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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 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.

  14. 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.

  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. 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.

  1. 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

  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. 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.

  14. 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.

  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. 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.

  1. 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.

  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. 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.

  5. 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.

  6. 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.

  7. 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.

  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. 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

  13. 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.

  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. 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.

  20. 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.

  1. 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.

  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. 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)

  16. 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.

  17. 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.

  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. 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.

  4. 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

  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. 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.

  20. 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.

  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. 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.

  3. 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

  4. 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.

  5. 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.

  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. 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

  10. 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

  11. 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

  12. 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

  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. 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.

  20. 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.

  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. 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.

  8. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  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.