CO2 laser in periodontal treatment

    NASA Astrophysics Data System (ADS)

    Hayase, Yasuhiro

    1994-09-01

    CO2 lasers in particular are expected to have many dental applications because the CO2 laser beam exhibits strong tissue transpirative actions, such as instant coagulation, carbonization, and vaporization, and because its wavelength at 10.6 micrometers is fully absorbed by water so that the ability to make precise incisions with a high degree of safety is excellent, without damaging the deep tissues. However, clinical application of the CO2 laser has been slowed since a fiber which can conduct the laser beam to the oral cavity has only recently developed. This new fiber is an extremely flexible fiber with a minimum bending radius of 20 mm and utilizes pulse wave modes that have improved the handling characteristics in the mouth, and this has enabled us to apply the CO2 laser to a variety of periodontal conditions. The aim of this study was to evaluate the effectiveness of CO2 lasers for the early treatment of inflammation and pain relief of acute periodontitis, curettage of periodontal pockets, healing after excision of gingiva, and early improvement of gingivitis.

  15. Ground-to-orbit laser propulsion: Advanced applications

    SciTech Connect

    Kare, J.T.

    1990-01-01

    Laser propulsion uses a large fixed laser to supply energy to heat an inert propellant in a rocket thruster. Such a system has two potential advantages: extreme simplicity of the thruster, and potentially high performance -- particularly high exhaust velocity. By taking advantage of the simplicity of the thruster, it should be possible to launch small (10--1000 kg) payloads to orbit using roughly 1 MW of average laser power per kg of payload. The incremental cost of such launches would be of order $200/kg for the smallest systems, decreasing to essentially the cost of electricity to run the laser (a few times $10/kg) for large systems. Although the individual payload size would be small, a laser launch system would be inherently high-volume, with the capacity to launch tens of thousands of payloads per year. Also, with high exhaust velocity, a laser launch system could launch payloads to high velocities -- geosynchronous transfer, Earth escape, or beyond -- at a relatively small premium over launches to LEO. In this paper, we briefly review the status of pulsed laser propulsion, including proposals for advanced vehicles. We then discuss qualitatively several unique applications appropriate to the early part of the next century, and perhaps valuable well into the next millenium: space habitat supply, deep space mission supply, nuclear waste disposal, and manned vehicle launching.

  16. Ground-to-orbit laser propulsion: Advanced applications

    NASA Technical Reports Server (NTRS)

    Kare, Jordin T.

    1990-01-01

    Laser propulsion uses a large fixed laser to supply energy to heat an inert propellant in a rocket thruster. Such a system has two potential advantages: extreme simplicity of the thruster, and potentially high performance, particularly high exhaust velocity. By taking advantage of the simplicity of the thruster, it should be possible to launch small (10 to 1000 kg) payloads to orbit using roughly 1 MW of average laser power per kg of payload. The incremental cost of such launches would be of an order of $200/kg for the smallest systems, decreasing to essentially the cost of electricity to run the laser (a few times $10/kg) for larger systems. Although the individual payload size would be smaller, a laser launch system would be inherently high-volume, with the capacity to launch tens of thousands of payloads per year. Also, with high exhaust velocity, a laser launch system could launch payloads to high velocities - geosynchronous transfer, Earth escape, or beyond - at a relatively small premium over launches to LEO. The status of pulsed laser propulsion is briefly reviewed including proposals for advanced vehicles. Several applications appropriate to the early part of the next century and perhaps valuable well into the next millennium are discussed qualitatively: space habitat supply, deep space mission supply, nuclear waste disposal, and manned vehicle launching.

  17. [Public food service in Milan city and Hinterland: food-handlers training level (Part 2)].

    PubMed

    Pontello, M; Dal Vecchio, A; Doria, M G; Bertini, I

    2005-01-01

    The prevention and control of foodborne diseases play an important role in public health and the responsibility of food-handlers is of great concern: their training on food safety is particularly required in the critical sector of public food service establishments. The food-handlers knowledge has been evaluated by a questionnaire filled up in two Public Health Units (PHU) in Milan City and Milan hinterland. Only 11.5% of food-handlers turned at to be good trained; the wrong answers are concentrated on the section titled "temperatures management" (68 and 59% in Milan City and in Milan hinterland, respectively). Only for 31.4% of food-handlers the attendance to training courses is well documented, although the knowledge level seems to be partially influenced by training activity: exclusively in Milan City food-handlers an highly significant difference has been found among "trained" and "no-trained" workers in correct answers about temperatures management (p= 0.0046). The frequency of exact answers isn't associated to the satisfaction level revealed during inspection of restaurants. Focusing the attention on the insufficient efficacy of training courses and the lacking connection between knowledge and behaviour, a critical revision of training activity quality seems to be necessary. In future some professional training activities in the field should be promoted. PMID:16041927

  18. Review of laser-driven ion sources and their applications.

    PubMed

    Daido, Hiroyuki; Nishiuchi, Mamiko; Pirozhkov, Alexander S

    2012-05-01

    For many years, laser-driven ion acceleration, mainly proton acceleration, has been proposed and a number of proof-of-principle experiments have been carried out with lasers whose pulse duration was in the nanosecond range. In the 1990s, ion acceleration in a relativistic plasma was demonstrated with ultra-short pulse lasers based on the chirped pulse amplification technique which can provide not only picosecond or femtosecond laser pulse duration, but simultaneously ultra-high peak power of terawatt to petawatt levels. Starting from the year 2000, several groups demonstrated low transverse emittance, tens of MeV proton beams with a conversion efficiency of up to several percent. The laser-accelerated particle beams have a duration of the order of a few picoseconds at the source, an ultra-high peak current and a broad energy spectrum, which make them suitable for many, including several unique, applications. This paper reviews, firstly, the historical background including the early laser-matter interaction studies on energetic ion acceleration relevant to inertial confinement fusion. Secondly, we describe several implemented and proposed mechanisms of proton and/or ion acceleration driven by ultra-short high-intensity lasers. We pay special attention to relatively simple models of several acceleration regimes. The models connect the laser, plasma and proton/ion beam parameters, predicting important features, such as energy spectral shape, optimum conditions and scalings under these conditions for maximum ion energy, conversion efficiency, etc. The models also suggest possible ways to manipulate the proton/ion beams by tailoring the target and irradiation conditions. Thirdly, we review experimental results on proton/ion acceleration, starting with the description of driving lasers. We list experimental results and show general trends of parameter dependences and compare them with the theoretical predictions and simulations. The fourth topic includes a review of

  19. Recent advances in VECSELs for laser projection applications

    NASA Astrophysics Data System (ADS)

    Lindberg, H.; Illek, S.; Pietzonka, I.; Furitsch, M.; Plößl, A.; Haupt, S.; Kühnelt, M.; Schulz, R.; Steegmüller, U.; Höfer, T.; Strauß, U.

    2011-03-01

    Laser projectors integrated in portable devices offer a new platform for media display but put strong demands on the laser sources in terms of efficiency, modulation band width, operating temperature range and device cost. Osram Opto Semiconductors has developed and produces synthetic green lasers for projection applications on which the latest results are reported. Based on vertical external cavity surface emitting laser (VECSEL) technology and second harmonic generation an output power of >75mW has been achieved. The maximum output power is to a large extent limited by the high thermal resistance of the monolithic VECSEL chip used. To overcome the thermal limitations a new thinfilm VECSEL chip design is proposed where the epitaxial layers are transferred to a silicon carrier and processed on wafer level, thus significantly lowering the thermal resistance and improving the maximum output power.

  20. Atypical Applications for Gas-coupled Laser Acoustic Detection

    NASA Astrophysics Data System (ADS)

    Caron, J. N.; Kunapareddy, P.

    2014-06-01

    Gas-coupled laser acoustic detection (GCLAD) was primarily developed to sense laser-generated ultrasound in composite materials. In a typical setup, a laser beam is directed parallel to the material surface. Radiated ultrasound waves deflect or displace the probe beam resulting from changes in the air's index of refraction. A position-sensitive photodetector senses the beam movement, and produces a signal proportional to the ultrasound wave. In this paper, we discuss three applications of GCLAD that take advantage of the unique detection characteristics. Directivity patterns of ultrasound amplitude in water demonstrate the use of GCLAD as a directional hydrophone. We also demonstrate the sensing of waveforms from a gelatin. The gelatin mimics ultrasound propagation through skin tissues. Lastly, we show how GCLAD can be used as a line receiver for continuous laser generation of ultrasound. CLGU may enable ultrasound scanning at rates that are orders of magnitude faster than current methods.

  1. Laser desorption mass spectrometry for biomolecule detection and its applications

    NASA Astrophysics Data System (ADS)

    Winston Chen, C. H.; Sammartano, L. J.; Isola, N. R.; Allman, S. L.

    2001-08-01

    During the past few years, we developed and used laser desorption mass spectrometry for biomolecule detections. Matrix-assisted laser desorption/ionization (MALDI) was successfully used to detect DNA fragments with the size larger than 3000 base pairs. It was also successfully used to sequence DNA with both enzymatic and chemical degradation methods to produce DNA ladders. We also developed MALDI with fragmentation for direct DNA sequencing for short DNA probes. Since laser desorption mass spectrometry for DNA detection has the advantages of fast speed and no need of labeling, it has a great potential for molecular diagnosis for disease and person identification by DNA fingerprinting. We applied laser desorption mass spectrometry to succeed in the diagnosis of cystic fibrosis and several other nerve degenerative diseases such as Huntington's disease. We also succeeded in demonstrating DNA typing for forensic applications.

  2. Laser-based nanoengineering of surface topographies for biomedical applications

    NASA Astrophysics Data System (ADS)

    Schlie, Sabrina; Fadeeva, Elena; Koroleva, Anastasia; Ovsianikov, Aleksandr; Koch, Jürgen; Ngezahayo, Anaclet; Chichkov, Boris. N.

    2011-04-01

    In this study femtosecond laser systems were used for nanoengineering of special surface topographies in silicon and titanium. Besides the control of feature sizes, we demonstrated that laser structuring caused changes in material wettability due to a reduced surface contact area. These laser-engineered topographies were tested for their capability to control cellular behavior of human fibroblasts, SH-SY5Y neuroblastoma cells, and MG-63 osteoblasts. We found that fibroblasts reduced cell growth on the structures, while the other cell types proliferated at the same rate. These findings make laser-surface structuring very attractive for biomedical applications. Finally, to explain the results the correlation between topography and the biophysics of cellular adhesion, which is the key step of selective cell control, is discussed.

  3. Medical applications of ultra-short pulse lasers

    SciTech Connect

    Kim, B M; Marion, J E

    1999-06-08

    The medical applications for ultra short pulse lasers (USPLs) and their associated commercial potential are reviewed. Short pulse lasers offer the surgeon the possibility of precision cutting or disruption of tissue with virtually no thermal or mechanical damage to the surrounding areas. Therefore the USPL offers potential improvement to numerous existing medical procedures. Secondly, when USPLs are combined with advanced tissue diagnostics, there are possibilities for tissue-selective precision ablation that may allow for new surgeries that cannot at present be performed. Here we briefly review the advantages of short pulse lasers, examine the potential markets both from an investment community perspective, and from the view. of the technology provider. Finally nominal performance and cost requirements for the lasers, delivery systems and diagnostics and the present state of development will be addressed.

  4. Optically pumped planar waveguide lasers: Part II: Gain media, laser systems, and applications

    NASA Astrophysics Data System (ADS)

    Grivas, Christos

    2016-01-01

    The field of optically pumped planar waveguide lasers has seen a rapid development over the last two decades driven by the requirements of a range of applications. This sustained research effort has led to the demonstration of a large variety of miniature highly efficient laser sources by combining different gain media and resonator geometries. One of the most attractive features of waveguide lasers is the broad range of regimes that they can operate, spanning from continuous wave and single frequency through to the generation of femtosecond pulses. Furthermore, their technology has experienced considerable advances to provide increased output power levels, deriving benefits from the relative immunity from the heat generated in the gain medium during laser operation and the use of cladding-pumped architectures. This second part of the review on optically pumped planar waveguide lasers provides a snapshot of the state-of-the-art research in this field in terms of gain materials, laser system designs, and as well as a perspective on the status of their application as real devices in various research areas.

  5. Applications of infrared laser spectroscopy to laser chemistry and laser development

    NASA Astrophysics Data System (ADS)

    McDowell, Robin S.; Viswanath, A. K.

    The impact on infrared molecular spectroscopy of high-resolution tunable laser sources and laser-controlled Fourier-transform spectrometers is discussed, with special reference to rovibrational spectra of spherical-top molecules such as CH4, OsO4, SiF4, SF6, and UF6. The role of tunable laser spectroscopy in analyzing the CF4 laser, resulting in the precise prediction of lasing frequencies between 605 and 655/cm, is described. Studies of overtone and combination bands of SF6 enable the vibrational anharmonicity to be determined, resulting in a more detailed description of the pump transitions involved in laser photochemistry, and of higher vibrational levels and pathways to excitation and dissociation. This permits more accurate calculations of vibrational state densities for spherical-top molecules. Implications for the photochemistry of species, such as SiF4, SF6, UF6, and Ni(Co)4, are discussed.

  6. Status and future prospects of laser fusion and high power laser applications

    NASA Astrophysics Data System (ADS)

    Mima, Kunioki

    2010-08-01

    In Asia, there are many institutes for the R&D of high power laser science and applications. They are 5 major institutes in Japan, 4 major institutes in China, 2 institutes in Korea, and 3 institutes in India. The recent achievements and future prospects of those institutes will be over viewed. In the laser fusion research, the FIREX-I project in Japan has been progressing. The 10kJ short pulse LFEX laser has completed and started the experiments with a single beam. About 1kJ pulse energy will be injected into a cone target. The experimental results of the FIREX experiments will be presented. As the target design for the experiments, a new target, namely, a double cone target was proposed, in which the high energy electrons are well confined and the heating efficiency is significantly improved. Together with the fusion experiments, Osaka University has carried out laboratory astrophysics experiments on photo ionizing plasmas to observe a unique X-ray spectrum from non-LTE plasmas. In 2008, Osaka university has started a new Photon research center in relation with the new program: Consortium for Photon Science and Technology: C-PhoST, in which ultra intense laser plasmas research and related education will be carried out for 10 years. At APRI, JAEA, the fundamental science on the relativistic laser plasmas and the applications of laser particle acceleration has been developed. The application of laser ion acceleration has been investigated on the beam cancer therapy since 2007. In China, The high power glass laser: Shenguan-II and a peta watt beam have been operated to work on radiation hydro dynamics at SIOFM Shanghai. The laser material and optics are developed at SIOFM and LFRC. The IAPCM and the IOP continued the studies on radiation hydrodynamics and on relativistic laser plasmas interactions. At LFRC in China, the construction of Shenguan III glass laser of 200kJ in blue has progressed and will be completed in 2012. Together with the Korean program, I will

  7. High power diode lasers: technology and application in Europe

    NASA Astrophysics Data System (ADS)

    Behringer, Martin; Eberhard, Franz; Herrmann, Gerhard; Luft, Johann; Maric, J.; Morgott, Stefan; Philippens, Marc; Teich, W.

    2003-03-01

    The application field of high power semiconductor lasers is growing rapidly and covers e.g. solid state laser pumping, metal and plastic welding, hard and soft soldering, suface treatment and others. Preferably those applications are attractive, which do not require extremely high beam quality. We have investigated high power diode-laser bars from 808 nm to 980 nm. The scope of this presentation is on focusability and beam quality. For better beam shaping structures with reduced fill factor of 25% to 30% were developed. They were operated in continuous wave operation at power levels of up to 55 W. Tests indicate extrapolated lifetimes of more than 100,000 hours at 40 W at 980 nm cw and about 10,000 hours at 45 W - 50 W at 940 nm and 808 nm. Monolithically stacked NonostacksR were investigated. Operation up to 100°C with excellent lifetimes could be demonstrated. New concepts and applications for low mode number high power diode lasers like tapered laser bars are presented. Examples for various current areas of interest in European research facilities will be given.

  8. Novel atmospheric extinction measurement techniques for aerospace laser system applications

    NASA Astrophysics Data System (ADS)

    Sabatini, Roberto; Richardson, Mark

    2013-01-01

    Novel techniques for laser beam atmospheric extinction measurements, suitable for manned and unmanned aerospace vehicle applications, are presented in this paper. Extinction measurements are essential to support the engineering development and the operational employment of a variety of aerospace electro-optical sensor systems, allowing calculation of the range performance attainable with such systems in current and likely future applications. Such applications include ranging, weaponry, Earth remote sensing and possible planetary exploration missions performed by satellites and unmanned flight vehicles. Unlike traditional LIDAR methods, the proposed techniques are based on measurements of the laser energy (intensity and spatial distribution) incident on target surfaces of known geometric and reflective characteristics, by means of infrared detectors and/or infrared cameras calibrated for radiance. Various laser sources can be employed with wavelengths from the visible to the far infrared portions of the spectrum, allowing for data correlation and extended sensitivity. Errors affecting measurements performed using the proposed methods are discussed in the paper and algorithms are proposed that allow a direct determination of the atmospheric transmittance and spatial characteristics of the laser spot. These algorithms take into account a variety of linear and non-linear propagation effects. Finally, results are presented relative to some experimental activities performed to validate the proposed techniques. Particularly, data are presented relative to both ground and flight trials performed with laser systems operating in the near infrared (NIR) at λ = 1064 nm and λ = 1550 nm. This includes ground tests performed with 10 Hz and 20 kHz PRF NIR laser systems in a large variety of atmospheric conditions, and flight trials performed with a 10 Hz airborne NIR laser system installed on a TORNADO aircraft, flying up to altitudes of 22,000 ft.

  9. Infrared Laser Desorption: Mechanisms and Applications

    NASA Astrophysics Data System (ADS)

    Maechling, Claude Ricketts

    1995-01-01

    This thesis describes the use of two-step laser mass spectrometry (L^2MS), a combination of infrared (IR) laser desorption with resonance-enhanced multiphoton ionization (REMPI) and time-of-flight (TOF) mass spectrometry, to investigate (1) the mechanism of IR laser desorption, (2) the composition of aromatic molecules in extraterrestrial samples, and (3) the measurement of compound-specific carbon isotope ratios. First, a description of the mechanism of IR laser desorption of monolayer and submonolayer coverages of molecules adsorbed to an insulator surface is presented. The vibrational and translational energy distributions of aniline-d7 molecules desorbed from single-crystal sapphire (Al_2 O_3) are recorded using L ^2MS. The energy distributions are found to be in equilibrium with each other and with the temperature of the surface at the time of desorption. The translational and angular distributions of monolayer coverages are altered by the collisions of desorbing molecules with each other. Second, spatial and chemical analyses of the carbonaceous components in chondritic meteorites are presented. A microprobe L^2MS instrument (mu L^2MS) capable of analyzing samples with a spatial resolution of 40 mu m and zeptomole (10^{-21} mole) sensitivity is described and used to investigate polycyclic aromatic hydrocarbons (PAHs) in small particles and heterogeneous samples. PAH distributions are used to distinguish between samples from different meteorite classes, and the effects of thermal processing within a given meteorite class are observed. Sliced wafers of meteorite are found to contain an inhomogeneous distribution of PAHs. muL^2MS studies of meteorite samples are coordinated with scanning electron microscopy studies, and the abundances of aromatic compounds across the surface of a sample are consistent with gross structural features but not with elemental or mineralogical features. Third, a description of a method for performing compound-specific carbon isotope

  10. Laser sclerostomy ab externo with the Erbium:YAG laser using a new flexible application system

    NASA Astrophysics Data System (ADS)

    Wetzel, Wolfgang; Scheu, M.; Brinkmann, Ralf; Birngruber, Reginald

    1992-08-01

    A fistula from the anterior chamber of the eye into the subconjunctival space can be created by laser application ab externo (laser sclerostomy). The success of the procedure mainly depends on the special application system. The pulsed Erbium-YAG laser (2940 nm) was used as the energy source. The laser energy was guided to the application system via a ZrFl fiber with low attenuation at this wavelength. Because this fiber cannot be used in direct contact to the sclera, an optical coupling unit transmitted the energy to a short quartz fiber. This fiber was inserted in a specially sharpened retractable cannula to guide it into the subconjunctival space. Then the laser energy could be applied directly to the sclera to form the fistula. The procedure was demonstrated in vivo using rabbit eyes. A working fistula with formation of a filtering bleb could be achieved. The trauma to the conjunctiva was as minimal as in a subconjunctival injection. The minor alteration of the conjunctiva in this procedure compared to traditional surgical methods like goniotrepanation or trabeculectomy may cause less scarification and therefore less failure.

  11. Pulsed laser-induced evaporation of liquids and its applications

    NASA Astrophysics Data System (ADS)

    Kim, Dongsik

    The interaction of laser irradiation with materials is very important in a variety of laser-based manufacturing processes and scientific studies. Particularly, the interaction of a short laser pulse with absorbing liquids or solid materials in contact with liquid is central to a number of applications, including laser cleaning of microcontaminants, pulsed laser deposition of thin film materials, laser tissue removal, and laser surface texturing. In this dissertation, experimental and theoretical works on the following topics are summarized: (1) physical mechanisms of pulsed laser induced ablation of absorbing liquids at laser fluence below the plasma ignition threshold, (2) analysis of rapid vaporization at the absorbing solid/transparent liquid interface, (3) laser cleaning of surface contaminates. Concerning the first topic, the near-threshold ablation process at low laser fluences and the high power explosive vaporization process accompanying subsequent ablation plume dynamics are elucidated. Acoustic-wave detection by a piezoelectric pressure transducer, visualization by laser flash photography, and optical reflection/transmission measurements are carried out for the in-situ diagnosis of the process. Quantification of the acoustic-field generation and detection of the bubble-nucleation dynamics in the rapid vaporization at the solid liquid interface are performed by photoacoustic beam deflection technique and optical interferometry, respectively. Finally, experiments are carried out for the development of a practical laser cleaning tool and the analysis of the contaminant-removal mechanism. The results show that the near-threshold ablation by a short laser pulse is initiated by the tensile component of the thermoelastic stress without significant increase of liquid temperature at low laser fluences. On the other hand, if the heating rate is rapid enough to achieve high degree of superheating of the liquid, explosive vaporization takes place due to the abrupt

  12. Military applications of the laser weapons in the future battlefield

    NASA Astrophysics Data System (ADS)

    Celik, Hasan; Adana, Saban; Yahsi, Erhan

    2013-05-01

    Contemporary operating environment requires a wide range of tools to respond to a myriad of regular and irregular threats. Accordingly, conventional weapons do not suffice in some cases. As technology improves exponentially, the dominance of conventional weapons is slowly fading away by the advances in laser technology. This study first outlines the characteristics of laser weapons, then provides the military applications of them in land, maritime, air and space domains and finally exhibits implications for battlefield functions. This study concludes that any country that is seeking primacy in military terms must allocate extra time and resources to obtain this emerging technology. Since it seems that there are not adequate studies about the military applications and operational concepts of the laser weapons, this study tries to increase awareness about their potential advantages.

  13. Laser-induced breakdown spectroscopy expands into industrial applications

    NASA Astrophysics Data System (ADS)

    Noll, Reinhard; Fricke-Begemann, Cord; Brunk, Markus; Connemann, Sven; Meinhardt, Christoph; Scharun, Michael; Sturm, Volker; Makowe, Joachim; Gehlen, Christoph

    This paper presents R&D activities in the field of laser-induced breakdown spectroscopy for industrial applications and shows novel LIBS systems running in routine operation for inline process control tasks. Starting with a comparison of the typical characteristics of LIBS with XRF and spark-discharge optical emission spectrometry, the principal structure of LIBS machines embedded for inline process monitoring will be presented. A systematic requirement analysis for LIBS systems following Ishikawa's scheme was worked out. Stability issues are studied for laser sources and Paschen-Runge spectrometers as key components for industrial LIBS systems. Examples of industrial applications range from handheld LIBS systems using a fiber laser source, via a set of LIBS machines for inline process control tasks, such as scrap analysis, coal analysis, liquid slag analysis and finally monitoring of drill dust.

  14. Laser-powered MHD generators for space application

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1986-01-01

    Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

  15. The Application of Ultrafast Laser Pulses to Laser Desorption Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Cui, Yang

    Ultrashort femtosecond laser pulses display exceptional performance for the selective ablation of materials, includes metals, semiconductors, and biological tissues. They do not damage the remaining unablated portion of a sample, which permits the possibility of depth profiling by repeat sampling at the same location. With sufficiently micro-focused fs laser pulse length beam, high lateral resolution mass spectrometry imaging is possible, while sample damage may degrade ultimate lateral resolution in some other methods. Combining imaging and depth profiling could ultimately leads to tomographical mass spectrometry or 3D imaging MS. Laser postionization, a "soft" ionization method, was combined with ultrafast laser desorption for enhanced molecular analysis. A customized femtosecond laser desorption/ablation postionization time-of-flight mass spectrometer was designed and built. The construction and performance of both phases including the VUV source are detailed. Instrument control software was written to operate this instrument, and many automated experiments were successfully demonstrated by this software. Elemental and molecular analysis was carried out on the instrument and demonstrated exceptional performance for fs laser pulse sampling of small areas. Studies demonstrated the imaging and depth profiling capability of fs-LDPI on metals, semiconductors and intact biofilm tissues. Attempts were made to reach the limit of lateral resolution of imaging by fs-LDPI-MS. The results showed similar lateral resolution of <2 mum for both fs 800 nm and 400 nm desorption beams. To improve the repetition rate for high speed imaging application, an alternative LDPI scheme was designed and constructed. The fs 800 beam was tripled to 267 nm and delivered into the ion source as an ionization laser, while a ns 349 nm pulse laser was used for desorption. Preliminary data showed certain intact molecular ions can be detected. Fragmentation tendency was measured against various

  16. Laser-light delivery microtools based on laser technology: design, fabrication, and applications

    NASA Astrophysics Data System (ADS)

    Veiko, Vadim P.; Voznesensky, Nikolay B.

    2001-06-01

    A set of new laser-light delivery microtools (LDM) based on laser technology is investigated and discussed. Wide application of LDM in different fields of science, medicine, biology, industry and information processing is considered. Fiber optical networks in medical diagnostics and technical, civil engineering and other technological areas are discussed. The general approach based on electromagnetic field equations-transformation for all range of dimensions (mini-, micro and nanodomain) is given. Laser-assisted technology for drawing-out and for microstructuring optical tools is investigated, high-speed movie has been applied to study the process and compared with theoretical description. Finally a number of fibers and micropipettes-based medical tools and SNOM-tips has been fabricated and tested. Applications of some tools for medical operations (thermocoagulation), protein rasters preparing, SNOM-microscopy investigation have been demonstrated.

  17. New developments in ophthalmic applications of ultrafast lasers

    NASA Astrophysics Data System (ADS)

    Spooner, Greg J. R.; Juhasz, Tibor; Ratkay-Traub, Imola; Djotyan, Gagik P.; Horvath, Christopher; Sacks, Zachary S.; Marre, Gabrielle; Miller, Doug L.; Williams, A. R.; Kurtz, Ron M.

    2000-05-01

    The eye is potentially an ideal target for high precision surgical procedures utilizing ultrafast lasers. We present progress on corneal applications now being tested in humans and proof of concept ex vivo demonstrations of new applications in the sclera and lens. Two corneal refractive procedures were tested in partially sighted human eyes: creation of corneal flaps prior to excimer ablation (Femto- LASIK) and creation of corneal channels and entry cuts for placement of intracorneal ring segments (Femto-ICRS). For both procedures, results were comparable to standard treatments, with the potential for improved safety, accuracy and reproducibility. For scleral applications, we evaluated the potential of femtosecond laser glaucoma surgery by demonstrating resections in ex vivo human sclera using dehydrating agents to induce tissue transparency. For lens applications, we demonstrate in an ex vivo model the use of photodisruptively-nucleated ultrasonic cavitation for local and non-invasive tissue interaction.

  18. Abstracts of the 5th International Conference on Lasers and their Applications

    NASA Astrophysics Data System (ADS)

    Results were presented in the fields of laser physics and laser applications including the development of laser light sources, laser frequencies in the UV and VUV spectral regions using anti-Stokes Raman scattering, nonlinear optical effects for the formation of ultrashort optical pulses, laser spectroscopy, collisionless multiphoton excitation processes using molecular beams, selective generation of free radicals by laser, laser applications in medicine, plasma diagnostics analyzing X-ray spectra for studying laser fusion problems, coherence properties in phase-sampling interferometric techniques, and fundamental problems in quantum physics and nonlinear processes.

  19. High efficiency solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, G. A.

    1995-01-01

    Understanding solar cell response to pulsed laser outputs is important for the evaluation of power beaming applications. The time response of high efficiency GaAs and silicon solar cells to a 25 nS monochromatic pulse input is described. The PC-1D computer code is used to analyze the cell current during and after the pulse for various conditions.

  20. The laser and its applications on environment and biotechnology research

    SciTech Connect

    Chen, C.H.; Chen, F.C.

    1993-10-01

    During the past few years, researchers at ORNL have developed four new instruments involving the use of a laser for environmental and biotechnology research. They are: (1) a single atom detector, (2) a rare gas atom counter, (3) biopolymer mass spectrometer, and (4) a refrigerant ratiometer. Their basic principles and applications are briefly described in this paper.

  1. Coolants with selective optical filtering characteristics for ruby laser applications

    NASA Technical Reports Server (NTRS)

    Mc Devitt, F. R.; Rasquin, J. R.

    1968-01-01

    Coolant-filtering medium developed consists of a solution of copper sulfate in a 4-1 volumetric mixture of ethanol and methanol. This solution should be a useful addition to ruby laser systems, particularily in large pulse or Q switching applications.

  2. Overview on new diode lasers for defense applications

    NASA Astrophysics Data System (ADS)

    Neukum, Joerg

    2012-11-01

    Diode lasers have a broad wavelength range, from the visible to beyond 2.2μm. This allows for various applications in the defense sector, ranging from classic pumping of DPSSL in range finders or target designators, up to pumping directed energy weapons in the 50+ kW range. Also direct diode applications for illumination above 1.55μm, or direct IR countermeasures are of interest. Here an overview is given on some new wavelengths and applications which are recently under discussion. In this overview the following aspects are reviewed: • High Power CW pumps at 808 / 880 / 940nm • Pumps for DPAL - Diode Pumped Alkali Lasers • High Power Diode Lasers in the range < 1.0 μm • Scalable Mini-Bar concept for high brightness fiber coupled modules • The Light Weight Fiber Coupled module based on the Mini-Bar concept Overall, High Power Diode Lasers offer many ways to be used in new applications in the defense market.

  3. Application of laser radar to autonomous spacecraft landing

    NASA Technical Reports Server (NTRS)

    Gleichman, Kurt; Tchoryk, Peter, Jr.; Sampson, Robert E.

    1991-01-01

    This paper discusses the scenario of an autonomous landing like that required for the Mars Rover Sample Return Mission. An application of laser radar for conducting autonomous hazard detection and avoidance is discussed. A trade-study is performed to identify operational and implementation constraints as well as the state of the art in component technology.

  4. Application of laser anemometry in turbine engine research

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.

    1983-01-01

    The application of laser anemometry to the study of flow fields in turbine engine components is reviewed. Included are discussions of optical configurations, seeding requirements, electronic signal processing, and data processing. Some typical results are presented along with a discussion of ongoing work.

  5. Application of laser anemometry in turbine engine research

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.

    1982-01-01

    The application of laser anemometry to the study of flow fields in turbine engine components is reviewed. Included are discussions of optical configurations, seeding requirements, electronic signal processing, and data processing. Some typical results are presented along with a discussion of ongoing work.

  6. Laser-based micro/nanoengineering for biological applications

    NASA Astrophysics Data System (ADS)

    Stratakis, E.; Ranella, A.; Farsari, M.; Fotakis, C.

    2009-09-01

    Controlling the interactions of light with matter is crucial for the success and scalability for materials processing applications at micro and nano-scales. The use of ultrafast pulsed lasers (i.e. lasers emitting pulses of duration shorter than 10 -12 s) for the micro/nano engineering of biomaterials or materials relevant to biological applications opens up several exciting possibilities in this respect. These possibilities rely on several attractive features of ultrafast laser-matter interaction processes which allow nanoscale spatial resolution, non-thermal and non-destructive engineering to take place. This article presents a review of novel laser-based techniques for the printing and micro- and nano- scale surface modification of materials for biological applications. Emphasis is placed on techniques appropriate for biochip and tissue engineering applications, for which there is an increasing demand over the last years. Besides presenting recent advances achieved by these techniques, this work also delineates existing limitations and highlights emerging possibilities and future prospects in this field.

  7. Mid - infrared solid state lasers for spectroscopic applications

    NASA Astrophysics Data System (ADS)

    Terekhov, Yuri

    This work is devoted to study of novel high power middle-infrared (Mid-IR) laser sources enabling development of portable platform for sensing of organic molecules with the use of recently discovered Quartz Enhanced Photo Acoustic Spectroscopy (QEPAS). The ability to detect small concentrations is beneficial to monitor atmosphere pollution as well for biomedical applications such as analysis of human breath to detect earlier stages of cancer or virus activities. A QEPAS technique using a quartz tuning fork (QTF) as a detector enables a strong enhancement of measured signal when pump laser is modulated with a frequency coinciding with a natural frequency of a QTF. It is known that the detectability of acousto-optics based sensors is proportional to the square root of the laser intensity used for detection of analyte. That is the reason why commercially available semiconductor Mid-IR lasers having small output power limit sensitivity of modern QEPAS based sensors. The lack of high power broadly tunable lasers operating with a modulation frequency of quartz forks (~ 32.768 kHz) is the major motivation of this study. Commercially available Mid-IR (2-3.3 microm), single frequency, continuous wave (CW) fiber pumped lasers based on transition metal doped chalcogenides (e.g. Cr:ZnSe) prove to be efficient laser sources for organic molecules detection. However, their direct modulation is limited to several kHz, and cannot be directly used in combination with QEPAS. Hence, one objective of this work is to study and develop fiber laser pumped Ho:YAG (Er:YAG)/Cr:ZnSe tandem laser system/s. Ho (Holmium) and/or Er (Erbium) ions having long radiation lifetime (~ 10 ms) can effectively accumulate population inversion under CW fiber laser excitation. Utilization of acousto-optic (AO) modulators in the cavity of Ho:YAG (Er:YAG) laser will enable effective Q-Switching with repetition rate easily reaching the resonance frequency of a QTF. It is expected that utilization of Ho:YAG (Er

  8. Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

    NASA Technical Reports Server (NTRS)

    Ramos-Izquierdo, Luis A.

    2011-01-01

    A diffractive optic element (DOE) can be used as a beam splitter to generate multiple laser beams from a single input laser beam. This technology has been recently used in LRO s Lunar Orbiter Laser Altimeter (LOLA) instrument to generate five laser beams that measure the lunar topography from a 50-km nominal mapping orbit (see figure). An extension of this approach is to use a multiple-zone DOE to allow a laser altimeter instrument to operate over a wider range of distances. In particular, a multiple-zone DOE could be used for applications that require both mapping and landing on a planetary body. In this case, the laser altimeter operating range would need to extend from several hundred kilometers down to a few meters. The innovator was recently involved in an investigation how to modify the LOLA instrument for the OSIRIS asteroid mapping and sample return mission. One approach is to replace the DOE in the LOLA laser beam expander assembly with a multiple-zone DOE that would allow for the simultaneous illumination of the asteroid with mapping and landing laser beams. The proposed OSIRIS multiple-zone DOE would generate the same LOLA five-beam output pattern for high-altitude topographic mapping, but would simultaneously generate a wide divergence angle beam using a small portion of the total laser energy for the approach and landing portion of the mission. Only a few percent of the total laser energy is required for approach and landing operations as the return signal increases as the inverse square of the ranging height. A wide divergence beam could be implemented by making the center of the DOE a diffractive or refractive negative lens. The beam energy and beam divergence characteristics of a multiple-zone DOE could be easily tailored to meet the requirements of other missions that require laser ranging data. Current single-zone DOE lithographic manufacturing techniques could also be used to fabricate a multiple-zone DOE by masking the different DOE zones during

  9. Review of selective laser melting: Materials and applications

    SciTech Connect

    Yap, C. Y.; Chua, C. K. Liu, Z. H. Zhang, D. Q. Loh, L. E. Sing, S. L.; Dong, Z. L.

    2015-12-15

    Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power laser have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following areas: (a) applications of SLM materials and (b) mechanical properties of SLM parts achieved in research publications. The review is not meant to put a ceiling on the capabilities of the SLM process but to enable readers to have an overview on the material properties achieved by the SLM process so far. Trends in research of SLM are also elaborated in the last section.

  10. Review of selective laser melting: Materials and applications

    NASA Astrophysics Data System (ADS)

    Yap, C. Y.; Chua, C. K.; Dong, Z. L.; Liu, Z. H.; Zhang, D. Q.; Loh, L. E.; Sing, S. L.

    2015-12-01

    Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power laser have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following areas: (a) applications of SLM materials and (b) mechanical properties of SLM parts achieved in research publications. The review is not meant to put a ceiling on the capabilities of the SLM process but to enable readers to have an overview on the material properties achieved by the SLM process so far. Trends in research of SLM are also elaborated in the last section.

  11. Applications of laser direct-write for embedding microelectronics

    NASA Astrophysics Data System (ADS)

    Piqué, Alberto; Charipar, Nicholas A.; Kim, Heungsoo; Auyeung, Ray C. Y.; Mathews, Scott A.

    2007-03-01

    The use of direct-write techniques might revolutionize the way microelectronic devices such as interconnects, passives, IC's, antennas, sensors and power sources are designed and fabricated. The Naval Research Laboratory has developed a laser-based microfabrication process for direct-writing the materials and components required for the assembly and interconnection of the above devices. This laser direct-write (LDW) technique is capable of operating in subtractive, additive, and transfer mode. In subtractive mode, the system operates as a laser micromachining workstation capable of achieving precise depth and surface roughness control. In additive mode, the system utilizes a laser-forward transfer process for the deposition of metals, oxides, polymers and composites under ambient conditions onto virtually any type of surface, thus functioning as a laser printer for patterns of electronic materials. Furthermore, in transfer mode, the system is capable of transferring individual devices, such as semiconductor bare die or surface mount devices, inside a trench or recess in a substrate, thus performing the same function of the pick-and-place machines used in circuit board manufacture. The use of this technique is ideally suited for the rapid prototyping of embedded microelectronic components and systems while allowing the overall circuit design and layout to be easily modified or adapted to any specific application or form factor. This paper describes the laser direct-write process as applied to the forward transfer of microelectronic devices.

  12. Low Energy Laser Biostimulation: New Prospects For Medical Applications

    NASA Astrophysics Data System (ADS)

    Castel, John C.; Abergel, R. Patrick; Willner, Robert E.; Baumann, James G.

    1987-03-01

    The therapeutic benefits of light-energy is not a new concept to the modern world. Documented applications from ancient times tell of the therapeutic effects of ordinary sun-light to treat such common ailments as painful body joints, wounds, compound fractures and tetanus. The discovery of laser light in the 1960's, opened up new prospects for the medical use of light. Laser light differs from other forms of electromagnetic spectrum in that a single wavelength rather than a spectrum of wavelengths is emitted. Since the early 1970's, low-energy laser radiation has been reported to enhance wound healing rates, reduce edema, and relieve musculoskeletal pain. There is no detectable thermal effect of this laser on the tissue being treated. The effects are considered to occur as a result of photochemical, non thermal effects of the laser beam. Photons are absorbed by the tissue being treated and, in turn, produce positive therapeutic effects such as reduction of pain and edema. Pre-clinical and clinical evaluations are, presently, underway to document the safety and efficacy of low energy laser therapy, which represents a significant advance in the non-invasive treatment of pain.

  13. Confocal scanning beam laser microscope/macroscope: applications in fluorescence

    NASA Astrophysics Data System (ADS)

    Dixon, Arthur E.; Damaskinos, Savvas; Ribes, Alfonso

    1996-03-01

    A new confocal scanning beam laser microscope/macroscope is described that combines the rapid scan of a scanning beam laser microscope with the large specimen capability of a scanning stage microscope. This instrument combines an infinity-corrected confocal scanning laser microscope with a scanning laser macroscope that uses a telecentric f*(Theta) laser scan lens to produce a confocal imaging system with a resolution of 0.25 microns at a field of view of 25 microns and 5 microns at a field of view of 75,000 microns. The frame rate is 5 seconds per frame for a 512 by 512 pixel image, and 25 seconds for a 2048 by 2048 pixel image. Applications in fluorescence are discussed that focus on two important advantages of the instrument over a confocal scanning laser microscope: an extremely wide range of magnification, and the ability to image very large specimens. Examples are presented of fluorescence and reflected-light images of high quality printing, fluorescence images of latent fingerprints, packaging foam, and confocal autofluorescence images of a cricket.

  14. New trends in laser shock wave physics and applications

    NASA Astrophysics Data System (ADS)

    Peyre, Patrice; Carboni, Christelle; Sollier, Arnault; Berthe, Laurent; Richard, Caroline; de Los Rios, E.; Fabbro, Remy

    2002-09-01

    Recent applications for laser-induced shock waves have been demonstrated in the aeronautical and nuclear industries, due to the development of new generations of lasers that enable high cadency rates with rather small designs. In this paper, we first aim at making an overview on basic physical processes involved in Laser Shock Processing, and a presentation of pressure loadings generated by different laser conditions. In a second part, a specific focus is given to new ranges of applications like wear resistance, uniform and localized corrosion or modeling of fatigue behaviour after LSP. For instance it is demonstrated that the pitting corrosion behaviour of 316L steel in saline medium can be improved by laser-induced pure mechanical effects surrounding inclusions. It is also shown that wear rates of a 100Cr6 tool steel can be reduced after LSP provided applied pressures are kept below a material deposit threshold. Last but not least, the fatigue cracking behaviour of 2024-T351 aluminum alloy after LSP was improved and calculated through a computed program taking into account work hardening together with residual stress effects.

  15. Satellite laser ranging and its applications

    NASA Technical Reports Server (NTRS)

    Tapley, B. D.; Schutz, B. E.; Eanes, R. J.

    1985-01-01

    Satellite laser ranging (SLR) provides an important capability for precise orbit determination and for geophysical parameter estimation to support a number of contemporary geodynamic and oceanographic investigations. The precision of the SLR measurement has improved from the early meter-level systems to the current capabilities of a few centimeters for the best systems. The accuracy of the orbits and geophysical parameter recovery have shown an associated improvement. Polar motion with accuracies of 2 mas, station coordinates better than 10 cm, and interstation baseline rates indicative of tectonic motion are determined routinely with the current set of global SLR data. This discussion reviews the SLR measurement, analysis approach, and some of the recent results derived from the current SLR data set.

  16. Solid state laser applications in photovoltaics manufacturing

    NASA Astrophysics Data System (ADS)

    Dunsky, Corey; Colville, Finlay

    2008-02-01

    Photovoltaic energy conversion devices are on a rapidly accelerating growth path driven by increasing government and societal pressure to use renewable energy as part of an overall strategy to address global warming attributed to greenhouse gas emissions. Initially supported in several countries by generous tax subsidies, solar cell manufacturers are relentlessly pushing the performance/cost ratio of these devices in a quest to reach true cost parity with grid electricity. Clearly this eventual goal will result in further acceleration in the overall market growth. Silicon wafer based solar cells are currently the mainstay of solar end-user installations with a cost up to three times grid electricity. But next-generation technology in the form of thin-film devices promises streamlined, high-volume manufacturing and greatly reduced silicon consumption, resulting in dramatically lower per unit fabrication costs. Notwithstanding the modest conversion efficiency of thin-film devices compared to wafered silicon products (around 6-10% versus 15-20%), this cost reduction is driving existing and start-up solar manufacturers to switch to thin-film production. A key aspect of these devices is patterning large panels to create a monolithic array of series-interconnected cells to form a low current, high voltage module. This patterning is accomplished in three critical scribing processes called P1, P2, and P3. Lasers are the technology of choice for these processes, delivering the desired combination of high throughput and narrow, clean scribes. This paper examines these processes and discusses the optimization of industrial lasers to meet their specific needs.

  17. Laser heating of dielectric particles for medical and biological applications.

    PubMed

    Tribelsky, Michael I; Fukumoto, Yasuhide

    2016-07-01

    We consider the general problem of laser pulse heating of a spherical dielectric particle embedded in a liquid. The discussed range of the problem parameters is typical for medical and biological applications. We focus on the case, when the heat diffusivity in the particle is of the same order of magnitude as that in the fluid. We perform quantitative analysis of the heat transfer equation based on interplay of four characteristic scales of the problem, namely the particle radius, the characteristic depth of light absorption in the material of the particle and the two heat diffusion lengths: in the particle and in the embedding liquid. A new quantitative characteristic of the laser action, that is the cooling time, describing the temporal scale of the cooling down of the particle after the laser pulse is over, is introduced and discussed. Simple analytical formulas for the temperature rise in the center of the particle and at its surface as well as for the cooling time are obtained. We show that at the appropriate choice of the problem parameters the cooling time may be by many orders of magnitude larger the laser pulse duration. It makes possible to minimize the undesirable damage of healthy tissues owing to the finite size of the laser beam and scattering of the laser radiation, simultaneously keeping the total hyperthermia period large enough to kill the pathogenic cells. An example of application of the developed approach to optimization of the therapeutic effect at the laser heating of particles for cancer therapy is presented. PMID:27446706

  18. Laser heating of dielectric particles for medical and biological applications

    PubMed Central

    Tribelsky, Michael I.

    2016-01-01

    We consider the general problem of laser pulse heating of a spherical dielectric particle embedded in a liquid. The discussed range of the problem parameters is typical for medical and biological applications. We focus on the case, when the heat diffusivity in the particle is of the same order of magnitude as that in the fluid. We perform quantitative analysis of the heat transfer equation based on interplay of four characteristic scales of the problem, namely the particle radius, the characteristic depth of light absorption in the material of the particle and the two heat diffusion lengths: in the particle and in the embedding liquid. A new quantitative characteristic of the laser action, that is the cooling time, describing the temporal scale of the cooling down of the particle after the laser pulse is over, is introduced and discussed. Simple analytical formulas for the temperature rise in the center of the particle and at its surface as well as for the cooling time are obtained. We show that at the appropriate choice of the problem parameters the cooling time may be by many orders of magnitude larger the laser pulse duration. It makes possible to minimize the undesirable damage of healthy tissues owing to the finite size of the laser beam and scattering of the laser radiation, simultaneously keeping the total hyperthermia period large enough to kill the pathogenic cells. An example of application of the developed approach to optimization of the therapeutic effect at the laser heating of particles for cancer therapy is presented. PMID:27446706

  19. Ultraprecise medical applications with ultrafast lasers: corneal surgery with femtosecond lasers

    NASA Astrophysics Data System (ADS)

    Loesel, Frieder H.; Kurtz, Ron M.; Horvath, Christopher; Sayegh, Samir I.; Mourou, Gerard A.; Bille, Josef F.; Juhasz, Tibor

    1999-02-01

    We investigated refractive corneal surgery in vivo and in vitro by intrastromal photodisruption using a compact ultrafast femtosecond laser system. Ultrashort-pulsed lasers operating in the femtosecond time regime are associated with significantly smaller and deterministic threshold energies for photodisruption, as well as reduced shock waves and smaller cavitation bubbles than the nanosecond or picosecond lasers. Our reliable all-solid-state laser system was specifically designed for real world medical applications. By scanning the 5 micron focus spot of the laser below the corneal surface, the overlapping small ablation volumes of single pulses resulted in contiguous tissue cutting and vaporization. Pulse energies were typically in the order of a few microjoules. Combination of different scanning patterns enabled us to perform corneal flap cutting, femtosecond-LASIK, and femtosecond intrastromal keratectomy in porcine, rabbit, and primate eyes. The cuts proved to be highly precise and possessed superior dissection and surface quality. Preliminary studies show consistent refractive changes in the in vivo studies. We conclude that the technology is capable to perform a variety of corneal refractive procedures at high precision, offering advantages over current mechanical and laser devices and enabling entirely new approaches for refractive surgery.

  20. Application and the key technology on high power fiber-optic laser in laser weapon

    NASA Astrophysics Data System (ADS)

    Qu, Zhou; Li, Qiushi; Meng, Haihong; Sui, Xin; Zhang, Hongtao; Zhai, Xuhua

    2014-12-01

    The soft-killing laser weapon plays an important role in photoelectric defense technology. It can be used for photoelectric detection, search, blinding of photoelectric sensor and other devices on fire control and guidance devices, therefore it draws more and more attentions by many scholars. High power fiber-optic laser has many virtues such as small volume, simple structure, nimble handling, high efficiency, qualified light beam, easy thermal management, leading to blinding. Consequently, it may be used as the key device of soft-killing laser weapon. The present study introduced the development of high power fiber-optic laser and its main features. Meanwhile the key technology of large mode area (LMA) optical fiber design, the beam combination technology, double-clad fiber technology and pumping optical coupling technology was stated. The present study is aimed to design high doping LMA fiber, ensure single mode output by increasing core diameter and decrease NA. By means of reducing the spontaneous emission particle absorbed by fiber core and Increasing the power density in the optical fiber, the threshold power of nonlinear effect can increase, and the power of single fiber will be improved. Meantime, high power will be obtained by the beam combination technology. Application prospect of high power fiber laser in photoelectric defense technology was also set forth. Lastly, the present study explored the advantages of high power fiber laser in photoelectric defense technology.

  1. Note: external multipass optical trap for counterpropagating pulsed laser applications.

    PubMed

    Graul, J S; Ketsdever, A D; Andersen, G P; Lilly, T C

    2013-07-01

    Pulses from a 12 mJ, frequency doubled, 5 ns FWHM, pulsed Nd:YAG laser were split and injected into opposing sides of a symmetric 2.44 m (96 in.) optical ring trap. Using a Pockels cell, the counterpropagating pulses were "locked" into the trap for ≥50 round trips. This optical trap has potential applications ranging from established cavity processes, e.g., laser-based absorption spectroscopy and x-ray production, to new processes such as non-resonant optical lattice gas heating and time-resolved coherent Rayleigh-Brillouin scattering diagnostic studies. PMID:23902119

  2. Application of in vivo laser scanning microscope in dermatology

    NASA Astrophysics Data System (ADS)

    Lademann, Juergen; Richter, H.; Otberg, N.; Lawrenz, F.; Blume-Peytavi, U.; Sterry, W.

    2003-10-01

    The state of the art of in-vivo and in-vitro penetration measurements of topically applied substances is described. Only optical techniques represent online measuring methods based on the absorption or scattering properties of the topically applied substances. Laser scanning microscopy (LSM) has become a promising method for investigations in dermatology and skin physiology, after it was possible to analyze the skin surface on any body side in-vivo. In the present paper the application of a dermatological laser scanning microscope for penetration and distribution measurements of topically applied substances is described. The intercellular and follicular penetration pathways were studied.

  3. Note: External multipass optical trap for counterpropagating pulsed laser applications

    NASA Astrophysics Data System (ADS)

    Graul, J. S.; Ketsdever, A. D.; Andersen, G. P.; Lilly, T. C.

    2013-07-01

    Pulses from a 12 mJ, frequency doubled, 5 ns FWHM, pulsed Nd:YAG laser were split and injected into opposing sides of a symmetric 2.44 m (96 in.) optical ring trap. Using a Pockels cell, the counterpropagating pulses were "locked" into the trap for ≥50 round trips. This optical trap has potential applications ranging from established cavity processes, e.g., laser-based absorption spectroscopy and x-ray production, to new processes such as non-resonant optical lattice gas heating and time-resolved coherent Rayleigh-Brillouin scattering diagnostic studies.

  4. Recommendations and guidelines for safe medical laser application

    NASA Astrophysics Data System (ADS)

    Meier, Thomas H.

    1996-12-01

    The better understanding of generation of by-products during laser application allows a rough risk assessment, which in turn results in a number of recommendations and guidelines. The main attention is directed to smoke evacuation systems in connection with sufficient room ventilation, both being obligatory for any invasive laser therapy. Minimal requirements and optimal use of such units are discussed and practical examples are presented. The important role of personal protection measures is pointed out. These measures are not new and more or less practiced in the past. However, they have been justified now in detail by the comprehensive investigations during the STILMED project.

  5. Advanced tunable laser source for DoD applications

    SciTech Connect

    Cockroft, N.; Early, J.; Johnson, C.; Lester, C.; Quick, C.; Shimada, T.; Tiee, J.

    1996-06-01

    This is a final report of a two year project at the Los Alamos National Laboratory (LANL). The project sought to develop a new solid- state laser transmitter that can be tuned over an exceptionally broad spectral range and integrated with LIDAR remote sensing systems for applications in species specific chemical sensing. Activities have included non-linear frequency conversion of tunable chromium doped LiSAF laser radiation to the ultraviolet and infrared spectral regions. This system is capable of the detection of chemical species previously unapproachable, as well as an improvement in detection sensitivity of 1-2 orders of magnitude for species currently studied.

  6. Ex vivo laser lipolysis assisted with radially diffusing optical applicator

    NASA Astrophysics Data System (ADS)

    Hwang, Jieun; Hau, Nguyen Trung; Park, Sung Yeon; Rhee, Yun-Hee; Ahn, Jin-Chul; Kang, Hyun Wook

    2016-05-01

    Laser-assisted lipolysis has been implemented to reduce body fat in light of thermal interactions with adipose tissue. However, using a flat fiber with high irradiance often needs rapid cannula movements and even undesirable thermal injury due to direct tissue contact. The aim of the current study was to explore the feasibility of a radially diffusing optical applicator to liquefy the adipose tissue for effective laser lipolysis. The proposed diffuser was evaluated with a flat fiber in terms of temperature elevation and tissue liquefaction after laser lipolysis with a 980-nm wavelength. Given the same power (20 W), the diffusing applicator generated a 30% slower temperature increase with a 25% lower maximum temperature (84±3.2°C in 1 min p<0.001) in the tissue, compared with the flat fiber. Under the equivalent temperature development, the diffuser induced up to fivefold larger area of the adipose liquefaction due to radial light emission than the flat fiber. Ex vivo tissue tests for 5-min irradiation demonstrated that the diffuser (1.24±0.15 g) liquefied 66% more adipose tissue than the flat fiber (0.75±0.05 g). The proposed diffusing applicator can be a feasible therapeutic device for laser lipolysis due to low temperature development and wide coverage of thermal treatment.

  7. Application of Laser Imaging for Bio/geophysical Studies

    NASA Technical Reports Server (NTRS)

    Hummel, J. R.; Goltz, S. M.; Depiero, N. L.; Degloria, D. P.; Pagliughi, F. M.

    1992-01-01

    SPARTA, Inc. has developed a low-cost, portable laser imager that, among other applications, can be used in bio/geophysical applications. In the application to be discussed here, the system was utilized as an imaging system for background features in a forested locale. The SPARTA mini-ladar system was used at the International Paper Northern Experimental Forest near Howland, Maine to assist in a project designed to study the thermal and radiometric phenomenology at forest edges. The imager was used to obtain data from three complex sites, a 'seed' orchard, a forest edge, and a building. The goal of the study was to demonstrate the usefulness of the laser imager as a tool to obtain geometric and internal structure data about complex 3-D objects in a natural background. The data from these images have been analyzed to obtain information about the distributions of the objects in a scene. A range detection algorithm has been used to identify individual objects in a laser image and an edge detection algorithm then applied to highlight the outlines of discrete objects. An example of an image processed in such a manner is shown. Described here are the results from the study. In addition, results are presented outlining how the laser imaging system could be used to obtain other important information about bio/geophysical systems, such as the distribution of woody material in forests.

  8. Blue laser diode (LD) and light emitting diode (LED) applications

    NASA Astrophysics Data System (ADS)

    Bergh, Arpad A.

    2004-09-01

    The family of blue LEDs, edge emitting and surface emitting lasers, enable a number of applications. Blue lasers are used in digital applications such as optical storage in high density DVDs. The resolution of the spot size and hence the storage density is diffraction limited and is inversely proportional to the square of the wavelength of the laser. Other applications include printing, optical scanners, and high-resolution photo-lithography.As light emitters, blue LEDs are used for signaling and in direct view large area emissive displays. They are also making inroads into signage and LCD back-lighting, mobile platforms, and decorative accent lighting in curtains, furniture, etc.Blue LEDs produce white light either with phosphor wavelength converters or in combination with red and green LEDs. The full potential of LED light sources will require three devices to enable complete control over color and intensity.Sensing and medical/bio applications have a major impact on home security, on monitoring the environment, and on health care. New emerging diagnostic and therapeutic applications will improve the quality and reduce the cost of health care.

  9. Laser-induced stress transients: applications for molecular delivery

    NASA Astrophysics Data System (ADS)

    Flotte, Thomas J.; Lee, Shun; Zhang, Hong; McAuliffe, Daniel J.; Douki, Tina; Doukas, Apostolos G.

    1995-05-01

    Lasers can be used to enhance the delivery of a number of molecules. Other investigators have demonstrated local release of molecules from liposomes following laser irradiation, microbeam disruption of the cell membrane to increase cell transport, microbeam ablation of the zona pellucida surrounding the ovum to increase the chances of fertilization, and increased transcutaneous transport following ablation of the stratum corneum. Our experiments have shown that laser-induced stress transients can be utilized as a vector for intracellular delivery of molecules that may or may not normally cross the cell membrane. These two conditions have been tested with Photofrin and DNA. This technology may have applications in cell and molecular biology, cancer therapy, gene therapy, and others.

  10. Scaling of solid state lasers for satellite power beaming applications

    SciTech Connect

    Friedman, H.; Albrecht, G.; Beach, R.

    1994-12-31

    The power requirements for a satellite power beaming laser system depend upon the diameter of the beam director, the performance of the adaptive optics system, and the mission requirements. For an 8 meter beam director and overall Strehl ratio of 50%, a 30 kW laser at 850 nm can deliver an equivalent solar flux to a satellite at geostationary orbit. Advances in Diode Pumped Solid State Lasers (DPSSL) have brought these small, efficient and reliable devices to high average power and they should be considered for satellite power beaming applications. Two solid state systems are described: a diode pumped Alexandrite and diode pumped Thulium doped YAG. Both can deliver high average power at 850 nm in a single aperture.

  11. Scaling of solid state lasers for satellite power beaming applications

    SciTech Connect

    Friedman, H.W.; Albrecht, G.F.; Beach, R.J.

    1994-01-01

    The power requirements for a satellite power beaming laser system depend upon the diameter of the beam director, the performance of the adaptive optics system, and the mission requirements. For an 8 meter beam director and overall Strehl ratio of 50%, a 30 kW laser at 850 nm can deliver an equivalent solar flux to a satellite at geostationary orbit. Advances in Diode Pumped Solid State Lasers (DPSSL) have brought these small, efficient and reliable devices to high average power and they should be considered for satellite power beaming applications. Two solid state systems are described: a diode pumped Alexandrite and diode pumped Thulium doped YAG. Both can deliver high average power at 850 nm in a single aperture.

  12. Compact laser diode drivers for military rangefinder applications

    NASA Astrophysics Data System (ADS)

    Giorgi, D.; Philippbar, J.

    2010-04-01

    Compact and high current laser diode drivers for pumping solid-state lasers have been developed and tested. Designed to operate from a single DL123 battery or equivalent, the OptiSwitch PLDD-150-1-1 delivers 150 A of peak current for 300 μs to a laser diode bar at a 1 Hz repetition rate. Measuring only 2.1 × 0.75 × 0.78 inches and weighing 15.2 g, the unit is suited for man-portable target designation, rangefinding, illumination, and remote sensing applications. This paper will discuss the design philosophy behind this class of drivers which offer peak currents up to 200 A plus lifetime testing of eight drivers all operating at elevated input voltage and temperature at 4.5 Hz for 10M shots without a single failure or degradation in performance. Lastly, temperature testing down to -40 degC will be discussed.

  13. Ultra high brightness laser diode arrays for pumping of compact solid state lasers and direct applications

    NASA Astrophysics Data System (ADS)

    Kohl, Andreas; Fillardet, Thierry; Laugustin, Arnaud; Rabot, Olivier

    2012-10-01

    High Power Laser Diodes (HPLD) are increasingly used in different fields of applications such as Industry, Medicine and Defense. Our significant improvements of performances (especially in power and efficiency) and a reproducible manufacturing process have led to reliable, highly robust components. For defense and security applications these devices are used predominantly for pumping of solid state lasers (ranging, designation, countermeasures, and sensors). Due to the drastically falling price per watt they are more and more replacing flash lamps as pump sources. By collimating the laser beam even with a bar to bar pitch of only 400μm. cutting edge brightness of our stacks.is achieved Due the extremely high brightness and high power density these stacks are an enabling technology for the development of compact highly efficient portable solid state lasers for applications as telemeters and designators on small platforms such as small UAVs and handheld devices. In combination with beam homogenizing optics their compact size and high efficiency makes these devices perfectly suited as illuminators for portable active imaging systems. For gated active imaging systems a very short pulse at high PRF operation is required. For this application we have developed a diode driver board with an efficiency several times higher than that of a standard driver. As a consequence this laser source has very low power consumption and low waste heat dissipation. In combination with its compact size and the integrated beam homogenizing optics it is therefore ideally suited for use in portable gated active imaging systems. The kWatt peak power enables a range of several hundred meters. The devices described in this paper mostly operate at wavelength between 800 nm and 980nm. Results from diodes operating between 1300 nm and 1550 nm are presented as well.

  14. New Applications of Lasers in Photobiology and Photochemistry

    NASA Astrophysics Data System (ADS)

    Badr, Y.; Kareim, M. A.

    2005-03-01

    Photonics spectra and optical medical diagnostic field for examination of biological tissues generally and human body specially cover many spectroscopic and laser technologies based on NIR spectroscopy, fluorescence and Raman spectroscopy, Optical coherent tomography (OCT), Confocal microscopy, Opto-acoustic tomography, photon correlation spectroscopy and imaging, and Speckle monitoring of biological flows. The recent achievements in light scattering and coherent light effects in tissues, and in the design of novel lasers and fiber optic techniques for examination of biological tissues are the real motive and the attracting factor for many labs to consider the mentioned above techniques. Our lab, as it contains most of these facilities, started to use these technologies since 1997 in several applications: 1. Applying a suitable setup for introducing exogenous DNA of pAB (with bar/ Gus gene) into cells of embryonic collie of Egyptian wheat based on 193 and 608 nm, 6 ns Excimer laser pulses introducing a modified procedure of Laser-Mediated gene transfer in Egyptian wheat Tridum Aestivum. 2. Applying laser technologies in early identification of abnormal tissues spectroscopically 3. We considered several types of tissues starting with breast cancer, which was subjected to intensive spectroscopic studies using NIR, MIR, FIR, Raman spectroscopy as well as photo-acoustic spectroscopy and imaging studies. Cell carcinoma was considered using Raman spectroscopy and a clear distinction between normal tissue before and after introduction of cell cancer as well as after treating of the tissues using PDT. 4. The application of 193 nm Excimer laser pulse to study photolysis of Acetone using time resolved spectroscopy. A locally designed setup was used to study the effect of delay time (1μs, 2μs, …., 10μs,….,50μs) on the CO and CH3 radicals resulting from the photolysis.

  15. Tunable Single-Frequency Near IR Lasers for DIAL Applications

    NASA Technical Reports Server (NTRS)

    Henderson, Sammy W.; Marquardt, John H.; Carrig, Timothy J.; Gatt, Phil; Smith, Duane D.; Hale, Charley P.

    2000-01-01

    Tunable single-frequency sources in the 2-4 micron wavelength region are useful for remote DIAL measurements of chemicals and pollutants. We are developing tunable single-frequency transmitters and receivers for both direct and coherent detection lidar measurement applications. We have demonstrated a direct-diode-pumped PPLN-based OPO that operates single frequency, produces greater than 10 mW cw and is tunable over the 2.5 - 3.9 micron wavelength region. This laser has been used to injection seed a pulsed PPLN OPO, pumped by a 1.064 micron Nd:YAG laser, producing 50-100 microJoule single-frequency pulses at 100 Hz PRF near 3.6 micron wavelength. In addition, we have demonstrated a cw Cr:ZnSe laser that is tunable over the 2.1 - 2.8 micron wavelength region. This laser is pumped by a cw diode-pumped Tm:YALO laser and has produced over 1.8 W cw. Tm- and Tm, Ho-doped single-frequency solid-state lasers that produce over 50 mW cw and are tunable over approximately 10 nm in the 2 -2.1 micron band with fast PZT tuning have also been demonstrated. A fast PZT-tunable Tm, Ho:YLF laser was used for a direct-detection column content DIAL measurement of atmospheric CO2. Modeling shows that that all these cw and pulsed sources are useful for column-content coherent DIAL measurements at several km range using topographic targets.

  16. Types of Lasers and Their Applications in Pediatric Dentistry

    PubMed Central

    Nazemisalman, Bahareh; Farsadeghi, Mahya; Sokhansanj, Mehdi

    2015-01-01

    Laser technology has been recently introduced into the dental field with the idea to replace drilling. Having a less painful first dental experience by the use of modern instruments like laser can be an efficient preventive and therapeutic strategy in pediatric dentistry. Pedodontists need to learn the new less invasive technologies and adopt them in their routine practice. This study aimed to review the available types of lasers and their applications in pediatric dentistry. An electronic search was carried out in IranMedex, InterScience, Scopus, Science Direct, PubMed, ProQuest, Medline and Google Scholar databases to find relevant articles published from 2000 to 2014. Relevant textbooks were reviewed as well. Laser can be used as a suitable alternative to many conventional diagnostic and therapeutic dental procedures. It is especially efficient for caries detection and removal, pulp therapy, lowering the risk of infection, inflammation and swelling and reducing bleeding. On the other hand, due to minimal invasion, laser treatment is well tolerated by children. Improved patient cooperation leads to higher satisfaction of the parents, dentists and the children themselves. PMID:26464775

  17. Laser Pyrolysis Techniques: Application To Catalysis, Combustion Diagnostics, And Kinetics

    NASA Astrophysics Data System (ADS)

    Smith, Gregory P.

    1984-05-01

    A pulsed laser pyrolysis method has been developed to study kinetic processes at high temperatures. A CO2 laser is used to irradiate a 100 torr mixture of an infrared absorber (SF6), bath gas (N2), and reactants. Rapid heating to 700-1400 K occurs, followed by two-stage cooling. Unimolecular reactions are studied by competitive kinetics with a known standard, using mass-spectrometric or gas-chromatographic analysis. Bimolecular processes are examined using laser-induced fluorescence (LIF). The technique offers great advantages in reaching reactive temperatures in a fast and time-resolved manner, without the complications of hot surfaces. It is thus an ideal tool for analyzing and measuring some of the basic processes occurring in more complicated, real, hot systems. Our recent applications of the laser pyrolysis method in the areas of catalysis and combustion are summarized here. Several transition metal-carbonyl bond dissociation energies have been measured, and catalysis by the hot metal particulate products was observed. Since the use of LIF as a flame diagnotic requires some knowledge of the fluorescence quenching rates at high temperatures, the laser pyrolysis method was used to measure these rates for the important OH radical. Its reaction rate with acetylene was also measured, with implications for flame modeling and the mechanism of soot formation. Finally, this method can be used to ignite low concentrations of fuel and oxidant, and then study the time-resolved evolution of the flame chemistry by LIF and chemiluminescence observations.

  18. Laser Processing of Metal Oxides for Plasmonic Applications

    NASA Astrophysics Data System (ADS)

    Kim, Heungsoo; Breckenfeld, Eric; Charipar, Nicholas; Pique, Alberto

    Noble metals such as Au and Ag have been used traditionally for plasmonic devices. However, conventional metals are not suitable for near infrared (IR) plasmonic applications due to their relatively large optical losses at these wavelengths. Metal oxides, on the other hand, have been considered for low loss metallic components in the near IR because they can provide a tunable carrier density by doping. The zero-cross-over permittivity values of these metal oxides, for example, can easily be tuned from 1.0 µm to 3 µm by adjusting doping levels. Optical losses in devices made from these metal oxide materials are generally found to be much lower than those obtained with conventional metals. We have investigated various laser processing techniques for synthesizing several types of metal oxides. First, pulsed laser deposition was used to grow metal oxide thin films such as, Al-doped ZnO, Sn-doped In2O3 and VO2. Second, a laser sintering technique was used to improve the properties of solution-processed VO2 coatings. Third, a laser printing technique was used to produce metal oxide films. We will present details on the use of laser processing techniques for synthesizing these metal oxides along with their electrical, optical, and structural properties. This work was funded by the Office of Naval Research (ONR) through the Naval Research Laboratory Basic Research Program.

  19. Development of fiber-based laser anemometer for SSME application

    NASA Technical Reports Server (NTRS)

    Modarress, Dariush; Fan, Robert

    1989-01-01

    A recent study by Rocketdyne for NASA identified laser anemometry, using a compact optical head, as a feasible diagnostic instrument for the Space Shuttle Main Engine (SSME) Model Verification experiments. Physical Research, Inc. (PRI) is presently under contract from NASA Lewis to develop and deliver such a laser anemometer system. For this application, it is desired to place the laser at a remote distance from the engine, and use single mode polarization preserving fiber optics for the transmission of the laser light to and from the measurement head. Other requirements are given. Analytical and experimental tools are being used to develop the technologies required for the laser anemometer. These include finite element analysis of the optical head and vibration tests for various optical and mechanical components. Design of the optical head and the fiber optic connectors are driven by the temperature and vibration requirements for the measurement environment. Results of the finite element analysis and the vibration tests of the components are included. Conceptual design of the fiber optic launcher and the optical probe has also been complete. Detailed design of the probe as well as the fabrication and assembly of the components is in progress.

  20. Laser acceleration of low emittance, high energy ions and applications

    NASA Astrophysics Data System (ADS)

    Fuchs, Julien; Audebert, Patrick; Borghesi, Marco; Pépin, Henri; Willi, Oswald

    2009-03-01

    Laser-accelerated ion sources have exceptional properties, i.e. high brightness and high spectral cut-off (56 MeV at present), high directionality and laminarity (at least 100-fold better than conventional accelerators beams), short burst duration (ps). Thanks to these properties, these sources open new opportunities for applications. Among these, we have already explored their use for proton radiography of fields in plasmas and for warm dense matter generation. These sources could also stimulate development of compact ion accelerators or be used for medical applications. To extend the range of applications, ion energy and conversion efficiency must however be increased. Two strategies for doing so using present-day lasers have been successfully explored in LULI experiments. In view of applications, it is also essential to control (i.e. collimate and energy select) these beams. For this purpose, we have developed an ultra-fast laser-triggered micro-lens providing tuneable control of the beam divergence as well as energy selection. To cite this article: J. Fuchs et al., C. R. Physique 10 (2009).

  1. Laser beacon adaptive optics for power beaming applications

    SciTech Connect

    Fugate, R.Q.

    1994-12-31

    This paper discusses the laser beam control system requirements for power beaming applications. Power beaming applications include electric and thermal engine propulsion for orbit transfer, station changing, and recharging batteries. Beam control includes satellite acquisition, high accuracy tracking, higher order atmospheric compensation using adaptive optics, and precision point-ahead. Beam control may also include local laser beam clean-up with a low order adaptive optics system. This paper also presents results of tracking and higher-order correction experiments on astronomical objects. The results were obtained with a laser beacon adaptive optics system at Phillips Laboratory`s Starfire Optical Range near Albuquerque, NM. At a wavelength of 0.85 {mu}m, the author has achieved Strehl ratios of {approximately}0.50 using laser beacons and {approximately}0.65 using natural stars for exposures longer than one minute on objects of {approximately}8{sup th} magnitude. The resulting point spread function has a full width half maximum (FWHM) of 0.13 arcsec.

  2. Laser-launched flyer plate and confined laser ablation for shock wave loading: validation and applications.

    PubMed

    Paisley, Dennis L; Luo, Sheng-Nian; Greenfield, Scott R; Koskelo, Aaron C

    2008-02-01

    We present validation and some applications of two laser-driven shock wave loading techniques: laser-launched flyer plate and confined laser ablation. We characterize the flyer plate during flight and the dynamically loaded target with temporally and spatially resolved diagnostics. With transient imaging displacement interferometry, we demonstrate that the planarity (bow and tilt) of the loading induced by a spatially shaped laser pulse is within 2-7 mrad (with an average of 4+/-1 mrad), similar to that in conventional techniques including gas gun loading. Plasma heating of target is negligible, in particular, when a plasma shield is adopted. For flyer plate loading, supported shock waves can be achieved. Temporal shaping of the drive pulse in confined laser ablation allows for flexible loading, e.g., quasi-isentropic, Taylor-wave, and off-Hugoniot loading. These techniques can be utilized to investigate such dynamic responses of materials as Hugoniot elastic limit, plasticity, spall, shock roughness, equation of state, phase transition, and metallurgical characteristics of shock-recovered samples. PMID:18315311

  3. Numerical modeling of arc plasma generator for chemical laser applications

    NASA Astrophysics Data System (ADS)

    Sagar, Vidya; Ravikant, Chhaya; Singhal, Gaurav; Mittal, Alok P.

    2012-05-01

    The results of the numerical modeling of arc discharge phenomenon relevant to hydrogen fluoride/deuterium fluoride (HF/DF) laser applications are given. The overall mechanics of arc discharge phenomena on the basis of numerical modeling employing the commercial code COMSOL is discussed. The equations for a 2D axisymmetric, weakly compressible, laminar flow with heat transfer and the coupled hydrodynamic and electromagnetic equations are solved using the SIMPLE algorithm. The variations in the material properties, temperature, and velocity due to the generated arc are studied. A comparison of the results obtained with those from the studies available in the literature validates the computational data. Since each designed plasma arc tunnel is unique in itself and specific in application, this would enable one to alter arc discharge parameters to optimize a specific laser.

  4. Laser-based profilometry -- Ever-expanding applications

    SciTech Connect

    Doyle, J.L.

    1996-12-31

    Over the past ten years, laser-based profilometry has evolved from a near-novelty to a reliable and cost-effective NDE technology. Employing miniature optics, high-speed digital signal processing electronics, and computer-graphic data presentation, systems have been developed for a broad spectrum of NDE and QC applications. These tools are not only capable of providing a high-resolution three-dimensional profile of the test surface but also a monochrome laser-video image of the surface. These devices are now being used for the inspection of tubular goods less than 5 mm in diameter, rifled gun tubes, and process piping. In addition, the technology has been extended to operation underwater and to the profiling of complex surfaces such as nuclear recirculation nozzles and solid rocket motors. This paper presents an overview of this rapidly growing NDE method and provides examples of recent industrial applications.

  5. Applications of laser-induced gratings to spectroscopy and dynamics

    SciTech Connect

    Rohlfing, E.A.

    1993-12-01

    This program has traditionally emphasized two principal areas of research. The first is the spectroscopic characterization of large-amplitude motion on the ground-state potential surface of small, transient molecules. The second is the reactivity of carbonaceous clusters and its relevance to soot and fullerene formation in combustion. Motivated initially by the desire to find improved methods of obtaining stimulated emission pumping (SEP) spectra of transients, most of our recent work has centered on the use of laser-induced gratings or resonant four-wave mixing in free-jet expansions. These techniques show great promise for several chemical applications, including molecular spectroscopy and photodissociation dynamics. The author describes recent applications of two-color laser-induced grating spectroscopy (LIGS) to obtain background-free SEP spectra of transients and double resonance spectra of nonfluorescing species, and the use of photofragment transient gratings to probe photodissociation dynamics.

  6. Applications of Light Amplification by Stimulated Emission of Radiation (Lasers) for Restorative Dentistry.

    PubMed

    Najeeb, Shariq; Khurshid, Zohaib; Zafar, Muhammad Sohail; Ajlal, Syed

    2016-01-01

    Light amplification by stimulated emission of radiation (laser) has been used widely in a range of biomedical and dental applications in recent years. In the field of restorative dentistry, various kinds of lasers have been developed for diagnostic (e.g. caries detection) and operative applications (e.g. tooth ablation, cavity preparation, restorations, bleaching). The main benefits for laser applications are patient comfort, pain relief and better results for specific applications. Major concerns for using dental lasers frequently are high cost, need for specialized training and sensitivity of the technique, thereby compromising its usefulness particularly in developing countries. The main aim of this paper is to evaluate and summarize the applications of lasers in restorative dentistry, including a comparison of the applications of lasers for major restorative dental procedures and conventional clinical approaches. A remarkable increase in the use of lasers for dental application is expected in the near future. PMID:26642047

  7. Novel oral applications of ultra-short laser pulses

    NASA Astrophysics Data System (ADS)

    Wieger, V.; Wernisch, J.; Wintner, E.

    2007-02-01

    In the past decades, many efforts have been made to replace mechanical tools in oral applications by various laser systems. The reasons therefore are manifold: i) Friction causes high temperatures damaging adjacent tissue. ii) Smear layers and rough surfaces are produced. iii) Size and shape of traditional tools are often unsuitable for geometrically complicated incisions and for minimum invasive treatment. iv) Mechanical damage of the remaining tissue occurs. v) Online diagnosis for feedback is not available. Different laser systems in the µs and sub-&mrgs-pulse regime, among them Erbium lasers, have been tested in the hope to overcome the mentioned drawbacks and, to some extent, they represent the current state of the art with respect to commercial and hence practical application. In the present work the applicability of scanned ultrashort pulse lasers (USPLs) for biological hard tissue as well as dental restoration material removal was tested. It is shown that cavities with features superior to mechanically treated or Erbium laser ablated cavities can be generated if appropriate scan algorithms and optimum laser parameters are matched. Smooth cavity rims, no microcracks, melting or carbonisation and precise geometry are the advantages of scanned USLP ablation. For bone treatment better healing conditions are expected as the natural structure remains unaffected by the preparation procedure. The novelty of this work is represented by a comprehensive compilation of various experimental results intended to assess the performance of USPLs. In this context, various pulse durations in the picosecond and femtosecond regime were applied to dental and bone tissue as well as dental restoration materials which is considered to be indispensable for a complete assessment. Parameters like ablation rates describing the efficiency of the ablation process, and ablation thresholds were determined - some of them for the first time - and compared to the corresponding Erbium

  8. Monitoring structure movement with laser tracking technology

    NASA Astrophysics Data System (ADS)

    Barazzetti, Luigi; Giussani, Alberto; Roncoroni, Fabio; Previtali, Mattia

    2013-04-01

    This paper presents the use of laser tracking technology for structure monitoring. In this field the use of this precise instrument is innovative and therefore new investigations are needed for civil structures, especially for applications carried out during unstable environmental conditions. On the other hand, as laser trackers are today very used in industrial applications aimed at collecting data at high speed with precisions superior to +/-0.05 mm, they seem quite promising for those civil engineering applications where numerous geodetic tools, often coupled with mechanical and electrical instruments, are usually used to inspect structure movements. This work illustrates three real civil engineering monitoring applications where laser tracking technology was used to detect object movements. The first one is a laboratory testing for the inspection of a beam (bending moment and shear). The second experiment is the stability inspection of a bridge. The last experiment is one of the first attempts where laser trackers tried to substitute traditional high precision geometric leveling for monitoring an important historical building: the Cathedral of Milan. The achieved results, pro and contra along with some practical issues are described.

  9. Laser assisted die bending: a new application of high power diode lasers

    NASA Astrophysics Data System (ADS)

    Schuöcker, D.; Schumi, T.; Spitzer, O.; Bammer, F.; Schuöcker, G.; Sperrer, G.

    2015-02-01

    Nowadays high power lasers are mainly used for cutting of sheet metals, for welding, hardening and rapid prototyping. In the forming of sheet metals as bending or deep drawing lasers are not used. Nevertheless a few years ago a new application of high power lasers has been invented, where bending of materials that break at room temperature becomes possible by heating them along the bending edge with high power lasers thus allowing their treatment without cracks and rupture. For this purpose a large number of diode lasers are arranged in the bottom tool of a bending machine (a V-shaped die) which heat up the initially flat sheet metal during the bending process what is performed by pressing it into the die with a knife shaped upper tool where due to the laser heating the material is softened and thus cracks are avoided. For the technical realization of the new process of laser assisted die bending, modules equipped with numerous laser diodes and a total beam power of 2,5 kW are used. The light emitted by these modules enters a tool with a length of 15cm and is deflected towards the workpiece. By using ten of these modules with adjacent dies and by integrating those in a bending press a bending edge of sheet metals with a length of 1500mm can be realized. Such a bending press with laser assistance also needs energization with a power of practically 50kW, a respective water flow, a heat exchanger system and also a control for all functions of this system. Special measures have also been developed to avoid radiating of those tools that are not covered by a workpiece in the case of bending edges shorter than the full length of the bending tools whereas individual short circuiting of diode modules can be performed. Specific measures to ensure a safe operation without any harm to the operational person have been realized. Exploitation of the bending process has been carried out for titanium, where material thicknesses up to 3mm have been bent successfully.

  10. Compact atomic clocks and stabilised laser for space applications

    NASA Astrophysics Data System (ADS)

    Mileti, Gaetano; Affolderbach, Christoph; Matthey-de-l'Endroit, Renaud

    2016-07-01

    We present our developments towards next generation compact vapour-cell based atomic frequency standards using a tunable laser diode instead of a traditional discharge lamp. The realisation of two types of Rubidium clocks addressing specific applications is in progress: high performance frequency standards for demanding applications such as satellite navigation, and chip-scale atomic clocks, allowing further miniaturisation of the system. The stabilised laser source constitutes the main technological novelty of these new standards, allowing a more efficient preparation and interrogation of the atoms and hence an improvement of the clock performances. However, before this key component may be employed in a commercial and ultimately in a space-qualified instrument, further studies are necessary to demonstrate their suitability, in particular concerning their reliability and long-term operation. The talk will present our preliminary investigations on this subject. The stabilised laser diode technology developed for our atomic clocks has several other applications on ground and in space. We will conclude our talk by illustrating this for the example of a recently completed ESA project on a 1.6 microns wavelength reference for a future space-borne Lidar. This source is based on a Rubidium vapour cell providing the necessary stability and accuracy, while a second harmonic generator and a compact optical comb generated from an electro-optic modulator allow to transfer these properties from the Rubidium wavelength (780nm) to the desired spectral range.

  11. Applications of laser wakefield accelerators for biomedical imaging

    NASA Astrophysics Data System (ADS)

    Najmudin, Zulfikar

    2014-10-01

    Laser-wakefield accelerators driven by high-intensity short-pulse lasers are a proven compact source of high-energy electron beams, with energy gains of ~GeV energy in centimetres of plasma demonstrated. One of the main proposed applications for these accelerators is to drive synchrotron light sources, in particular for x-ray applications. It has also been shown that the same plasma accelerator can also act as a wigglers, capable of the production of high brightness and spatially coherent hard x-ray beams. In this latest work, we demonstrate the application of these unique light-sources for biological and medical applications. The experiments were performed with the Astra Gemini laser at the Rutherford Appleton Laboratory in the UK. Gemini produces laser pulses with energy exceeding 10 J in pulse lengths down to 40 fs. A long focal length parabola (f / 20) is used to focus the laser down to a spot of size approximately 25 μ m (fwhm) into a gas-cell of variable length. Electrons are accelerated to energies up to 1 GeV and a bright beam of x-rays is observed simultaneously with the accelerated beam. The length of the gas cell was optimised to produce high contrast x-ray images of radiographed test objects. This source was then used for imaging a number of interesting medical and biological samples. Full tomographic imaging of a human trabecular bone sample was made with resolution easily exceeding the ~100 μm level required for CT applications. Phase-contrast imaging of human prostrate and mouse neonates at the micron level was also demonstrated. These studies indicate the usefulness of these sources in research and clinical applications. They also show that full 3D imaging can be made possible with this source in a fraction of the time that it would take with a corresponding x-ray tube. The JAI is funded by STFC Grant ST/J002062/1.

  12. Proposal of a defense application for a chemical oxygen laser

    NASA Astrophysics Data System (ADS)

    Takehisa, K.

    2015-05-01

    Defense application for a chemical oxygen laser (COL) is explained. Although a COL has not yet been successful in lasing, the oscillator was estimated to produce a giant pulse with the full width at half maximum (FWHM) of ~0.05ms which makes the damage threshold for the mirrors several-order higher than that for a typical solid-state laser with a ~10ns pulse width. Therefore it has a potential to produce MJ class output considering the simple scalability of being a chemical laser. Since within 0.05ms a supersonic aircraft can move only a few centimeters which is roughly equal to the spot size of the focused beam at ~10km away using a large-diameter focusing mirror, a COL has a potential to make a damage to an enemy aircraft by a single shot without beam tracking. But since the extracted beam can propagate up to a few kilometers due to the absorption in the air, it may be suitable to use in space. While a chemical oxygen-iodine laser (COIL) can give a pulsed output with a width of ~2 ms using a high-pressure singlet oxygen generator (SOG). Therefore a pulsed COIL may also not require beam tracking if a target aircraft is approaching. Another advantage for these pulsed high-energy lasers (HELs) is that, in case of propagating in cloud or fog, much less energy is required for a laser for aerosol vaporization (LAV) than that of a LAV for a CW HEL. Considerations to use a COL as a directed energy weapon (DEW) in a point defense system are shown.

  13. Infrared glass fiber cables for CO laser medical applications

    NASA Astrophysics Data System (ADS)

    Arai, Tsunenori; Mizuno, Kyoichi; Sensaki, Koji; Kikuchi, Makoto; Watanabe, Tamishige; Utsumi, Atsushi; Takeuchi, Kiyoshi; Akai, Yoshiro

    1993-05-01

    We developed the medical fiber cables which were designed for CO laser therapy, i.e., angioplasty and endoscopic therapy. As-S chalcogenide glass fibers were used for CO laser delivery. A 230 micrometers core-diameter fiber was used for the angioplasty laser cable. The outer diameter of this cable was 600 micrometers . The total length and insertion length of the angioplasty laser cable were 2.5 m and 1.0 m, respectively. Typically, 2.0 W of fiber output was used in the animal experiment in vivo for the ablation of the model plaque which consisted of human atheromatous aorta wall. The transmission of the angioplasty laser cable was approximately 35%, because the reflection loss occurred at both ends of the fiber and window. Meanwhile, the core diameter of the energy delivery fiber for the endoscopic therapy was 450 micrometers . The outer diameter of this cable was 1.7 mm. Approximately 4.5 W of fiber output was used for clinical treatment of pneumothorax through a pneumoscope. Both types of the cables had the ultra-thin thermocouples for temperature monitoring at the tip of the cables. This temperature monitoring was extremely useful to prevent the thermal destruction of the fiber tip. Moreover, the As-S glass fibers were completely sealed by the CaF2 windows and outer tubes. Therefore, these cables were considered to have sufficient safety properties for medical applications. These laser cables were successfully used for the in vivo animal experiments and/or actual clinical therapies.

  14. Applicability of laser to assist coronary balloon angioplasty.

    PubMed

    Lee, G; Chan, M C; Ikeda, R M; Rink, J L; Dukich, J; Peterson, L; Lee, K K; Reis, R L; Mason, D T

    1985-12-01

    Severe atherosclerotic obstructed coronary artery disease (CAD) may preclude passage of a balloon catheter for transluminal coronary angioplasty (TCA). Since lasers have been shown to effectively vaporize CAD plaque, the initial application of laser to effect a lumen large enough to accommodate the angioplasty catheter for further dilatation was explored. Eleven postmortem human CAD segments which did not permit passage of a 1.33 mm shaft diameter angioplasty catheter were studied. Argon laser radiation (14 to 90 J) transmitted via 400 micron core diameter quartz fiber onto the stenotic channel of 0.58 mm created a vaporized lumen of 1.77 mm (mean increase of 1.31 +/- 0.25 mm, p less than 0.001). The laser procedure allowed the balloon angioplasty catheter to be pushed into the stenosis. TCA was then performed (7 atm, 45 seconds) and expanded the channel to 2.12 mm (additional mean increase of 0.38 +/- 0.07 mm, p less than 0.001). In terms of percent luminal narrowing, laser radiation reduced obstruction from 80% to 45% (mean difference of -38.7 +/- 4.6%, p less than 0.001), and TCA caused a further decrease to 37% (mean difference of -9.3 +/- 1.9%, p less than 0.001). Thus, in tight atherosclerotic lesions, the laser may be useful in creating an initial opening enabling the placement of the balloon angioplasty catheter which, in turn, can further dilate the lased stenotic coronary lumen. PMID:2933943

  15. Laser Isotope Enrichment for Medical and Industrial Applications

    SciTech Connect

    Leonard Bond

    2006-07-01

    Laser Isotope Enrichment for Medical and Industrial Applications by Jeff Eerkens (University of Missouri), Jay Kunze (Idaho State University), and Leonard Bond (Idaho National Laboratory) The principal isotope enrichment business in the world is the enrichment of uranium for commercial power reactor fuels. However, there are a number of other needs for separated isotopes. Some examples are: 1) Pure isotopic targets for irradiation to produce medical radioisotopes. 2) Pure isotopes for semiconductors. 3) Low neutron capture isotopes for various uses in nuclear reactors. 4) Isotopes for industrial tracer/identification applications. Examples of interest to medicine are targets to produce radio-isotopes such as S-33, Mo-98, Mo-100, W-186, Sn-112; while for MRI diagnostics, the non-radioactive Xe-129 isotope is wanted. For super-semiconductor applications some desired industrial isotopes are Si-28, Ga-69, Ge-74, Se-80, Te-128, etc. An example of a low cross section isotope for use in reactors is Zn-68 as a corrosion inhibitor material in nuclear reactor primary systems. Neutron activation of Ar isotopes is of interest in industrial tracer and diagnostic applications (e.g. oil-logging). . In the past few years there has been a sufficient supply of isotopes in common demand, because of huge Russian stockpiles produced with old electromagnetic and centrifuge separators previously used for uranium enrichment. Production of specialized isotopes in the USA has been largely accomplished using old ”calutrons” (electromagnetic separators) at Oak Ridge National Laboratory. These methods of separating isotopes are rather energy inefficient. Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation

  16. Application of ring lasers to determine the directions to the poles of Earth's rotation

    SciTech Connect

    Golyaev, Yu D; Kolbas, Yu Yu

    2012-10-31

    Application of a ring laser to determine the directions to the poles of Earth's rotation is considered. The maximum accuracy of determining the directions is calculated, physical and technical mechanisms that limit the accuracy are analysed, and the instrumental errors are estimated by the example of ring He - Ne lasers with Zeeman biasing. (laser applications and other topics in quantum electronics)

  17. Applications of laser diagnostics in energy conservation research

    SciTech Connect

    Hutchinson, R.A.

    1985-02-01

    During the past decade, intensive research and development has demonstrated the feasibility, checked the accuracy, and extended the sensitivity of laser diagnostics for combustion systems. Combinations of diagnostics can now provide in-situ, time-, and space-resolved measurements of temperature, velocity, and species concentration. Although these tools are powerful, they also can be exceedingly difficult to use, and their application remains largely in the hands of specialized instrument developers rather than problem-oriented researchers. This report outlines a variety of applications for existing diagnostics that may interest both instrument developers and researchers in particular fields.

  18. Novel Applications of Laser Doppler Vibration Measurements to Medical Imaging

    NASA Astrophysics Data System (ADS)

    Tabatabai, Habib; Oliver, David E.; Rohrbaugh, John W.; Papadopoulos, Christopher

    2013-06-01

    Laser Doppler Vibrometry (LDV) has been widely used in engineering applications involving non-contact vibration and sound measurements. This technique has also been used in some biomedical applications including hearing research. The detectable frequencies are in the range of near-DC to 1 GHz or higher. This paper reviews applications of LDV in biomedical engineering and proposes new medical imaging applications based on measuring surface vibrations of tissues and organs. Tests were conducted on human skin using single point and scanning laser vibrometers. These tests suggest that skin vibrations due to the forcing excitation from the heart can be used in imaging of blood flow. The results of these tests illustrate the potential of such vibration measurements in a variety of diagnostic medical imaging applications including blood flow/restrictions, real-time monitoring of blood pressure variations, wound healing, muscle movements, etc. The fact that the measurements can be conducted remotely (non-contact) is an important benefit that adds to the promise of this approach.

  19. ELIMED, future hadrontherapy applications of laser-accelerated beams

    NASA Astrophysics Data System (ADS)

    Cirrone, Giuseppe A. P.; Carpinelli, Massimo; Cuttone, Giacomo; Gammino, Santo; Bijan Jia, S.; Korn, Georg; Maggiore, Mario; Manti, Lorenzo; Margarone, Daniele; Prokupek, Jan; Renis, Marcella; Romano, Francesco; Schillaci, Francesco; Tomasello, Barbara; Torrisi, Lorenzo; Tramontana, Antonella; Velyhan, Andriy

    2013-12-01

    Laser-ion acceleration has recently gained a great interest as an alternative to conventional and more expensive acceleration techniques. These ion beams have desirable qualities such as small source size, high luminosity and small emittance to be used in different fields as Nuclear Physics, Medical Physics, etc. This is very promising specially for the future perspective of a new concept of hadrontherapy based on laser-based devices could be developed, replacing traditional accelerating machines. Before delivering laser-driven beams for treatments they have to be handled, cleaned from unwanted particles and characterized in order to have the clinical requirements. In fact ion energy spectra have exponential trend, almost 100% energy spread and a wide angular divergence which is the biggest issue in the beam transport and, hence, in a wider use of this technology. In order to demonstrate the clinical applicability of laser-driven beams new collaboration between ELI-Beamlines project researchers from Prague (Cz) and a INFN-LNS group from Catania (I) has been already launched and scientists from different countries have already express their will in joining the project. This cooperation has been named ELIMED (MEDical application at ELIBeamlines) and will take place inside the ELI-Beamlines infrastructure located in Prague. This work describes the schedule of the ELIMED project and the design of the energy selector which will be realized at INFN-LNS. The device is an important part of the whole transport beam line which will be realised in order to make the ion beams suitable for medical applications.

  20. LIGHT - from laser ion acceleration to future applications

    NASA Astrophysics Data System (ADS)

    Roth, Markus; Light Collaboration

    2013-10-01

    Creation of high intensity multi-MeV ion bunches by high power lasers became a reliable tool during the last 15 years. The laser plasma source provides for TV/m accelerating field gradients and initially sub-ps bunch lengths. However, the large envelope divergence and the continuous exponential energy spectrum are substential drawbacks for many possible applications. To face this problem, the LIGHT collaboration was founded (Laser Ion Generation, Handling and Transport). The collaboration consists of several university groups and research centers, namely TU Darmstadt, JWGU Frankfurt, HI Jena, HZDR Dresden and GSI Darmstadt. The central goal is building a test beamline for merging laser ion acceleration with conventional accelerator infrastructure at the GSI facility. In the latest experiments, low divergent proton bunches with a central energy of up to 10 MeV and containing >109 particles could be provided at up to 2.2 m behind the plasma source, using a pulsed solenoid. In a next step, a radiofrequency cavity will be added to the beamline for phase rotation of these bunches, giving access to sub-ns bunch lengths and reaching highest intensities. An overview of the LIGHT objectives and the recent experimental results will be given. This work was supported by HIC4FAIR.

  1. Experimental grounds for YAG:Er laser application to dentistry

    NASA Astrophysics Data System (ADS)

    Bol'shakov, E. N.; Dolgikh, Robert A.; Zazulevskaya, Lidiya Y.; Zubov, Boris V.; Lobachyov, V. A.; Murina, T. M.; Prokhorov, Alexander M.

    1990-09-01

    Stornatologic service is most popular of all kinds of medical aid, since up to 90% of people suffer from caries, parodontosis holds the second place after such a widespread disease as cardiovascular pathology. The treatment of the tooth hard tissue, intervention into pulp and parodontium using conventional methods are accompanied with painfulness and unpleasant sensation. A lack of efficient methods of anesthesia and pulp devitalization, a high percentage of complica tions after pulpitis treatment made it necessary to search for new methods of treatment which exclude these negative aspects. Application of laser radiation may be one of the ways in resolving this problem. Such attempts have been made repeatedly with the development of laser technology.'3 However, not all of them turned out to be successful. The greatest difficulties occurred on surgical intervention into hard tooth tissue. The best results have been so far attained when using pulsed CO2 laser operated at the wavelength A =1O.61um. For instance, at pulse width 1O1us and frequency 10-20 Hz, the tooth channel drilling was efficient at energy density in pulse P . 10 JIcm2. 4'5 The electron-microscopic investigations have proved the tooth microstructure to be preserved for this laser operation mode. The traces of graphitization were observed only in the vicinity of the lateral walls of the channel.

  2. Fundamentals and industrial applications of ultrashort pulsed lasers at Bosch

    NASA Astrophysics Data System (ADS)

    König, Jens; Bauer, Thorsten

    2011-03-01

    Fundamental results of ablation processes of metals with ultrashort laser pulses in the far threshold fluence regime are shown and discussed. Time-resolved measurements of the plasma transmission exhibit two distinctive minima. The minima occurring within the first nanoseconds can be attributed to electrons and sublimated material emitted from the target surface, whereas the subsequent minimum after several 10 ns is due to particles and droplets after a thermal boiling process. Industrial applications of ultrashort pulsed laser micro machining in the Bosch Group are also shown with the production of exhaust gas sensors and common rail diesel systems. Since 2007, ultrashort laser pulses are used at the BOSCH plant in Bamberg for producing lambda-probes, which are made of a special ceramic layer system and can measure the exhaust gas properties faster and more accurately. This enables further reduction of emissions by optimized combustion control. Since 2009, BOSCH uses ultrashort pulsed lasers for micro-structuring the injector of common rail diesel systems. A drainage groove allows a tight system even at increased pressures up to 2000 bar. Diesel injection is thus even more reliable, powerful and environment-friendly.

  3. Pulse laser assisted optical tweezers for biomedical applications.

    PubMed

    Sugiura, Tadao; Maeda, Saki; Honda, Ayae

    2012-01-01

    Optical tweezers which enables to trap micron to nanometer sized objects by radiation pressure force is utilized for manipulation of particles under a microscope and for measurement of forces between biomolecules. Weak force of optical tweezers causes some limitations such as particle adhesion or steric barrier like lipid membrane in a cell prevent further movement of objects. For biomedical applications we need to overcome these difficulties. We have developed a technique to exert strong instantaneous force by use of a pulse laser beam and to assist conventional optical tweezers. A pulse laser beam has huge instantaneous laser power of more than 1000 times as strong as a conventional continuous-wave laser beam so that the instantaneous force is strong enough to break chemical bonding and molecular force between objects and obstacles. We derive suitable pulse duration for pulse assist of optical tweezers and demonstrate particle manipulation in difficult situations through an experiment of particle removal from sticky surface of glass substrate. PMID:23366922

  4. Three-dimensional laser window formation for industrial application

    NASA Technical Reports Server (NTRS)

    Verhoff, Vincent G.; Kowalski, David

    1993-01-01

    The NASA Lewis Research Center has developed and implemented a unique process for forming flawless three-dimensional, compound-curvature laser windows to extreme accuracies. These windows represent an integral component of specialized nonintrusive laser data acquisition systems that are used in a variety of compressor and turbine research testing facilities. These windows are molded to the flow surface profile of turbine and compressor casings and are required to withstand extremely high pressures and temperatures. This method of glass formation could also be used to form compound-curvature mirrors that would require little polishing and for a variety of industrial applications, including research view ports for testing devices and view ports for factory machines with compound-curvature casings. Currently, sodium-alumino-silicate glass is recommended for three-dimensional laser windows because of its high strength due to chemical strengthening and its optical clarity. This paper discusses the main aspects of three-dimensional laser window formation. It focuses on the unique methodology and the peculiarities that are associated with the formation of these windows.

  5. Multifrequency Nd:YAG laser application for tumor fluorescence diagnosis

    NASA Astrophysics Data System (ADS)

    Yova, Dido M.; Halkiotis, Konstantinos N.; Manolopoulos, Athanassios; Ouzounoglou, Nikolaos K.; Hovhannisyan, Vladimir A.; Avanessian, Lia A.

    1999-12-01

    A computerized fiber-optic spectrofluorometer based on a multifrequency Nd:YAG laser ((lambda) equals 355, 440, 532 and 660 nm, f equals 25 Hz, E equals 1 - 10 mJ, (tau) equals 12 ns) for tissue fluorescence registration in vivo and ex vivo has been developed. The less intensive fluorescence from a tumor of Sarcoma-45 bearing animal model in comparison with the surrounding normal tissue was observed at the spectral region around 450 nm. The influence of reabsorption, energy transfer and other physical factors on tumor fluorescence, sensitized by Photohem (hematoporphyrin derivative), disodium salt of fluorescein (FL) and chlorin e6 (Chl) was investigated. The pharmacokinetic behavior of Chl in different organs and tumors of the animal models has been estimated. The most intensive Chl fluorescence of tumor tissue was observed at 18 hours after photosensitizer injection. The maximum of the tumor-to-healthy tissue ratio of fluorescence was reached 10 at 27 hours after pigment injection. The fluorescence spectra from different types of human tumors after i/v injection with FL or topical application of ALA were studied. A simple model of Nd:YAG laser system for tumor fluorescence diagnosis has been elaborated. Advantages of the laser fluorescence diagnosis of malignant tumors by solid state multifrequency Nd:YAG laser and the increase in accuracy and specificity of this method is discussed.

  6. Microgravity Spray Cooling Research for High Powered Laser Applications

    NASA Technical Reports Server (NTRS)

    Zivich, Chad P.

    2004-01-01

    An extremely powerful laser is being developed at Goddard Space Flight Center for use on a satellite. This laser has several potential applications. One application is to use it for upper atmosphere weather research. In this case, the laser would reflect off aerosols in the upper atmosphere and bounce back to the satellite, where the aerosol velocities could be calculated and thus the upper atmosphere weather patterns could be monitored. A second application would be for the US. Air Force, which wants to use the laser strategically as a weapon for satellite defense. The Air Force fears that in the coming years as more and more nations gain limited space capabilities that American satellites may become targets, and the laser could protect the satellites. Regardless of the ultimate application, however, a critical step along the way to putting the laser in space is finding a way to efficiently cool it. While operating the laser becomes very hot and must be cooled to prevent overheating. On earth, this is accomplished by simply running cool tap water over the laser to keep it cool. But on a satellite, this is too inefficient. This would require too much water mass to be practical. Instead, we are investigating spray cooling as a means to cool the laser in microgravity. Spray cooling requires much less volume of fluid, and thus could be suitable for use on a satellite. We have inherited a 2.2 second Drop Tower rig to conduct our research with. In our experiments, water is pressurized with a compressed air tank and sprayed through a nozzle onto our test plate. We can vary the pressure applied to the water and the temperature of the plate before an experiment trial. The whole process takes place in simulated microgravity in the 2.2 second Drop Tower, and a high speed video camera records the spray as it hits the plate. We have made much progress in the past few weeks on these experiments. The rig originally did not have the capability to heat the test plate, but I did

  7. LASER PLASMA AND LASER APPLICATIONS: Plasma transparency in laser absorption waves in metal capillaries

    NASA Astrophysics Data System (ADS)

    Anisimov, V. N.; Kozolupenko, A. P.; Sebrant, A. Yu

    1988-12-01

    An experimental investigation was made of the plasma transparency to heating radiation in capillaries when absorption waves propagated in these capillaries as a result of interaction with a CO2 laser pulse of 5-μs duration. When the length of the capillary was in excess of 20 mm, total absorption of the radiation by the plasma was observed at air pressures of 1-100 kPa. When the capillary length was 12 mm, a partial recovery of the transparency took place. A comparison was made with the dynamics and recovery of the plasma transparency when breakdown of air took place near the free surface.

  8. Direct Laser Cladding , Current Status and Future Scope of Application

    NASA Astrophysics Data System (ADS)

    Weisheit, A.; Gasser, A.; Backes, G.; Jambor, T.; Pirch, N.; Wissenbach, K.

    During the last decades Direct Laser Cladding has become an established technique in many industrial fields for applying wear and corrosion protection layers on metallic surfaces as well as for the repair of high value-added components. The most important application fields are die and tool making, turbine components for aero engines and power generation, machine components such as axes and gears, and oil drilling components. Continuous wave (CW) lasers with a power up to 18 kW are used on automated machines with three or more axes, enabling 3D cladding . The outstanding feature of DLC is the high precision which leads to a minimum heat input into the work piece and a very low distortion. Due to the high cooling rates a fine grained microstructure is achieved during solidification. A new development in laser cladding is micro cladding in a size range below 50 \\upmum especially for electronic and medical applications. Furthermore, additive manufacturing is coming again into focus as a clean and resource-efficient method to manufacture and modify functional prototypes as well as unique and small lot parts.

  9. Smart imaging using laser targeting: a multiple barcodes application

    NASA Astrophysics Data System (ADS)

    Amin, M. Junaid; Riza, Nabeel A.

    2014-05-01

    To the best of our knowledge, proposed is a novel variable depth of field smart imager design using intelligent laser targeting for high productivity multiple barcodes reading applications. System smartness comes via the use of an Electronically Controlled Variable Focal-Length Lens (ECVFL) to provide an agile pixel (and/or pixel set) within the laser transmitter and optical imaging receiver. The ECVFL in the receiver gives a flexible depth of field that allows clear image capture over a range of barcode locations. Imaging of a 660 nm wavelength laser line illuminated 95-bit one dimensional barcode is experimentally demonstrated via the smart imager for barcode target distances ranging from 10 cm to 54 cm. The smart system captured barcode images are evaluated using a proposed barcode reading algorithm. Experimental results after computer-based post-processing show a nine-fold increase in barcode target distance variation range (i.e., range variation increased from 2.5 cm to 24.5 cm) when compared to a conventional fixed lens imager. Applications for the smart imager include industrial multiple product tracking, marking, and inspection systems.

  10. Threshold analysis of pulsed lasers with application to a room-temperature Co:MgF2 laser

    NASA Technical Reports Server (NTRS)

    Harrison, James; Welford, David; Moulton, Peter F.

    1989-01-01

    Rate-equation calculations are used to model accurately the near-threshold behavior of a Co:MgF2 laser operating at room temperature. The results demonstrate the limitations of the conventional threshold analysis in cases of practical interest. This conclusion is applicable to pulsed solid-state lasers in general. The calculations, together with experimental data, are used to determine emission cross sections for the Co:MgF2 laser.

  11. Combinations of biomarkers and Milan criteria for predicting hepatocellular carcinoma recurrence after liver transplantation.

    PubMed

    Chaiteerakij, Roongruedee; Zhang, Xiaodan; Addissie, Benyam D; Mohamed, Essa A; Harmsen, William S; Theobald, Paul J; Peters, Brian E; Balsanek, Joseph G; Ward, Melissa M; Giama, Nasra H; Moser, Catherine D; Oseini, Abdul M; Umeda, Naoki; Venkatesh, Sudhakar; Harnois, Denise M; Charlton, Michael R; Yamada, Hiroyuki; Satomura, Shinji; Algeciras-Schimnich, Alicia; Snyder, Melissa R; Therneau, Terry M; Roberts, Lewis R

    2015-05-01

    Growing evidence suggests that pretransplant alpha-fetoprotein (AFP) predicts outcomes of hepatocellular carcinoma (HCC) patients treated with liver transplantation. We aimed to determine whether pretransplant AFP, Lens culinaris agglutinin-reactive alpha-fetoprotein (AFP-L3), and des-gamma-carboxyprothrombin (DCP) predicted HCC recurrence after transplantation. A retrospective cohort study of 313 HCC patients undergoing transplantation between 2000 and 2008 was conducted, and 48 (15.3%) developed recurrence during a median follow-up of 90.8 months. The 127 patients with available serum drawn before transplantation were included; they included 86 without recurrence and 41 with recurrence. Serum was tested for AFP, AFP-L3%, and DCP in a blinded fashion with the μTASWako i30 immunoanalyzer. All biomarkers were significantly associated with HCC recurrence. The hazard ratios (HRs) were 3.5 [95% confidence interval (CI), 1.9-6.7; P < 0.0001] for DCP ≥ 7.5 ng/mL and 2.8 (95% CI, 1.4-5.4; P = 0.002) for AFP ≥ 250 ng/mL. The HR increased to 5.2 (95% CI, 2.3-12.0; P < 0.0001) when AFP ≥ 250 ng/mL and DCP ≥7.5 ng/mL were considered together. When they were combined with the Milan criteria, the HR increased from 2.6 (95% CI, 1.4-4.7; P = 0.003) for outside the Milan criteria to 8.6 (95% CI, 3.0-24.6; P < 0.0001) for outside the Milan criteria and AFP ≥ 250 ng/mL and to 7.2 (95% CI, 2.8-18.1; P < 0.0001) for outside the Milan criteria and DCP ≥7.5 ng/mL. Our findings suggest that biomarkers are useful for predicting the risk of HCC recurrence after transplantation. Using both biomarkers and the Milan criteria may be better than using the Milan criteria alone in optimizing the decision of liver transplantation eligibility. PMID:25789635

  12. A handheld laser-induced fluorescence detector for multiple applications.

    PubMed

    Fang, Xiao-Xia; Li, Han-Yang; Fang, Pan; Pan, Jian-Zhang; Fang, Qun

    2016-04-01

    In this paper, we present a compact handheld laser-induced fluorescence (LIF) detector based on a 450 nm laser diode and quasi-confocal optical configuration with a total size of 9.1 × 6.2 × 4.1 cm(3). Since there are few reports on the use of 450 nm laser diode in LIF detection, especially in miniaturized LIF detector, we systematically investigated various optical arrangements suitable for the requirements of 450 nm laser diode and system miniaturization, including focusing lens, filter combination, and pinhole, as well as Raman effect of water at 450 nm excitation wavelength. As the result, the handheld LIF detector integrates the light source (450 nm laser diode), optical circuit module (including a 450 nm band-pass filter, a dichroic mirror, a collimating lens, a 525 nm band-pass filter, and a 1.0mm aperture), optical detector (miniaturized photomultiplier tube), as well as electronic module (including signal recording, processing and displaying units). This detector is capable of working independently with a cost of ca. $2000 for the whole instrument. The detection limit of the instrument for sodium fluorescein solution is 0.42 nM (S/N=3). The broad applicability of the present system was demonstrated in capillary electrophoresis separation of fluorescein isothiocyanate (FITC) labeled amino acids and in flow cytometry of tumor cells as an on-line LIF detector, as well as in droplet array chip analysis as a LIF scanner. We expect such a compact LIF detector could be applied in flow analysis systems as an on-line detector, and in field analysis and biosensor analysis as a portable universal LIF detector. PMID:26838391

  13. Applications of laser-accelerated particle beams for radiation therapy

    NASA Astrophysics Data System (ADS)

    Ma, C.-M.; Fourkal, E.; Li, J. S.; Veltchev, I.; Luo, W.; Fan, J. J.; Lin, T.; Tafo, A.

    2011-05-01

    Proton beams are more advantageous than high-energy photons and electrons for radiation therapy because of their finite penetrating range and the Bragg peak near the end of their range, which have been utilized to achieve better dose conformity to the treatment target allowing for dose escalation and/or hypofractionation to increase local tumor control, reduce normal tissue complications and/or treatment time/cost. Proton therapy employing conventional particle acceleration techniques is expensive because of the large accelerators and treatment gantries that require excessive space and shielding. Compact proton acceleration systems are being sought to improve the cost-effectiveness for proton therapy. This paper reviews the physics principles of laser-proton acceleration and the development of prototype laserproton therapy systems as a solution for widespread applications of advanced proton therapy. The system design, the major components and the special delivery techniques for energy and intensity modulation are discussed in detail for laser-accelerated proton therapy.

  14. [Laser Raman Spectroscopy and Its Application in Gas Hydrate Studies].

    PubMed

    Fu, Juan; Wu, Neng-you; Lu, Hai-long; Wu, Dai-dai; Su, Qiu-cheng

    2015-11-01

    Gas hydrates are important potential energy resources. Microstructural characterization of gas hydrate can provide information to study the mechanism of gas hydrate formation and to support the exploitation and application of gas hydrate technology. This article systemly introduces the basic principle of laser Raman spectroscopy and summarizes its application in gas hydrate studies. Based on Raman results, not only can the information about gas composition and structural type be deduced, but also the occupancies of large and small cages and even hydration number can be calculated from the relative intensities of Raman peaks. By using the in-situ analytical technology, laser Raman specstropy can be applied to characterize the formation and decomposition processes of gas hydrate at microscale, for example the enclathration and leaving of gas molecules into/from its cages, to monitor the changes in gas concentration and gas solubility during hydrate formation and decomposition, and to identify phase changes in the study system. Laser Raman in-situ analytical technology has also been used in determination of hydrate structure and understanding its changing process under the conditions of ultra high pressure. Deep-sea in-situ Raman spectrometer can be employed for the in-situ analysis of the structures of natural gas hydrate and their formation environment. Raman imaging technology can be applied to specify the characteristics of crystallization and gas distribution over hydrate surface. With the development of laser Raman technology and its combination with other instruments, it will become more powerful and play a more significant role in the microscopic study of gas hydrate. PMID:26978895

  15. Encapsulated and monolithic resonant structures for laser applications

    NASA Astrophysics Data System (ADS)

    Pung, Aaron Joseph

    Typically, the composition of a laser system includes a gain medium, a pump illumination source, and an external feedback cavity. This cavity consists of a highly reflective mirror and an outcoupler component. The geometry of the outcoupler can be engineered to tailor the reflected or transmitted beam's spatial and spectral distribution. Functionally, the transmitted beam profile is dependent on the laser application. Broadband reflection profiles can be obtained by utilizing a distributed Bragg reflector (DBR). A DBR device consists of multiple layers of alternating materials. Constructive interference of the reflected light off each interface between different materials produces the spectrally broadband response. The spectral response is a function of the fabrication and material parameters of the DBR. In contrast, guided-mode resonance filters (GMRF) exploit phase matching between evanescent- and guided-waves to provide a strong reflection. Based on the materials in the structure, the spectral response can demonstrate broadband or narrowband reflectivity. The operation wavelength of a GMRF is dependent on the structural parameters of the device as well as the angle of incidence. However, conventional designs of resonant optics leave critical aspects of the structure exposed to the surrounding environment. Additional damage or contamination to the waveguide or grating layer will significantly alter the device's spectral response. This dissertation introduces two GMRF geometries aimed at device integration, development of similar-material resonant devices, and full-device protection from outside influence. Unlike distributed Bragg reflectors, these geometries do not rely heavily on strict material and deposition requirements. Instead, they take advantage of the deposition processes to minimize coating deposition, achieve high reflectivity and demonstrate control over polarization dependence. Given their versatility in design and ability to withstand high power

  16. Laser-activated remote phosphor light engine for projection applications

    NASA Astrophysics Data System (ADS)

    Daniels, Martin; Mehl, Oliver; Hartwig, Ulrich

    2015-09-01

    Recent developments in blue emitting laser diodes enable attractive solutions in projection applications using phosphors for efficient light conversion with very high luminance levels. Various commercially available projectors incorporating this technology have entered the market in the past years. While luminous flux levels are still comparable to lamp-based systems, lifetime expectations of classical lamp systems are exceeded by far. OSRAM GmbH has been exploring this technology for several years and has introduced the PHASER® brand name (Phosphor + laser). State-of-the-art is a rotating phosphor wheel excited by blue laser diodes to deliver the necessary primary colors, either sequentially for single-imager projection engines, or simultaneously for 3-panel systems. The PHASER® technology enables flux and luminance scaling, which allows for smaller imagers and therefore cost-efficient projection solutions. The resulting overall efficiency and ANSI lumen specification at the projection screen of these systems is significantly determined by the target color gamut and the light transmission efficiency of the projection system. With increasing power and flux level demand, thermal issues, especially phosphor conversion related, dominate the opto-mechanical system design requirements. These flux levels are a great challenge for all components of an SSL-projection system (SSL:solid-state lighting). OSRAḾs PHASER® light engine platform is constantly expanded towards higher luminous flux levels as well as higher luminance levels for various applications. Recent experiments employ blue laser pump powers of multiple 100 Watts to excite various phosphors resulting in luminous flux levels of more than 40 klm.

  17. Application of femtosecond-laser induced nanostructures in optical memory.

    PubMed

    Shimotsuma, Yasuhiko; Sakakura, Masaaki; Miura, Kiyotaka; Qiu, Jiarong; Kazansky, Peter G; Fujita, Koji; Hirao, Kazuyuki

    2007-01-01

    The femtosecond laser induced micro- and nanostructures for the application to the three-dimensional optical data storage are investigated. We have observed the increase of refractive index due to local densification and atomic defect generation, and demonstrated the real time observation of photothermal effect after the femtosecond laser irradiation inside a glass by the transient lens (TrL) method. The TrL signal showed a damped oscillation with about an 800 ps period. The essential feature of the oscillation can be reproduced by the pressure wave creation and propagation to the outward direction from the irradiated region. The simulation based on elastodynamics has shown that a large thermoelastic stress is relaxed by the generation of the pressure wave. In the case of soda-lime glass, the velocity of the pressure wave is almost same as the longitudinal sound velocity at room temperature (5.8 microm/ns). We have also observed the localized photo-reduction of Sm3+ to Sm2+ inside a transparent and colorless Sm(3+)-doped borate glass. Photoluminescence spectra showed that some the Sm3+ ions in the focal spot within the glass sample were reduced to Sm2+ ions after femtosecond laser irradiation. A photo-reduction bit of 200 nm in three-dimensions can be recorded with a femtosecond laser and readout clearly by detecting the fluorescence excited by Ar+ laser (lambda = 488 nm). A photo-reduction bit can be also erased by photo-oxidation with a cw Ar+ laser (lambda = 514.5 nm). Since photo-reduction bits can be spaced 150 nm apart in a layer within glass, a memory capacity of as high as 1 Tbit can be achieved in a glass piece with dimensions of 10 mm x 10 mm x 1 mm. We have also demonstrated the first observation of the polarization-dependent periodic nanostructure formation by the interference between femtosecond laser light and electron acoustic waves. The observed nanostructures are the smallest embedded structures ever created by light. The period of self

  18. A linewidth-narrowed and frequency-stabilized dye laser for application in laser cooling of molecules.

    PubMed

    Dai, D P; Xia, Y; Yin, Y N; Yang, X X; Fang, Y F; Li, X J; Yin, J P

    2014-11-17

    We demonstrate a robust and versatile solution for locking the continuous-wave dye laser for applications in laser cooling of molecules which need linewidth-narrowed and frequency-stabilized lasers. The dye laser is first stabilized with respect to a reference cavity by Pound-Drever-Hall (PDH) technique which results in a single frequency with the linewidth 200 kHz and short-term stabilization, by stabilizing the length of the reference cavity to a stabilized helium-neon laser we simultaneously transfer the ± 2 MHz absolute frequency stability of the helium-neon laser to the dye laser with long-term stabilization. This allows the dye laser to be frequency chirped with the maximum 60 GHz scan range while its frequency remains locked. It also offers the advantages of locking at arbitrary dye laser frequencies, having a larger locking capture range and frequency scanning range to be implemented via software. This laser has been developed for the purpose of laser cooling a molecular magnesium fluoride beam. PMID:25402105

  19. Case studies of industrial applications of high-power diode laser in Finland

    NASA Astrophysics Data System (ADS)

    Hovikorpi, Jari; Jansson, Anssi; Salminen, Antti

    2003-06-01

    The high power diode laser is a new industrial tool. It has several advantages and disadvantages compared to the conventional industrially used CO2 and Nd:YAG laser. The most promising areas of application of diode laser have been considered to be thin sheet welding and hardening. Quite a few feasibility studies of the use of diode laser have been carried out in Finland. So far there has been some application in which diode laser is the most suitable laser. Typically, the HPDL is integrated to an industrial robot. The welding of stainless steel housing, car door lock and catalytic converters are typical examples of applications in which diode laser has technological as well as economical advantages over the conventional laser and welding techniques. The welding of these products requires good control over the heat input, short through put time and low investment. The weld cross-section of a diode laser weld is, because of conduction limited welding process, more suitable for these applications than the keyhole welding. Hardening of a large gear wheel presents also a good example of an application in which the diode laser makes it possible to economically produce structures that have not earlier been possible. Hardening requires a special form of heat delivery in order to ensure evenly hardened zone and acceptable quality. The application was performed with two high power diode lasers. The case studies of these four applications are presented and discussed in details in this paper.

  20. Tunable Diode Laser Applications To Cigarette Smoke Analysis

    NASA Astrophysics Data System (ADS)

    Vilcins, Gunars; Harward, Charles N.; Parrish, Milton E.; Forrest, Gary T.

    1983-11-01

    High resolution infrared tunable diode laser spectroscopy (TDL) has been applied to the study of cigarette smoke for qualitative and quantitative determinations involved in tobacco blend and cigarette filter developments. As examples of the different types of application of this work, several TDL studies are presented. The measurements of smoke components on a puff-by-puff basis in confined sample chambers and flowing streams were used to study the smoke component deliveries and the effects of filter dilution. The study of isotopes generated during combustion of chemically treated tobaccos was another application of the TDL system to complex gas mixtures without prior separation of compo-nents. The application of the TDL to the study of cigarette filters and smoke delivery simultaneously was demonstrated by using two well resolved absorption lines of two different gases which occur on a single TDL wavelength scan.

  1. Applications of tunable high energy/pressure pulsed lasers to atmospheric transmission and remote sensing

    NASA Technical Reports Server (NTRS)

    Hess, R. V.; Seals, R. K.

    1974-01-01

    Atmospheric transmission of high energy C12 O2(16) lasers were improved by pulsed high pressure operation which, due to pressure broadening of laser lines, permits tuning the laser 'off' atmospheric C12 O2(16) absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers, and for vertical transmission through the entire atmosphere. The atmospheric transmission of tuned C12 O2(16) lasers compares favorably with C12 O2(18) isotope lasers and CO lasers. The advantages of tunable, high energy, high pressure pulsed lasers over tunable diode lasers and waveguide lasers, in combining high energies with a large tuning range, are evaluated for certain applications to remote sensing of atmospheric constituents and pollutants. Pulsed operation considerably increases the signal to noise ratio without seriously affecting the high spectral resolution of signal detection obtained with laser heterodyning.

  2. Emerging ps-TW CO{sub 2} laser technology for high energy physics applications

    SciTech Connect

    Pogorelsky, I.V.

    1998-02-01

    A brief overview of laser acceleration techniques and a comparative analysis of the picosecond terawatt (ps-TW) CO{sub 2} laser technology versus T{sup 3} solid state lasers for prospective HEP applications. Special attention is given to two laser accelerator schemes. The first one is the far-field staged laser accelerator, STELLA, which is under exploration at the ATF using a CO{sub 2} laser. The second is a laser wakefield accelerator where ps-TW CO{sub 2} lasers have a great potential. Inverse to the laser accelerator, a prospective monochromatic x-ray source feasible at the ATF will also utilize a 50 MeV subpicosecond electron beam and the first ps-TW CO{sub 2} laser, PITER I.

  3. Materials Development and Evaluation of Selective Laser Sintering Manufacturing Applications

    SciTech Connect

    Smith, Peter F.; Mitchell, Russell R.

    1997-01-15

    This report summarizes the FY96 accomplishments for CRADA No. LA95C10254, "Materials Development and Evaluation of Laser Sintering Manufacturing Applications". To research the potential for processing additional materials using DTM Corporations Selective Laser Sintering rapid prototyping technology and evaluate the capability for rapid manufacturing applications, the following materials were processed experimentally using the Sinterstation 2000 platform; Linear Low Density Polyethylene thermoplastic; Polypropylene thermoplastic; Polysulfone thermoplastic; Polymethylpentene (TPX) thermoplastic; Carbon microsphere filled nylon 11; "APO-BMI" Apocure bismaleimide thermoset polyimide glass m.icrosphere filled and carbon microsphere filled formulations; and 900-24 physical properties mock for plastic bonded TATB high explosive These materials have been successfully processed to a "proof of concept" level or better (with the exception of No. 7). While none of these materials have been introduced as a standard product as of this date, the potential to do so is viable. Present status of materials processing efforts is presented in Section A 2.0. Some recent efforts in manufacturing applications is discussed in Section A 4.0.

  4. Simple laser vision sensor calibration for surface profiling applications

    NASA Astrophysics Data System (ADS)

    Abu-Nabah, Bassam A.; ElSoussi, Adnane O.; Al Alami, Abed ElRahman K.

    2016-09-01

    Due to the relatively large structures in the Oil and Gas industry, original equipment manufacturers (OEMs) have been implementing custom-designed laser vision sensor (LVS) surface profiling systems as part of quality control in their manufacturing processes. The rough manufacturing environment and the continuous movement and misalignment of these custom-designed tools adversely affect the accuracy of laser-based vision surface profiling applications. Accordingly, Oil and Gas businesses have been raising the demand from the OEMs to implement practical and robust LVS calibration techniques prior to running any visual inspections. This effort introduces an LVS calibration technique representing a simplified version of two known calibration techniques, which are commonly implemented to obtain a calibrated LVS system for surface profiling applications. Both calibration techniques are implemented virtually and experimentally to scan simulated and three-dimensional (3D) printed features of known profiles, respectively. Scanned data is transformed from the camera frame to points in the world coordinate system and compared with the input profiles to validate the introduced calibration technique capability against the more complex approach and preliminarily assess the measurement technique for weld profiling applications. Moreover, the sensitivity to stand-off distances is analyzed to illustrate the practicality of the presented technique.

  5. Laser Welded Corrugated Steel Panels in Industrial Applications

    NASA Astrophysics Data System (ADS)

    Kananen, M.; Mäntyjärvi, K.; Keskitalo, M.; Hietala, M.; Järvenpää, A.; Holappa, K.; Saine, K.; Teiskonen, J.

    Corrugated core steel panels are an effective way to reduce weight and increase stiffness of steel structures. In numerous applications, these panels have shown very promising commercial possibilities. This study presents the design, manufacturing and commercializing process for two practical examples: Case 1) a fly wheel cover for a diesel engine and Case 2) rotationally symmetrical panel for an electric motor. Test materials of various kinds were used for corrugated cores and skin plates: conventional low-carbon steel grade EN 10130 and ferritic stainless steel grade 1.4509 with plate the thicknesses of 0.5, 0.6 and 0.75 mm. To manufacture different kinds of corrugated core steel panels, flexible manufacturing tools and cost-effective processes are needed. The most important criterion for laser welding panels was the capability of forming tools for producing high quality geometry for the core. Laser welding assembly showed that the quality of the core in both studied cases was good enough for welding the lap joints properly. Developed panels have been tested in industrial applications with excellent feedback. If thickness of a corrugated panel structure is not a limiting issue, these panels are good solution on application where stiffness and lighter weight are required as well as vibrational aspect considered.

  6. Damage-controlled high power lasers and plasma mirror application

    NASA Astrophysics Data System (ADS)

    Kiriyama, Hiromitsu; Ochi, Yoshihiro; Nishikino, Masaharu; Nagashima, Keisuke; Kawachi, Tetsuya; Itakura, Ryoji; Sugiyama, Akira; Kando, Masaki; Pirozhkov, A. S.; Nishiuchi, Mamiko; Bulanov, Sergei V.; Kondo, Kimonori; Kato, Yoshiaki

    2015-07-01

    Following three different types of high power lasers at Kansai Photon Science Institute are overviewed and controlling the laser damages in these laser systems are described: (1) PW-class Ti:sapphire laser for high field science, (2) zig-zag slab Nd:glass laser for x-ray laser pumping, and (3) high-repetition Yb:YAG thin-slab laser for THz generation. Also reported is the use of plasma mirror for characterization of short-wavelength ultrashort laser pulses. This new method will be useful to study evolution of plasma formation which leads to laser damages.

  7. Health assessment for Milan Army Ammunition Plant, Milan, Carrol and Gibson Counties, Tennessee, Region 4. CERCLIS No. TND210020582. Preliminary report

    SciTech Connect

    Not Available

    1989-04-10

    The Milan Army Ammunition Plant Site (MAAP) is located in Milan (Carrol and Gibson Counties), Tennessee. MAAP produces munitions for the U.S. Army. From 1942 to 1978 wastewater from a munition demilitarization process line was discharged into 11 unlined settling ponds. These ponds were dredged in 1971 with the soils placed near the side of the ponds. A multilayer cap was placed on top of the ponds and the dredged soils (1984). Access to the site is restricted. Removal actions have not occurred. Preliminary on-site groundwater sampling results have identified cyclonite (RDX), homocyclonite (HMX), 2,4,6-trinitrotoluene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, 1,3,5-trinitrobenzene. In addition, cadmium, chromium, and lead were detected in on-site groundwater. Off-site surface water sampling results identified RDX and HMX. The site is considered to be of potential public health concern because of the risk to human health caused by the possibility of human exposure to hazardous substances. Direct contact and ingestion with groundwater from on-site wells, off-site soils and bioaccumulation of site-related contaminants in fish, waterfowl, and crops with uptake from irrigation, and subsequent ingestion by area residents are possible human exposure pathways.

  8. Ultrafast laser inscribed fiber Bragg gratings for sensing applications

    NASA Astrophysics Data System (ADS)

    Mihailov, Stephen J.

    2016-05-01

    Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature stable gratings based on femtosecond infrared laser-material processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This tutorial paper will present a review of some of the more recent developments.

  9. Application Of Laser Fluorimetry To Enzyme-Linked Immunoassay

    NASA Astrophysics Data System (ADS)

    Hinsberg, William D.; Milby, Kristin H.; Lidofsky, Steven D.; Zare, Richard N.

    1981-09-01

    An enzyme-linked sandwich immunoassay for insulin is described. Horseradish peroxidase is employed as an enzyme label for antibody, and enzyme activity is measured via the fluorogenic substrate, p-hydroxyphenylacetic acid. The product is detected by excitation of fluorescence with the 325 nm line of a cw helium-cadmium ion laser on-line with reverse phase high performance liquid chromatography. The method requires a total incubation time of 45 minutes, and the limit of insulin detection is 1.1 μU/ml (6.6 pM). This assay is applicable to the analysis of human serum samples.

  10. Center of Excellence for Laser Applications in Medicine, Microlaser Microscope

    SciTech Connect

    Webb, R. H.

    2003-01-17

    The Center of Excellence for Laser Applications in Medicine at the Schepens Eye Research Institute (SERI) is a Center for: A core group of researchers who support each other and their various projects for real-time medical imaging and diagnostics in contiguous space at SERI. Clinical collaborators who participate in the core research at SERI, MEEI, and local ophthalmology practices, and at associated sites around the world. Industrial partners who transfer our technology to commercial products that will reach clinical usage everywhere. Students, post-doctoral associates and medical fellows who work with us and learn how to practice real-time medical imaging and diagnostics.

  11. Living Donor Liver Transplantation Outcomes for Hepatocellular Carcinoma Beyond Milan or UCSF Criteria.

    PubMed

    Gunay, Yusuf; Guler, Necdet; Yaprak, Onur; Dayangac, Murat; Akyildiz, Murat; Altaca, Gulum; Yuzer, Yildiray; Tokat, Yaman

    2015-12-01

    Liver transplantation (LT) is the most effective treatment for hepatocellular carcinoma (HCC) that arises from cirrhosis. The Milan and the University of California, San Francisco (UCSF) selection criteria have resulted in major improvements in patient survival. We assessed our outcomes for patients with HCC that were beyond the Milan and UCSF criteria after living donor liver transplantation. We reviewed the data for 109 patients with cirrhosis and HCC who underwent living donor right lobe liver transplantation (living donor liver transplantation; LDLT) during the period from July 2004 to July 2012. Sixteen (14.7 %) patients had HCC recurrences during a mean follow-up of 35.4 ± 26.2 months (range 4-100 months). The mean time to recurrence was 11 ± 9.4 months (range 4-26 months). Survival rates were not significantly different between patients with HCC that met and were beyond the Milan and UCSF criteria (p = 0.761 and p = 0.861, respectively). The Milan and UCSF criteria were not independent risk factors for HCC recurrence or patient survival. Only poorly differentiated tumors were associated with a lower survival rate (OR = 8.656, 95 % confidence interval (CI) 2.01-37.16; p = 0.004). Survival rates for patients with HCC that were beyond conventional selection criteria should encourage reconsidering the acceptable thresholds of these criteria so that more HCC patients may undergo LT without affecting outcomes. PMID:27011489

  12. Fundamentals and applications of polymers designed for laser ablation

    NASA Astrophysics Data System (ADS)

    Lippert, T.; Hauer, M.; Phipps, C. R.; Wokaun, A.

    The ablation characteristics of various polymers were studied at low and high fluences for an irradiation wavelength of 308 nm. The polymers can be divided into three groups, i.e. polymers containing triazene groups, designed ester groups, and reference polymers, such as polyimide. The polymers containing the photochemically most active group (triazene) exhibit the lowest thresholds of ablation (as low as 25 mJcm-2) and the highest etch rates (e.g. 250 nm/pulse at 100 mJcm-2), followed by the designed polyesters and then polyimide. Neither the linear nor the effective absorption coefficients have a clear influence on the ablation characteristics. The different behavior of polyimide might be explained by a pronounced thermal part in the ablation mechanism. The laser-induced decomposition of the designed polymers was studied by nanosecond interferometry and shadowgraphy. The etching of the triazene polymer starts and ends with the laser pulse, indicating photochemical ablation. Shadowgraphy reveals mainly gaseous products and a pronounced shockwave in air. The designed polymers were tested for an application as the polymer fuel in laser plasma thrusters.

  13. Application of laser pulse stretching scheme for efficiently delivering laser energy in photoacoustic imaging

    PubMed Central

    Wang, Tianheng; Kumavor, Patrick D.

    2012-01-01

    Abstract. High-energy and short-duration laser pulses are desirable to improve the photoacoustic image quality when imaging deeply seated lesions. In many clinical applications, the high-energy pulses are coupled to tissue using optical fibers. These pulses can damage fibers if the damage threshold is exceeded. While keeping the total energy under the Food and Drug Administration limit for avoiding tissue damage, it is necessary to reduce the peak intensity and increase the pulse duration for minimizing fiber damage and delivering sufficient light for imaging. We use laser-pulse-stretching to address this problem. An initial 17-ns pulse was stretched to 27 and 37 ns by a ring-cavity laser-pulse-stretching system. The peak power of the 37-ns stretched pulse reduced to 42% of the original, while the fiber damage threshold was increased by 1.5-fold. Three ultrasound transducers centered at 1.3-, 3.5-, and 6-MHz frequencies were simulated, and the results showed that the photoacoustic signal of a 0.5-mm-diameter target obtained with 37-ns pulse was about 98, 91, and 80%, respectively, using the same energy as the 17-ns pulse. Simulations were validated using a broadband hydrophone. Quantitative comparisons of photoacoustic images obtained with three corresponding transducers showed that the image quality was not affected by stretching the pulse. PMID:22734748

  14. Application of laser pulse stretching scheme for efficiently delivering laser energy in photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Wang, Tianheng; Kumavor, Patrick D.; Zhu, Quing

    2012-06-01

    High-energy and short-duration laser pulses are desirable to improve the photoacoustic image quality when imaging deeply seated lesions. In many clinical applications, the high-energy pulses are coupled to tissue using optical fibers. These pulses can damage fibers if the damage threshold is exceeded. While keeping the total energy under the Food and Drug Administration limit for avoiding tissue damage, it is necessary to reduce the peak intensity and increase the pulse duration for minimizing fiber damage and delivering sufficient light for imaging. We use laser-pulse-stretching to address this problem. An initial 17-ns pulse was stretched to 27 and 37 ns by a ring-cavity laser-pulse-stretching system. The peak power of the 37-ns stretched pulse reduced to 42% of the original, while the fiber damage threshold was increased by 1.5-fold. Three ultrasound transducers centered at 1.3-, 3.5-, and 6-MHz frequencies were simulated, and the results showed that the photoacoustic signal of a 0.5-mm-diameter target obtained with 37-ns pulse was about 98, 91, and 80%, respectively, using the same energy as the 17-ns pulse. Simulations were validated using a broadband hydrophone. Quantitative comparisons of photoacoustic images obtained with three corresponding transducers showed that the image quality was not affected by stretching the pulse.

  15. Passively cooled diode laser for high-power applications

    NASA Astrophysics Data System (ADS)

    Bonati, Guido F.; Hennig, Petra; Schmidt, Karsten

    2004-06-01

    For the usage of diode lasers in industrial applications, customers ask today for expected lifetimes of more then 30.000 hours. To match the request for low costs per Watt as well, the output power has to be as high as possible. To achieve a maximum power out of a diode laser bar, heat removal must be extremely efficient. Today, micro channel heatsinks (MCHS) are the only way to achieve the high power level of 50W. But due to erosion/corrosion effects the lifetime of MCHS is limited at 15000...20.000 hours today. Finally we have to determine that for selected semiconductor materials not the semiconductor but the heatsink is limiting the expected lifetime of high power diode lasers today. Passive heat sinks based on solid copper are not limiting lifetime expectations in any way. But as cooling efficiency is lower, the power has to be reduced to a level of 30...40W. The first time ever, the JENOPTIK Laserdiode can present today a cooling technique that combines the passive cooling of a diode laser bar with the optical output a power of a bar, mounted on a MCHS. Using a special heat exchanger called DCB (patent pending) we were able to increase the power to 50W per bar while looking forward to extend the expected lifetime to more than 30.000 hours for selected materials. Restrictions on the quality of the water by means of deionization grade or PH- level are no longer necessary. The device is operating with regular water. The flow rate is as low as on MCHS, the pressure drop over the DCB is comparable. Additionally, the measurements will show an even lower thermal resistance compared to MCHS. The second generationof engineering samples is built up for pumping rows. A vertical stack design will be available for evaluating purposes soon. All these efforts are part of the JENOPTIK Laserdiode's LongLifeTechnology.

  16. Evaluation of various organic fertilizer substrates and hydraulic retention times for enhancing anaerobic degradation of explosives-contaminated groundwater while using constructed wetlands at the Milan Army Ammunition Plant, Milan, Tennessee. Final report

    SciTech Connect

    Behrends, L.L.; Almond, R.A.; Kelly, D.A.; Phillips, W.D.; Rogers, W.J.

    1998-05-01

    This document describes studies conducted at the Milan Army Ammunition Plant (MAAP) to improve the design, operation, and cost of gravel-based anaerobic cells when phytoremediating explosives-contaminated groundwater. To conduct this study, small-scale anaerobic test cells were used to determine: (1) If the hydraulic retention time of a large demonstration-scale anaerobic cell at MAAP could be reduced, and (2) if other carbon sources could be used as an anaerobic feedstock. The study results indicated that: (1) The existing anaerobic cell`s 7.5-day retention time should not be reduced since residual explosive by-products were present in the effluent of treatments with a 3.5-day retention time. (2) Daily application of a relatively soluble substrate, such as molasses syrup, will provide better explosives removal than periodic application of less soluble substrates like milk replacement starter and sewage sludge. (3) Molasses syrup could be, and should be, used as a substitute for milk replacement power. The recommendation to use molasses syrup was based on: (1) The lower cost of molasses syrup as compared to milk replacement starter, (2) molasses syrup`s higher solubility (which makes it easier to apply), and (3) molasses syrup`s ability to provide enhanced explosives removal.

  17. Applications of laser lithography on oxide film to titanium micromachining

    NASA Astrophysics Data System (ADS)

    Chauvy, P.-F.; Hoffmann, P.; Landolt, D.

    2003-03-01

    Due to its good biocompatibility titanium is widely used for dental and orthopaedics implants and for biomedical microsystems. For these applications one needs specific micromachining methods. A new four-step method for electrochemical micromachining of titanium is presented here, which implies anodic oxidation, Excimer laser sensitising irradiation, anodic dissolution, and ultrasonic cleaning. The method is applied to the fabrication of two 3D model structures, surface structuring of a cylinder and machining of a complex two-level architecture. The absence of debris and of a heat affected zone as well as the resulting surface smoothness are the main advantages of the process. Ways to improve the still limited processing speed are discussed with regards to potential applications.

  18. Laser reconditioning of crankshafts: From lab to application

    NASA Astrophysics Data System (ADS)

    Koehler, H.; Partes, K.; Seefeld, T.; Vollertsen, F.

    In marine diesel engines, damaged crankshafts are common and expensive defects. Worn surfaces of main bearings and crankpin journals often require a complete replacement of these components. This paper presents the development of a repair procedure on its way to application. As an alternative to the method of grinding the accordant surfaces and using matched bearing shells, a rebuild to the original diameter is the goal of this investigation. This paper describes the development of a controlled diode laser cladding process in the lab and the characterization of flat specimens particularly by metallographic analysis and hardness testing. In preparation of the industrial application, previously ground crankpin journals of crankshafts could successfully be cladded with identical parameters as found on flat specimens in the lab. The claddings show a high quality in terms of connection to the base material and dilution. In hardness tests steep gradients from heat affected zone to unaffected base material could be measured.

  19. Compact laser vibrometer for industrial and medical applications

    NASA Astrophysics Data System (ADS)

    Lewin, Andrew C.

    1998-06-01

    Laser interferometric vibrometers are now well known and accepted as sensitive, accurate, high bandwidth and linear measurement system. For many applications the internal complexity and resultant size of the interferometric sensor head limits the widespread use. This paper describes the performance and principle of operation of a new miniaturized interferometric sensor head which retains the important characteristics of the previously mentioned systems, but embodied in a robust compact housing no larger thana typical torchlight. Velocity resolution in the acoustic range has been found to be up to 50 nanometers/sec in a 10 Hz RBW. The size of this new sensor head allows it to be mounted on balanced microscope assemblies or within machinery, and the waterproof design allows disinfectant cleaning in clinical applications or operation in industrial environments.

  20. Laser beam joining of material combinations for automotive applications

    NASA Astrophysics Data System (ADS)

    Schubert, Emil; Zerner, Ingo; Sepold, Gerd

    1997-08-01

    An ideal material for automotive applications would combine the following properties: high corrosion resistance, high strength, high stiffness and not at least a low material price. Today a single material is not able to meet all these requirements. Therefore, in the future different materials will be placed where they meet the requirements best. The result of this consideration is a car body with many different alloys and metals, which have to be joined to one another. BIAS is working on the development of laser based joining technologies for different material combinations, especially for thin sheets used in automotive applications. One result of the research is a joining technology for an aluminum-steel-joint. Using a Nd:YAG laser the problem of brittle intermetallic phases between these materials was overcome. Using suitable temperature-time cycles, elected by a FEM-simulation, the thickness of intermetallic phases was kept below 10 micrometers . This technology was also applied to coated steels, which were joined with different aluminum alloys. Further it is demonstrated that titanium alloys, e.g. used for racing cars, can also be joined with aluminum alloys.

  1. Qualification and Selection of Flight Diode Lasers for Space Applications

    NASA Technical Reports Server (NTRS)

    Liebe, Carl C.; Dillon, Robert P.; Gontijo, Ivair; Forouhar, Siamak; Shapiro, Andrew A.; Cooper, Mark S.; Meras, Patrick L.

    2010-01-01

    The reliability and lifetime of laser diodes is critical to space missions. The Nuclear Spectroscopic Telescope Array (NuSTAR) mission includes a metrology system that is based upon laser diodes. An operational test facility has been developed to qualify and select, by mission standards, laser diodes that will survive the intended space environment and mission lifetime. The facility is situated in an electrostatic discharge (ESD) certified clean-room and consist of an enclosed temperature-controlled stage that can accommodate up to 20 laser diodes. The facility is designed to characterize a single laser diode, in addition to conducting laser lifetime testing on up to 20 laser diodes simultaneously. A standard laser current driver is used to drive a single laser diode. Laser diode current, voltage, power, and wavelength are measured for each laser diode, and a method of selecting the most adequate laser diodes for space deployment is implemented. The method consists of creating histograms of laser threshold currents, powers at a designated current, and wavelengths at designated power. From these histograms, the laser diodes that illustrate a performance that is outside the normal are rejected and the remaining lasers are considered spaceborne candidates. To perform laser lifetime testing, the facility is equipped with 20 custom laser drivers that were designed and built by California Institute of Technology specifically to drive NuSTAR metrology lasers. The laser drivers can be operated in constant-current mode or alternating-current mode. Situated inside the enclosure, in front of the laser diodes, are 20 power-meter heads to record laser power throughout the duration of lifetime testing. Prior to connecting a laser diode to the current source for characterization and lifetime testing, a background program is initiated to collect current, voltage, and resistance. This backstage data collection enables the operational test facility to have full laser diode

  2. Single frequency and wavelength stabilized near infrared laser source for water vapor DIAL remote sensing application

    NASA Astrophysics Data System (ADS)

    Chuang, Ti; Walters, Brooke; Shuman, Tim; Losee, Andrew; Schum, Tom; Puffenberger, Kent; Burnham, Ralph

    2015-02-01

    Fibertek has demonstrated a single frequency, wavelength stabilized near infrared laser transmitter for NASA airborne water vapor DIAL application. The application required a single-frequency laser transmitter operating at 935 nm near infrared (NIR) region of the water vapor absorption spectrum, capable of being wavelength seeded and locked to a reference laser source and being tuned at least 100 pm across the water absorption spectrum for DIAL on/off measurements. Fibertek is building a laser transmitter system based on the demonstrated results. The laser system will be deployed in a high altitude aircraft (ER-2 or UAV) to autonomously perform remote, long duration and high altitude water vapor measurements.

  3. Simulation of Laser Cooling and Trapping in Engineering Applications

    NASA Technical Reports Server (NTRS)

    Ramirez-Serrano, Jaime; Kohel, James; Thompson, Robert; Yu, Nan; Lunblad, Nathan

    2005-01-01

    An advanced computer code is undergoing development for numerically simulating laser cooling and trapping of large numbers of atoms. The code is expected to be useful in practical engineering applications and to contribute to understanding of the roles that light, atomic collisions, background pressure, and numbers of particles play in experiments using laser-cooled and -trapped atoms. The code is based on semiclassical theories of the forces exerted on atoms by magnetic and optical fields. Whereas computer codes developed previously for the same purpose account for only a few physical mechanisms, this code incorporates many more physical mechanisms (including atomic collisions, sub-Doppler cooling mechanisms, Stark and Zeeman energy shifts, gravitation, and evanescent-wave phenomena) that affect laser-matter interactions and the cooling of atoms to submillikelvin temperatures. Moreover, whereas the prior codes can simulate the interactions of at most a few atoms with a resonant light field, the number of atoms that can be included in a simulation by the present code is limited only by computer memory. Hence, the present code represents more nearly completely the complex physics involved when using laser-cooled and -trapped atoms in engineering applications. Another advantage that the code incorporates is the possibility to analyze the interaction between cold atoms of different atomic number. Some properties that cold atoms of different atomic species have, like cross sections and the particular excited states they can occupy when interacting with each other and light fields, play important roles not yet completely understood in the new experiments that are under way in laboratories worldwide to form ultracold molecules. Other research efforts use cold atoms as holders of quantum information, and more recent developments in cavity quantum electrodynamics also use ultracold atoms to explore and expand new information-technology ideas. These experiments give a hint

  4. Laser-Ultrasonic Testing and its Applications to Nuclear Reactor Internals

    NASA Astrophysics Data System (ADS)

    Ochiai, M.; Miura, T.; Yamamoto, S.

    2008-02-01

    A new nondestructive testing technique for surface-breaking microcracks in nuclear reactor components based on laser-ultrasonics is developed. Surface acoustic wave generated by Q-switched Nd:YAG laser and detected by frequency-stabilized long pulse laser coupled with confocal Fabry-Perot interferometer is used to detect and size the cracks. A frequency-domain signal processing is developed to realize accurate sizing capability. The laser-ultrasonic testing allows the detection of surface-breaking microcrack having a depth of less than 0.1 mm, and the measurement of their depth with an accuracy of 0.2 mm when the depth exceeds 0.5 mm including stress corrosion cracking. The laser-ultrasonic testing system combined with laser peening system, which is another laser-based maintenance technology to improve surface stress, for inner surface of small diameter tube is developed. The generation laser in the laser-ultrasonic testing system can be identical to the laser source of the laser peening. As an example operation of the system, the system firstly works as the laser-ultrasonic testing mode and tests the inner surface of the tube. If no cracks are detected, the system then changes its work mode to the laser peening and improves surface stress to prevent crack initiation. The first nuclear industrial application of the laser-ultrasonic testing system combined with the laser peening was completed in Japanese nuclear power plant in December 2004.

  5. Applications of a single-longitudinal-mode alexandrite laser for diagnostics of parameters of combustion interest

    NASA Astrophysics Data System (ADS)

    Li, Z. S.; Afzelius, M.; Zetterberg, J.; Aldén, M.

    2004-10-01

    We report on the applications of a single-longitudinal-mode (SLM) pulsed alexandrite laser system for diagnostics of parameters of flow/combustion interest. The laser system is characterized by its narrow linewidth, high peak power, and broad tunablity. The absolute frequency of the laser output was monitored by a wavelength diagnostic system, which included a high-resolution confocal etalon and a molecular iodine laser-induced fluorescence (LIF) detection system. Different nonlinear frequency conversion schemes were used to cover a large frequency range from the infrared to the deep UV. The versatility of the laser system for flow/combustion diagnostics is demonstrated in three applications, namely filtered Rayleigh scattering, high-resolution Doppler-free two-photon LIF of CO, and infrared LIF and polarization spectroscopy of CO2. The potential impacts of using this SLM laser system in laser flow/combustion diagnostic applications are discussed.

  6. High-power, high-pressure pulsed CO{sub 2} lasers and their applications

    SciTech Connect

    Baranov, G A; Kuchinsky, A A

    2005-03-31

    The paper is devoted to problems associated with the construction of high-power pulsed CO{sub 2} lasers and high-pressure amplifiers and to an analysis of the possible ways of their solution. Prospects of the development of such lasers and their applications in technological processes are considered. Original designs of a laser complex for obtaining the carbon-13 isotope and a superatmospheric-pressure CO{sub 2} amplifier are presented. (lasers)

  7. The Development Of Gold And Copper Vapour Lasers For Medical Applications In Australia

    NASA Astrophysics Data System (ADS)

    Stanco, Alex

    1987-04-01

    The first fully automated mobile copper and gold vapour lasers for medical applications were developed in Australia. The history of this development program is presented in this paper. These lasers have been tested in several clinical programs and success with the gold vapour laser in cancer phototherapy using HpD has been achieved in various types of tumours. Trials have commenced on the use of the 578 nm yellow line of the copper vapour laser for dermatology and plastic surgery.

  8. The Milan-Marseille Future Astronomical Software Environment Prototype

    NASA Astrophysics Data System (ADS)

    Garilli, B.; Paioro, L.; Fenouillet, T.; Surace, C.

    2007-10-01

    The European OPTICON Network 3.6, in collaboration with theUS National Virtual Observatory, is working on the definition of requirements and general architecture of a new scalable and interoperable software environment. Such environment, named the Future Astronomical Software Environment (FASE), is intended to be a common platform for data reduction and analysis applications, supporting and exploiting (but not replacing) new technologies like Virtual Observatory and Grids. The advanced status of the study and design has led to the need of putting such ideas in a concrete form, implementing a first prototype. We present the FASE prototype developed by INAF-IASF Milano and LAM Marseille and the practical application of its engineering to the VIPGI data reduction package. We show the technologies adopted, the problems solved and to be tackled, and possible future developments.

  9. Development of laser induced breakdown spectroscopy instrumentatin for safeguards applications

    SciTech Connect

    Barefield Il, James E; Clegg, Samuel M; Le, Loan A; Lopez, Leon N

    2010-01-01

    In September 2006, a Technical Meeting on Application of Laser Spectrometry Techniques in IAEA Safeguards was held at IAEA headquarters (HQ). One of the principal recommendations from this meeting was the need to 'pursue the development of novel complementary access instrumentation based on laser induced breakdown spectroscopy (LIBS) for the detection of gaseous and solid signatures and indicators of nuclear fuel cycle processes and associated materials.' Pursuant to this recommendation the Department of Safeguards (SG) under the Division of Technical Support (SGTS) convened the Experts and Users Advisory Meeting on Laser Induced Breakdown Spectroscopy (LIBS) for Safeguards Applications. This meeting was held at IAEA HQ from July 7-11,2008 and hosted by the Novel Technologies Unit (NTU). The meeting was attended by 12 LIBS experts from the Czech Republic, the European Commission, France, the Republic of Korea, the United States of America, Germany, the United Kingdom of Great Britain, Canada, and Northern Ireland. After a presentation of the needs of the IAEA inspectors, the LIBS experts were in agreement that needs as presented could be partially or fully fulfilled using LIBS instrumentation. The needs of the IAEA inspectors were grouped in the following broad categories: (1) Improvements to in-field measurements/environmental sampling; (2) Monitoring status of activity in a Hot Cell; (3) Verifying status of activity at a declared facility via process monitoring; and (4) Need for pre-screening of environmental samples before analysis. Under the Department of Energy/National Nuclear Security Administration (DOE/NNSA) Next Generation Safeguards Initiative (NGSI) Los Alamos National Laboratory is exploring three potential applications of LIBS for international safeguards. As part of this work, we are developing: (1) a user-friendly man-portable LIBS system to characterize samples across a wide range of elements in the periodic table from hydrogen up to heavy elements

  10. Tm,Ho:YAG laser with tunable range of 2.08-2.12 microns and its applications to spectroscopy

    NASA Technical Reports Server (NTRS)

    Asai, Kazuhiro; Itabe, Toshikazu

    1992-01-01

    In recent advanced lasers, 2 micron solid-state lasers such as Tm:YAG and Ho:YAG lasers are very attractive for laser radar remote sensing technologies because of eye safety, realizations of all solid-state laser pumped by diode laser and smaller dimension, tunability of lasing wavelength, possibility of coherent detection, etc. Featuring these advantages, 2 micron lasers have been candidated as laser transmitters for use in water vapor Differential Absorption Lidar (DIAL), laser altimeter, Doppler wind sensor, Mie lidar, etc. Characterization of a tunable Cr, Tm, Ho:YAG laser and its applications to spectroscopy concerning absorption and reflectance are reported.

  11. Mid-wave/long-wave infrared lasers and their sensing applications

    NASA Astrophysics Data System (ADS)

    Law, K. K.; Shori, R.; Miller, J. K.; Sharma, S.

    2011-06-01

    Many advances have been made recently in both solid-state and semiconductor based mid-wave infrared (MWIR) and long-wave infrared (LWIR) laser technologies, and there is an ever growing demand for these laser sources for Naval, DOD and homeland security applications. We will present various current and future programs and efforts at Naval Air Warfare Center Weapons Division (NAWCWD) on the development of high-power, broadly tunable MWIR/LWIR lasers for sensing applications.

  12. Pulsed Laser Synthesized Magnetic Cobalt Oxide Nanoparticles for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Bhatta, Hari; Gupta, Ram; Ghosh, Kartik; Kahol, Pawan; Delong, Robert; Wanekawa, Adam

    2011-03-01

    Nanomaterials research has become a major attraction in the field of advanced materials research in the area of Physics, Chemistry, and Materials Science. Biocompatible and chemically stable magnetic metal oxide nanoparticles have biomedical applications that includes drug delivery, cell and DNA separation, gene cloning, magnetic resonance imaging (MRI). This research is aimed at the fabrication of magnetic cobalt oxide nanoparticles using a safe, cost effective, and easy to handle technique that is capable of producing nanoparticles free of any contamination. Cobalt oxide nanoparticles have been synthesized at room temperature using cobalt foil by pulsed laser ablation technique. These cobalt oxide nanoparticles were characterized using UV-Visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and dynamic laser light scattering (DLLS). The magnetic cobalt oxides nanoparticles were stabilized in glucose solutions of various concentrations in deionized water. The presence of UV-Vis absorption peak at 270 nm validates the nature of cobalt oxide nanoparticles. The DLLS size distributions of nanoparticles are in the range of 110 to 300 nm, which further confirms the presence nanoparticles. This work is partially supported by National Science Foundation (DMR- 0907037).

  13. Applications of laser in ischemic heart disease in China

    NASA Astrophysics Data System (ADS)

    Chen, Mingzhe; Zhang, Yongzhen

    1999-09-01

    Current data demonstrate that laser coronary angioplasty is most useful in complex lesions not well suited for percutaneous transluminal coronary angioplasty (PTCA). It is not `stand-alone' procedure, and should be considered an adjunct to PTCA or stenting. To date, there are not data supporting reduction of restenosis. Direct myocardial revascularization (DMR), either transmyocardial revascularization (TMR) or percutaneous (catheter-based) myocardial revascularization (PMR), uses laser to create channels between ischemic myocardium and left ventricular cavity. Candidates include patients with chronic, severe, refractory angina and those unable to undergo angioplasty or bypass surgery because conduits or acceptable target vessels are lacking. Although the mechanisms of action of DMR have not yet been clearly elucidated, but several theories have been proposed, including channel patency, angiogenesis, and denervation. TMR, typically requiring open thoracotomy, is effective for improving myocardial perfusion and reducing angina. Pilot studies demonstrate that clinical application of PMR is feasible and safe and effective for decreasing angina. Late sequelae also remain to be determined. An ongoing randomized clinical trial is comparing PMR with conventional medical therapy in patients with severe, refractory angina and disease unamenable to angioplasty or bypass surgery.

  14. Laser-induced breakdown spectroscopy in industrial and security applications

    SciTech Connect

    Bol'shakov, Alexander A.; Yoo, Jong H.; Liu Chunyi; Plumer, John R.; Russo, Richard E.

    2010-05-01

    Laser-induced breakdown spectroscopy (LIBS) offers rapid, localized chemical analysis of solid or liquid materials with high spatial resolution in lateral and depth profiling, without the need for sample preparation. Principal component analysis and partial least squares algorithms were applied to identify a variety of complex organic and inorganic samples. This work illustrates how LIBS analyzers can answer a multitude of real-world needs for rapid analysis, such as determination of lead in paint and children's toys, analysis of electronic and solder materials, quality control of fiberglass panels, discrimination of coffee beans from different vendors, and identification of generic versus brand-name drugs. Lateral and depth profiling was performed on children's toys and paint layers. Traditional one-element calibration or multivariate chemometric procedures were applied for elemental quantification, from single laser shot determination of metal traces at {approx}10 {mu}g/g to determination of halogens at 90 {mu}g/g using 50-shot spectral accumulation. The effectiveness of LIBS for security applications was demonstrated in the field by testing the 50-m standoff LIBS rasterizing detector.

  15. a Light-Weight Laser Scanner for Uav Applications

    NASA Astrophysics Data System (ADS)

    Tommaselli, A. M. G.; Torres, F. M.

    2016-06-01

    Unmanned Aerial Vehicles (UAV) have been recognized as a tool for geospatial data acquisition due to their flexibility and favourable cost benefit ratio. The practical use of laser scanning devices on-board UAVs is also developing with new experimental and commercial systems. This paper describes a light-weight laser scanning system composed of an IbeoLux scanner, an Inertial Navigation System Span-IGM-S1, from Novatel, a Raspberry PI portable computer, which records data from both systems and an octopter UAV. The performance of this light-weight system was assessed both for accuracy and with respect to point density, using Ground Control Points (GCP) as reference. Two flights were performed with the UAV octopter carrying the equipment. In the first trial, the flight height was 100 m with six strips over a parking area. The second trial was carried out over an urban park with some buildings and artificial targets serving as reference Ground Control Points. In this experiment a flight height of 70 m was chosen to improve target response. Accuracy was assessed based on control points the coordinates of which were measured in the field. Results showed that vertical accuracy with this prototype is around 30 cm, which is acceptable for forest applications but this accuracy can be improved using further refinements in direct georeferencing and in the system calibration.

  16. Analytical application of femtosecond laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Melikechi, Noureddine; Markushin, Yuri

    2015-05-01

    We report on significant advantages provided by femtosecond laser-induced breakdown spectroscopy (LIBS) for analytical applications in fields as diverse as protein characterization and material science. We compare the results of a femto- and nanosecond-laser-induced breakdown spectroscopy analysis of dual-elemental pellets in terms of the shot-to-shot variations of the neutral/ionic emission line intensities. This study is complemented by a numerical model based on two-dimensional random close packing of disks in an enclosed geometry. In addition, we show that LIBS can be used to obtain quantitative identification of the hydrogen composition of bio-macromolecules in a heavy water solution. Finally, we show that simultaneous multi-elemental particle assay analysis combined with LIBS can significantly improve macromolecule detectability up to near single molecule per particle efficiency. Research was supported by grants from the National Science Foundation Centers of Research Excellence in Science and Technology (0630388), National Aeronautics and Space Administration (NX09AU90A). Our gratitude to Dr. D. Connolly, Fox Chase Cancer Center.

  17. Development and applications of laser-induced incandescence

    NASA Technical Reports Server (NTRS)

    Vanderwal, Randy L.; Dietrich, Daniel L.; Zhou, Zhiquang; Choi, Mun Y.

    1995-01-01

    Several NASA-funded investigations focus on soot processes and radiative influences of soot in diffusion flames given their simplicity, practical significance, and potential for theoretical modeling. Among the physical parameters characterizing soot, soot volume fraction, f(sub v), a function of particle size and number density, is often of chief practical interest in these investigations, as this is the geometrical property that directly impacts radiative characteristics and the temperature field of the flame and is basic to understanding soot growth and oxidation processes. Diffusion flames, however, present a number of challenges to the determination of f(sub v) via traditional extinction measurements. Laser-induced incandescence (LII) possesses several advantages compared to line-of-sight extinction techniques for determination of f(sub v). Since LII is not a line-of-sight technique, similar to fluorescence, it possesses geometric versatility allowing spatially resolved measurements of f(sub v) in real time in nonaxisymmetric systems without using deconvolution techniques. The spatial resolution of LII is determined by the detector and imaging magnification used. Neither absorption by polycyclic aromatic hydrocarbons (PAH's) nor scattering contributes to the signal. Temporal capabilities are limited only by the laser pulse and camera gate duration, with measurements having been demonstrated with 10 ns resolution. Because of these advantages, LII should be applicable to a variety of combustion processes involving both homogeneous and heterogeneous phases. Our work has focussed on characterization of the technique as well as exploration of its capabilities and is briefly described.

  18. Laser surgery in dermatology with application of superthin optical fiber by contact and noncontact method

    NASA Astrophysics Data System (ADS)

    Garipova, A.; Denissov, I. A.; Solodovnikov, Vladimir; Digilova, I.

    1999-06-01

    At present nobody doubts the advantages of minor laser surgery over the conventional one.Bloodless manipulations, ablation, minor injury to the tissues while using laser equipment ensures its wide application in such fields as dermatology and cosmetology, especially since the semiconductor lasers because available at the technological market. No doubt CO2 and solid laser are still playing an important role, however, their imperfect fiber optic qualities limit their use in these field,s where advantages of diode lasers with flexible and fine quartz-polymeric optical fiber are obvious. The elaboration of new diode surgical lasers made it possible to invent new surgical equipment for solving many medical problems in the optimal way. Application of contact and noncontact laser methods in dermatology, gynecological plastic surgery and otolaryngology is discussed. A combined use of these methods demonstrates a positive effect on therapy results and healing time.

  19. The application research of laser ultrasonic technique used in testing compound material

    NASA Astrophysics Data System (ADS)

    Xu, Jun; Kong, Lingjian; Gu, Xiaofei; Luo, Jijun; Hou, Xun

    2005-01-01

    The principles of laser ultrasonic generation and measurements with pulsed laser are presented. There are two kinds of means to actuate ultrasonic pulse: elasticity actuating and ablation actuating. The progress in laser ultrasonic about laser ultrasound generation, detection, propagation and its applications is introduced briefly. Applications in the field of Non-Destructive Testing (NDT) are reviewed. In the field of Non-Destructive Testing, according to the principle, the laser ultrasonic testing system consists of laser system, laser interferometer, photoelectric detector and receiving system with signal amplifier. Thus, long-range and non-contact on-line detection of ultrasonic testing system was realized. In view of some of the problems, the developing trends of such techniques are analyzed.

  20. Conditional versus unconditional industrial agglomeration: disentangling spatial dependence and spatial heterogeneity in the analysis of ICT firms' distribution in Milan

    NASA Astrophysics Data System (ADS)

    Espa, Giuseppe; Arbia, Giuseppe; Giuliani, Diego

    2013-01-01

    A series of recent papers have introduced some explorative methods based on Ripley's K-function (Ripley in J R Stat Soc B 39(2):172-212, 1977) analyzing the micro-geographical patterns of firms. Often the spatial heterogeneity of an area is handled by referring to a case-control design, in which spatial clusters occur as over-concentrations of firms belonging to a specific industry as opposed to the distribution of firms in the whole economy. Therefore, positive, or negative, spatial dependence between firms occurs when a specific sector of industry is seen to present a more aggregated pattern (or more dispersed) than is common in the economy as a whole. This approach has led to the development of relative measures of spatial concentration which, as a consequence, are not straightforwardly comparable across different economies. In this article, we explore a parametric approach based on the inhomogeneous K-function (Baddeley et al. in Statistica Nederlandica 54(3):329-350, 2000) that makes it possible to obtain an absolute measure of the industrial agglomeration that is also able to capture spatial heterogeneity. We provide an empirical application of the approach taken with regard to the spatial distribution of high-tech industries in Milan (Italy) in 2001.

  1. [Objective evaluation the application of femtosecond laser in cataract surgery].

    PubMed

    Liu, Y Z

    2016-02-01

    Femtosecond laser-assisted cataract surgery (FLACS) is a novel technology and the biggest revolution in the field of cataract in the latest several years. However, increasing large-scale population randomized controlled trials (RCT) have demonstrated that FLACS does not provide significant advantages over conventional phacoemulsification cataract surgery (CPCS) for common cataract patients. Furthermore, the cost and space requirement of the femtosecond equipment are another two limitations for the universal application of FSL in cataract surgery. However, FLACS may be beneficial for complex cataract situations, such as lens dislocation, zonular laxity, traumatic cataract, low preoperative endothelial cell values, and significant corneal astigmatism. With the progress of science and technology, FLACS can be expected to achieve integration with phacoemulsification systems, and equipment costs can be reduced, making it more widely used in clinical practice in the future. PMID:26906700

  2. LASER BIOLOGY AND MEDICINE: Application of tunable diode lasers for a highly sensitive analysis of gaseous biomarkers in exhaled air

    NASA Astrophysics Data System (ADS)

    Stepanov, E. V.; Milyaev, Varerii A.

    2002-11-01

    The application of tunable diode lasers for a highly sensitive analysis of gaseous biomarkers in exhaled air in biomedical diagnostics is discussed. The principle of operation and the design of a laser analyser for studying the composition of exhaled air are described. The results of detection of gaseous biomarkers in exhaled air, including clinical studies, which demonstrate the diagnostic possibilities of the method, are presented.

  3. Nonlinear 6-fold enhancement of laser drilling efficiency by double pulse mode: prospective in medicine application

    NASA Astrophysics Data System (ADS)

    Pershina, N. S.; Pershin, S. M.; Cech, M.; Prochazka, I.

    2009-05-01

    The efficiency of laser ablation drilling of metal and dielectric (ceramic, glasses, etc.) samples with single and multiple laser pulses per one laser shot was experimentally studied. The laser is operated on the fundamental (1064 nm) wavelength of Nd:YAG laser with 30 ns pulse length or its second (532 nm) and third (351 nm) harmonics, respectively. The laser shot repletion rate was 1 Hz. The pulses in train were separated by 25-45 μs interval. The crater depth and drilling speed dependence increasing on pulse number in multipulse train was studied. The laser ablation normalized per pulse energy in train dependence is not linear function. The strong ablation enhancement was observed. The optimal (in sense the total pulse energy using) drilling can be obtained with double pulse mode compared with 3 - 5 pulses. Nonlinear more than 6 fold increasing of crater depth produced by the second pulse in train was detected. The mechanism of selective increasing of the second pulse interaction efficiency with the hard target is discussed. Experimental results explained in terms of double pulse mode laser ablation model. Spectroscopy study of laser plasma was observed to confirm discussed model of high efficiency for two laser pulse laser ablation. Efficiency of double pulse mode compared with multipulse mode is discussed to be more perspective for various applications of laser ablation. The medicine (surgery, dentist, ophthalmology and so on) application is the most prospective, for instance, the teeth drilling or glaucoma perforation, can be done with smaller energy value.

  4. Efficient high-brightness diode laser modules offer new industrial applications

    NASA Astrophysics Data System (ADS)

    Revermann, Markus; Timmermann, Andre; Meinschien, Jens; Bruns, Peter

    2007-02-01

    We present new developed high power diode laser modules which are performing at outstanding brightness and their applications. The combination of recently designed laser diode bars on passive heat sinks and optimized micro-optics results to laser modules up to 50W out of a 100μm fibre with a 0.22 NA at one single wavelength based on broad area laser bars (BALB) and up to 50W out of 50μm fibre with a 0.22 NA based on single-mode emitter array laser (SEAL) bars. The fibre coupled systems are based on diode lasers with a collimated beam of superior beam data, namely < 10 mm x 10 mm beam diameter (FW1/e2) and < 2mrad x 2mrad divergence (FW1/e2). Such free beam diode lasers deliver 30 W or 60 W output power. The applications for such laser diode modules varies from direct marking, cutting and welding of metals and other materials up to pumping of fibre lasers and amplifiers. Marking speed with up to 30mm/s on stainless steel was observed with 20W laser power and 50μm fibre with a conventional marking setup. Cutting speed of about 1m/min of 0.2mm Kovar sheet was shown with a diode laser module with 50W laser power from a 100μm fibre.

  5. Applications of quantum cascade lasers in plasma diagnostics: a review

    NASA Astrophysics Data System (ADS)

    Röpcke, J.; Davies, P. B.; Lang, N.; Rousseau, A.; Welzel, S.

    2012-10-01

    Over the past few years mid-infrared absorption spectroscopy based on quantum cascade lasers operating over the region from 3 to 12 µm and called quantum cascade laser absorption spectroscopy or QCLAS has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry of molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, nitrogen oxides and organo-silicon compounds has led to further applications of QCLAS because most of these compounds and their decomposition products are infrared active. QCLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species at time resolutions below a microsecond, which is of particular importance for the investigation of reaction kinetics and dynamics. Information about gas temperature and population densities can also be derived from QCLAS measurements. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of QCLAS techniques to industrial requirements including the development of new diagnostic equipment. The recent availability of external cavity (EC) QCLs offers a further new option for multi-component detection. The aim of this paper is fourfold: (i) to briefly review spectroscopic issues arising from applying pulsed QCLs, (ii) to report on recent achievements in our understanding of molecular phenomena in plasmas and at surfaces, (iii) to describe the current status of industrial process monitoring in the mid-infrared and (iv) to discuss the potential of advanced instrumentation based on EC-QCLs for plasma diagnostics.

  6. Design investigation of solar powered lasers for space applications

    NASA Technical Reports Server (NTRS)

    Taussig, R.; Bruzzone, C.; Quimby, D.; Nelson, L.; Christiansen, W.; Neice, S.; Cassady, P.; Pindroh, A.

    1979-01-01

    The feasibility of solar powered lasers for continuous operation in space power transmission was investigated. Laser power transmission in space over distances of 10 to 100 thousand kilometers appears possible. A variety of lasers was considered, including solar-powered GDLs and EDLs, and solar-pumped lasers. An indirect solar-pumped laser was investigated which uses a solar-heated black body cavity to pump the lasant. Efficiencies in the range of 10 to 20 percent are projected for these indirect optically pumped lasers.

  7. Improvements of high-power diode laser line generators open up new application fields

    NASA Astrophysics Data System (ADS)

    Meinschien, J.; Bayer, A.; Bruns, P.; Aschke, L.; Lissotschenko, V. N.

    2009-02-01

    Beam shaping improvements of line generators based on high power diode lasers lead to new application fields as hardening, annealing or cutting of various materials. Of special interest is the laser treatment of silicon. An overview of the wide variety of applications is presented with special emphasis of the relevance of unique laser beam parameters like power density and beam uniformity. Complementary to vision application and plastic processing, these new application markets become more and more important and can now be addressed by high power diode laser line generators. Herewith, a family of high power diode laser line generators is presented that covers this wide spectrum of application fields with very different requirements, including new applications as cutting of silicon or glass, as well as the beam shaping concepts behind it. A laser that generates a 5m long and 4mm wide homogeneous laser line is shown with peak intensities of 0.2W/cm2 for inspection of railway catenaries as well as a laser that generates a homogeneous intensity distribution of 60mm x 2mm size with peak intensities of 225W/cm2 for plastic processing. For the annealing of silicon surfaces, a laser was designed that generates an extraordinary uniform intensity distribution with residual inhomogeneities (contrast ratio) of less than 3% over a line length of 11mm and peak intensities of up to 75kW/cm2. Ultimately, a laser line is shown with a peak intensity of 250kW/cm2 used for cutting applications. Results of various application tests performed with the above mentioned lasers are discussed, particularly the surface treatment of silicon and the cutting of glass.

  8. Second Hepatectomy Improves Survival in Patients With Microvascular Invasive Hepatocellular Carcinoma Meeting the Milan Criteria

    PubMed Central

    Hou, Yi-Fu; Li, Bo; Wei, Yong-Gang; Yang, Jia-Yin; Wen, Tian-Fu; Xu, Ming-Qing; Yan, L.V.-Nan; Chen, Ke-Fei

    2015-01-01

    Abstract Microvascular invasion (MVI) is a strong risk factor for patients with hepatocellular carcinoma (HCC) meeting the Milan criteria and who have received curative hepatectomy. The relevance of a second hepatectomy in patients with MVI-positive recurrent HCC remains controversial. We had 329 cases of HCC hepatectomy meeting the Milan criteria and compared data on patient demographics, liver function, and tumor pathology between MVI-positive and MVI-negative group. We analyzed potential risk factors of overall survival (OS) and disease-free survival (DFS). Furthermore, newly developed pathological features following the second hepatectomy were also analyzed. The median OS and DFS were significantly superior in the MVI-negative group than in the MVI-positive group, 61 (10–81) versus 49 (11–82) months (P < 0.01) and 41 (7–75) versus 13 (3–69) months (P < 0.01), respectively. The presence of MVI and a total tumor diameter >3 cm were independent risk factors associated with both OS and DFS. Overall survival was significantly improved by a second hepatectomy in the MVI-positive group compared with the original MVI-positive group, 60 (26–82) versus 49 (11–82) months, respectively. This was now comparable to the MVI-negative group, 60 (26–82) versus 61 (10–81) months (P = 0.72). A second hepatectomy was consistently associated with better survival in the MVI-negative group as compared to the MVI-positive group. A second hepatectomy improves survival in patients with MVI HCC meeting the Milan criteria. The biology of MVI may change following a second hepatectomy. The absence of MVI is a good prognostic sign for patients undergoing second hepatectomy. PMID:26632890

  9. Coilable single crystals fibers of doped-YAG for high power laser applications

    NASA Astrophysics Data System (ADS)

    Soleimani, Nazila; Ponting, Bennett; Gebremichael, Eminet; Ribuot, Antoine; Maxwell, Gisele

    2014-05-01

    Single crystal fibers are an intermediate between laser crystals and doped glass fibers. They have the advantages of both guiding laser light and matching efficiencies found in bulk crystals, which make them ideal candidates for high-power laser and fiber laser applications. This work focuses on the growth of a flexible fiber with a core of dopant (Er, Nd, Yb, etc.) that will exhibit good wave guiding properties. Direct growth or a combination of growth and cladding experiments are described. Scattering loss measurements at visible wavelengths along with dopant profile characterization are also presented. Laser characterization for these fibers is in progress.

  10. Coilable single crystals fibers of doped-YAG for high power laser applications

    NASA Astrophysics Data System (ADS)

    Soleimani, Nazila; Ponting, Bennett; Gebremichael, Eminet; Ribuot, Antoine; Maxwell, Gisele

    2014-02-01

    Single crystal fibers are an intermediate between laser crystals and doped glass fibers. They have the advantages of both guiding laser light and matching the efficiencies found in bulk crystals, which is making them ideal candidates for high-power laser and fiber laser applications. This work focuses on the growth of a flexible fiber with a core of dopant (Er, Nd, Yb, etc…) that will exhibit good wave guiding properties. Direct growth or a combination of growth and cladding experiments are described. Scattering loss measurements at visible wavelengths along with dopant profile characterization are also presented. Laser characterization for these fibers is in progress.

  11. Lasers, their development, and applications at M.I.T. Lincoln Laboratory

    NASA Technical Reports Server (NTRS)

    Rediker, R. H.; Melngailis, I.; Mooradian, A.

    1984-01-01

    A historical account of the work on lasers at MIT Lincoln Laboratory is presented. Highlighted are the efforts that led to the coinvention of the semiconductor laser and the Laboratory's later role in establishing the feasibility of GaInAsP/InP semiconductor lasers for use in fiber telecommunications at 1.3-1.5 micron wavelengths. Descriptions of other important developments include tunable lead-salt semiconductor and solid-state lasers for spectroscopy and LIDAR applications, respectively, as well as ultrastable CO2 lasers for coherent infrared radar.

  12. A compact high brightness laser synchrotron light source for medical applications

    NASA Astrophysics Data System (ADS)

    Nakajima, Kazuhisa

    1999-07-01

    The present high-brightness hard X-ray sources have been developed as third generation synchrotron light sources based on large high energy electron storage rings and magnetic undulators. Recently availability of compact terawatt lasers arouses a great interest in the use of lasers as undulators. The laser undulator concept makes it possible to construct an attractive compact synchrotron radiation source which has been proposed as a laser synchrotron light source. This paper proposes a compact laser synchrotron light source for mediacal applications, such as an intravenous coronary angiography and microbeam therapy.

  13. Application of CO2 laser for electronic components soldering

    NASA Astrophysics Data System (ADS)

    Mascorro-Pantoja, J.; Soto-Bernal, J. J.; Nieto-Pérez, M.; Gonzalez-Mota, R.; Rosales-Candelas, I.

    2011-10-01

    Laser provides a high controllable and localized spot for soldering joint formation and this is a valuable tool in Sn/Pb Soldering process on electronic industry, in recent years, laser beam welding has become an emerging welding technique, the use of laser in welding area is a high efficiency method. A 60 Watts CO2 continuous laser was used on this study, during welding experimental results indicated the laser could significantly improve speed and weld quality. In this work, the welding interactions of CO2 laser with Sn/Pb wire have been investigated in details through varying the energy ratios of laser. And at the same time, the effect of distance from laser spot to material.

  14. Milan Štefánik and the rotation period of Venus: a centenary for 2007

    NASA Astrophysics Data System (ADS)

    McKim, R. J.

    2007-02-01

    Exactly 100 years ago a paper about Venus appeared in the Journal of the Royal Astronomical Society of Canada. Its author was a young Slovak astronomer, Milan Rastislav Štefánik. From his studies of the planet from the Mont Blanc observatory he had deduced a rotation period for Venus of 23 hours and 20 to 25 minutes. This was entirely typical of the periods being quoted at that time: most astronomers opted for a synchronous rotation, or for one of about 24 hours. What was more remarkable was the extraordinarily diverse career the young astronomer followed.

  15. Asymmetric dee-voltage compensation of beam off-centering in the milan superconducting cyclotron

    SciTech Connect

    Milinkovic, Lj.; Fabrici, E.; Ostojic, R.

    1985-10-01

    An analysis of the effects of orbit off-centering on the beam extraction in the Milan superconducting cyclotron is made, and the sensitivity of axial beam loss and radial phase space distortions to beam off-centering determined for various acceleration conditions. We conclude that the first field harmonic compensation of beam off-centering is ineffective in the region of the operating diagram where the Walkinshaw resonance precedes the ..nu.. /SUB r/ =1 resonance. Asymmetric dee-voltage compensation is considered in these cases, and the domain of validity of the method determined. A semi-empirical relation for dee-voltage distribution is deduced, and the extraction efficiency discussed.

  16. AlGaInN laser diode technology and systems for defence and security applications

    NASA Astrophysics Data System (ADS)

    Najda, Stephen P.; Perlin, Piotr; Suski, Tadek; Marona, Lucja; Boćkowski, Mike; Leszczyński, Mike; Wisniewski, Przemek; Czernecki, Robert; Kucharski, Robert; Targowski, Grzegorz; Watson, Scott; Kelly, Antony E.

    2015-05-01

    The latest developments in AlGaInN laser diode technology are reviewed for defence and security applications such as underwater communications. The AlGaInN material system allows for laser diodes to be fabricated over a very wide range of wavelengths from u.v., ~380nm, to the visible ~530nm, by tuning the indium content of the laser GaInN quantum well. Thus AlGaInN laser diode technology is a key enabler for the development of new disruptive system level applications in displays, telecom, defence and other industries.

  17. Application of copper vapour lasers for controlling activity of uranium isotopes

    SciTech Connect

    Barmina, E V; Sukhov, I A; Lepekhin, N M; Priseko, Yu S; Filippov, V G; Simakin, Aleksandr V; Shafeev, Georgii A

    2013-06-30

    Beryllium nanoparticles are generated upon ablation of a beryllium target in water by a copper vapour laser. The average size of single crystalline nanoparticles is 12 nm. Ablation of a beryllium target in aqueous solutions of uranyl chloride leads to a significant (up to 50 %) decrease in the gamma activity of radionuclides of the uranium-238 and uranium-235 series. Data on the recovery of the gamma activity of these nuclides to new steady-state values after laser irradiation are obtained. The possibility of application of copper vapour lasers for radioactive waste deactivation is discussed. (laser applications and other topics in quantum electronics)

  18. Laser rods with undoped, flanged end-caps for end-pumped laser applications

    DOEpatents

    Meissner, Helmuth E.; Beach, Raymond J.; Bibeau, Camille; Sutton, Steven B.; Mitchell, Scott; Bass, Isaac; Honea, Eric

    1999-01-01

    A method and apparatus for achieving improved performance in a solid state laser is provided. A flanged, at least partially undoped end-cap is attached to at least one end of a laserable medium. Preferably flanged, undoped end-caps are attached to both ends of the laserable medium. Due to the low scatter requirements for the interface between the end-caps and the laser rod, a non-adhesive method of bonding is utilized such as optical contacting combined with a subsequent heat treatment of the optically contacted composite. The non-bonded end surfaces of the flanged end-caps are coated with laser cavity coatings appropriate for the lasing wavelength of the laser rod. A cooling jacket, sealably coupled to the flanged end-caps, surrounds the entire length of the laserable medium. Radiation from a pump source is focussed by a lens duct and passed through at least one flanged end-cap into the laser rod.

  19. Laser processing of ormosils for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Matei, A.; Zamfirescu, M.; Radu, C.; Dinescu, M.; Buruiana, E. C.; Buruiana, T.; Sima, L. E.; Petrescu, S. M.

    2011-09-01

    Hybrid methacrylates based on silane derivates (ormosils) have been considered for applications in electronics, microtechnology, corrosion resistant coatings, dentistry, and biomedical implants. The presence of both inorganic chains, responsible for chemical and thermal stability, hardness, and transparency, and organic groups, which bring new advantages such as the possibility of functionalization and easy, low temperature processing, can result in the appearance of unique properties. 2D structures of hybrid polymers were produced by Two Photon Polymerization (2PP). A Ti: Sapphire laser having 200 fs pulse duration and 2 kHz repetition rate, working at a wavelength of 775 nm, was used for the 2PP experiments. The biocompatibility of the obtained structures (scaffolds) was tested in different cell cultures, which is a first step toward exploring their potential for applications in tissue engineering. Cells morphology, adhesion, and alignment were studied on polymeric structures with different shapes, obtained in various experimental conditions. Their interaction with normal human epidermal melanocytes (NHEM) and dysplastic oral keratinocytes (DOK) was investigated, with the aim of obtaining an epidermal graft.

  20. Programmable phase plate for tool modification in laser machining applications

    DOEpatents

    Thompson Jr., Charles A.; Kartz, Michael W.; Brase, James M.; Pennington, Deanna; Perry, Michael D.

    2004-04-06

    A system for laser machining includes a laser source for propagating a laser beam toward a target location, and a spatial light modulator having individual controllable elements capable of modifying a phase profile of the laser beam to produce a corresponding irradiance pattern on the target location. The system also includes a controller operably connected to the spatial light modulator for controlling the individual controllable elements. By controlling the individual controllable elements, the phase profile of the laser beam may be modified into a desired phase profile so as to produce a corresponding desired irradiance pattern on the target location capable of performing a machining operation on the target location.

  1. Laser hardening techniques on steam turbine blade and application

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Zhang, Qunli; Kong, Fanzhi; Ding, Qingming

    Different laser surface hardening techniques, such as laser alloying and laser solution strengthening were adopted to perform modification treatment on the local region of inset edge for 2Cr13 and 17-4PH steam turbine blades to prolong the life of the blades. The microstructures, microhardness and anti-cavitation properties were investigated on the blades after laser treatment. The hardening mechanism and technique adaptability were researched. Large scale installation practices confirmed that the laser surface modification techniques are safe and reliable, which can improve the properties of blades greatly with advantages of high automation, high quality, little distortion and simple procedure.

  2. Optical and laser spectroscopic diagnostics for energy applications

    NASA Astrophysics Data System (ADS)

    Tripathi, Markandey Mani

    The continuing need for greater energy security and energy independence has motivated researchers to develop new energy technologies for better energy resource management and efficient energy usage. The focus of this dissertation is the development of optical (spectroscopic) sensing methodologies for various fuels, and energy applications. A fiber-optic NIR sensing methodology was developed for predicting water content in bio-oil. The feasibility of using the designed near infrared (NIR) system for estimating water content in bio-oil was tested by applying multivariate analysis to NIR spectral data. The calibration results demonstrated that the spectral information can successfully predict the bio-oil water content (from 16% to 36%). The effect of ultraviolet (UV) light on the chemical stability of bio-oil was studied by employing laser-induced fluorescence (LIF) spectroscopy. To simulate the UV light exposure, a laser in the UV region (325 nm) was employed for bio-oil excitation. The LIF, as a signature of chemical change, was recorded from bio-oil. From this study, it was concluded that phenols present in the bio-oil show chemical instability, when exposed to UV light. A laser-induced breakdown spectroscopy (LIBS)-based optical sensor was designed, developed, and tested for detection of four important trace impurities in rocket fuel (hydrogen). The sensor can simultaneously measure the concentrations of nitrogen, argon, oxygen, and helium in hydrogen from storage tanks and supply lines. The sensor had estimated lower detection limits of 80 ppm for nitrogen, 97 ppm for argon, 10 ppm for oxygen, and 25 ppm for helium. A chemiluminescence-based spectroscopic diagnostics were performed to measure equivalence ratios in methane-air premixed flames. A partial least-squares regression (PLS-R)-based multivariate sensing methodology was investigated. It was found that the equivalence ratios predicted with the PLS-R-based multivariate calibration model matched with the

  3. High Power Lasers And Their Application In Materials Processing

    NASA Astrophysics Data System (ADS)

    Bohn, W. L.

    1985-02-01

    The idea of using a laser for materials processing is more than 20 years old. Although the concept of a non-contact method for processing with a beam of light has been pursued with great interest and enthusiasm, the practical use of laser beam processing was slow to develop. The lasers available in the 1960's were fragile and of relatively low power. In the 1970's lasers in the multi-kilowatt range were developed but the problem of laser acceptance by the customer had to be overcome. Today, reliable Nd-Yag and CO2-lasers are available and laser processing is a fast growing market. An additional boost is expected with the development of the next generation of lasers and with increased knowledge of the physical phenomena that underlie laser material processing. This paper will review latest developments in laser technology and laser-workpiece interaction with special emphasis on the impact of high speed photography on the research work in these areas.

  4. Research on the application of laser ultrasonic technique in weaponry

    NASA Astrophysics Data System (ADS)

    Kong, Lingjian; Xu, Jun; Yan, Yisheng; Gu, Xiaofei; Zhu, Guifang

    2005-12-01

    Laser Ultrasonics is a new branch in Ultrasonics, which is based on the generation of ultrasonic by a laser and the detection of stress wave with laser interferometer, and is an ideal combination of laser and ultrasonic for non-destructive testing. It is a noncontact, remote and precise technique for nondestructive testing of materials and products. Firstly, this paper introduces the principles of laser ultrasonic generation, and the ablation excitation theory. And then optical detection method of laser-induced ultrasonic with the confocal Fabry-Perot interferometer is introduced. Based on the principles of laser-induced ultrasonic generation and detection, the integrated structure of the laser ultrasonic induced by laser line source and detected by a confocal Fabry-Perot interferometer is presented to detect multilayer structure such as solid propellant rocket motor structures in weaponry. Considering how laser ultrasonics would be used in the field and some mostly effects to the results. The laser system, accepting its present limitations, was optimized and developed for the inspection of the multilayer structure of solid propellant rocket motor as the experimental program progressed.

  5. Studies on laser peening of spring steel for automotive applications

    NASA Astrophysics Data System (ADS)

    Ganesh, P.; Sundar, R.; Kumar, H.; Kaul, R.; Ranganathan, K.; Hedaoo, P.; Tiwari, Pragya; Kukreja, L. M.; Oak, S. M.; Dasari, S.; Raghavendra, G.

    2012-05-01

    Present experimental laser shock peening study on SAE 9260 spring steel, performed with an in-house developed 2.5 J/7 ns pulsed Nd:YAG laser, aimed to evaluate laser shock peening process as a possible alternative to existing shot peening practice for enhancing fatigue life of leaf springs. In the investigated range of process parameters, laser shock peening yielded largely comparable magnitude of surface compressive stress and shallower compressed surface layer than those achieved with existing shot peening practice. In contrast to considerably rougher shot peened surface with numerous defects, laser shock peening produced largely unaltered surface finish without peening-induced defects. With respect to shot peening, laser shock peening brought about significant increase in fatigue life. Improved fatigue performance of laser shock peened specimens is attributed to their better surface finish without peening-induced surface defects, which were potential fatigue crack nucleation sites in shot peened specimens.

  6. Application systems for the intracorporal laser-induced shockwave lithotripsy using the Nd:YAG Q-switched laser

    NASA Astrophysics Data System (ADS)

    Frank, Klaus H.; Eichenlaub, M.; Hessel, Stefan F. F.; Wondrazek, Fritz

    1990-06-01

    For the laser-induced shockwave lithotripsy the electromagnetic energy of a laser light pulse is converted intracorporally into the acoustic energy of a shock wave. The lithotriptor is based on a specially developed, Q-switched Nd:YAG laser whose high power light pulses (70 mJ, 25 ns) are coupled into a flexible quartz fiber of 600 pim core diameter. Using focussing elements energy densities higher than 6 1O J m2 can be achieved resulting in an optical breakdown in water followed by a shock wave. As a result of different absorption mechanisms the breakdown threshold can be decreased by placing a metallic target into the laser beam. The different shockwave formations of such optomechanical transducers have been measured. First clinical applications have been performed.

  7. A scalable high-energy diode-pumped solid state laser for laser-plasma interaction science and applications

    NASA Astrophysics Data System (ADS)

    De Vido, M.; Ertel, K.; Mason, P. D.; Banerjee, S.; Phillips, P. J.; Butcher, T. J.; Smith, J. M.; Shaikh, W.; Hernandez-Gomes, C.; Greenhalgh, R. J. S.; Collier, J. L.

    2016-05-01

    Laser systems efficiently generating nanosecond pules at kJ energy levels and at multi-Hz repetition rates are required in order to translate laser-plasma interactions into practical applications. We have developed a scalable, actively-cooled diode-pumped solid state laser amplifier design based on a multi-slab ceramic Yb:YAG architecture called DiPOLE (Diode-Pumped Optical Laser for Experiments) capable of meeting such requirements. We demonstrated 10.8 J, 10 Hz operation at 1030 nm using a scaled-down prototype, reaching an optical-to-optical efficiency of 22.5%. Preliminary results from a larger scale version, delivering 100 J pulse energy at 10 Hz, are also presented.

  8. Rigrod laser-pumped-laser resonator model: II. Application to thin and optically-dilute laser media

    NASA Astrophysics Data System (ADS)

    Brown, D. C.

    2014-08-01

    In part I of this paper, and to set the foundation for this part II, we derived the resonator equations describing the normalized intensities, output power, gain, and extraction efficiency for a standard resonator incorporating two dielectric mirrors and a gain element. We then generalized the results to include an absorbing region representing a second laser crystal characterized by a small-signal transmission T0. Explicit expressions were found for the output power extracted into absorption by the second laser crystal and the extraction efficiency, and the limits to each were discussed. It was shown that efficient absorption by a thin or dilute second laser crystal can be realized in resonators in which the mirror reflectivities were high and in which the single-pass absorption was low, due to the finite photon lifetime and multi-passing of the absorbing laser element. In this paper, we apply the model derived in part I to thin or dilute laser materials, concentrating on a Yb, Er:glass intracavity pumped by a 946 nm Nd:YAG laser, a Yb, Er:glass laser-pumped intracavity by a 977 nm diode laser, and an Er:YAG laser-pumped intracavity to a 1530 nm diode laser. It is shown that efficient absorption can be obtained in all cases examined.

  9. An application of laser-plasma acceleration: towards a free-electron laser amplification

    NASA Astrophysics Data System (ADS)

    Couprie, M. E.; Labat, M.; Evain, C.; Marteau, F.; Briquez, F.; Khojoyan, M.; Benabderrahmane, C.; Chapuis, L.; Hubert, N.; Bourassin-Bouchet, C.; El Ajjouri, M.; Bouvet, F.; Dietrich, Y.; Valléau, M.; Sharma, G.; Yang, W.; Marcouillé, O.; Vétéran, J.; Berteaud, P.; El Ajjouri, T.; Cassinari, L.; Thaury, C.; Lambert, G.; Andriyash, I.; Malka, V.; Davoine, X.; Tordeux, M. A.; Miron, C.; Zerbib, D.; Tavakoli, K.; Marlats, J. L.; Tilmont, M.; Rommeluère, P.; Duval, J. P.; N'Guyen, M. H.; Rouqier, A.; Vanderbergue, M.; Herbeaux, C.; Sebdouai, M.; Lestrade, A.; Leclercq, N.; Dennetière, D.; Thomasset, M.; Polack, F.; Bielawski, S.; Szwaj, C.; Loulergue, A.

    2016-03-01

    The laser-plasma accelerator (LPA) presently provides electron beams with a typical current of a few kA, a bunch length of a few fs, energy in the few hundred MeV to several GeV range, a divergence of typically 1 mrad, an energy spread of the order of 1%, and a normalized emittance of the order of π.mm.mrad. One of the first applications could be to use these beams for the production of radiation: undulator emission has been observed but the rather large energy spread (1%) and divergence (1 mrad) prevent straightforward free-electron laser (FEL) amplification. An adequate beam manipulation through the transport to the undulator is then required. The key concept proposed here relies on an innovative electron beam longitudinal and transverse manipulation in the transport towards an undulator: a ‘demixing’ chicane sorts the electrons according to their energy and reduces the spread from 1% to one slice of a few ‰ and the effective transverse size is maintained constant along the undulator (supermatching) by a proper synchronization of the electron beam focusing with the progress of the optical wave. A test experiment for the demonstration of FEL amplification with an LPA is under preparation. Electron beam transport follows different steps with strong focusing with permanent magnet quadrupoles of variable strength, a demixing chicane with conventional dipoles, and a second set of quadrupoles for further focusing in the undulator. The FEL simulations and the progress of the preparation of the experiment are presented.

  10. Laser-Damage-Resistant Photoalignment Layers for High-Peak-Power Liquid Crystal Device Applications

    SciTech Connect

    Marshall, K.L.; Gan, J.; Mitchell, G.; Papernov, S.; Rigatti, A.L.; Schmid, A.W.; Jacobs, S.D.

    2008-10-23

    Large-aperture liquid crystal (LC) devices have been in continuous use since 1995 as polarization control devices in the 40-TW, 351-nm, 60-beam OMEGA Nd:glass laser system at the University of Rochester’s Laboratory for Laser Energetics. The feasibility of using a noncontacting alignment method for high-peak-power LC laser optics by irradiation of a linearly photopolymerizable polymer with polarized UV light was recently investigated. These materials were found to have surprisingly large laser-damage thresholds at 1054 nm, approaching that of bare fused silica (30 to 60 J/cm^2). Their remarkable laser-damage resistance and ease in scalability to large apertures of these photoalignment materials, along with the ability to produce multiple alignment states by photolithographic patterning, opens new doorways for their application in LC devices for optics, photonics, and high-peak-power laser applications.

  11. Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission

    NASA Technical Reports Server (NTRS)

    Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, Joe T. (Technical Monitor)

    2002-01-01

    Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

  12. Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

    PubMed Central

    Leahy-Hoppa, Megan R.; Miragliotta, Joseph; Osiander, Robert; Burnett, Jennifer; Dikmelik, Yamac; McEnnis, Caroline; Spicer, James B.

    2010-01-01

    Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS), coherent Raman spectroscopy, and terahertz (THz) spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications. PMID:22399883

  13. Progresses on the Theoretical and Experimental Studies in Laser Technologies Research and Application Center In Kocaeli

    SciTech Connect

    Akman, E.; Atalay, B.; Candan, L.; Canel, T.; Demir, A.; Demir, P.; Erturk, S.; Genc, B.; Kacar, E.; Kenar, N.; Koymen, E.; Mutlu, M.; Sinmazcelik, T.; Urhan, O.

    2007-04-23

    Laser Technologies Research and Application Center (LATARUM) was established in 2005 with interdisciplinary cooperation to obtain product based on projects, to train personnel with at highest academic level with knowledge to use latest technology. There are electro-optics, laser material processing and modelling and simulation groups working on projects. Theoretical modeling studies are performed for x-ray laser media. Ne-like nickel and iron and Ni-like tin and molybdenum x-ray laser media for different pumping laser configurations have been modeled using EHYBRID. Theoretical and experimental studies on spectrometer design for wavelength range between X-ray and IR are carried out by electro-optic group. Material processing studies using Nd-YAG laser are performed. Materials of titanium, aluminum and stainless steel have been welded in different laser pulse, power, and repetition rate conditions. Optimum parameters for these welding processes have been obtained.

  14. Laser-induced fluorescence imaging of coronary arteries for open-heart surgery applications

    NASA Astrophysics Data System (ADS)

    Taylor, Roderick S.; Gladysz, D.; Brown, Derek W.; Higginson, Lyall A. J.

    1991-07-01

    A technique utilizing laser induced fluorescence has been developed to obtain direct real-time imaging of the coronary artery network for open heart surgery applications. Both excimer pumped dye and cw argon-ion laser radiation transmitted through a fused silica fiber were used as laser sources to irradiate swine, bovine, and human cadaver hearts whose coronary arteries had been injected with strongly fluorescent dyes. The laser induces fluorescence originating from within the coronary arteries and detected by the surgeon's eye, allows the entire coronary network to be directly viewed. A comparison between laser induced fluorescence and the use of direct visual inspection of arteries following injection of the dye Cardio-Green(R) as well as conventional thermal imaging is presented. The limitations imposed on each technique by layers of fat on top of the coronary arteries are also described. The possibility of using these techniques to detect mechanical or laser beam perforations during laser endarterectomy procedures is discussed.

  15. Watt-level red-emitting diode lasers and modules for display applications

    NASA Astrophysics Data System (ADS)

    Paschke, Katrin; Blume, Gunnar; Feise, David; Pohl, Johannes; Sumpf, Bernd

    2016-02-01

    Red-emitting lasers for display applications require high output powers and a high visibility. We demonstrate diode lasers and modules in the red spectral range based on AlGaInP with optical output powers up to 1 W and a nearly diffraction limited beam. These high-luminance light sources based on tapered lasers are well suited for laser TVs and projectors for virtual reality simulators based on the flying spot technology. Additionally, we developed diode lasers with internal distributed Bragg reflector (DBR) surface gratings. These DBR tapered lasers and master-oscillator power-amplifiers based on DBR ridge-waveguide lasers and tapered amplifiers feature high power, single mode emission with coherence lengths up to several meters, which are suitable for the next-generation 3D displays based on holography.

  16. Study, optimization, and design of a laser heat engine. [for satellite applications

    NASA Technical Reports Server (NTRS)

    Taussig, R. T.; Cassady, P. E.; Zumdieck, J. F.

    1978-01-01

    Laser heat engine concepts, proposed for satellite applications, are analyzed to determine which engine concept best meets the requirements of high efficiency (50 percent or better), continuous operation in space using near-term technology. The analysis of laser heat engines includes the thermodynamic cycles, engine design, laser power sources, collector/concentrator optics, receiving windows, absorbers, working fluids, electricity generation, and heat rejection. Specific engine concepts, optimized according to thermal efficiency, are rated by their technological availability and scaling to higher powers. A near-term experimental demonstration of the laser heat engine concept appears feasible utilizing an Otto cycle powered by CO2 laser radiation coupled into the engine through a diamond window. Higher cycle temperatures, higher efficiencies, and scalability to larger sizes appear to be achievable from a laser heat engine design based on the Brayton cycle and powered by a CO laser.

  17. Event-Based Surveillance During EXPO Milan 2015: Rationale, Tools, Procedures, and Initial Results

    PubMed Central

    Manso, Martina Del; Caporali, Maria Grazia; Napoli, Christian; Linge, Jens P.; Mantica, Eleonora; Verile, Marco; Piatti, Alessandra; Pompa, Maria Grazia; Vellucci, Loredana; Costanzo, Virgilio; Bastiampillai, Anan Judina; Gabrielli, Eugenia; Gramegna, Maria; Declich, Silvia

    2016-01-01

    More than 21 million participants attended EXPO Milan from May to October 2015, making it one of the largest protracted mass gathering events in Europe. Given the expected national and international population movement and health security issues associated with this event, Italy fully implemented, for the first time, an event-based surveillance (EBS) system focusing on naturally occurring infectious diseases and the monitoring of biological agents with potential for intentional release. The system started its pilot phase in March 2015 and was fully operational between April and November 2015. In order to set the specific objectives of the EBS system, and its complementary role to indicator-based surveillance, we defined a list of priority diseases and conditions. This list was designed on the basis of the probability and possible public health impact of infectious disease transmission, existing statutory surveillance systems in place, and any surveillance enhancements during the mass gathering event. This article reports the methodology used to design the EBS system for EXPO Milan and the results of 8 months of surveillance. PMID:27314656

  18. Demonstration of surgical telerobotics and virtual telepresence by Internet + ISDN from Monterey (USA) to Milan (Italy).

    PubMed

    Rovetta, A; Sala, R; Bressanelli, M; Garavaldi, M E; Lorini, F; Pegoraro, R; Canina, M

    1998-01-01

    This paper deals with the connection which has been held on 8th July 1997 in collaboration with the JPL of the NASA, Pasadena, California, between the Eighth International Conference on the Advanced Robotics (ICAR '97) in course at Monterey, California and the Telerobotics Laboratory of Politecnico di Milano connected in a multipoint teleconference through the MCU of Rome with the Aula Magna of the same Politecnico and the Palace Business of the Giureconsulti of the Chamber of Commerce of Milan. The demonstration has allowed to telecontrol a scara robot of the Sankyo and an ABB robot, which have affected simulations of operations of biopsy to the prostate, to the liver and to the breast, a mechanical hand and a model of a car, disposed in a space destined to reproduce the Martian ground, from Monterey to Milan by means of the INTERNET+ISDN connection from. In fact the event has taken place four days after the landing on Mars happily successful of the spatial probe Pathfinder from which it has gone out the "Sojourner" robot, telecontrolled from the JPL of the NASA, which has begun to take photos of the Martian ground and also some of these images have been transmitted in the course of the connection. PMID:10180591

  19. Preliminary Statistics from the NASA Alphasat Beacon Receiver in Milan, Italy

    NASA Technical Reports Server (NTRS)

    Zemba, Michael J.; Nessel, James A.; Morse, Jacquelynne R.

    2015-01-01

    NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have initiated a joint propagation campaign within the framework of the Alphasat propagation experiment to characterize rain attenuation, scintillation, and gaseous absorption effects of the atmosphere in the 40 GHz band. NASA GRC has developed and installed a KQ-band (20-40 GHz) beacon receiver at the POLIMI campus in Milan, Italy, which receives the 20-40 GHz signals broadcast from the Alphasat Aldo Paraboni TDP5 beacon payload. The primary goal of these measurements is to develop a physical model to improve predictions of communications systems performance within the Q-band. Herein, we provide an overview of the design and data calibration procedure, and present 6 months of preliminary statistics of the NASA propagation terminal, which has been installed and operating in Milan since May 2014. The Q-band receiver has demonstrated a dynamic range of 40 dB at an 8-Hz sampling rate. A weather station with an optical disdrometer is also installed to characterize rain drop size distribution for correlation with physical based models

  20. Preliminary Statistics from the NASA Alphasat Beacon Receiver in Milan, Italy

    NASA Technical Reports Server (NTRS)

    Nessel, James; Zemba, Michael; Morse, Jacquelynne; Luini, Lorenzo; Riva, Carlo

    2015-01-01

    NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have initiated a joint propagation campaign within the framework of the Alphasat propagation experiment to characterize rain attenuation, scintillation, and gaseous absorption effects of the atmosphere in the 40 gigahertz band. NASA GRC has developed and installed a K/Q-band (20/40 gigahertz) beacon receiver at the POLIMI campus in Milan, Italy, which receives the 20/40 gigahertz signals broadcast from the Alphasat Aldo Paraboni TDP no. 5 beacon payload. The primary goal of these measurements is to develop a physical model to improve predictions of communications systems performance within the Q-band. Herein, we provide an overview of the design and data calibration procedure, and present 6 months of preliminary statistics of the NASA propagation terminal, which has been installed and operating in Milan since May 2014. The Q-band receiver has demonstrated a dynamic range of 40 decibels at an 8-hertz sampling rate. A weather station with an optical disdrometer is also installed to characterize rain drop size distribution for correlation with physical based models.

  1. Event-Based Surveillance During EXPO Milan 2015: Rationale, Tools, Procedures, and Initial Results.

    PubMed

    Riccardo, Flavia; Manso, Martina Del; Caporali, Maria Grazia; Napoli, Christian; Linge, Jens P; Mantica, Eleonora; Verile, Marco; Piatti, Alessandra; Pompa, Maria Grazia; Vellucci, Loredana; Costanzo, Virgilio; Bastiampillai, Anan Judina; Gabrielli, Eugenia; Gramegna, Maria; Declich, Silvia

    2016-01-01

    More than 21 million participants attended EXPO Milan from May to October 2015, making it one of the largest protracted mass gathering events in Europe. Given the expected national and international population movement and health security issues associated with this event, Italy fully implemented, for the first time, an event-based surveillance (EBS) system focusing on naturally occurring infectious diseases and the monitoring of biological agents with potential for intentional release. The system started its pilot phase in March 2015 and was fully operational between April and November 2015. In order to set the specific objectives of the EBS system, and its complementary role to indicator-based surveillance, we defined a list of priority diseases and conditions. This list was designed on the basis of the probability and possible public health impact of infectious disease transmission, existing statutory surveillance systems in place, and any surveillance enhancements during the mass gathering event. This article reports the methodology used to design the EBS system for EXPO Milan and the results of 8 months of surveillance. PMID:27314656

  2. Possible applications of powerful pulsed CO{sub 2}-lasers in tokamak reactors

    SciTech Connect

    Nastoyashchii, A.F.; Morozov, I.N.; Hassanein, A.

    1998-08-01

    Applications of powerful pulsed CO{sub 2}-lasers for injection of fuel tablets or creation of a protective screen from the vapor of light elements to protect against the destruction of plasma-facing components are discussed, and the corresponding laser parameters are determined. The possibility of using CO{sub 2}-lasers in modeling the phenomena of powerful and energetic plasma fluxes interaction with a wall, as in the case of a plasma disruption, is considered.

  3. Applications of high power lasers in the battlefield

    NASA Astrophysics Data System (ADS)

    Kalisky, Yehoshua

    2009-09-01

    Laser weapon is currently considered as tactical as well as strategic beam weapons, and is considered as a part of a general layered defense system against ballistic missiles and short-range rockets. This kind of weapon can disable or destroy military targets or incoming objects used by small groups of terrorists or countries, at the speed of light. Laser weapon is effective at long or short distances, owing to beam's unique characteristics such as narrow bandwidth, high brightness, coherent both in time and space, and it travels at the speed of light. Unlike kinetic weapon, laser weapon converts the energy stored in an electromagnetic laser beam into a large amount of heat aimed on a small area spot at the skin of the missile, usually close to the liquid fuel storage tank, warhead case or engine area, following by a temperature increase and finally-catastrophic failure by material ablation or melt. The usefulness of laser light as a weapon has been studied for decades but only in recent years became feasible. There are two types of lasers being used: gas lasers and solid state lasers, including fiber lasers. All these types of lasers will be discussed below.

  4. Laser applications to chemical analysis: an introduction by the feature editors

    NASA Astrophysics Data System (ADS)

    Jeffries, Jay B.; Ramsey, J. Michael; Lucht, Robert P.

    1995-06-01

    This issue of Applied Optics features papers on the application of laser technology to chemical analysis. Many of the contributions, although not all, result from papers presented at the Fourth OSA Topical Meeting on Laser Applications to Chemical Analysis, which was held at Jackson Hole, Wyoming, March, 1994. This successful meeting, with nearly one hundred participants, continued the tradition of earlier LACA meetings to focus on the optical science of laser-based measurements of temperature and trace chemical assays in a wide variety of practical applications.

  5. Lasers and applications in parts cleaning and surface pre-treatment

    NASA Astrophysics Data System (ADS)

    Burdel, Thomas; Weiler, Sascha; Faißt, Birgit; Schneider, Till; Heckl, Oliver; Birkel, Jörn; Luzius, Severin

    2013-02-01

    A number of upcoming industrial applications prove that the laser offers great possibilities for parts cleaning and surface pretreatment. Thereby laser technology enables solutions to reduce production costs and to increase productivity and quality in the manufacturing process. Examples are the removal of oil, grease, phosphate layers or corrosion with the laser. This paper will focus on parts cleaning and surface pretreatment applications within the automotive industry. For a range of examples it will be shown that the laser not only offers advantages to carry out the described production step (such as cleaning or the creation of functional textures) but also offers great advantages for a following production step within the chain, such as a welding or gluing process. It will be demonstrated that several ns and ps laser sources and systems can be selected, depending on the application.

  6. Industrial fiber beam delivery system for ultrafast lasers: applications and recent advances

    NASA Astrophysics Data System (ADS)

    Eilzer, Sebastian; Funck, Max C.; Wedel, Björn

    2016-03-01

    Fiber based laser beam delivery is the method of choice for high power laser applications whenever great flexibility is required. For cw-lasers fiber beam delivery has long been established but has recently also become available for ultrafast lasers. Using micro-structured hollow core fibers that guide the laser beam mostly inside a hollow core, nonlinear effects and catastrophic damage that arise in conventional glass fibers can be avoided. Today, ultrafast pulses with several 100 μJ and hundreds of MW can be transmitted in quasi single mode fashion. In addition, the technology opens new possibilities for beam delivery systems as the pulse propagation inside the fiber can be altered on purpose. For example to shorten the pulse duration of picosecond lasers down into the femtosecond regime. We present a modular fiber beam delivery system for micromachining applications with industrial pico- and femtosecond lasers that is flexibly integrated into existing applications. Micro-structured hollow core fibers inside the sealed laser light cable efficiently guide high-power laser pulses over distances of several meters with excellent beam quality, while power, pulse duration and polarization are maintained. Robust and stable beam transport during dynamic operation as in robot or gantry systems will be discussed together with optional pulse compression.

  7. Diode pumped alkali vapor lasers for high power applications

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Krupke, B.; Komashko, A.

    2008-02-01

    General Atomics has been engaged in the development of diode pumped alkali vapor lasers. We have been examining the design space looking for designs that are both efficient and easily scalable to high powers. Computationally, we have looked at the effect of pump bandwidth on laser performance. We have also looked at different lasing species. We have used an alexandrite laser to study the relative merits of different designs. We report on the results of our experimental and computational studies.

  8. Laser lithotripsy: a review of 20 years of research and clinical applications.

    PubMed

    Dretler, S P

    1988-01-01

    Four new technologies have transformed the treatment of urinary calculi: electrohydraulic lithotripsy, ultrasonic lithotripsy, extracorporeal shock wave lithotripsy, and laser lithotripsy. Initial attempts to ablate urinary calculi by continuous wave CO2, ruby, and Nd-YAG lasers failed because of excess thermal injury and inability to pass the laser energy via a flexible fiber. Basic laboratory studies then demonstrated that short pulsed laser energy absorbed by the calculus resulted in fragmentation. The parameters that produced optimal urinary calculus fragmentation were found using the flashlamp pumped tunable dye laser, with the following parameters: wavelength: 504 nm; pulse duration: 1 microsec; fiber: 250 micro silica-coated quartz; repetition: 5-20 Hz. Use of pulsed dye laser caused no tissue damage. The mechanism of fragmentation is light absorption, plasma development, and repetitive acoustic shock wave action with resultant fragmentation. The techniques for application of laser to calculi have been successful, and new, miniature instruments have been developed. Laser lithotripsy is a successful method for fragmenting ureteral calculi. The small caliber of the laser fiber makes this method useful for treating calculi in narrow, tortuous ureters; impacted calculi; distal calculi in ureters that cannot be dilated, via the percutaneous route for stones in calyces or impacted in the upper ureter. Investigations are continuing to optimize fragmentation of harder calculi and to use laser fragmentation within the kidney. Laser lithotripsy may also be used to fragment biliary calculi. PMID:2902498

  9. Laser induced micro plasma processing of polymer substrates for biomedical implant applications

    NASA Astrophysics Data System (ADS)

    French, P. W.; Rosowski, A.; Murphy, M.; Irving, M.; Sharp, M. C.

    2015-07-01

    This paper reports the experimental results of a new hybrid laser processing technique; Laser Induced Micro Plasma Processing (LIMP2). A transparent substrate is placed on top of a medium that will interact with the laser beam and create a plasma. The plasma and laser beam act in unison to ablate material and create micro-structuring on the "backside" of the substrate. We report the results of a series of experiments on a new laser processing technique that will use the same laser-plasma interaction to micromachining structures into glass and polymer substrates on the "topside" of the substrate and hence machine non-transparent material. This new laser processing technique is called Laser Induced Micro Plasma Processing (LIMP2). Micromachining of biomedical implants is proving an important enabling technology in controlling cell growth on a macro-scale. This paper discusses LIMP2 structuring of transparent substrate such as glasses and polymers for this application. Direct machining of these materials by lasers in the near infrared is at present impossible. Laser Induced Micro Plasma Processing (LIMP2) is a technique that allows laser operating at 1064 nm to machine microstructures directly these transparent substrates.

  10. Coagulative and ablative characteristics of a novel diode laser system (1470nm) for endonasal applications

    NASA Astrophysics Data System (ADS)

    Betz, C. S.; Havel, M.; Janda, P.; Leunig, A.; Sroka, R.

    2008-02-01

    Introduction: Being practical, efficient and inexpensive, fibre guided diode laser systems are preferable over others for endonasal applications. A new medical 1470 nm diode laser system is expected to offer good ablative and coagulative tissue effects. Methods: The new 1470 nm diode laser system was compared to a conventional 940 nm system with regards to laser tissue effects (ablation, coagulation, carbonization zones) in an ex vivo setup using fresh liver and muscle tissue. The laser fibres were fixed to a computer controlled stepper motor, and the light was applied using comparable power settings and a reproducible procedure under constant conditions. Clinical efficacy and postoperative morbidity was evaluated in two groups of 10 patients undergoing laser coagulation therapy of hyperplastic nasal turbinates. Results: In the experimental setup, the 1470 nm laser diode system proved to be more efficient in inducing tissue effects with an energy factor of 2-3 for highly perfused hepatic tissue to 30 for muscular tissue. In the clinical case series, the higher efficacy of the 1470 nm diode laser system led to reduced energy settings as compared to the conventional system with comparable clinical results. Postoperative crusting was less pronounced in the 1470 nm laser group. Conclusion: The 1470 nm diode laser system offers a highly efficient alternative to conventional diode laser systems for the coagulation of hyperplastic nasal turbinates. According to the experimental results it can be furthermore expected that it disposes of an excellent surgical potential with regards to its cutting abilities.

  11. Double-Pulsed 2-micron Laser Transmitter for Multiple Lidar Applications

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong

    2002-01-01

    A high energy double-pulsed Ho:Tm:YLF 2-micron laser amplifier has been demonstrated. 600 mJ per pulse pair under Q-switch operation is achieved with the gain of 4.4. This solid-state laser source can be used as lidar transmitter for multiple lidar applications such as coherent wind and carbon dioxide measurements.

  12. Applications using a Picosecond 14.7 nm X-Ray Laser

    SciTech Connect

    Dunn, J; Smith, R F; Nilsen, J; Shlyaptsev, V N; Filevich, J; Rocca, J J; Marconi, M C

    2001-09-21

    We report recent application experiments on the LLNL COMET tabletop facility using the picosecond, 14.7 nm Ni-like Pd x-ray laser. This work includes measurements of a laser-produced plasma density profile with a diffraction grating interferometer.

  13. Laser systems with acoustical optical control of output parameters for medical applications

    NASA Astrophysics Data System (ADS)

    Kazaryan, M. A.; Mokrushin, Yu. M.; Morozova, E. A.; Shakin, O. V.

    2006-05-01

    A high-speed system for controlling spectral and temporal parameters of copper vapor laser radiation was developed and studied. The laser is designed for medical applications, in particular, for photodynamic therapy and thermal destruction of pathological neoplasm formations. Repetition frequency of pulses and their on-off time ratio are synchronized by pumping pulses and can be independently controlled from a computer.

  14. Laser photovoltaic power system synergy for SEI applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Hickman, J. M.

    1991-01-01

    Solar arrays can provide reliable space power, but do not operate when there is no solar energy. Photovoltaic arrays can also convert laser energy with high efficiency. One proposal to reduce the required mass of energy storage required is to illuminate the photovoltaic arrays by a ground laser system. It is proposed to locate large lasers on cloud-free sites at one or more ground locations, and use large lenses or mirrors with adaptive optical correction to reduce the beam spread due to diffraction or atmospheric turbulence. During the eclipse periods or lunar night, the lasers illuminate the solar arrays to a level sufficient to provide operating power.

  15. Basics of Lasers: History, Physics, and Clinical Applications.

    PubMed

    Franck, Philipp; Henderson, Peter W; Rothaus, Kenneth O

    2016-07-01

    Lasers are increasingly used by plastic surgeons to address issues such as wrinkles and textural changes, skin laxity, hyperpigmentation, vascularity, and excess fat accumulation. A fundamental understanding of the underlying science and physics of laser technology is important for the safe and efficacious use of laser in medical settings. The purpose of this article was to give clinicians with limited exposure to lasers a basic understanding of the underlying science. In that manner, they can confidently make appropriate decisions as to the best device to use on a patient (or the best device to purchase for a practice). PMID:27363764

  16. Laser-based ion sources for medical applications

    NASA Astrophysics Data System (ADS)

    Bychenkov, V. Yu.; Brantov, A. V.

    2015-10-01

    Interaction of relativistic short laser pulses with thin foils is studied by using 3D PIC simulations in the context of ICAN's "dream laser". It is shown that such a laser will make it possible to accelerate protons and deuterons to multi-MeV energies with a current density of 100 A/cm2. The laser-triggered hadron beams may trigger nuclear reactions of interest for nuclear medicine and pharmacy. As an example, the yields C-11 for PET, of Tc-99m for SPECT, and neutrons for therapy have been analyzed.

  17. Semiconductor Laser Linewidth Measurements for Space Interferometry Applications

    NASA Technical Reports Server (NTRS)

    Dougherty, D. J.; Guttierrez, R. C.; Dubovitsky, S.; Forouhar, S.

    2000-01-01

    Narrow linewidth (<100KHz) semiconductor lasers are expected to be a key technology in NASA's stellar interferometry missions to search for planets around nearby stars. Long coherence length lasers are needed for precise (20 pm to 5 mn) measurements of the optical path difference. This work discusses results using the self-heterodyne delay technique to measure 1.3 micrometer InP based DFB lasers. We will also address practical issues concerning detection and elimination of back reflections, choice of fiber length and resolution, and measurement of laser 1/f and current supply noise.

  18. Investigation on the applications of fiber grating lasers in industrial sensing and pollution monitoring

    NASA Astrophysics Data System (ADS)

    Xu, Yuanzhong

    laser. On the other hand, strong pump absorption in Er/Yb fiber was found to cause significant thermal effects in Er/Yb fiber grating lasers, which can be eliminated by ensuring proper thermal dissipation. Because of fiber laser's long lifetime at the upper laser level, its wavelength cannot be directly modulated at high speed. The widely used wavelength modulation spectroscopy (WMS) method is thus not suitable when using fiber laser sources in gas detection. The wavelength sweep scheme was thus employed as an alternative. Laser wavelength/frequency requirement and noise cancellation in this scheme are discussed. For a demonstration of fiber grating laser's application to pollutant monitoring and industrial sensing, laser spectroscopy of C2H 2 gas was undertaken with the Er/Yb codoped fiber-grating laser. A 10 -4 detection sensitivity was achieved. This is the first time, to our knowledge, that a single frequency fiber-grating laser was used in rapid laser spectroscopy. The investigation has shown that the fiber grating lasers are high performance as well as low cost, rugged and portable laser sources, very suitable for industrial sensing and pollution monitoring. A number of important pollutants, such as CO, CO2, H2S and C2H2 have absorption peaks around 1.55-μm wavelength and thus can be sensed with these lasers. Although the fiber lasers investigated here operate in the 1.5-μm window, the results are also very useful for fiber lasers that use the same operation principle in other wavelength regions.

  19. High capacity aerodynamic air bearing (HCAB) for laser scanning applications

    NASA Astrophysics Data System (ADS)

    Coleman, Sean M.

    2005-08-01

    A high capacity aerodynamic air bearing (HCAB) has been developed for the laser scanning market. The need for increasing accuracies in the prepress and print plate-making market is causing a shift from ball bearing to air bearing scanners. Aerostatic air bearings are a good option to meet this demand for better performance however, these bearings tend to be expensive and require an additional air supply, filtering and drying system. Commercially available aerodynamic bearings have been typically limited to small mirrors, on the order of 3.5" diameter and less than 0.5" thick. A large optical facet, hence a larger mirror, is required to generate the high number of pixels needed for this type of application. The larger optic necessitated the development of a high capacity 'self-generating' or aerodynamic air bearing that would meet the needs of the optical scanning market. Its capacity is rated up to 6.0" diameter and 1.0" thick optics. The performance of an aerodynamic air bearing is better than a ball bearing and similar to an aerostatic air bearing. It retains the low costs while eliminating the need for ancillary equipment required by an aerostatic bearing.

  20. Direct laser deposition of nanostructured tungsten oxide for sensing applications

    NASA Astrophysics Data System (ADS)

    Palla-Papavlu, Alexandra; Filipescu, Mihaela; Schneider, Christof W.; Antohe, Stefan; Ossi, Paolo M.; Radnóczi, György; Dinescu, Maria; Wokaun, Alexander; Lippert, Thomas

    2016-05-01

    Nanostructured tungsten trioxide (WO3) thin films are deposited by pulsed laser deposition (PLD) and radio-frequency (RF) assisted PLD onto interdigitated sensor structures. Structural characterization by x-ray diffraction and Raman spectroscopy shows the WO3 films are polycrystalline, with a pure monoclinic phase for the PLD grown films. The as-fabricated WO3 sensors are tested for ammonia (NH3) detection, by measuring the electrical response to NH3 at different temperatures. Sensors based on WO3 deposited by RF-PLD do not show any response to NH3. In contrast, sensors fabricated by PLD operating at 100 °C and 200 °C show a slow recovery time whilst at 300 °C, these sensors are highly sensitive in the low ppm range with a recovery time in the range of a few seconds. The microstructure of the films is suggested to explain their excellent electrical response. Columnar WO3 thin films are obtained by both deposition methods. However, the WO3 films grown by PLD are porous, (which may allow NH3 molecules to diffuse through the film) whereas RF-PLD films are dense. Our results highlight that WO3 thin films deposited by PLD can be applied for the fabrication of gas sensors with a performance level required for industrial applications.

  1. Laser mass spectrometry for DNA fingerprinting for forensic applications

    SciTech Connect

    Chen, C.H.; Tang, K.; Taranenko, N.I.; Allman, S.L.; Chang, L.Y.

    1994-12-31

    The application of DNA fingerprinting has become very broad in forensic analysis, patient identification, diagnostic medicine, and wildlife poaching, since every individual`s DNA structure is identical within all tissues of their body. DNA fingerprinting was initiated by the use of restriction fragment length polymorphisms (RFLP). In 1987, Nakamura et al. found that a variable number of tandem repeats (VNTR) often occurred in the alleles. The probability of different individuals having the same number of tandem repeats in several different alleles is very low. Thus, the identification of VNTR from genomic DNA became a very reliable method for identification of individuals. DNA fingerprinting is a reliable tool for forensic analysis. In DNA fingerprinting, knowledge of the sequence of tandem repeats and restriction endonuclease sites can provide the basis for identification. The major steps for conventional DNA fingerprinting include (1) specimen processing (2) amplification of selected DNA segments by PCR, and (3) gel electrophoresis to do the final DNA analysis. In this work we propose to use laser desorption mass spectrometry for fast DNA fingerprinting. The process and advantages are discussed.

  2. Application of the laser Doppler velocimeter in aerodynamic flows

    NASA Technical Reports Server (NTRS)

    Yanta, W. J.; Ausherman, D. W.

    1982-01-01

    Applications of the laser doppler velocimeter (LDV) are discussed. Measurements were made of the flowfield around a tangent-ogive model in a low turbulent, incompressible flow at an incidence of 45 deg. The free-stream velocity was 80 ft per second. The flowfield velocities in several cross-flow planes were measured with a 2-D, two-color LDC operated in a backscatter mode. Measurements were concentrated in the secondary separation region. A typical survey is given. The survey was taken at a model location where the maximum side force occurs. The overall character of the leeward flowfield with the influence of the two body vorticles are shown. Measurements of the velocity and density flowfields in the shock-layer region of a reentry-vehicle indented nose configuration were carried out at Mach 5. The velocity flowfield was measured with a 2-color, 2-D, forward-scatter LDV system. Because of the need to minimize particle lag in the shock-layer region, polystyrene particles with a mean diameter of 0.312 microns were used for the scattering particles. The model diameter was 6 inches.

  3. Application of laser speckle displacement analysis to clinical dentistry

    NASA Astrophysics Data System (ADS)

    Cumberpatch, G. K. D.; Hood, J. A. A.

    1997-03-01

    Success of dental restorations is dependent on the integrity of the tooth/restoration interface. Distortion of teeth due to operative procedures has previously been measured using LVDT's and strain-gauges and has provided useful but limited information. This paper reports on the verification of a system for laser speckle photography and its use to quantitative distortions in teeth from matrix band application and the use of bonded composite resin restorations. Tightening of matrix bands around teeth results in an inward deformation of the cusps, increasing incrementally as the band is tightened. Deflections of 50 micrometer/cusp were recorded. A delayed recovery was noted consistent with the viscoelastic behavior of dentine. For bonded restorations recovery will place the adhesion interface in a state of tension when the band is released and may cause premature failure. Premolar teeth restored with bonded resin restorations exhibited inward displacement of cusps of 12 - 15 micrometer. Deformation was not within the buccal-lingual axis as suggested by prior studies. Molar teeth bonded with composite resin restoration exhibit complex and variable cusp displacement in both magnitude (0 - 30 micrometer) and direction. Complete and partial debonding could be detected. Interproximal cusp bending could be quantitated and lifting of the restoration from the cavity floor was detectable. Deformations evidenced indicate the tooth/restoration interface is in a stressed state and this may subsequently lead to failure. The technique has the potential to aid in development of restoration techniques that minimize residual stress.

  4. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Optical velocimeter based on a semiconductor laser

    NASA Astrophysics Data System (ADS)

    Belousov, P. Ya; Dubnishchev, Yu N.; Meledin, V. G.

    1988-03-01

    It is shown that optical velocimeters using diffraction beam splitters are not critically sensitive to the stability of the emission wavelength of a semiconductor laser. A functional scheme of a semiconductor laser source with systems for stabilization of the temperature and pump current is described. The technical characteristics are given of a semiconductor-laser velocimeter for the determination of the velocity and length of rolling stock.

  5. Birefringence of solid-state laser media: broadband tuning discontinuities and application to laser line narrowing

    SciTech Connect

    Krasinski, J.S.; Band, Y.B.; Chin, T.; Heller, D.F.; Morris, R.C.; Papanestor, P.

    1989-04-15

    Spectral consequences that result from using birefringent media with broadband gain inside of laser cavities containing polarizing elements are described. We show that the laser intensity is modulated as a function of the output frequency unless the cavity elements are carefully aligned so that their polarization axis coincides with a principal optical axis of the gain medium. Analysis of the tuning characteristics of a birefringent polarization-dependent gain medium is exploited to provide a simple method for line narrowing the laser output. By introduction of an intracavity birefringent compensator the narrow-band output can be continuously tuned. Experimental results for alexandrite lasers are presented.

  6. High resolution applications of laser-induced breakdown spectroscopy for environmental and forensic applications

    NASA Astrophysics Data System (ADS)

    Martin, Madhavi Z.; Labbé, Nicole; André, Nicolas; Harris, Ronny; Ebinger, Michael; Wullschleger, Stan D.; Vass, Arpad A.

    2007-12-01

    Laser-induced breakdown spectroscopy (LIBS) has been used in the elemental analysis for a variety of environmental samples and as a proof of concept for a host of forensic applications. In the first application, LIBS was used for the rapid detection of carbon from a number of different soil types. In this application, a major breakthrough was achieved by using a multivariate analytical approach that has brought us closer towards a "universal calibration curve". In a second application, it has been demonstrated that LIBS in combination with multivariate analysis can be employed to analyze the chemical composition of annual tree growth rings and correlate them to external parameters such as changes in climate, forest fires, and disturbances involving human activity. The objectives of using this technology in fire scar determinations are: 1) To determine the characteristic spectra of wood exposed to forest fires and 2) To examine the viability of this technique for detecting fire occurrences in stems that did not develop fire scars. These examples demonstrate that LIBS-based techniques are inherently well suited for diverse environmental applications. LIBS was also applied to a variety of proof of concept forensic applications such as the analysis of cremains (human cremation remains) and elemental composition analysis of prosthetic implants.

  7. High Resolution Applications of Laser-Induced Breakdown Spectroscopy for Environmental and Forensic Applications

    SciTech Connect

    Martin, Madhavi Z; Labbe, Nicole; Andre, Nicolas O; Harris, Ronny D; Ebinger, Michael H; Wullschleger, Stan D; Vass, Arpad Alexander

    2007-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been used in the elemental analysis for a variety of environmental samples and as a proof of concept for a host of forensic applications. In the first application, LIBS was used for the rapid detection of carbon from a number of different soil types. In this application, a major breakthrough was achieved by using a multivariate analytical approach that has brought us closer towards a "universal calibration curve". In a second application, it has been demonstrated that LIBS in combination with multivariate analysis can be employed to analyze the chemical composition of annual tree growth rings and correlate them to external parameters such as changes in climate, forest fires, and disturbances involving human activity. The objectives of using this technology in fire scar determinations are: 1) To determine the characteristic spectra of wood exposed to forest fires and 2) To examine the viability of this technique for detecting fire occurrences in stems that did not develop fire scars. These examples demonstrate that LIBS-based techniques are inherently well suited for diverse environmental applications. LIBS was also applied to a variety of proof of concept forensic applications such as the analysis of cremains (human cremation remains) and elemental composition analysis of prosthetic implants.

  8. Pulsed Fiber Lasers from ns to ms range and their applications

    NASA Astrophysics Data System (ADS)

    Westphäling, Tim

    Fiber lasers are widely used in industry for various applications. For marking applications the most common types are pulsed fiber lasers with low average power (10-20 W), pulse lengths of 100 ns and pulse energy in 0,5-1 mJ range. However for applications of high speed ablations and cleaning of surfaces higher average power and pulse energy is needed to realize shorter production cycle times. For this purpose pulsed fiber lasers with morehockey 17 h than 500 W average power and 50 mJ pulse energy have been developed to realize economic processes. In the long pulse range (μs to ms pulse length) QCW fiber lasers have been introduced that fulfil the demands of high pulse energy (up to 60 J) at lower average power (few 100 W range). These lasers fulfil the requirements that so far only lamp pumped Nd:YAG-lasers have been realized: high peak power and pulse energy with low average power in order to reduce investment costs for such devices. This presentation describes the latest development of such pulsed fiber lasers and their industrial applications and focuses in more details on drilling applications.

  9. The Efficiency of Laser Application on the Enamel Surface: A Systematic Review

    PubMed Central

    Karandish, Maryam

    2014-01-01

    Used in conjunction with or as a replacement for traditional methods, it is expected that specific laser technologies will become an essential component of contemporary dental practice over the next decade. The current review is designed to focus on the acid resistance of laser application and tries to introduce laser settings capable to achieve this feature for clinical application. Application of laser for its acid resistance might be a valuable adjunct to conventional acid etching for susceptible sites in high caries risk patients such as patients with rampant caries, who cannot follow oral hygiene instructions due to their systematic disabilities, or those under orthodontic treatment with plaque retentive attachment on their teeth. The key words “enamel acid resistance” and “laser” were searched in PubMed. In brief, the current paper involves the results on 5 items: A summary on laser application; Suggested mechanisms of acid resistance; Different types of laser beams used in acid resistance; Comparison of application of different laser types; and Conclusion. PMID:25653808

  10. Test bench for studying the outlook for industrial applications of an oxygen-iodine laser

    SciTech Connect

    Adamenkov, A A; Bakshin, V V; Bogachev, A V; Buryak, E V; Vdovkin, L A; Velikanov, S D; Vyskubenko, B A; Garanin, Sergey G; Gorbacheva, E V; Grigorovich, Sergei V; Il'in, S P; Il'kaev, R I; Ilyushin, Yurii N; Kalashnik, A M; Kolobyanin, Yu V; Leonov, M L; Svischev, V V; Troshkin, M V

    2007-07-31

    We report the development and tests of a chemical oxygen-iodine laser test bench based on a twisted-aerosol-flow singlet-oxygen generator and a supersonic laser model for studying the outlook for industrial applications of this laser. The maximal output power of the laser is {approx}65 kW (the average power is {approx}50 kW), corresponding to a specific output power of {approx}110 W cm{sup -2}. The maximal chemical efficiency is {approx}34%. (letters)

  11. Research and Development of Laser Diode Based Instruments for Applications in Space

    NASA Technical Reports Server (NTRS)

    Krainak, Michael; Abshire, James; Cornwell, Donald; Dragic, Peter; Duerksen, Gary; Switzer, Gregg

    1999-01-01

    Laser diode technology continues to advance at a very rapid rate due to commercial applications such as telecommunications and data storage. The advantages of laser diodes include, wide diversity of wavelengths, high efficiency, small size and weight and high reliability. Semiconductor and fiber optical-amplifiers permit efficient, high power master oscillator power amplifier (MOPA) transmitter systems. Laser diode systems which incorporate monolithic or discrete (fiber optic) gratings permit single frequency operation. We describe experimental and theoretical results of laser diode based instruments currently under development at NASA Goddard Space Flight Center including miniature lidars for measuring clouds and aerosols, water vapor and wind for Earth and planetary (Mars Lander) use.

  12. CO2-laser-based coating process for high power fiber application

    NASA Astrophysics Data System (ADS)

    Boehme, S.; Hirte, K.; Fabian, S.; Hupel, Ch.; Schreiber, T.; Eberhardt, R.; Tünnermann, A.

    2014-03-01

    The generation of high power in active fiber application and the transmission of high laser power via fiber cables both require protection from misdirected laser light. The following paper presents a new approach to removing this unwanted part of light. The deposition of fused silica material on the fiber cladding applied with CO2 laser processes constitutes a robust cladding light stripper suitable for high power levels. The CO2 laser processes are easy to apply, obviate the need for any dangerous liquids and promise greater mechanical stability in handling and assembly.

  13. Development of State of the Art Solid State Lasers for Altimetry and other LIDAR Applications

    NASA Technical Reports Server (NTRS)

    Kay, Richard B.

    1997-01-01

    This report describes work performed and research accomplished through the end of 1997. During this time period, we have designed and fabricated two lasers for flight LIDAR applications to medium altitudes (Laser Vegetation Imaging System designs LVIS 1 and LVIS 2), designed one earth orbiting LIDAR transmitter (VCL-Alt), and continued work on a high rep-rate LIDAR laser (Raster Scanned Altimeter, RASCAL). Additionally, a 'White Paper' was prepared which evaluates the current state of the art of Nd:YAG lasers and projects efficiencies to the year 2004. This report is attached as Appendix 1 of this report.

  14. Recent advances in the applications of pulsed lasers in the hydrosphere. [considering airborne bathymetry system

    NASA Technical Reports Server (NTRS)

    Hickman, G. D.

    1975-01-01

    Laboratory and field measurements have been performed on the transmission/scattering characteristics of a pulsed neon laser as a function of water turbidity. These results have been used to establish the criteria for an airborne laser bathymetry system. Extensive measurements have been made of laser induced fluorescence using a pulsed tunable dye laser. Feasibility has been demonstrated for remote detection and possible identification of various types of algae and oils. Similar measurements made on a wide variety of organic dyes have shown this technique to have applications in remote measurements of subsurface currents, temperature and salinity.

  15. Use of the 810 nm diode laser: soft tissue management and orthodontic applications of innovative technology.

    PubMed

    Sarver, David M

    2006-10-01

    Innovative technologies such as the diode laser have provided considerable benefit to dental patients and professionals. Facilitating efficient cutting of tissue and subsequent coagulation, the soft tissue laser enhances tissue healing and can reduce postsurgical complications. Due to the conservative nature of treatment accomplished with the laser this technology is very useful in orthodontic procedures. The diode laser is utilized in both esthetic enhancement of the smile, and treatment management of soft tissue issues that impede efficient orthodontic treatment. Its clinical application will be illustrated in a series of orthodontic cases. PMID:17139948

  16. Laser Applications to Chemical, Security, and Environmental Analysis: introduction to the feature issue

    SciTech Connect

    Dreizler, Andreas; Fried, Alan; Gord, James R

    2007-07-01

    This Applied Optics feature issue on Laser Applications to Chemical, Security,and Environmental Analysis (LACSEA) highlights papers presented at theLACSEA 2006 Tenth Topical Meeting sponsored by the Optical Society ofAmerica.

  17. Laser-beam power for lunar and space applications

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Williams, Michael D.; Schuster, Gregory L.; Iles, Peter A.

    1992-01-01

    GaAlAs/GaAs heteroface converters were experimentally tested using DIRECT laser irradiation of photovoltaic devices. It is concluded that the two types of converters are promising for converting diode-laser radiation to electricity. Conversion efficiency as high as 45 and 34.2 percent was obtained using GaAS and Si converters of the SSF type, respectively.

  18. Ultracompact visible R-G-B lasers for defense applications

    NASA Astrophysics Data System (ADS)

    Hu, Wentao; Yang, Xiaodong; Wang, Chun; Gewirtz, Yossi; Osowski, Mark L.; Lammert, Robert M.; Oh, Se W.; Elarde, Victor C.; Vaissie, Laurent; Patel, Falgun D.; Rudy, Paul T.; Ungar, Jeffrey E.

    2009-05-01

    Compact, efficient visible lasers are important for heads up displays, pointing and illumination, undersea communications, and less than lethal threat detection. We report on high power red, green, and blue lasers with output powers above 3 watts and efficiencies greater than 20%, 15%, and 5% respectively.

  19. New trends in urological laser research and applications

    NASA Astrophysics Data System (ADS)

    Hofstetter, Alfons G.

    1993-03-01

    It is no exaggeration to state, no single specialty of medicine has so thoroughly investigated the different possibilities of laser systems as urology. Twenty years of experimental and clinical use of laser technology has led to a number of standard procedures.

  20. Laser materials processing applications at Lawrence Livermore National Laboratory

    NASA Astrophysics Data System (ADS)

    Hargrove, R. S.; Dragon, Ernest P.; Hackel, Richard P.; Kautz, Douglas D.; Warner, Bruce E.

    1993-05-01

    Copper and dye laser systems are currently being developed at LLNL for uranium enrichment production facilities. The goals of this program are to develop low-cost, reliable and maintainable industrial laser systems. Chains of copper lasers currently operate at more than 1.5 kW output and achieve mean time between failures of more than 1000 hours. The beam quality of copper vapor lasers is approximately three times the diffraction limit. Dye lasers have near diffraction limited beam quality at greater than 1.0 kW. Diode laser pumped, Nd:YAG slab lasers are also being developed at LLNL. Current designs achieve powers of greater than 1.0 kW and projected beam quality is in the two to five times diffraction limited range. Results from cutting and drilling studies in titanium and stainless steel alloys show that cuts and holes with extremely fine features can be made with dye and copper-vapor lasers. High radiance beams produce low distortion and small heat-affected zones. We have accomplished very high aspect ratio holes in drilling tests (> 60:1) and features with micron scale (5 - 50 micrometers ) sizes.

  1. Clinical applications of laser therapy on the dental practice

    NASA Astrophysics Data System (ADS)

    Pinheiro, Antonio L. B.

    2004-09-01

    Dental practice consists of a series of laboring procedures which demands the use of several types of equipment and materials. Usually patient"s fears brings additional burden to the Dentists. The use of Lasers for treating and diagnosis in Dentistry is quite new comparing to other medical areas. Initially Laser technology was used as an alternative method for treating dental caries in order to substitute the use of the drill. Lately surgical Lasers have shown themselves very useful for treating several pathologies and began to be used as a powerful tool on the treatment of several conditions affecting the maxillofacial complex and later on, the era of the use of Laser therapy began. The advent of the diode Lasers made possible the introduction of small units at the dental office and Laser therapy was used to improve healing and later included also caries diagnosis. This paper discuss the use of Laser therapy on Restorative Dentistry, Periodondology, Oral and Maxillofacial Surgery, Oral implantology and other. Clinical and laboratorial experience has demonstrated that Laser therapy does improve the healing of both mineralized and soft tissues, reduces pain and inflammation, and also reduces both cost and length of the dental treatment.

  2. Semiconductor Laser Line-width Measurements for Space Interferometry Applications

    NASA Technical Reports Server (NTRS)

    Dougherty, D.; Guttierrez, R.; Dubovitsky, S.; Forouhar, S.

    1999-01-01

    This work discusses results using the self-heterodyne delay atechnique to measure 1.3 um InP based DFB lasers. We will also address practical issues concerning detection and elimination of back reflections, choice of fiber length and resolution, and measurement of laser 1/f and current supply noise.

  3. Application of YAG laser welding to gas turbine components

    NASA Astrophysics Data System (ADS)

    Tsubota, Shuho; Mega, Masahiko; Takahashi, Koji; Uemura, Yoshitaka; Hirota, Norihide; Yamaguchi, Kengo

    2003-03-01

    An investigation to apply YAG laser welding to gas turbine components was carried out. The materials of gas turbine such as Ni base alloy are difficult to weld by conventional arc welding methods because of large heat affection. But laser welding can reduce heat input compared with conventional methods and keeps the good repeatability. The welding parameter survey was carried out to satisfy the designing requirements. The YAG laser welding under appropriate conditions enables to prevent welding defects such as HAZ cracks and improves the weld joints quality and performance. Tensile test and low cycle fatigue test were carried out. Tensile strength and fatigue life of laser weld joints are same or higher than that of conventional manual TIG weld joints. The Automatic YAG laser welding system was also developed and put into practical use.

  4. Accidental Thawing of Embryos, Cryopreserved for Transfer. Two Italian cases, Milan and Rome.

    PubMed

    Busardò, Francesco P; Vergallo, Gianluca Montanari; Turillazzi, Emanuela; Bolino, Giorgio; Vullo, Annamaria; Frati, Paola

    2016-01-01

    The bioethical and juridical debate on the status of frozen embryos sometimes adds new issues arising from new scientific evidence or by accidental occurrences that bring to the attention of the scientific community the need for new practical solutions. Within this scenario, there have been, in recent years, episodes concerning the accidental thawing of embryos, which have been cryopreserved for transfer. Two Italian cases (the Milan and the Rome cases) are here reported: the Milan case involves a couple undergoing artificial insemination. Three eggs were collected for insemination and two of them had been fertilized. During the night of 8/9 May 2007 a short circuit occurred, resulting in an electricity blackout, which caused the loss of the embryos in culture, which should have been transferred to the woman's uterus on 9 May. The couple applied for damage compensation from the hospital following the loss of the embryos. The case went to Court and the result was a judgment issued by the Milan civil court, which recognized that the centre was to blame for irreparable damage to the embryos. The Rome case, involves two couples (A and B) affected by sterility who applied to an authorized public centre to undergo an ART program. Following the medical procedures, two of the embryos produced were transferred to the woman in couple A and five were frozen, whereas three embryos produced by couple B were transferred to the uterus of the woman and six eggs were cryopreserved in the centre. Two years after the procedure there was an electricity blackout, and the backup electricity generator failed to function, causing the loss of the gametes and the embryos cryopreserved in the centre. Legal proceedings begun by the couples to obtain compensation for damages are still underway. The above reported cases have significantly intensified the bioethical debate on the lawfulness of such practices and on the fate of the cryopreserved embryos, at the same time opening new frontiers in

  5. Submicron aerosol mass balance at urban and semirural sites in the Milan area (Italy)

    NASA Astrophysics Data System (ADS)

    Putaud, J. P.; van Dingenen, Rita; Raes, Frank

    2002-11-01

    During the Pianura Padana Produzione di Ozono (PIPAPO) field campaign (May-June 1998), aerosol measurements were performed at an urban site and a semirural site to determine the particulate matter chemical composition in the Milan area. Aerosol samples were collected on filters for subsequent chemical analysis using virtual impactors. Possible sampling artifacts for semivolatile particulate species were addressed. Our NH4NO3 measurements were successfully compared with artifact free wet denuder-wet aerosol collector sampler data. Positive sampling artifacts for organic species were corrected using the back-to-back filter technique, allowing us to assess the lower limit for particulate organic carbon (POC) concentrations. Aerosol size distributions were measured on-line with differential mobility analyzers (DMA). The variations in the submicron aerosol mass concentration estimated from chemical analyses compared well with the variations in the submicron particle volume calculated from number size distributions. At both sites, 70% of the PM10 mass was found in the submicron fraction. The mean submicron aerosol mass concentrations were 28 μg m-3 and 20 μg m-3 at the urban site and the semirural site, respectively. The correlations between NH4+ and NO3- + 2SO4= indicate that strong acids were fully neutralized at both sites. At the urban site the submicron concentrations of NH4NO3, (NH4)2SO4, and POC were 8.1 μg m-3, 6.3 μg m-3, and 6.4 μgC m-3, respectively. At the semi-rural site, these concentrations were 4.9 μg m-3, 4.0 μg m-3, and 5.6 μgC m-3, respectively. These results show that sulfate and nitrate contribute about the same amount to submicron aerosol mass concentration, and that particulate organic matter (POM) could be the major component of the aerosol submicron mass in the Milan region, especially in semirural areas. The correlation between normalized concentrations of POM and O3 observed at the semirural site suggests that POM results at least

  6. Binder characterisation of mortars used at different ages in the San Lorenzo church in Milan

    SciTech Connect

    Bertolini, Luca Carsana, Maddalena Gastaldi, Matteo Lollini, Federica Redaelli, Elena

    2013-06-15

    The paper describes a study on the mortars of the basilica of San Lorenzo in Milan, which was carried out to support an archaeological study aimed at dating and documenting the construction techniques used throughout the centuries. The church, which was founded between the 4th and 5th century, at the end of the period when Milan was the capital of the Roman Empire, was subjected in time to extensions, collapses and reconstructions that lasted until the Renaissance period and even later on. Thanks to the good state of conservation, San Lorenzo church is a collection of materials and construction techniques throughout a period of more than a millennium. Mortars were investigated in order to compare the binders used for structural elements built in different historical ages. From an archaeological study, samples of mortars attributed to the late Roman period, the Middle Ages and the Renaissance were available. The binder of each sample was separated by the aggregates and it was characterised on the basis of X-ray diffraction analysis, thermogravimetric analysis and scanning electron microscopy. Constituents of the binder were identified and their origin is discussed in order to investigate if they could be attributed to the original composition of the binder or to possible alteration in time due to atmospheric pollution. Results show that, even though the binder is mainly based on magnesian lime, there are significant differences in the microstructure of the binding matrix used in mortars ascribed to the different historical periods. In the Roman period, in correspondence of the structural elements that required higher strength, also hydraulic cocciopesto mortars were detected. Gypsum was found in most samples, which was maybe added intentionally. - Highlights: • Binders of mortars of San Lorenzo church in Milan were investigated. • Roman, Middle Ages and Renaissance samples were studied by XRD, TG and SEM. • Magnesian-lime binders containing silico

  7. Brightness and average power as driver for advancements in diode lasers and their applications

    NASA Astrophysics Data System (ADS)

    Hengesbach, Stefan; Poprawe, Reinhart; Hoffmann, Dieter; Traub, Martin; Schwarz, Thomas; Holly, Carlo; Eibl, Florian; Weisheit, Andreas; Vogt, Sabrina; Britten, Simon; Ungers, Michael; Thombansen, Ulrich; Engelmann, Christoph; Mamuschkin, Viktor; Lott, Philipp

    2015-03-01

    Spatial and spectral emission characteristics and efficiency of high-power diode laser (HPDL) based pump sources enable and define the performance of the fundamental solid state laser concepts like disk, fiber and slab lasers. HPDL are also established as a versatile tool for direct materials processing substituting other laser types like CO2 lasers and lamp pumped solid state lasers and are starting to substitute even some of the diode pumped solid state lasers. Both, pumping and direct applications will benefit from the further improvement of the brightness and control of the output spectrum of HPDL. While edge emitting diodes are already established, a new generation of vertical emitting diode lasers (VCSELs) made significant progress and provides easy scalable output power in the kW range. Beneficial properties are simplified beam shaping, flexible control of the temporal and spatial emission, compact design and low current operation. Other characteristics like efficiency and brightness of VCSELs are still lagging behind the edge emitter performance. Examples of direct applications like surface treatment, soldering, welding, additive manufacturing, cutting and their requirements on the HPDL performance are presented. Furthermore, an overview on process requirements and available as well as perspective performance of laser sources is derived.

  8. Modeling of high efficiency solar cells under laser pulse for power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, Geoffrey A.

    1994-01-01

    Solar cells have been used to convert sunlight to electrical energy for many years and also offer great potential for non-solar energy conversion applications. Their greatly improved performance under monochromatic light compared to sunlight, makes them suitable as photovoltaic (PV) receivers in laser power beaming applications. Laser beamed power to a PV array receiver could provide power to satellites, an orbital transfer vehicle, or a lunar base. Gallium arsenide (GaAs) and indium phosphide (InP) solar cells have calculated efficiencies of more than 50 percent under continuous illumination at the optimum wavelength. Currently high power free-electron lasers are being developed which operate in pulsed conditions. Understanding cell behavior under a laser pulse is important in the selection of the solar cell material and the laser. An experiment by NAsA lewis and JPL at the AVLIS laser facility in Livermore, CA presented experimental data on cell performance under pulsed laser illumination. Reference 5 contains an overview of technical issues concerning the use of solar cells for laser power conversion, written before the experiments were performed. As the experimental results showed, the actual effects of pulsed operation are more complicated. Reference 6 discusses simulations of the output of GaAs concentrator solar cells under pulsed laser illumination. The present paper continues this work, and compares the output of Si and GaAs solar cells.

  9. AlGaInN laser diode technology and systems for defence and security applications

    NASA Astrophysics Data System (ADS)

    Najda, Stephen P.; Perlin, Piotr; Suski, Tadek; Marona, Lujca; Boćkowski, Mike; Leszczyński, Mike; Wisniewski, Przemek; Czernecki, Robert; Kucharski, Robert; Targowski, Grzegorz; Watson, Scott; Kelly, Antony E.

    2015-10-01

    AlGaInN laser diodes is an emerging technology for defence and security applications such as underwater communications and sensing, atomic clocks and quantum information. The AlGaInN material system allows for laser diodes to be fabricated over a very wide range of wavelengths from u.v., ~380nm, to the visible ~530nm, by tuning the indium content of the laser GaInN quantum well. Thus AlGaInN laser diode technology is a key enabler for the development of new disruptive system level applications in displays, telecom, defence and other industries. Ridge waveguide laser diodes are fabricated to achieve single mode operation with optical powers up to 100mW with the 400-440nm wavelength range with high reliability. Visible free-space and underwater communication at frequencies up to 2.5GHz is reported using a directly modulated 422nm GaN laser diode. Low defectivity and highly uniform GaN substrates allow arrays and bars to be fabricated. High power operation operation of AlGaInN laser bars with up to 20 emitters have been demonstrated at optical powers up to 4W in a CS package with common contact configuration. An alternative package configuration for AlGaInN laser arrays allows for each individual laser to be individually addressable allowing complex free-space or optical fibre system integration with a very small form-factor.

  10. Solar Pumped High Power Solid State Laser for Space Applications

    NASA Technical Reports Server (NTRS)

    Fork, Richard L.; Laycock, Rustin L.; Green, Jason J. A.; Walker, Wesley W.; Cole, Spencer T.; Frederick, Kevin B.; Phillips, Dane J.

    2004-01-01

    Highly coherent laser light provides a nearly optimal means of transmitting power in space. The simplest most direct means of converting sunlight to coherent laser light is a solar pumped laser oscillator. A key need for broadly useful space solar power is a robust solid state laser oscillator capable of operating efficiently in near Earth space at output powers in the multi hundred kilowatt range. The principal challenges in realizing such solar pumped laser oscillators are: (1) the need to remove heat from the solid state laser material without introducing unacceptable thermal shock, thermal lensing, or thermal stress induced birefringence to a degree that improves on current removal rates by several orders of magnitude and (2) to introduce sunlight at an effective concentration (kW/sq cm of laser cross sectional area) that is several orders of magnitude higher than currently available while tolerating a pointing error of the spacecraft of several degrees. We discuss strategies for addressing these challenges. The need to remove the high densities of heat, e.g., 30 kW/cu cm, while keeping the thermal shock, thermal lensing and thermal stress induced birefringence loss sufficiently low is addressed in terms of a novel use of diamond integrated with the laser material, such as Ti:sapphire in a manner such that the waste heat is removed from the laser medium in an axial direction and in the diamond in a radial direction. We discuss means for concentrating sunlight to an effective areal density of the order of 30 kW/sq cm. The method integrates conventional imaging optics, non-imaging optics and nonlinear optics. In effect we use a method that combines some of the methods of optical pumping solid state materials and optical fiber, but also address laser media having areas sufficiently large, e.g., 1 cm diameter to handle the multi-hundred kilowatt level powers needed for space solar power.

  11. Exploring the Potential of Table-Top X-Ray Lasers and Capillary Discharge for Applications

    SciTech Connect

    Shlyaptev, V N; Dunn, J; Smith, R F; Moon, S J; Fournier, K B; Nilsen, J; Osterheld, A L; Kuba, J; Wootton, A J; Lee, R W; Rocca, J J; Rahman, A; Hammarsten, E; Filevich, J; Jankovska, E; Marconi, M C; Fornaciari, N; Buchenauer, D; Hender, H A; Kari,M S; Kanouff, M; Dimkoff, J; Kubiak, G; Shimkaveg, G; Silfvast, W T

    2003-05-08

    The advantages of using of table top x-ray lasers (XRLs) for different applications have been described. Examples of the first successful use of XRLs, the current efforts in applying them and the potential applications where an XRL can be used in future have been discussed. Modeling results showing the possibility of 3-4 times shorter wavelength capillary discharge x-ray lasers and calculated spectrum of Xe capillary EUV source are presented.

  12. Laser propulsion for space applications: Is it another myth or a real potential?

    NASA Astrophysics Data System (ADS)

    Cook, Joung R.

    2007-05-01

    This paper discusses different principles of inducing propulsive power using lasers and examines the performance limits along with pros and cons with respect to different space propulsion applications: satellite launching, orbital transfer, space debris clearing, satellite propulsion, and space travels. It concludes that a use of electrical propulsion, in conjunction with laser power beaming, is the most feasible application with technological and economic advantages for commercial use within the next decades.

  13. The Evolution of the Demand for Post-Compulsory Education in the Urban Area of Milan: Perspectives and Problems.

    ERIC Educational Resources Information Center

    Pasini, Roberto

    1984-01-01

    The consequences of three events on the demand for postcompulsory education in the urban area of Milan are examined: the population growth, the transformation of the city's economy and the consequential trend of the labor market, and the lack of upper-secondary school reform. (MLW)

  14. Carlo Borromeo, Archbishop of Milan, in the Midst of Religious Disciplining, Pastoral Renewal and Christian Education (1564-1584)

    ERIC Educational Resources Information Center

    Patrizi, Elisabetta

    2008-01-01

    The twenty year period of pastoral action of the Milan Archbishop Carlo Borromeo, are examined in the light of the "social disciplining," that was a basic component of the Reform, and a sign of the evolution of the modern State and society after the Tridentine turning point. The Borromaic pastoral aimed at putting into effects the Tridentine…

  15. Organisation and Management of a Complete Bachelor Degree Offered Online at the University of Milan for Ten Years

    ERIC Educational Resources Information Center

    Milani, Manuela; Papini, Sabrina; Scaccia, Daniela; Scarabottolo, Nello

    2014-01-01

    This paper is aimed at presenting some reflections on organisation and management of SSRI online: an e-learning initiative started at the University of Milan (Italy) in the academic year 2004/05 and offered to students over the last ten years. The initiative consisted in implementing the online version of an already existing three-year bachelor…

  16. Laser rods with undoped, flanged end-caps for end-pumped laser applications

    DOEpatents

    Meissner, H.E.; Beach, R.J.; Bibeau, C.; Sutton, S.B.; Mitchell, S.; Bass, I.; Honea, E.

    1999-08-10

    A method and apparatus for achieving improved performance in a solid state laser is provided. A flanged, at least partially undoped end-cap is attached to at least one end of a laserable medium. Preferably flanged, undoped end-caps are attached to both ends of the laserable medium. Due to the low scatter requirements for the interface between the end-caps and the laser rod, a non-adhesive method of bonding is utilized such as optical contacting combined with a subsequent heat treatment of the optically contacted composite. The non-bonded end surfaces of the flanged end-caps are coated with laser cavity coatings appropriate for the lasing wavelength of the laser rod. A cooling jacket, sealably coupled to the flanged end-caps, surrounds the entire length of the laserable medium. Radiation from a pump source is focused by a lens duct and passed through at least one flanged end-cap into the laser rod. 14 figs.

  17. Arthroscopic shoulder surgery with three different laser systems: an evaluation of laser applications.

    PubMed

    Vangsness, C T; Smith, C F

    1995-12-01

    Twelve cadaveric shoulder arthroscopies were performed to evaluate the use of lasers as an adjunctive tool in arthroscopic shoulder surgery. The three most common lasers historically used in orthopedic surgery were examined: Holmium:YAG, Neodymium:YAG, and the CO2. The following parameters were evaluated for each laser system: (1) ease of use of the laser system and handpiece; (2) ability to excise and trim bursae, synovium, ligament, tendon, bone, and articular cartilage; and (3) ability to contract ligaments and capsule by heat transfer. None of these lasers efficiently cut bone, whereas all three systems readily debrided the soft tissues around the shoulder. The free-beam Ho:YAG and CO2 systems heat contracted soft tissues with more control than the contact Nd:YAG. The fiberoptic delivery system of the Neodymium:YAG and Holmium:YAG laser performed well in the saline arthroscopy, and the CO2 delivery system was cumbersome. Overall, the CO2 system removed tissue better than the others, but its difficult use favored the Holmium laser as the best overall current laser system for shoulder arthroscopy. PMID:8679031

  18. A fiberoptic compatible midinfrared laser with CO2 laser-like effect: application to atherosclerosis.

    PubMed

    Oz, M C; Treat, M R; Trokel, S L; Andrew, J E; Nowygrod, R

    1989-12-01

    In theory, pulses of laser light in the 2-microns range should ablate tissue in a manner similar to that of the 10.6-microns CO2 laser with the added advantage of efficient transmission through flexible quartz fibers. Using 200-microseconds pulses of 2.15-microns thulium-holmium-chromium:YAG (THC:YAG) laser light, we were able to create 700-microns-diameter holes through calcific atherosclerosis in vitro. In vivo evaluation of thrombogenicity and healing was accomplished by exposing the luminal surface of rabbit aortas to the THC:YAG laser. Serial histologic examinations of laser-treated rabbit aortae revealed a time course of resolution of the lesions which was very similar to that observed with like-sized lesions created with the same amount of continuous wave CO2 energy. No significant differences in thrombogenicity nor healing response were noted. The excellent in vivo response observed is due in part to the pulsed nature of the THC:YAG laser output as well as to the efficient tissue absorption at the 2.15-microns wavelength. We feel that excellent ablative effects with minimal collateral thermal damage can be obtained through fiberoptic delivery systems by taking advantage of laser wavelengths corresponding to the infrared absorption peak of water in the 2-microns region and pulsed delivery of the laser energy. PMID:2511380

  19. Genotype-inspired laser material processing: a new experimental approach and potential applications to protean materials

    NASA Astrophysics Data System (ADS)

    Livingston, F. E.; Steffeney, L. F.; Helvajian, H.

    2008-10-01

    We have developed a new direct-write experimental technique that enables the delivery of preprogrammed laser pulse scripts to a substrate with high fidelity during patterning and motion sequences. The laser technique can be readily applied to fundamental investigations of complex laser-material interaction phenomena, and easily integrated into laser-material processing schemes for commercial and industrial applications. The laser direct-write technique has been crafted by association with the genome and genotype concepts, where predetermined and prescribed laser pulse scripts are synchronously linked with the tool path geometry, and each concatenated pulse sequence is intended to express a specific material attribute. This laser processing method is particularly well suited for protean or mutable materials that can be altered with extreme sensitivity by the application of high precision photon exposures. We envision that multifunctional materials can be altered on a localized scale to create integrated “devices” on a common substrate. The synchronized laser pulse amplitude modulation scheme and application to a candidate photosensitive glass ceramic are the focus of this paper.

  20. Applications of picosecond lasers and pulse-bursts in precision manufacturing

    NASA Astrophysics Data System (ADS)

    Knappe, Ralf

    2012-03-01

    Just as CW and quasi-CW lasers have revolutionized the materials processing world, picosecond lasers are poised to change the world of micromachining, where lasers outperform mechanical tools due to their flexibility, reliability, reproducibility, ease of programming, and lack of mechanical force or contamination to the part. Picosecond lasers are established as powerful tools for micromachining. Industrial processes like micro drilling, surface structuring and thin film ablation benefit from a process, which provides highest precision and minimal thermal impact for all materials. Applications such as microelectronics, semiconductor, and photovoltaic industries use picosecond lasers for maximum quality, flexibility, and cost efficiency. The range of parts, manufactured with ps lasers spans from microscopic diamond tools over large printing cylinders with square feet of structured surface. Cutting glass for display and PV is a large application, as well. With a smart distribution of energy into groups of ps-pulses at ns-scale separation (known as burst mode) ablation rates can be increased by one order of magnitude or more for some materials, also providing a better surface quality under certain conditions. The paper reports on the latest results of the laser technology, scaling of ablation rates, and various applications in ps-laser micromachining.