Precision laser range finder system design for Advanced Technology Laboratory applications

NASA Technical Reports Server (NTRS)

Golden, K. E.; Kohn, R. L.; Seib, D. H.

1974-01-01

Preliminary system design of a pulsed precision ruby laser rangefinder system is presented which has a potential range resolution of 0.4 cm when atmospheric effects are negligible. The system being proposed for flight testing on the advanced technology laboratory (ATL) consists of a modelocked ruby laser transmitter, course and vernier rangefinder receivers, optical beacon retroreflector tracking system, and a network of ATL tracking retroreflectors. Performance calculations indicate that spacecraft to ground ranging accuracies of 1 to 2 cm are possible.

Observations on Bubble Dynamics at High Pressures and Bubble Dynamics in Stagnation Flow.

DTIC Science & Technology

1982-11-30

reverse side It nocooeuAn aifdentifly by block mt..bet) S 1 Cavitation, High Speed Photography, Ruby Laser . 20. AFSTAACT Co.nflno on revere side Of...AT NIGH ASIE3r.T PRESSUrES A.T. Ellis and J.E. Starrect University of California, San Diego Recent developsent by the authors of a unique ruby laser ...1,000,300 frames per second with exposure clue of approximately 2vl0- seconds. The coherent nature of the laser illuminacion revealed shock waves

Note: A portable, light-emitting diode-based ruby fluorescence spectrometer for high-pressure calibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng Yejun

2011-04-15

Ruby (Al{sub 2}O{sub 3}, with {approx}0.5 wt. % Cr doping) is one of the most widely used manometers at the giga-Pascal scale. Traditionally, its fluorescence is excited with intense laser sources. Here, I present a simple, robust, and portable design that employs light-emitting diodes (LEDs) instead. This LED-based system is safer in comparison with laser-based ones.

Background-free, high sensitivity staining of proteins in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gels using a luminescent ruthenium complex.

PubMed

Berggren, K; Chernokalskaya, E; Steinberg, T H; Kemper, C; Lopez, M F; Diwu, Z; Haugland, R P; Patton, W F

2000-07-01

SYPRO Ruby dye is a permanent stain comprised of ruthenium as part of an organic complex that interacts noncovalently with proteins. SYPRO Ruby Protein Gel Stain provides a sensitive, gentle, fluorescence-based method for detecting proteins in one-dimensional and two-dimensional sodium dodecyl sulfate-polyacrylamide gels. Proteins are fixed, stained from 3h to overnight and then rinsed in deionized water or dilute methanol/acetic acid solution for 30 min. The stain can be visualized using a wide range of excitation sources commonly used in image analysis systems including a 302 nm UV-B transilluminator, 473 nm second harmonic generation (SHG) laser, 488 nm argon-ion laser, 532 nm yttrium-aluminum-garnet (YAG) laser, xenon arc lamp, blue fluorescent light bulb or blue light-emitting diode (LED). The sensitivity of SYPRO Ruby Protein Gel Stain is superior to colloidal Coomassie Brilliant Blue (CBB) stain or monobromobimane labeling and comparable with the highest sensitivity silver or zinc-imidazole staining procedures available. The linear dynamic range of SYPRO Ruby Protein Gel stain extends over three orders of magnitude, which is vastly superior to silver, zinc-imidazole, monobromobimane and CBB stain. The fluorescent stain does not contain superfluous chemicals (formaldehyde, glutaraldehyde, Tween-20) that frequently interfere with peptide identification in mass spectrometry. While peptide mass profiles are severely altered in protein samples prelabeled with monobromobimane, successful identification of proteins by peptide mass profiling using matrix-assisted laser desorption/ionization mass spectrometry was easily performed after protein detection with SYPRO Ruby Protein Gel stain.

Comparison of high-intensity pulsed and continuous-wave irradiation on benzoporphyrin derivative-induced photosensitization of bladder cancer cells

NASA Astrophysics Data System (ADS)

Diddens, Heyke C.; Gillies, Robert; Hasan, Tayyaba

1994-08-01

Benzoporphyrin derivative, monoacid ring A (BPD-MA) is a second generation porphyrin photosensitizer, with a significant absorption at 692 nm. The ability of two different lasers (a high-intensity pulsed ruby laser, and a continuous wave (cw) argon-ion laser pumped dye laser) in producing photodynamic damage to human bladder carcinoma cells in vitro under similar conditions was compared. Cells incubated in 0.14 (mu) M BPD-MA for 3 hours were irradiated with 1 or 3 J/cm2 with either pulsed or cw irradiation at 694 nm. Cell survival was determined using an MTT assay. With the ruby laser essentially no phototoxicity was observed at the high intensity pulsed irradiances used, whereas 38% and 6% survival rates were observed for 1 and 3 J/cm2, respectively, using cw irradiation. Possible explanations for the lack of BPD-MA phototoxicity using the ruby laser are: rapid photodegradation, saturation and excitation into higher excited states of the sensitizer. No BPD-MA photodegradation was observed in 1.4 (mu) M BPD-MA in 10% fetal calf serum solutions using the ruby laser. However, an oxygen-dependent photodegradation with the formation of a chlorin-type photoproduct was observed in these solutions using cw irradiation. A simple calculation indicated that the high pulse irradiances used in this study (4.4 X 107 W/cm2) were approximately 3 orders of magnitude greater than required for the onset of saturation. If higher excited states (Sn or Tn) are populated, they do not undergo any photochemistry resulting in phototoxicity or in photoproduct formation. These results show that with the low saturation threshold of BPD-MA, the choice of source and irradiance are important considerations in planning a therapeutic regime.

Formation of highly toxic hydrogen cyanide upon ruby laser irradiation of the tattoo pigment phthalocyanine blue.

PubMed

Schreiver, Ines; Hutzler, Christoph; Laux, Peter; Berlien, Hans-Peter; Luch, Andreas

2015-08-05

Since laser treatment of tattoos is the favored method for the removing of no longer wanted permanent skin paintings, analytical, biokinetics and toxicological data on the fragmentation pattern of commonly used pigments are urgently required for health safety reasons. Applying dynamic headspace-gas chromatography with mass spectrometric detection (DHS-GC/MS) and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-ToF-MS), we identified 1,2-benzene dicarbonitrile, benzonitrile, benzene, and the poisonous gas hydrogen cyanide (HCN) as main fragmentation products emerging dose-dependently upon ruby laser irradiation of the popular blue pigment copper phthalocyanine in suspension. Skin cell viability was found to be significantly compromised at cyanide levels of ≥1 mM liberated during ruby laser irradiation of >1.5 mg/ml phthalocyanine blue. Further, for the first time we introduce pyrolysis-GC/MS as method suitable to simulate pigment fragmentation that may occur spontaneously or during laser removal of organic pigments in the living skin of tattooed people. According to the literature such regular tattoos hold up to 9 mg pigment/cm(2) skin.

Formation of highly toxic hydrogen cyanide upon ruby laser irradiation of the tattoo pigment phthalocyanine blue

PubMed Central

Schreiver, Ines; Hutzler, Christoph; Laux, Peter; Berlien, Hans-Peter; Luch, Andreas

2015-01-01

Since laser treatment of tattoos is the favored method for the removing of no longer wanted permanent skin paintings, analytical, biokinetics and toxicological data on the fragmentation pattern of commonly used pigments are urgently required for health safety reasons. Applying dynamic headspace—gas chromatography with mass spectrometric detection (DHS—GC/MS) and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC—ToF-MS), we identified 1,2-benzene dicarbonitrile, benzonitrile, benzene, and the poisonous gas hydrogen cyanide (HCN) as main fragmentation products emerging dose-dependently upon ruby laser irradiation of the popular blue pigment copper phthalocyanine in suspension. Skin cell viability was found to be significantly compromised at cyanide levels of ≥1 mM liberated during ruby laser irradiation of >1.5 mg/ml phthalocyanine blue. Further, for the first time we introduce pyrolysis-GC/MS as method suitable to simulate pigment fragmentation that may occur spontaneously or during laser removal of organic pigments in the living skin of tattooed people. According to the literature such regular tattoos hold up to 9 mg pigment/cm2 skin. PMID:26243473

Formation of highly toxic hydrogen cyanide upon ruby laser irradiation of the tattoo pigment phthalocyanine blue

NASA Astrophysics Data System (ADS)

Schreiver, Ines; Hutzler, Christoph; Laux, Peter; Berlien, Hans-Peter; Luch, Andreas

2015-08-01

Since laser treatment of tattoos is the favored method for the removing of no longer wanted permanent skin paintings, analytical, biokinetics and toxicological data on the fragmentation pattern of commonly used pigments are urgently required for health safety reasons. Applying dynamic headspace—gas chromatography with mass spectrometric detection (DHS—GC/MS) and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC—ToF-MS), we identified 1,2-benzene dicarbonitrile, benzonitrile, benzene, and the poisonous gas hydrogen cyanide (HCN) as main fragmentation products emerging dose-dependently upon ruby laser irradiation of the popular blue pigment copper phthalocyanine in suspension. Skin cell viability was found to be significantly compromised at cyanide levels of ≥1 mM liberated during ruby laser irradiation of >1.5 mg/ml phthalocyanine blue. Further, for the first time we introduce pyrolysis-GC/MS as method suitable to simulate pigment fragmentation that may occur spontaneously or during laser removal of organic pigments in the living skin of tattooed people. According to the literature such regular tattoos hold up to 9 mg pigment/cm2 skin.

Synchronizable Q-switched, mode-locked, and cavity-dumped ruby laser for plasma diagnostics

NASA Astrophysics Data System (ADS)

Houtman, H.; Meyer, J.

1985-06-01

We report on the design and operation of an optimized version of a Q-switched, mode-locked, and cavity-dumped ruby-laser oscillator. The modulator window is much narrower than that assumed in conventional active mode-lock theory, and is shown to yield much shorter pulses than the latter in cases where the number of round trips is restricted. To allow a high-power pulse (≊1 GW) to evolve in the oscillator, and to allow simple synchronization to a (˜100 ns fixed delay) CO2 laser, a limit of 23 round trips was chosen, but similar limits may be imposed by lasers having short-gain duration as in an excimer laser. Details are given on the single spark gap switching element and Pockels cells, with an analysis of their expected switching speeds, in order to establish the effectiveness of the modulator, as compared to conventional sinusoidally driven active mode lockers. Single pulses of 50-70 mJ are reliably cavity-dumped after only 100-ns delay (23 round trips) with pulse length adjustable from 50-100 ps with ±5-ps stability. Relative timing between the main (CO2) and probe (ruby) pulses allows a measurement accuracy of ±50 ps to be attained.

Synchronizable Q-switched, mode-locked, and cavity-dumped ruby laser for plasma diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houtman, H.; Meyer, J.

We report on the design and operation of an optimized version of a Q-switched, mode-locked, and cavity-dumped ruby-laser oscillator. The modulator window is much narrower than that assumed in conventional active mode-lock theory, and is shown to yield much shorter pulses than the latter in cases where the number of round trips is restricted. To allow a high-power pulse (roughly-equal1 GW) to evolve in the oscillator, and to allow simple synchronization to a (approx.100 ns fixed delay) CO/sub 2/ laser, a limit of 23 round trips was chosen, but similar limits may be imposed by lasers having short-gain duration asmore » in an excimer laser. Details are given on the single spark gap switching element and Pockels cells, with an analysis of their expected switching speeds, in order to establish the effectiveness of the modulator, as compared to conventional sinusoidally driven active mode lockers. Single pulses of 50--70 mJ are reliably cavity-dumped after only 100-ns delay (23 round trips) with pulse length adjustable from 50--100 ps with +- 5-ps stability. Relative timing between the main (CO/sub 2/) and probe (ruby) pulses allows a measurement accuracy of +- 50 ps to be attained.« less

SPECTRAL AND MODE PROPERTIES OF SOLID-STATE LASERS AND OPTICAL DYNAMIC EFFECTS.

DTIC Science & Technology

LASERS , OPTICAL PROPERTIES), THERMAL PROPERTIES, FREQUENCY, RUBY, KERR CELLS, ELECTROMAGNETIC PULSES, PHASE LOCKED SYSTEMS, GARNET, NEODYMIUM, CAVITY RESONATORS, INTERFEROMETERS, LIGHT PULSES, PROPAGATION

Correct calibration procedure for the Q-switched ruby laser and checking the treatment irradiation pattern

PubMed Central

Ohshiro, Takafumi; Sasaki, Katsumi; Takenouchi, Kiyofumi; Kozuma, Mituaki; Ohshiro, Naoyuki; Kageyama, Yuichi

2013-01-01

Background and aims: There are many Q-switched lasers. The Q-switched ruby laser is the one most popularly used in dermatology, aesthetic surgery and plastic surgery, to remove pigmented lesions or tattoos. Correct and regular calibration of such a system is essential. However, some clinics fail to perform this with the excuse of having no measuring instrument (MI) in their offices or treatment rooms in some of their hospitals or clinics, or even the case of well-known medical universities in Japan. The present article explains the precise calibration procedure and beam pattern checking for the Q-switched ruby systems in the first author's clinic. Rationale: In the case of treatment with a medical laser, the calibration and the irradiated pattern (IP) check of the laser being used for treatment are the most important factors for treatment efficacy and safety. If these factors change, the treatment result could be different from that expected. Such kind of data are not acceptable as scientific information for a presentation or published paper. With such unreliable results and incorrect beam pattern, replicating such a study would be impossible Regular calibration check: In our clinic, we have 2 Q-switched ruby laser systems. On a daily basis, the beam patterns, both the optical axis of the beam and its treatment footprint, are checked on dedicated printed sheets and footprint paper, respectively, at the beginning of the day and after the last procedure. Every two weeks we calibrate our systems in-house using a precise MI. Every six months we calibrate the systems in-house with the MI, and then we send the systems back to the manufacturers for calibration. Once every year, we have our MI calibrated by an accredited facility in Japan. In this way, we are not only ensuring accurate and safe treatment for our patients, but we are also producing accurate system and treatment data which can be replicated by others, the basis of evidence-based medicine. PMID:24204090

Treatment of infraorbital dark circles using 694-nm fractional Q-switched ruby laser.

PubMed

Xu, Tian-Hua; Li, Yuan-Hong; Chen, John Z S; Gao, Xing-Hua; Chen, Hong-Duo

2016-12-01

The objective of this study was to evaluate the efficacy and safety of using a 694-nm fractional Q-switched ruby laser to treat infraorbital dark circles. Thirty women with infraorbital dark circles (predominant color: dark/brown) participated in this open-labeled study. The participants received eight sessions of 694-nm fractional Q-switched ruby laser treatment using a fluence of 3.0-3.5 J/cm 2 , at an interval of 7 days. The melanin deposition in the lesional skin was observed in vivo using reflectance confocal microscopy (RCM). The morphological changes were evaluated using a global evaluation, an overall self-assessment, and a Mexameter. Twenty-eight of the 30 patients showed global improvements that they rated as excellent or good. Twenty-six patients rated their overall satisfaction as excellent or good. The melanin index indicated a substantial decrease from 240.44 (baseline) to 194.56 (P < 0.05). The RCM results showed a dramatic decrease in melanin deposition in the upper dermis. The adverse effects were minimal. The characteristic finding of dark/brown infraorbital dark circles is caused by increased melanin deposition in the upper dermis. The treatment of these infraorbital dark circles using a 694-nm fractional QSR laser is safe and effective.

The measurement of atmospheric visibility with Lidar: TSC field test results

DOT National Transportation Integrated Search

1974-03-01

The report represents a technical feasibility study of the use of lidar for determining the atmospheric extinction coefficient in low visibility. Measurements were made with three laser sources: a Q-switched ruby laser, a GaAlAs diode laser array, an...

Laser surgery and medicine including photodynamic therapy in China today

NASA Astrophysics Data System (ADS)

Li, Junheng

2000-10-01

The development of laser medicine in China is correlated with the development of laser science in China. After the first Chinese laser, ruby laser came into being in 1961, Chinese medical scientists began to do the studies about laser medicine in the middle 1960s. For example, ruby laser was adopted for the retina coagulation experiment in 1965. Since 1970s, through the free choice of utilizing Co2, He-Ne, Nd:YAG argon, ruby lasers, laser surgery and medicine has been widely applied to the treatment for diseases of the eyes, ENT, dermatology, surgery, gynecology, tumors and diseases suitable to physical therapy or acupuncture with satisfactory effects. In June 1977, a nation-wide laser medicine symposium was held at Wuhan, Hubei Province with 200 participants including medical doctors and laser technologies from 23 provinces and municipal towns. Till the end of seventies, utilization of lasers has been extended to Nd glass laser, N laser and tunable dye lasers. The scope covered most of the clinical sections. After Dr. Thomas J. Dougherty developed the PDT for cancers in Roswell Park Memorial Institute in Buffalo in late 1970s and Professor Yoshihiro Hayata successfully applied the PDT in clinical treatment for lung cancer in 1980, Chinese pharmacists successfully produced the Chinese HpD and the first case of PDT, a lower eyelid basal cell carcinoma patient was treated with the Chinese laser equipment in 1981 in Beijing. Its success brought attention establishing a research group supported by the government in 1982. The members of the group consisted the experts on preclinical and clinical research, pharmaceutical chemistry, laser physicists and technologists. A systemic research on PDT was then carried out and obvious result was achieved. The step taken for PDT also accelerated the researchers on other kinds of laser medicine and surgery because the medical doctors had begun to master the knowledge about laser science. The prosperous situation of rapid development of laser science, bio-medical lasers, laser medicine and surgery as well as PDT was prolonged in the whole nineteen eighties.

Biological applications and effects of optical masers

NASA Astrophysics Data System (ADS)

Ham, William T., Jr.; Mueller, Harold A.; Williams, Ray C.; Geeraets, Walter J.; Ruffolo, John J., Jr.

1988-02-01

Research experiments and projects pertaining to the ocular hazards of lasers and other optical sources are reviewed and discussed in some detail. Early studies to determine threshold retinal damage in the rabbit from ruby and neodymium lasers are described and followed by more elaborate experiments with monkeys using the He;Ne laser. A comparison between threshold retinal lesions in human volunteers, monkeys and rabbits is given. Retinal damage in the rhesus monkey is evaluated in terms of visual acuity. Quantitative data on solar retinitis as determined in the rhesus monkey are provided and the effects of wavelength on light toxicity are evaluated for eight monochromatic laser lines. Experiments performed at Los Alamos to evaluate the ocular effects and hazards of picosecond and nanosecond pulses of radiation from CO2 and HF lasers are described. A list of published papers describing the above research is included. The HF laser effects on the rabbit cornea were very similar to those caused by exposure to the CO2 laser. The energy from the CO2 and HF lasers is completely absorbed in the superficial layers of the cornea, creating a sharp sonic or shock wave which can disrupt the epithelial cells but does not penetrate to the stroma.

Growth of ruby crystals by the heat exchanger method, phase 1: NSF small business innovation research

NASA Astrophysics Data System (ADS)

Schmid, F.; Khattak, C. P.

1980-03-01

Conditions for the growth of large, uniformly doped laser crystals by the heat exchanger method are explored. Determination of the melt point, selection of crucible material and establishment of furnace operating parameters are discussed. The melt point of ruby was found to be 2040 plus or minus 10 C. Molybdenum crucibles can be used to contain ruby in vacuum as well as under argon atmospheres at desired superheat temperatures over extended periods required for crystal growth. Thermodynamic analysis was conducted and vapor pressures of volatile species calculated. Experimentally, volatilization of chromium oxides was suppressed by using welded covers on crucibles and operating under an argon pressure in the furnace.

Laser Tattoo Removal: A Clinical Update

PubMed Central

Ho, Stephanie GY; Goh, Chee Leok

2015-01-01

Techniques for tattoo removal have evolved significantly over the years. The commonly used Quality-switched (QS) ruby, alexandrite, and Nd:YAG lasers are the traditional workhorses for tattoo removal. Newer strategies using combination laser treatments, multi-pass treatments, and picosecond lasers offer promising results. The tattoo color and skin type of the patient are important considerations when choosing the appropriate laser. Standard protocols can be developed for the effective and safe treatment of tattoos. PMID:25949017

A web based Radiation Oncology Dose Manager with a rich User Interface developed using AJAX, ruby, dynamic XHTML and the new Yahoo/EXT User Interface Library.

PubMed

Vali, Faisal; Hong, Robert

2007-10-11

With the evolution of AJAX, ruby on rails, advanced dynamic XHTML technologies and the advent of powerful user interface libraries for javascript (EXT, Yahoo User Interface Library), developers now have the ability to provide truly rich interfaces within web browsers, with reasonable effort and without third-party plugins. We designed and developed an example of such a solution. The User Interface allows radiation oncology practices to intuitively manage different dose fractionation schemes by helping estimate total dose to irradiated organs.

Research investigation directed toward extending the useful range of the electromagnetic spectrum

NASA Technical Reports Server (NTRS)

Hartmann, S. R.

1971-01-01

The lifetimes and fine structure of He(-) were studied using time-of-flight techniques and quenching by a static axial magnetic field. Using level-crossing spectroscopy the hyperfine constants A and B and the lifetime of the 3 2P3/2 state of Li-7 were measured. Polarization of the Ru 7S level was created as a first step in determining the hyperfine structure of the alkali excited S state. The parametric interaction between light and microwaves in optically pumped Rb-87 vapor were investigated. Measurements and analyses of transitions in formaldehyde and its isotopic species and in the lowest two excited vibrational states of H2CO were also made, as well as of transitions in furan, pyrrole, formic acid, and cyanoacetylene. The Hanle effect was studied in the NO molecule, and RF oscillators were developed with flat, wideband output to observe excited state hyperfine transitions at zero field. Data was generated on the time-dependent behavior of photon echoes in ruby. Stimulated Raman scattering was studied in atomic Tl vapor. A Q switched, temperature-tuned ruby laser was developed which operates between 6934 and 6938 A. The frequency shift due to resonant interaction between identical radiating atoms was calculated.

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.

Bibliography of Soviet Laser Developments, Number 89, May-June 1987

DTIC Science & Technology

1988-04-20

RESEARCH A. Solid State Lasers 1. Crystal a. Miscellaneous ....................... 1 b . Ruby --- c. LiF ................................ 2 2. Rare Earth a...Miscellaneous ....................... 2 b . Nd3+ . ............................... 3 C. Er3+ . ............................... 3 d. Ho3...3 e Tm3+ ---................ 3. Semiconductor a. Theory ............................. 4 b . Miscellaneous Homojunction ...... 4 c

Comparison of fluorescent and high-pressure sodium lamps on growth of leaf lettuce

NASA Technical Reports Server (NTRS)

Koontz, H. V.; Prince, R. P.; Koontz, R. F.; Knott, W. M. (Principal Investigator)

1987-01-01

Radiation from high-pressure sodium (HPS) lamps provided more than a 50% increased yield (fresh and dry weight of tops) of loose-leaf lettuce cultivars Grand Rapids Forcing and RubyConn, compared to that obtained by radiation from cool-white fluorescent (CWF) lamps at equal photosynthetic photon flux; yet, input wattage was approximately 36% less. It was postulated that the considerable output of 700 to 850 nm radiation from the HPS lamp was a significant factor of the increased yield. Under HPS lamps, the leaves of both cultivars were slightly less green with very little red pigmentation ('RubyConn') and slightly elongated, compared to CWF, but plant productivity per unit electrical energy input was vastly superior with HPS.

Laser reflector with an interference coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vol'pyan, O D; Semenov, A A; Yakovlev, P P

1998-10-31

An analysis was made of the reflectivity of interference coatings intended for the use in optical pumping of solid-state lasers. Ruby and Nd{sup 3+}:YAG lasers were used as models in comparative pumping efficiency measurements, carried out employing reflectors with interference and silver coatings. Estimates of the service life of reflectors with interference coatings were obtained. The power of a thermo-optical lens was reduced by the use of such coatings in cw lasers. (laser system components)

Treatment of pigmentary disorders in patients with skin of color with a novel 755 nm picosecond, Q-switched ruby, and Q-switched Nd:YAG nanosecond lasers: A retrospective photographic review.

PubMed

Levin, Melissa Kanchanapoomi; Ng, Elise; Bae, Yoon-Soo Cindy; Brauer, Jeremy A; Geronemus, Roy G

2016-02-01

Laser procedures in skin of color (SOC) patients are challenging due to the increased risk of dyspigmentation and scarring. A novel 755 nm alexandrite picosecond laser has demonstrated effectiveness for tattoo removal and treatment of acne scars. No studies to date have evaluated its applications in pigmentary disorders. The purpose of this retrospective study was to evaluate the safety profile and efficacy of the picosecond alexandrite laser compared to the current standard treatment, Q-switched ruby and neodynium (Nd):YAG nanosecond lasers, for pigmentary disorders in SOC patients. A retrospective photographic and chart evaluation of seventy 755 nm alexandrite picosecond, ninety-two Q-switched frequency doubled 532 nm and 1,064 nm Nd:YAG nanosecond, and forty-seven Q-switched 694 nm ruby nanosecond laser treatments, in forty-two subjects of Fitzpatrick skin types III-VI was conducted in a single laser specialty center. The picosecond laser was a research prototype device. Treatment efficacy was assessed by two blinded physician evaluators, using a visual analog scale for percentage of pigmentary clearance in standard photographs. Subject assessment of efficacy, satisfaction, and adverse events was performed using a questionnaire survey. The most common pigmentary disorder treated was Nevus of Ota (38.1%), followed by solar lentigines (23.8%). Other pigmentary disorders included post-inflammatory hyperpigmentation, congenital nevus, café au lait macule, dermal melanocytosis, Nevus of Ito, and Becker's nevus. Clinical efficacy of the Q-switched nanosecond lasers and picosecond laser treatments were comparable for lesions treated on the face with a mean visual analog score of 2.57 and 2.44, respectively, corresponding to approximately 50% pigmentary clearance. Subject questionnaires were completed in 58.8% of the picosecond subjects and 52.0% of the Q-switched subjects. Eighty four percent of subjects receiving Q-switched nanosecond laser treatments and 50% of the subjects receiving alexandrite 755 nm picosecond laser treatments felt satisfied to completely satisfied. Side effects observed in subjects treated with the alexandrite 755 nm picosecond laser were similar to those commonly observed and reported with the nanosecond Q-switched technology. All side effects were temporary, resolving within one month, and no long-term complications were noted. All patients who were very satisfied with their picosecond laser treatment for Nevus of Ota noted a delayed improvement only after 3 months. The 755 nm alexandrite picosecond, 694 nm ruby, 532 nm, and 1064 nm neodynium:YAG nanosecond lasers appear to be safe and effective modalities for removal of pigmentary disorders in skin of color patients with no long-term complications if used appropriately. This study demonstrates the potential of the 755 nm alexandrite picosecond laser in further clinical applications beyond tattoo removal. While the Q-switched lasers were effective, promising results were also observed using an early version of the novel picosecond laser for the removal of pigmentary lesions in SOC patients. As we continue to improve our understanding of the 755 nm picosecond laser, this device may prove to be a safe and effective alternative to the Q-switched lasers for the treatment of facial pigmented lesions in patients with skin of color. © 2016 Wiley Periodicals, Inc.

Unusual ruby-sapphire transition in alluvial megacrysts, Cenozoic basaltic gem field, New England, New South Wales, Australia

NASA Astrophysics Data System (ADS)

Sutherland, Frederick L.; Graham, Ian T.; Harris, Stephen J.; Coldham, Terry; Powell, William; Belousova, Elena A.; Martin, Laure

2017-05-01

Rare ruby crystals appear among prevailing sapphire crystals mined from placers within basaltic areas in the New England gem-field, New South Wales, Australia. New England ruby (NER) has distinctive trace element features compared to those from ruby elsewhere in Australia and indeed most ruby from across the world. The NER suite includes ruby (up to 3370 ppm Cr), pink sapphire (up to 1520 ppm Cr), white sapphire (up to 910 ppm) and violet, mauve, purple, or bluish sapphire (up to 1410 ppm Cr). Some crystals show outward growth banding in this respective colour sequence. All four colour zones are notably high in Ga (up to 310 ppm) and Si (up to 1820 ppm). High Ga and Ga/Mg values are unusual in ruby and its trace element plots (laser ablation-inductively coupled plasma-mass spectrometry) and suggests that magmatic-metasomatic inputs were involved in the NER suite genesis. In situ oxygen isotope analyses (secondary ion mass spectrometry) across the NER suite colour range showed little variation (n = 22; δ18O = 4.4 ± 0.4, 2σ error), and are values typical for corundum associated with ultramafic/mafic rocks. The isolated NER xenocryst suite, corroded by basalt transport and with few internal inclusions, presents a challenge in deciphering its exact origin. Detailed consideration of its high Ga chemistry in relation to the known geology of the surrounding region was used to narrow down potential sources. These include Late Palaeozoic-Triassic fractionated I-type granitoid magmas or Mesozoic-Cenozoic felsic fractionates from basaltic magmas that interacted with early Palaeozoic Cr-bearing ophiolite bodies in the New England Orogen. Other potential sources may lie deeper within lower crust-mantle metamorphic assemblages, but need to match the anomalous high-Ga geochemistry of the New England ruby suite.

Bibliography of Soviet Laser Developments, Number 77, May - June 1985.

DTIC Science & Technology

1986-09-01

B . CONTRACT OR GRANT NUMBER(S) 9. PERFORMING ORGANIZATION NAME AND ADDRESS I0. PROGRAM ELEMENT. PROJECT, TASK Defense Intelligence Agency AREA...TABLE OF CONTENTS I. BASIC RESEARCH A. Solid State Lasers 1. Crystal a. Miscellaneous ................... 1 b . Ruby .. . . . . . . .. . . . . . - c...LiF ............................. 1 2. Rare Earth a. Miscellaneous .......... .. . 1 b . Nd3+ . .. . . . .. . .0 . . . . c. Er3

Research progress on laser crystals in China

NASA Astrophysics Data System (ADS)

Yingxia, Z.

1985-01-01

Current Chinese research on laser crystals is now quite extensive and involves more than 30 research teams with nearly 1,000 technicians and workers actively engaged in the study of more than 20 types of laser cyrstals. Neodymium-doped yttrium aluminum garnet (Nd:YAG) and ruby (Cr:Al2O3) lasers have been manufactured and are widely employed. There are several new and promising crystals now under study which will find applications, and both basic and exploratory research have given rise to new developments.

Lasers: The Magic Wand in Esthetic Dentistry!!

PubMed Central

Shajahan, P A; Kumar, P Ranjith; Hariprasad, A; Mathew, Jyothis; Shaji, A P; Ahammed, M Fazeel

2015-01-01

In this era of fast developing technologies and innovative ideas, the need for faster treatment has become a necessity. Treatment with lasers that is much less time-consuming and painless is accepted and appreciated by the patient. Use of Lasers is not new; they have been in use for decades since their development by Maiman in 1960. Lasers have travelled a long way from ruby lasers to erbium lasers and are being fondly used in every aspect of dental treatment. This article aims at elaborate the use and applications of lasers in the field of esthetic dentistry. PMID:26124614

An Inexpensive Fast-Light Detector for Student Laboratories

ERIC Educational Resources Information Center

Sanders, Steven G.; and others

1969-01-01

An optical dectector consisting of a high-speed PIN diode and a transistor was evaluated for use in student experiments with a pulsed-ruby laser. Pulses with 36-nsec risetimes were clearly resolved. (LC)

Nonradiative relaxation in tunable solid state laser crystals

NASA Technical Reports Server (NTRS)

Gayen, S. K.; Wang, W. B.; Petricevic, V.; Alfano, R. R.

1986-01-01

The characteristics of nonradiative transitions between the 4T2 and 2E excited states of trivalent-chromium-ion-activated ruby (containing 0.04 percent Cr2O3 by weight) and alexandrite (containing 0.4 at. percent chromium ion) laser crystals were studied using the technique described by Gayen et al. (1985). In this technique, a 527-nm pulse excites the 4T2 band of the Cr(3+), and the subsequent population kinetics among excited states is monitored by an IR picosecond probe pulse as a function of pump-probe delay. In ruby, a resolution-limited sharp rise in the excited state population was followed by a long-lifetime decay, leading to an upper limit of 7 ps for the 4T2-state nonradiative lifetime. In alexandrite, a longer rise time was followed by a multicomponent decay. A theoretical model is proposed for explaining the induced absorption and the transition dynamics observed in these crystals.

Bibliography of Soviet Laser Developments, No. 17, July - September 1974

DTIC Science & Technology

1975-01-29

A . N. Tokare and V . M. Usova (0). Effect of structural differ va. ences in flashlamps on the efficiency of solid state lasers...USATYUK, V.V. USHAKOV. A . Yt». USMANOV, A . G. USMANOV, R.G. USOVA , V . M. UZKIY. A . E. VALYASHKO, YE.G. VAREOLOMEYEV. A.A...ot’ power oulpul In a ruby laser with self-Q- switching. ZhPS, v . 20, no. 6, 1974, 987-989. 2, Kopvillem, U. Kh. , V .

USSR and Eastern Europe Scientific Abstracts, Physics and Mathematics, Number 34

DTIC Science & Technology

1977-04-27

Russian abstract provided by the source] [Text] The relationship of duration and intensity of ultrashort pulses in a mode-locked ruby laser with Q...Excess charge carriers have been found to appear in pure Ge and Si crystals irradiated with short pulses from a C02 laser . The high purity and perfection...Illustrations 2; References 15: 8 Russian, 7 Western. USSR UDC 621.378.325 CONTROL OF DURATION OF ULTRASHORT PULSES IN MODE-LOCKED LASERS ZHURNAL

Combined therapy using Q-switched ruby laser and bleaching treatment with tretinoin and hydroquinone for periorbital skin hyperpigmentation in Asians.

PubMed

Momosawa, Akira; Kurita, Masakazu; Ozaki, Mine; Miyamoto, Shinpei; Kobayashi, Yo; Ban, Izumi; Harii, Kiyonori

2008-01-01

Periorbital skin hyperpigmentation, so-called dark circles, is of major concern for many people. However, only a few reports refer to the morbidity and treatment, and as far as the authors know, there are no reports of the condition in Asians. A total of 18 Japanese patients underwent combined therapy using Q-switched ruby laser to eliminate dermal pigmentation following topical bleaching treatment with tretinoin aqueous gel and hydroquinone ointment performed initially (6 weeks) to reduce epidermal melanin. Both steps were repeated two to four times until physical clearance of the pigmentation was confirmed and patient satisfaction was achieved. Skin biopsy was performed at baseline in each patient and at the end of treatment in three patients, all with informed consent. Clinical and histologic appearances of periorbital hyperpigmentation were evaluated and rated as excellent, good, fair, poor, or default. Seven of 18 patients (38.9 percent) showed excellent clearing after treatment and eight (44.4 percent) were rated good. Only one (5.6 percent) was rated fair and none was rated poor. Postinflammatory hyperpigmentation was observed in only two patients (11.1 percent). Histologic examination showed obvious epidermal hyperpigmentation in 10 specimens. Dermal pigmentation was observed in all specimens but was not considered to be melanocytosis. Remarkable reduction of dermal pigmentation was observed in the biopsy specimens of three patients after treatment. The new treatment protocol combining Q-switched ruby laser and topical bleaching treatment using tretinoin and hydroquinone is considered effective for improvement of periorbital skin hyperpigmentation, with a low incidence of postinflammatory hyperpigmentation.

Lasers in periodontics.

PubMed

Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

2012-08-01

Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20(th) century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

Lasers in periodontics

PubMed Central

Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

2012-01-01

Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics. PMID:23066266

Laser technology for high precision satellite tracking

NASA Technical Reports Server (NTRS)

Plotkin, H. H.

1974-01-01

Fixed and mobile laser ranging stations have been developed to track satellites equipped with retro-reflector arrays. These have operated consistently at data rates of once per second with range precision better than 50 cm, using Q-switched ruby lasers with pulse durations of 20 to 40 nanoseconds. Improvements are being incorporated to improve the precision to 10 cm, and to permit ranging to more distant satellites. These include improved reflector array designs, processing and analysis of the received reflection pulses, and use of sub-nanosecond pulse duration lasers.

Gadolinium Scandium Gallium Garnet (GSGG) as a Solid-State Laser Host

DTIC Science & Technology

1987-07-01

o*SATI CODSi1.SBEC EM (otne nrvrs fnceayad dniy nb)k ubr ~~~~~~~~ Gadolinium Scandium Gallium Garnet (GSGG)asaSldtteLerHt 17. ABSTRACT 6.SUJCTTEM...certain other garnet materials for replacement. It also addresses the solid-state laser host material Gadolinium Scandium Gal- lium Garnet (GSGG) and its...by neodymium-doped yttrium aluminum garnet (Nd:YAG) or other mate- rials for most applications. In the years after the invention of the ruby laser, in

75 FR 63814 - Notice of Petitions by Firms for Determination of Eligibility To Apply for Trade Adjustment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-18

... machinery heat 80223. exchangers and laser components. Euro Marble & Granite, Inc.... 4552 N. Ruby Street, 10/7/2010 The firm manufactures cut stone and stone Schiller Park, IL products such as countertops...

Laser debonding of ceramic brackets: a comprehensive review.

PubMed

Azzeh, Ezz; Feldon, Paul J

2003-01-01

Since the invention of the ruby laser in the early 1960s, tremendous advances have been made in optic laser technology. Orthodontists have found various uses for lasers, including the debonding of ceramic brackets. Laser energy degrades the adhesive resin used to bond brackets. Consequently, lower forces can be used than when mechanical debonding is performed, reducing the risk of enamel damage. However, the heat produced by some lasers can damage the tooth pulp. Selecting the appropriate laser, resin, and bracket combination can minimize risks and make debonding more efficient. The purpose of this article is to give the clinician an up-to-date, comprehensive literature review about the clinical characteristics of debonding ceramic brackets with lasers.

50 years LASERS: in vitro diagnostics, clinical applications and perspectives.

PubMed

Spyropoulos, Basile

2011-01-01

1960 Theodore Maiman built the first Ruby-LASER, starting-point for half a century of R&D on Biomedical LASER continuous improvement. The purpose of this paper is to contribute a review of the often disregarded, however, extremely important Industrial Property documents of LASER-based in vitro Diagnostics devices. It is an attempt to sketch-out the patent-trail leading towards the modern Biomedical Laboratory and to offer an introduction to the employment of "exotic" systems, such as the Free Electron LASER (FEL), that are expected to focus on the fundamental processes of life, following chemical reactions and biological processes as they happen, on unprecedented time and size scales. There are various in vitro LASER applications, however, the most important ones include: Hybrid Coulter Principle-LASER Hematology Analyzers. Flow Cytometry systems. Fluorescent in situ Hybridization (FISH Techniques). Confocal LASER Scanning Microscopy and Cytometry. From the first fluorescence-based flow Cytometry device developed in 1968 by Wolfgang Göhde until nowadays, numerous improvements and new features related to these devices appeared. The relevant industrial property milestone-documents and their overall numeral trends are presented. In 1971, J. Madey invented and developed the Free Electron LASER (FEL), a vacuum-tube that uses a beam of relativistic electrons passing through a periodic, transverse magnetic field (wiggler) to produce coherent radiation, contained in an optical cavity defined by mirrors. A resonance condition that involves the energy of the electron beam, the strength of the magnetic field, and the periodicity of the magnet determines the wavelength of the radiation. The FEL Coherent Light Sources like the Linac Coherent Light Source (LCLS) at Stanford, CA, USA or the Xray Free Electron LASER (XFEL) at Hamburg, Germany, will work much like a high-speed (< 100 femtoseconds) camera, enabling scientists to take stop-motion pictures, on the nanoscale, of atoms and molecules in motion. The curve of FEL-related patents of the last 20 years is much smoother than the corresponding one for in vitro Diagnostics conventional LASERS. If the diodes brought a LASER into almost everyone's pocket, the above-mentioned super-imaging systems are huge facilities of enormous cost--the price to steal a look at the fundamental processes of life.

Ar-Ar and U-Pb ages of marble-hosted ruby deposits from Central and South-east Asia

NASA Astrophysics Data System (ADS)

Garnier, V.; Giuliani, G.; Maluski, H.; Ohnenstetter, D.; Deloule, E.

2003-04-01

Marble-hosted ruby deposits represent the first source of gemstones in Asia. The deposits from Jegdalek (Afghanistan), Hunza Valley (Pakistan), Nangimali (Azad-Kashmir), Chumar, Ruyil (Nepal), Mogok (Myanmar), Luc Yen, Yen Bai and Quy Chau (Vietnam) were dated using the 40Ar-39Ar laser stepwise heating technique on syngenetic micas. The following ages were obtained : 24.7 ± 0.3 Ma at Jegdalek ; 10.8 ± 0.3 to 5.4 ± 0.3 Ma at Hunza ; 17.2 ± 0.2 to 15.3 ± 0.1 Ma at Nangimali ; 4.6 ± 0.1 Ma at Ruyil ; 5.6 ± 0.4 Ma at Chumar ; 18.7 ± 0.2 to 17.1 ± 0.2 Ma at Mogok ; 33.8 ± 0.4 to 30.8 ± 0.8 Ma at Luc Yen ; 24.4 ± 0.4 to 23.2 ± 0.6 Ma at Yen Bai, 22.1 ± 0.6 to 21.6 ± 0.7 Ma at Quy Chau. These ages represent cooling ages and thus minimum ages for ruby formation. The ages obtained for Nangimali are close to the Ar-Ar cooling age of 19 Ma recorded in the Chichi granite, North to the ruby deposit. However, (C,O)-isotopic studies of the ruby-bearing marbles show no genetic relation between granite emplacement and ruby deposition in this area. The age found at Jegdalek is similar to the K-Ar ages obtained on the Sairobi pegmatitic dykes (20-26 Ma) and of the Jalalabad pluton (25 Ma), located close to the ruby deposit. At Mogok, the ruby deposits yield ages close to those obtained on high grade metamorphic and foliated intrusive regional rocks (15.8 ± 0.7 - 19.5 ± 1.0 Ma). The ages obtained at Chumar and Ruyil agree with those of the Lesser Himalaya Formation (12 - 6 Ma). Those found at Quy Chau agree with those found for the shear zone activity. Furthermore, U-Pb dating was done on zircons included in a ruby from Luc Yen and spinels in marble from Luc Yen and Hunza. The wide range of 238U-206Pb ages obtained for Luc Yen (266 - 45 Ma) evidences a complex metamorphic history. Ruby crystallised at 45 Ma during ductile activity of the Red River shear zone. At Hunza, an 238U-206Pb age of 94.0 ± 2.1 Ma obtained on inherited zircons confirms the U-Pb age obtained on zircons from the Karakorum batholith (95 Ma). Asian marble-hosted ruby deposits are directly linked with the tectonometamorphic activity of Cenozoic structures resulting from deformation of the Asian plate during India-Asia collision. Geochemical studies evidence that these rubies have a metamorphic origin and thus dating of these deposits provide an essential clue to decipher the timing of continental collision in Central and South-east Asia.

Bibliography of Soviet Laser Developments

DTIC Science & Technology

1975-09-22

Nagibarov, V. R. , I. A. Nagibarova, and A. M. Shegeda (0). Nonresonant supermigration [of energy ] in concentrated specimens of ruby. ZhETF P...Korniyenko (1). Relationship of luminescence energies of various transitions with the metastable level of the Nd ion in glass. KE, no. 2, 1975...12Ye8) 98. 99. 100. Anan’kin, A. I. (0). Calculating the energy characteriitJcs of a thermally excited CG-, laser. KE, no. 1, 1975

Investigation of laser holographic interferometric techniques for structure inspection

NASA Technical Reports Server (NTRS)

Chu, W. P.

1973-01-01

The application of laser holographic interferometric techniques for nondestructive inspection of material structures commonly used in aerospace works is investigated. Two types of structures, composite plate and solid fuel rocket engine motor casing, were examined. In conducting the experiments, both CW HeNe gas lasers and Q-switched ruby lasers were used as light sources for holographic recording setups. Different stressing schemes were investigated as to their effectiveness in generating maximum deformation at regions of structural weakness such as flaws and disbonds. Experimental results on stressing schemes such as thermal stressing, pressurized stressing, transducer excitation, and mechanical impact are presented and evaluated.

Depth-resolved photo- and ionoluminescence of LiF and Al2O3

NASA Astrophysics Data System (ADS)

Skuratov, V. A.; Kirilkin, N. S.; Kovalev, Yu. S.; Strukova, T. S.; Havanscak, K.

2012-09-01

Microluminescence and laser confocal scanning microscopy techniques have been used to study spatial distribution of F-type color centers in LiF and mechanical stress profiles in Al2O3:Cr single crystals irradiated with 1.2 MeV/amu Ar, Kr, Xe and 3 MeV/amu Kr and Bi ions. It was found that F2 and F3+-center profiles at low ion fluences correlate with ionizing energy loss profiles. With increasing ion fluence, after ion track halo overlapping, the luminescence yield is defined by radiation defects formed in elastic collisions in the end-of-range area. Stress profiles and stress tensor components in ruby crystals across swift heavy ion irradiated layers have been deduced from depth-resolved photo-stimulated spectra using piezospectroscopic effect. Experimental data show that that stresses are compressive in basal plane and tensile in perpendicular direction in all samples irradiated with high energy ions.

Uranium plasma emission at gas-core reaction conditions

NASA Technical Reports Server (NTRS)

Williams, M. D.; Jalufka, N. W.; Hohl, F.; Lee, J. H.

1976-01-01

The results of uranium plasma emission produced by two methods are reported. For the first method a ruby laser was focused on the surface of a pure U-238 sample to create a plasma plume with a peak plasma density of about 10 to the 20th power/cu cm and a temperature of about 38,600 K. The absolute intensity of the emitted radiation, covering the range from 300 to 7000 A was measured. For the second method, the uranium plasma was produced in a 20 kilovolt, 25 kilojoule plasma-focus device. The 2.5 MeV neutrons from the D-D reaction in the plasma focus are moderated by polyethylene and induce fissions in the U-235. Spectra of both uranium plasmas were obtained over the range from 30 to 9000 A. Because of the low fission yield the energy input due to fissions is very small compared to the total energy in the plasma.

Bibliography of Soviet Laser Developments, Number 23, January - March 1976

DTIC Science & Technology

1976-09-15

A . N. Tokareva, and V . M. Usova 0). Exper*nental study of the effect of a ...VORONIN, A .!1. 76 J1 USHAKOV. V . T. 53 VORONOV, V . V . 100 USHKOV, F. V . 93 VOROSHILOV, YU. V . 94 USOL’TSEV, 1. F. 23 VOYTENKO, A . M. 99 USOVA , V : M...131 I IC ’I tA 11 V I. BASIC RESEARCH I A . SOLID STATE LASERS 1. Crystal: Ruby 1. Agashkov, A . V ., L. A . Lavrovskiy,

Lasers in medicine

NASA Astrophysics Data System (ADS)

Peng, Qian; Juzeniene, Asta; Chen, Jiyao; Svaasand, Lars O.; Warloe, Trond; Giercksky, Karl-Erik; Moan, Johan

2008-05-01

It is hard to imagine that a narrow, one-way, coherent, moving, amplified beam of light fired by excited atoms is powerful enough to slice through steel. In 1917, Albert Einstein speculated that under certain conditions atoms could absorb light and be stimulated to shed their borrowed energy. Charles Townes coined the term laser (light amplification by stimulated emission of radiation) in 1951. Theodore Maiman investigated the glare of a flash lamp in a rod of synthetic ruby, creating the first human-made laser in 1960. The laser involves exciting atoms and passing them through a medium such as crystal, gas or liquid. As the cascade of photon energy sweeps through the medium, bouncing off mirrors, it is reflected back and forth, and gains energy to produce a high wattage beam of light. Although lasers are today used by a large variety of professions, one of the most meaningful applications of laser technology has been through its use in medicine. Being faster and less invasive with a high precision, lasers have penetrated into most medical disciplines during the last half century including dermatology, ophthalmology, dentistry, otolaryngology, gastroenterology, urology, gynaecology, cardiology, neurosurgery and orthopaedics. In many ways the laser has revolutionized the diagnosis and treatment of a disease. As a surgical tool the laser is capable of three basic functions. When focused on a point it can cauterize deeply as it cuts, reducing the surgical trauma caused by a knife. It can vaporize the surface of a tissue. Or, through optical fibres, it can permit a doctor to see inside the body. Lasers have also become an indispensable tool in biological applications from high-resolution microscopy to subcellular nanosurgery. Indeed, medical lasers are a prime example of how the movement of an idea can truly change the medical world. This review will survey various applications of lasers in medicine including four major categories: types of lasers, laser-tissue interactions, therapeutics and diagnostics.

Photosynthetic characteristics and mycosporine-like amino acids under UV radiation: a competitive advantage of Mastocarpus stellatus over Chondrus crispus at the Helgoland shoreline?

NASA Astrophysics Data System (ADS)

Bischof, K.; Kräbs, G.; Hanelt, D.; Wiencke, C.

2000-05-01

Chondrus crispus and Mastocarpus stellatus both inhabit the intertidal and upper sublittoral zone of Helgoland, but with C. crispus generally taking a lower position. Measurements of chlorophyll fluorescence, activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), and content and composition of UV absorbing mycosporine-like amino acids (MAAs) were conducted in the laboratory, to test whether susceptibility to UV radiation may play a role in the vertical distribution of these two species. Effective and maximal quantum yield of photochemistry as well as maximal electron transport rate (ETRmax) in C. crispus were more strongly affected by UV-B radiation than in M. stellatus. In both species, no negative effects of the respective radiation conditions were found on total activity of RubisCO. Total MAA content in M. stellatus was up to 6-fold higher than in C. crispus and the composition of MAAs in the two species was different. The results indicate that, among others, UV-B sensitivity may be a factor restricting C. crispus to the lower intertidal and upper sublittoral zone, whereas M. stellatus is better adapted to UV radiation and is therefore more competitive in the upper intertidal zone.

Effect of 16 and 24 hours daily radiation (light) on lettuce growth

NASA Technical Reports Server (NTRS)

Koontz, H. V.; Prince, R. P.; Knott, W. M. (Principal Investigator)

1986-01-01

A 50% increase in total radiation by extending the photoperiod from 16 to 24 hr doubled the weight of all cultivars of loose-leaf lettuce (Lactuca sativa L.) 'Grand Rapids Forcing', 'Waldmanns Green', 'Salad Bowl', and 'RubyConn', but not a Butterhead cultivar, 'Salina'. When total daily radiation (moles of photons) was the same, plants under continuous radiation weighed 30% to 50% more than plants under a 16 hr photoperiod. By using continuous radiation on loose-leaf lettuce, fewer lamp fixtures were required and yield was increased.

A peek into the history of sapphire crystal growth

NASA Astrophysics Data System (ADS)

Harris, Daniel C.

2003-09-01

After the chemical compositions of sapphire and ruby were unraveled in the middle of the 19th century, chemists set out to grow artificial crystals of these valuable gemstones. In 1885 a dealer in Geneva began to sell ruby that is now believed to have been created by flame fusion. Gemnologists rapidly concluded that the stones were artificial, but the Geneva ruby stimulated A. V. L. Verneuil in Paris to develop a flame fusion process to produce higher quality ruby and sapphire. By 1900 there was brisk demand for ruby manufactured by Verneuil's method, even though Verneuil did not publicly announce his work until 1902 and did not publish details until 1904. The Verneuil process was used with little alteration for the next 50 years. From 1932-1953, S. K. Popov in the Soviet Union established a capability for manufacturing high quality sapphire by the Verneuil process. In the U.S., under government contract, Linde Air Products Co. implemented the Verneuil process for ruby and sapphire when European sources were cut off during World War II. These materials were essential to the war effort for jewel bearings in precision instruments. In the 1960s and 1970s, the Czochralski process was implemented by Linde and its successor, Union Carbide, to make higher crystal quality material for ruby lasers. Stimulated by a government contract for structural fibers in 1966, H. LaBelle invented edge-defined film-fed growth (EFG). The Saphikon company, which is currently owned by Saint-Gobain, evolved from this effort. Independently and simultaneously, Stepanov developed edge-defined film-fed growth in the Soviet Union. In 1967 F. Schmid and D. Viechnicki at the Army Materials Research Lab grew sapphire by the heat exchanger method (HEM). Schmid went on to establish Crystal Systems, Inc. around this technology. Rotem Industries, founded in Israel in 1969, perfected the growth of sapphire hemispheres and near-net-shape domes by gradient solidification. In the U.S., growth of near-net-shape sapphire domes was demonstrated by both the EFG and HEM methods in the 1980s under government contract, but neither method entered commercial production. Today, domes in the U.S. are made by "scooping" sapphire boules with diamond-impregnated cutting tools. Commercial markets for sapphire, especially in the semiconductor industry, are healthy and growing at the dawn of the 21st century.

Lasers for tattoo removal: a review.

PubMed

Choudhary, Sonal; Elsaie, Mohamed L; Leiva, Angel; Nouri, Keyvan

2010-09-01

Tattoos have existed and have been used as an expression of art by man for ages-and so have the techniques to remove them. Lasers based on the principle of selective photothermolysis are now being used to remove black as well as colorful tattoos with varying successes. The commonly used lasers for tattoo removal are the Q-switched 694-nm ruby laser, the Q-switched 755-nm alexandrite laser, the 1,064-nm Nd:YAG laser, and the 532-nm Nd:YAG laser. Newer techniques and methods are evolving in tattoo removal with lasers. Choosing the right laser for the right tattoo color is necessary for a successful outcome. Our review aims to understand the principles of laser tattoo removal and their applications for different types and colors of tattoos. The review also highlights the complications that can occur such as dyspigmentation, allergic reactions, epidermal debris, ink darkening, and so on, in this process and how to prevent them.

Initiation of insensitive explosives by laser energy

NASA Technical Reports Server (NTRS)

Menichelli, V. J.; Yang, L. C.

1972-01-01

Instantaneous longitudinal detonations were observed in confined columns of pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and tetryl when these materials were pulsed with light energy from a focused Q-switch ruby laser. The laser energy ranged from 0.5 to 4.2 J with a pulse width of 25 ns. Enhancement of the ignition mechanism is hypothesized when a 100-nm (1000-A) thick aluminum film is vacuum-deposited on the explosive side of the window. Upon irradiation from the laser, a shock is generated at the aluminum explosive interface. Steady state detonations can be reached in less than 0.5 microseconds with less than 10% variation in detonation velocity for PETN and RDX.

The role of scattering and absorption on the optical properties of birefringent polycrystalline ceramics: Modeling and experiments on ruby (Cr:Al2O3)

NASA Astrophysics Data System (ADS)

Penilla, E. H.; Hardin, C. L.; Kodera, Y.; Basun, S. A.; Evans, D. R.; Garay, J. E.

2016-01-01

Light scattering due to birefringence has prevented the use of polycrystalline ceramics with anisotropic optical properties in applications such as laser gain media. However, continued development of processing technology has allowed for very low porosity and fine grains, significantly improving transparency and is paving the way for polycrystalline ceramics to be used in demanding optical applications. We present a method for producing highly transparent Cr3+ doped Al2O3 (ruby) using current activated pressure assisted densification. The one-step doping/densification process produces fine grained ceramics with well integrated (doped) Cr, resulting in good absorption and emission. In order to explain the light transmission properties, we extend the analytical model based on the Rayleigh-Gans-Debye approximation that has been previously used for undoped alumina to include absorption. The model presented captures reflection, scattering, and absorption phenomena in the ceramics. Comparison with measured transmission confirms that the model adequately describes the properties of polycrystalline ruby. In addition the measured emission spectra and emission lifetime are found to be similar to single crystals, confirming the high optical quality of the ceramics.

Emulsions for pulsed holography: new and improved processing schemes

NASA Astrophysics Data System (ADS)

Rodin, Alexey M.; Taylor, Rob

2003-05-01

Recent improvements in the processing of commercially available holographic recording materials for pulsed holography are reviewed. Harmonics of pulsed Nd:YLF/Nd:Phosphate Glass, Nd:YLF, Nd:YAG laser's, and the fundamental wavelength of a pulsed Ruby laser were used as radiation sources for the recording of transmission and reflection holography gratings. It is shown that ultra-fine grain size materials such as PFG-03C and Ultimate-15 can be successfully applied for small and medium format pulsed holography applications. These small grain size emulsions are especially important in the areas of artistic archival portraiture and contact Denisyuk micro-holography of living objects, where noiseless image reconstruction is of a primary concern. It suggests that HOE's, such as full-color image projection screens, may be successfully recorded on PFG-03C holographic emulsions using a pulsed RGB laser. A range of commercial RGB pulsed lasers suitable for these applications are introduced. Visible wavelengths currently produced from these lasers covers the spectrum of 440 - 660nm. Latest developments of a full range of pulsed holographic camera systems manufactured by GEOLA that are suitable for medium and large format portraiture, medical imaging, museum artifact archival recording, and other types of holography are also reviewed with particular reference to new integrated digital mastering features. Finally, the initial commercial production of a new photopolymer film with a sensitivity range of 625-680nm is introduced. Initial CW exposure energies at 633nm were 30 - 50mJ/cm2; with diffraction efficiencies of 75 - 80% observed with this new material.

BioRuby: bioinformatics software for the Ruby programming language.

PubMed

Goto, Naohisa; Prins, Pjotr; Nakao, Mitsuteru; Bonnal, Raoul; Aerts, Jan; Katayama, Toshiaki

2010-10-15

The BioRuby software toolkit contains a comprehensive set of free development tools and libraries for bioinformatics and molecular biology, written in the Ruby programming language. BioRuby has components for sequence analysis, pathway analysis, protein modelling and phylogenetic analysis; it supports many widely used data formats and provides easy access to databases, external programs and public web services, including BLAST, KEGG, GenBank, MEDLINE and GO. BioRuby comes with a tutorial, documentation and an interactive environment, which can be used in the shell, and in the web browser. BioRuby is free and open source software, made available under the Ruby license. BioRuby runs on all platforms that support Ruby, including Linux, Mac OS X and Windows. And, with JRuby, BioRuby runs on the Java Virtual Machine. The source code is available from http://www.bioruby.org/. katayama@bioruby.org

Laser ignition of traumatically embedded firework debris.

PubMed

Taylor, C R

1998-01-01

The Q-switched ruby laser (QSRL) has a good track record for traumatic tattoo removal. An unusual case of QSRL-treatment of a traumatic tattoo composed of firework debris is presented. A young man's traumatic tattoo, composed of firework debris, underwent QSRL ablation at 4-7 J/cm2 (pulse width 5 mm; duration 20 ns). Each test pulse produced visible sparks and focal projectile ejection of skin with pox-like scar formation. Caution is advised when using the QSRL for the treatment of traumatic tattoos composed of potentially combustible debris.

Pulse Width Dependence Of Pigment Cell Damage At 694 nm In Guinea Pig Skin

NASA Astrophysics Data System (ADS)

Dover, Jeffrey S.; Polla, Luigi L.; Margolis, Randall J.; Whitaker, Diana; Watanabe, Schinichi; Murphy, George F.; Parrish, John A.; Anderson, R. R.

1987-03-01

351 nm, 20-nsec XeF excimer laser irradiation has previously been shown to selectively target and damage melanosomes in human skin. In the following studies selective targeting with melanosomal photodisruption has been demonstrated in pigmented guinea pig skin with a Q-switched 40-nsec ruby laser, and a 750-nsec pulsed dye laser but not with a 400-usec pulsed dye laser. The pulse width dependence of melanosomal disruption, occurring only at pulsewidths shorter than the thermal relaxation time of the melanosome (0.5 - 1.0 usec), is in accordance with the theory of selective photothermolysis. Possible mechanisms of melanosomal photodisruption include development of sudden thermal gradients leading to cavitation or shock wave production.

Light and Laser Modalities in the Treatment of Cutaneous Sarcoidosis: A Systematic Review.

PubMed

Lima, Ana Luiza; Goetze, Steven; Illing, Tanja; Elsner, Peter

2018-04-27

Sarcoidosis is a systemic non-caseating granulomatous disease of unknown aetiology. Cutaneous manifestations are present in approximately 10-30% of the patients with the systemic form. Therapy is indicated in case of disabling symptoms, organ dysfunction or cosmetically distressing manifestation. Despite different therapeutic possibilities, cutaneous sarcoidosis remains exceptionally difficult to treat. Light and laser therapy may be a promising alternative. In this systematic review, we summarised the available treatments according to the literature concerning light and laser therapy for cutaneous sarcoidosis. Publications written in English and German, published between January 1990 and July 2016 in the database PubMed, MEDLINE, Embase, and Scopus were analysed. Light therapy with intense pulsed light, photodynamic therapy, and ultraviolet A light therapy, as well as laser therapy with pulsed dye laser, YAG laser, and Q-switched ruby laser were described. The results are based on individual case reports and small case series. Randomised controlled studies are lacking.

Vanadium-rich ruby and sapphire within Mogok Gemfield, Myanmar: implications for gem color and genesis

NASA Astrophysics Data System (ADS)

Zaw, Khin; Sutherland, Lin; Yui, Tzen-Fu; Meffre, Sebastien; Thu, Kyaw

2015-01-01

Rubies and sapphires are of both scientific and commercial interest. These gemstones are corundum colored by transition elements within the alumina crystal lattice: Cr3+ yields red in ruby and Fe2+, Fe3+, and Ti4+ ionic interactions color sapphires. A minor ion, V3+ induces slate to purple colors and color change in some sapphires, but its role in coloring rubies remains enigmatic. Trace element and oxygen isotope composition provide genetic signatures for natural corundum and assist geographic typing. Here, we show that V can dominate chromophore contents in Mogok ruby suites. This raises implications for their color quality, enhancement treatments, geographic origin, exploration and exploitation and their comparison with rubies elsewhere. Precise LA-ICP-MS analysis of ruby and sapphire from Mogok placer and in situ deposits reveal that V can exceed 5,000 ppm, giving V/Cr, V/Fe and V/Ti ratios up to 26, 78, and 97 respectively. Such values significantly exceed those found elsewhere suggesting a localized geological control on V-rich ruby distribution. Our results demonstrate that detailed geochemical studies of ruby suites reveal that V is a potential ruby tracer, encourage comparisons of V/Cr-variation between ruby suites and widen the scope for geographic typing and genesis of ruby. This will allow more precise comparison of Asian and other ruby fields and assist confirmation of Mogok sources for rubies in historical and contemporary gems and jewelry.

Expression of endogenous and foreign ribulose 1,5-bisphosphate carboxylase-oxygenase (RubisCO) genes in a RubisCO deletion mutant of Rhodobacter sphaeroides.

PubMed Central

Falcone, D L; Tabita, F R

1991-01-01

A Rhodobacter sphaeroides ribulose 1,5-bisphosphate carboxylase-oxygenase (RubisCO) deletion strain was constructed that was complemented by plasmids containing either the form I or form II CO2 fixation gene cluster. This strain was also complemented by genes encoding foreign RubisCO enzymes expressed from a Rhodospirillum rubrum RubisCO promoter. In R. sphaeroides, the R. rubrum promoter was regulated, resulting in variable levels of disparate RubisCO molecules under different growth conditions. Photosynthetic growth of the R. sphaeroides deletion strain complemented with cyanobacterial RubisCO revealed physiological properties reflective of the unique cellular environment of the cyanobacterial enzyme. The R. sphaeroides RubisCO deletion strain and R. rubrum promoter system may be used to assess the properties of mutagenized proteins in vivo, as well as provide a potential means to select for altered RubisCO molecules after random mutagenesis of entire genes or gene regions encoding RubisCO enzymes. Images PMID:1900508

Laser-assisted hair removal for facial hirsutism in women: A review of evidence.

PubMed

Lee, Chun-Man

2018-06-01

Poly cystic ovarian syndrome (PCOS) has been described as the common diagnosis for hirsutism in women. Facial hirsutism is by far the most distressing symptom of hyperandrogenism in women with PCOS. A statistically significant improvement in psychological well-being has been reported in patients with PCOS allocated for laser-assisted hair removal. The theory of selective photothermolysis has revolutionized laser hair removal in that it is effective and safe, when operated by sufficiently trained and experienced professionals. Long-pulsed ruby (694 nm), long-pulsed alexandrite (755 nm), diode (800-980 nm), and long-pulsed Nd:YAG (1064 nm) are commercially available laser devices for hair removal most widely studied. This article will introduce the fundamentals and mechanism of action of lasers in hair removal, in a contemporary literature review looking at medium to long term efficacy and safety profiles of various laser hair removal modalities most widely commercially available to date.

Laser techniques in high-pressure geophysics

NASA Technical Reports Server (NTRS)

Hemley, R. J.; Bell, P. M.; Mao, H. K.

1987-01-01

Laser techniques in conjunction with the diamond-anvil cell can be used to study high-pressure properties of materials important to a wide range of problems in earth and planetary science. Spontaneous Raman scattering of crystalline and amorphous solids at high pressure demonstrates that dramatic changes in structure and bonding occur on compression. High-pressure Brillouin scattering is sensitive to the pressure variations of single-crystal elastic moduli and acoustic velocities. Laser heating techniques with the diamond-anvil cell can be used to study phase transitions, including melting, under deep-earth conditions. Finally, laser-induced ruby fluorescence has been essential for the development of techniques for generating the maximum pressures now possible with the diamond-anvil cell, and currently provides a calibrated in situ measure of pressure well above 100 gigapascals.

Pulsed Holographic Nondestructive Testing On Aircraft

NASA Astrophysics Data System (ADS)

Fagot, Hubert; Smigielski, Paul; Albe, Felix; Arnaud, Jean-Louis

1983-06-01

An holographic camera composed of two ruby lasers was built at ISL. It provides double exposure holograms with an adjustable time interval ranging from few ns to infinity. Various aircraft structures were first tested at ISL in laboratory conditions: honeycomb panels, wings ... The industrial tests on a military aircraft in maintenance checking were performed in a hangar of the SNIAS at Saint-Nazaire: wings, trap-door of the rear landing gear, air-brake... Electromechanical shocks were used to make the structure vibrate and to allow a fast trigger of the lasers. This avoids disturbance due to ambiant noises and vibrations.

A function-based screen for seeking RubisCO active clones from metagenomes: novel enzymes influencing RubisCO activity.

PubMed

Böhnke, Stefanie; Perner, Mirjam

2015-03-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is a key enzyme of the Calvin cycle, which is responsible for most of Earth's primary production. Although research on RubisCO genes and enzymes in plants, cyanobacteria and bacteria has been ongoing for years, still little is understood about its regulation and activation in bacteria. Even more so, hardly any information exists about the function of metagenomic RubisCOs and the role of the enzymes encoded on the flanking DNA owing to the lack of available function-based screens for seeking active RubisCOs from the environment. Here we present the first solely activity-based approach for identifying RubisCO active fosmid clones from a metagenomic library. We constructed a metagenomic library from hydrothermal vent fluids and screened 1056 fosmid clones. Twelve clones exhibited RubisCO activity and the metagenomic fragments resembled genes from Thiomicrospira crunogena. One of these clones was further analyzed. It contained a 35.2 kb metagenomic insert carrying the RubisCO gene cluster and flanking DNA regions. Knockouts of twelve genes and two intergenic regions on this metagenomic fragment demonstrated that the RubisCO activity was significantly impaired and was attributed to deletions in genes encoding putative transcriptional regulators and those believed to be vital for RubisCO activation. Our new technique revealed a novel link between a poorly characterized gene and RubisCO activity. This screen opens the door to directly investigating RubisCO genes and respective enzymes from environmental samples.

Research in nonlinear optics

NASA Technical Reports Server (NTRS)

Yariv, A.

1972-01-01

A theoretical investigation revealed that a steady state mode-locked solution appropriate to ultrashort pulses is induced by Kerr liquids. An experimental investigation using a Q-switched ruby laser passively mode-locked by the insertion of a Kerr liquid verified the theory. Pulses of about 10 to the -11th power sec were generated when the relaxation time of the liquid was temperature tuned to approximately 10 to the -11th power sec.

Optimization strategies for a fluorescent dye with bimodal excitation spectra: application to semiautomated proteomics

NASA Astrophysics Data System (ADS)

Patton, Wayne F.; Berggren, Kiera N.; Lopez, Mary F.

2001-04-01

Facilities engaged in proteome analysis differ significantly in the degree that they implement automated systems for high-throughput protein characterization. Though automated workstation environments are becoming more routine in the biotechnology and pharmaceutical sectors of industry, university-based laboratories often perform these tasks manually, submitting protein spots excised from polyacrylamide gels to institutional core facilities for identification. For broad compatibility with imaging platforms, an optimized fluorescent dye developed for proteomics applications should be designed taking into account that laser scanners use visible light excitation and that charge-coupled device camera systems and gas discharge transilluminators rely upon UV excitation. The luminescent ruthenium metal complex, SYPRO Ruby protein gel stain, is compatible with a variety of excitation sources since it displays intense UV (280 nm) and visible (470 nm) absorption maxima. Localization is achieved by noncovalent, electrostatic and hydrophobic binding of dye to proteins, with signal being detected at 610 nm. Since proteins are not covalently modified by the dye, compatibility with downstream microchemical characterization techniques such as matrix-assisted laser desorption/ionization-mass spectrometry is assured. Protocols have been devised for optimizing fluorophore intensity. SYPRO Ruby dye outperforms alternatives such as silver staining in terms of quantitative capabilities, compatibility with mass spectrometry and ease of integration into automated work environments.

Underwater Test Diagnostics Using Explosively Excited Argon And Laser Light Photography Techniques

NASA Astrophysics Data System (ADS)

Wisotski, John

1990-01-01

This paper presents results of photographic methods employed in underwater tests used to study high-velocity fragment deceleration, deformation and fracture during the perforation of water-backed plates. These methods employed overlapping ultra-high and very high speed camera recordings using explosively excited argon and ruby-laser light sources that gave ample light to penetrate across a 2.3-meter (7.54-foot) diameter tank of water with enough intensity to photograph displacement-time histories of steel cubes with impact speeds of 1000 to 1500 m/s (3280 to 4920 ft/s) at camera framing rates of 250,000 and 17,000 fr/s, respectively.

Particle sizing in rocket motor studies utilizing hologram image processing

NASA Technical Reports Server (NTRS)

Netzer, David; Powers, John

1987-01-01

A technique of obtaining particle size information from holograms of combustion products is described. The holograms are obtained with a pulsed ruby laser through windows in a combustion chamber. The reconstruction is done with a krypton laser with the real image being viewed through a microscope. The particle size information is measured with a Quantimet 720 image processing system which can discriminate various features and perform measurements of the portions of interest in the image. Various problems that arise in the technique are discussed, especially those that are a consequence of the speckle due to the diffuse illumination used in the recording process.

RubisCO Gene Clusters Found in a Metagenome Microarray from Acid Mine Drainage

PubMed Central

Guo, Xue; Yin, Huaqun; Cong, Jing; Dai, Zhimin; Liang, Yili

2013-01-01

The enzyme responsible for carbon dioxide fixation in the Calvin cycle, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), is always detected as a phylogenetic marker to analyze the distribution and activity of autotrophic bacteria. However, such an approach provides no indication as to the significance of genomic content and organization. Horizontal transfers of RubisCO genes occurring in eubacteria and plastids may seriously affect the credibility of this approach. Here, we presented a new method to analyze the diversity and genomic content of RubisCO genes in acid mine drainage (AMD). A metagenome microarray containing 7,776 large-insertion fosmids was constructed to quickly screen genome fragments containing RubisCO form I large-subunit genes (cbbL). Forty-six cbbL-containing fosmids were detected, and six fosmids were fully sequenced. To evaluate the reliability of the metagenome microarray and understand the microbial community in AMD, the diversities of cbbL and the 16S rRNA gene were analyzed. Fosmid sequences revealed that the form I RubisCO gene cluster could be subdivided into form IA and IB RubisCO gene clusters in AMD, because of significant divergences in molecular phylogenetics and conservative genomic organization. Interestingly, the form I RubisCO gene cluster coexisted with the form II RubisCO gene cluster in one fosmid genomic fragment. Phylogenetic analyses revealed that horizontal transfers of RubisCO genes may occur widely in AMD, which makes the evolutionary history of RubisCO difficult to reconcile with organismal phylogeny. PMID:23335778

Ruby Splendor nectarine

USDA-ARS?s Scientific Manuscript database

The Agricultural Research Service hereby releases for propagation the new nectarine variety ‘Ruby Splendor,’ tested previously as Y426-227. ‘Ruby Splendor’ was first selected in 2001 among 70 seedlings from the planned hybridization of two unnamed nectarine selections. Fruit of ‘Ruby Splendor’ ripen...

The Ruby UCSC API: accessing the UCSC genome database using Ruby.

PubMed

Mishima, Hiroyuki; Aerts, Jan; Katayama, Toshiaki; Bonnal, Raoul J P; Yoshiura, Koh-ichiro

2012-09-21

The University of California, Santa Cruz (UCSC) genome database is among the most used sources of genomic annotation in human and other organisms. The database offers an excellent web-based graphical user interface (the UCSC genome browser) and several means for programmatic queries. A simple application programming interface (API) in a scripting language aimed at the biologist was however not yet available. Here, we present the Ruby UCSC API, a library to access the UCSC genome database using Ruby. The API is designed as a BioRuby plug-in and built on the ActiveRecord 3 framework for the object-relational mapping, making writing SQL statements unnecessary. The current version of the API supports databases of all organisms in the UCSC genome database including human, mammals, vertebrates, deuterostomes, insects, nematodes, and yeast.The API uses the bin index-if available-when querying for genomic intervals. The API also supports genomic sequence queries using locally downloaded *.2bit files that are not stored in the official MySQL database. The API is implemented in pure Ruby and is therefore available in different environments and with different Ruby interpreters (including JRuby). Assisted by the straightforward object-oriented design of Ruby and ActiveRecord, the Ruby UCSC API will facilitate biologists to query the UCSC genome database programmatically. The API is available through the RubyGem system. Source code and documentation are available at https://github.com/misshie/bioruby-ucsc-api/ under the Ruby license. Feedback and help is provided via the website at http://rubyucscapi.userecho.com/.

The Ruby UCSC API: accessing the UCSC genome database using Ruby

PubMed Central

2012-01-01

Background The University of California, Santa Cruz (UCSC) genome database is among the most used sources of genomic annotation in human and other organisms. The database offers an excellent web-based graphical user interface (the UCSC genome browser) and several means for programmatic queries. A simple application programming interface (API) in a scripting language aimed at the biologist was however not yet available. Here, we present the Ruby UCSC API, a library to access the UCSC genome database using Ruby. Results The API is designed as a BioRuby plug-in and built on the ActiveRecord 3 framework for the object-relational mapping, making writing SQL statements unnecessary. The current version of the API supports databases of all organisms in the UCSC genome database including human, mammals, vertebrates, deuterostomes, insects, nematodes, and yeast. The API uses the bin index—if available—when querying for genomic intervals. The API also supports genomic sequence queries using locally downloaded *.2bit files that are not stored in the official MySQL database. The API is implemented in pure Ruby and is therefore available in different environments and with different Ruby interpreters (including JRuby). Conclusions Assisted by the straightforward object-oriented design of Ruby and ActiveRecord, the Ruby UCSC API will facilitate biologists to query the UCSC genome database programmatically. The API is available through the RubyGem system. Source code and documentation are available at https://github.com/misshie/bioruby-ucsc-api/ under the Ruby license. Feedback and help is provided via the website at http://rubyucscapi.userecho.com/. PMID:22994508

Optical Spectroscopy Of Materials With Restricted Dimensions

NASA Astrophysics Data System (ADS)

Yen, William M...

1989-05-01

In this paper, we discuss various experimental advantages which are gained by using samples which have special dimensions and/or geometries. We limit our discussion here to the cylindrical geometry appropriate for optical fibers which are employed for various optoelectronic applications. We present results of laser spectroscopic studies of nominally pure and activated single crystal and glass fibers to illustrate some of these advantages. For example, we have succeeded for the first time in obtaining the dependence of the ruby R-lines and of the Raman spectra of sapphire on tensile stress. We further discuss a novel laser spectroscopic method, Dilution Narrowed Laser Spectroscopy or DNLS; we demonstrate this form of spectroscopy on single mode glass fibers activated with rare earth ions and consider the possibilities inherent in this technique.

Method using laser irradiation for the production of atomically clean crystalline silicon and germanium surfaces

DOEpatents

Ownby, Gary W.; White, Clark W.; Zehner, David M.

1981-01-01

This invention relates to a new method for removing surface impurities from crystalline silicon or germanium articles, such as off-the-shelf p- or n-type wafers to be doped for use as junction devices. The principal contaminants on such wafers are oxygen and carbon. The new method comprises laser-irradiating the contaminated surface in a non-reactive atmosphere, using one or more of Q-switched laser pulses whose parameters are selected to effect melting of the surface without substantial vaporization thereof. In a typical application, a plurality of pulses is used to convert a surface region of an off-the-shelf silicon wafer to an automatically clean region. This can be accomplished in a system at a pressure below 10.sup.-8 Torr, using Q-switched ruby-laser pulses having an energy density in the range of from about 60 to 190 MW/cm.sup.2.

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy

NASA Astrophysics Data System (ADS)

Kertzscher, Gustavo; Beddar, Sam

2016-11-01

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from  >5% to  <1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was  <3% as long as the source distance from the scintillator was  <7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by  >5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we recommend avoiding ruby crystals that exhibit significant time-dependent luminescence.

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy

PubMed Central

Kertzscher, Gustavo; Beddar, Sam

2016-01-01

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from > 5% to < 1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was < 3% as long as the source distance from the scintillator was < 7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by > 5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we recommend avoiding ruby crystals that exhibit significant time-dependent luminescence. PMID:27740947

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy.

PubMed

Kertzscher, Gustavo; Beddar, Sam

2016-11-07

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from  >5% to  <1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was  <3% as long as the source distance from the scintillator was  <7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by  >5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we recommend avoiding ruby crystals that exhibit significant time-dependent luminescence.

Metal silicides with energetic pulses

NASA Astrophysics Data System (ADS)

D'Anna, E.; Leggieri, G.; Luches, A.; Majni, G.; Nava, F.; Ottaviani, G.

1986-07-01

Samples formed of a thin metal film deposited on silicon single crystal were annealed with electron and laser (ruby and excimer) pulses over a wide range of fluences. From a comparison of the experimental results with the temperature profiles of the irradiated samples, it turns out that suicide formation starts when the metal/silicon interface reaches the lowest eutectic temperature of the binary metal/silicon system. The growth rate of reacted layers is of the order of 1 m/s.

77 FR 21805 - Notice of Intent To Collect Fees on Public Land in Mesa County, CO (Ruby-Horsethief Stretch of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-11

... Intent To Collect Fees on Public Land in Mesa County, CO (Ruby-Horsethief Stretch of the Colorado River... fees for overnight camping on the Ruby-Horsethief stretch of the Colorado River, between Loma, Colorado, and the Colorado State Line, Mesa County, Colorado. The Ruby-Horsethief stretch of the Colorado River...

A short history of RubisCO: the rise and fall (?) of Nature's predominant CO2 fixing enzyme.

PubMed

Erb, Tobias J; Zarzycki, Jan

2018-02-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is arguably one of the most abundant proteins in the biosphere and a key enzyme in the global carbon cycle. Although RubisCO has been intensively studied, its evolutionary origins and rise as Nature's most dominant carbon dioxide (CO 2 )-fixing enzyme still remain in the dark. In this review we will bring together biochemical, structural, physiological, microbiological, as well as phylogenetic data to speculate on the evolutionary roots of the CO 2 -fixation reaction of RubisCO, the emergence of RubisCO-based autotrophic CO 2 -fixation in the context of the Calvin-Benson-Bassham cycle, and the further evolution of RubisCO into the 'RubisCOsome', a complex of various proteins assembling and interacting with the enzyme to improve its operational capacity (functionality) under different biological and environmental conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Stimulated low-frequency Raman scattering in plant virus suspensions

NASA Astrophysics Data System (ADS)

Donchenko, E. K.; Karpova, O. V.; Kudryavtseva, A. D.; Pershin, S. M.; Savichev, V. I.; Strokov, M. A.; Tcherniega, N. V.; Zemskov, K. I.

2017-11-01

The study deals with laser pulse interaction with plant viruses: we investigated tobacco mosaic virus (TMV) and two types of potato viruses (PVX and PVA) in Tris-HCl pH7.5 buffer and in water. We used 20 ns ruby laser pulses for excitation. We employed Fabry-Pérot interferometers to record spectra of the light passing through the sample and reflected from it. For TMV and PVX in Tris-HCl pH7.5 buffer, same as for PVA in water, we observed additional spectral lines corresponding to the stimulated low-frequency Raman scattering (SLFRS). We believe we were the first to measure SLFRS frequency shifts, conversion efficiency and threshold. High conversion efficiency of the scattered light is evidence of laser pulses efficiently exciting gigahertz vibrations in viruses. SLFRS can be used to identify and affect biological nanoparticles.

Photographic laboratory studies of explosions.

NASA Technical Reports Server (NTRS)

Kamel, M. M.; Oppenheim, A. K.

1973-01-01

Description of a series of cinematographic studies of explosions made with a high-speed rotating-mirror streak camera which uses a high-frequency stroboscopic ruby laser as the light source. The results obtained mainly concern explosions initiated by focused laser irradiation from a pulsed neodymium laser in a detonating gas consisting essentially of an equimolar mixture of acetylene and oxygen at an initial pressure of 100 torr at room temperature. Among the most significant observations were observations of a spherical blast wave preceded by a Chapman-Jouguet detonation which is stabilized immediately after initiation, the merging of a spherical flame with a shock front of the blast wave in which the flame is propagating, the division of a spherical detonation front into a shock wave and flame, and the generation of shock waves by a network of spherical flames.

A description of the lunar ranging station at McDonald Observatory.

NASA Technical Reports Server (NTRS)

Silverberg, E. C.; Currie, D. G.

1972-01-01

The equipment of this station which has been in operation since the deployment of the first corner reflector by the Apollo 11 astronauts. The McDonald 2.7-m telescope is used for both transmission and reception of pulsed ruby laser light during three 45-minute daily laser runs about three weeks in a month. The present laser pulse width, timing system, calibration procedures, and signal levels are designed to achieve ranging with an accuracy to 1 nanosecond. The data rates obtained since September, 1970, are consistent with the scientific commitments of the lunar ranging program. Most of the over 200 acquisitions obtained have an accuracy to better than plus or minus 30 cm. Details of the telescope matching optics, guiding and timing equipment, and calibration procedures are discussed. Representative lunar range data are included.

Diversity and expression of different forms of RubisCO genes in polluted groundwater under different redox conditions.

PubMed

Alfreider, Albin; Schirmer, Mario; Vogt, Carsten

2012-03-01

Groundwater polluted with methyl-tert-butyl ether (MTBE) and ammonium was investigated for chemolithoautotrophic CO(2) fixation capabilities based on detailed analyses of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large subunit genes. Samples retrieved from a groundwater conditioning unit, characterized by different redox conditions, were examined for the presence of form IA, form IC (cbbL) and form II (cbbM) RubisCO genes and transcripts obtained from DNA- and RNA-extracts. Form IA RubisCO sequences, which revealed a complex and distinct variety in different sampling stations, were expressed in the original groundwater and in samples amended with oxygen, but not in the aquifer groundwater enriched with nitrate. Form IC RubisCO genes were exclusively detected in groundwater supplied with oxygen and sequences were affiliated with cbbL genes in nitrifying bacteria. cbbM genes were not expressed in the oxygen-amended groundwater, probably due to the low CO(2) /O(2) substrate specificity of this enzyme. Most form II RubisCO transcripts were affiliated with RubisCO genes of denitrifiers, which are important residents in the groundwater supplied with nitrate. The distinct distribution pattern and diversity of RubisCO genes and transcripts obtained in this study suggest that the induction of different RubisCO enzymes is highly regulated and closely linked to the actual environmental conditions. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

The Application of Particle Image Velocimetry (PIV) in a Short Duration Transonic Annular Turbine Cascade

DTIC Science & Technology

1991-03-01

series of experiments have been performed to create a plane of light with a ruby pulse laser and photograph demonstrate the application of Particle...using a SIT 1. INTRODUCTION (silicon intensified tube) camera developed 6y Wernet at NASA Lewis (1989). Optical diagnostics have now become essential...lens for the PIV tests. Fig 2 shows a photograph of the As a result of this the potential sensitivity of the technique has nozzle guide vanes

Survey of Beamed Energy Propulsion Concepts by the MSFC Space Environmental Effects Team

NASA Technical Reports Server (NTRS)

Gray, P. A.; Nehls, M. K.; Edwards, D. L.; Carruth, M. R., Jr.; Munafo, Paul M. (Technical Monitor)

2002-01-01

This will be a survey paper of work that was performed by the Space Environmental Effects Team at NASA's Marshall Space Flight Center in the area of laser energy propulsion concepts. Two types of laser energy propulsion techniques were investigated. The first was ablative propulsion, which used a pulsed ruby laser impacting on single layer coatings and films. The purpose of this investigation was to determine the laser power density that produced an optimum coupling coefficient for each type of material tested. A commercial off-the-shelf multi-layer film was also investigated for possible applications in ablative micro-thrusters, and its optimum coupling coefficient was determined. The second type of study measured the purely photonic force provided by a 300W CW YAG laser. In initial studies, the photon force resulting from the momentum of incident photons was measured directly using a vacuum compatible microbalance and these results were compared to theory. Follow-on work used the same CW laser to excite a stable optical cavity for the purpose of amplifying the available force from incident photons.

Depigmentation therapy in vitiligo universalis with topical 4-methoxyphenol and the Q-switched ruby laser.

PubMed

Njoo, M D; Vodegel, R M; Westerhof, W

2000-05-01

Monobenzylether of hydroquinone is used worldwide to remove residual pigment in patients with vitiligo universalis. Because of the side effects reported with this drug, the use of monobenzylether of hydroquinone has been restricted in The Netherlands. Our purpose was to evaluate the long-term effectiveness and safety of a combination therapy consisting of topical 4-methoxyphenol (4-MP) cream and Q-switched ruby (QSR) laser in 16 patients with vitiligo universalis. In a retrospective study, patient record forms were evaluated. Data were collected regarding history as well as physical and histologic examination. The patients came to the institute for a follow-up visit after a treatment-free period of 2 to 36 months. Thirteen patients received both therapies. Three patients only used the cream. None of the areas was treated by the cream and QSR laser at the same time. In 11 of the 16 patients (69%; 95% confidence interval [CI], 41%-89%) total depigmentation was achieved using the 4-MP cream. Onset of depigmentation was between 4 and 12 months. Four of the 5 patients who did not respond to the 4-MP cream had successful depigmentation with the QSR laser. Mild burning or itching was reported with the cream in 4 cases (25%). Of the 11 patients who responded to the 4-MP cream, 4 had recurrence of pigmentation (relapse rate of 36%; 95% CI, 11%-69%) after a treatment-free period of 2 to 36 months. In 9 of the 13 patients (69%; 95% CI, 39%-91%) total depigmentation was achieved after QSR laser therapy. Onset of depigmentation was between 7 and 14 days after the treatment. Three of the 4 unresponsive patients showed total depigmentation after application of the 4-MP cream. No side effects were observed. Of the 9 patients who responded to QSR laser therapy, 4 had recurrence of pigmentation (relapse rate of 44%; 95% CI, 14%-79%) after a treatment-free period of 2 to 18 months. These patients had a negative Koebner phenomenon. Depigmentation therapy using a 4-MP cream and/or QSR laser therapy is an effective and safe method to remove disfiguring residual pigment in patients with vitiligo universalis. Patients should be warned that repigmentation may occur, even after total depigmentation has been achieved.

History of lasers.

PubMed

Gross, Andreas J; Herrmann, Thomas R W

2007-06-01

The developments of laser technology from the cradle of modern physics in 1900 by Planck to its latest medical boundaries is an exciting example of how basic physics finds its way into clinical practice. This article merits the protagonists and their contribution to the steps in this development. The competition between the different research groups finally led to the award of the Nobel Prize to Townes, Basov and Prokhorov in 1964 for the scientific basis on quantum electronics, which led to the construction of oscillators and amplifiers based on the laser-maser principle. Forty-three years after Einstein's first theories Maiman introduced the first ruby laser for commercial use. This marked the key step for the laser application and pioneered fruitful cooperations between basic and clinical science. The pioneers of lasers in clinical urology were Parsons in 1966 with studies in canine bladders and Mulvany 1968 with experiments in calculi fragmentation. The central technological component for the triumphal procession of lasers in urology is the endoscope. Therefore lasers are currently widely used, being the tool of choice in some areas, such as endoscopical lithotriptic stone treatment or endoluminal organ-preserving tumor ablation. Furthermore they show promising treatment alternatives for the treatment of benign prostate hyperplasia.

UV lidar measurements of the stratospheric aerosol layer and comparison with other optical data

NASA Technical Reports Server (NTRS)

Uchino, O.

1985-01-01

After the violent volcanic eruptions of El Chichon in Mexico (17.33 deg. N, 93.20 deg. W) in late March and early April 1982, enhanced stratospheric aerosols have been monitored by ruby (lasing wavelength lambda=694.3 nm) or Nd:YAG lidars (lambda=1064 or 532 nm). By these lidars, visible or near-infrared optical informations of stratospheric aerosols and their space-time variations can be obtained. It is usually difficult to measure the background level of stratospheric aerosols by an ultraviolet (UV) lidar, since Rayleigh scattering prevails over Mie scattering in the stratosphere. However, after the large volcanic eruptions, UV lidar measurements of stratospheric aerosols are possible. In order to obtain UV optical properties of stratospheric aerosols, measurements have been made at Fukuoka (33.65 deg. N, 130.35 deg. E) by a p-terphenyl dye laser at a wavelength of 340.5 nm. Observational results during October 1982, through May 1983, are shown and are compared with the results obtained by a ruby lidar at Tsukuba (36.05 deg. N, 140.13 deg. E).

Are Einstein's transition probabilities for spontaneous emission constant in plasmas?

NASA Technical Reports Server (NTRS)

Griem, H. R.; Huang, Y. W.; Wang, J.-S.; Moreno, J. C.

1991-01-01

An investigation is conducted with a ruby laser to experimentally confirm the quenching of spontaneous emission coefficients and propose a mechanism for the phenomenon. Results of previous experiments are examined to determine the consistency and validity of interpretations of the spontaneous emissions. For the C IV 3s-3p and 2s-3p transitions, the line-intensity ratios are found to be dependent on the separation of the laser from the target. Density gradients and Stark broadening are proposed to interpret the results in a way that does not invalidate the Einstein A values. The interpretation is extended to C III and N V, both of which demonstrate similar changes in A values in previous experiments. The apparent quenching of Ar II by photon collisions is explained by Rabi oscillations and power broadening in the argon-ion laser cavity. It is concluded that the changes in A values cannot result from dense plasma effects.

Optical SETI: Moving Toward the Light

NASA Astrophysics Data System (ADS)

Ross, Monte; Kingsley, Stuart

In 2009, the SETI community celebrated a half-century since the classic paper by Giuseppe Cocconi and Philip Morrison in Nature, that described how we might look for radio transmissions from extraterrestrial civilizations. It is propitious that the publication of this book in 2010 marks both the 50th anniversary of Frank Drake's Project Ozma, and the 50th anniversary of the demonstration of the first (ruby) laser by Theodore Maiman. The invention of the laser was based on the maser work by Arthur Schawlow and Charles Townes and the simultaneous work of Gordon Gould. During this first half-century of SETI, most observing has been carried out in the radio spectrum, during which time there have been enormous developments in laser technology. Only during the past two decades has the optical approach to SETI, otherwise known as optical SETI, been given the attention it deserves.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertzscher, G; Beddar, S

Purpose: To study the promising potential of inorganic scintillator detectors (ISDs) and investigate various unwanted luminescence properties which may compromise their accuracy. Methods: The ISDs were comprised of a ruby crystal coupled to a polymethyl methacrylate (PMMA) fiber-optic cable and a charged coupled device camera. A new type of ISD was manufactured and included a long-pass filter that was sandwiched between the crystal and the fiber-optic cable. The purpose of the filter was to suppress the Cerenkov and fluorescence background light induced in the PMMA (the stem signal) from striking the ruby crystal, generating unwanted ruby excitation. A variety ofmore » experiments were performed to characterize the ruby based ISDs. The relative contribution of the induced ruby signal and the stem signal were quantified while exposing the detector and a bare fiber-optic cable to a high dose rate (HDR) brachytherapy (BT) source, respectively. The unwanted ruby excitation was quantified while irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and a comparison to other commonly used organic scintillator detectors (BCF-12, BCF-60). Results: When the BT source dwelled 0.5 cm away from the fiber-optic cable, the unwanted ruby excitation amounted to >5% of the total signal if the source-distance from the scintillator was >7 cm. However, the unwanted excitation was suppressed to <1% if the ISD incorporated an optic filter. The stem signal was suppressed with a 20 nm band-pass filter and was <3% as long as the source-distance was <7 cm. The ruby based ISDs generated signal up to 20(40) times that of BCF-12(BCF-60). Conclusion: The study presents solutions to unwanted luminescence properties of ruby based ISDs for HDR BT. An optic filter should be sandwiched between the scintillator volume and the fiber-optic cable to prevent the stem signal to excite the ruby crystal.« less

mRuby, a Bright Monomeric Red Fluorescent Protein for Labeling of Subcellular Structures

PubMed Central

Kredel, Simone; Oswald, Franz; Nienhaus, Karin; Deuschle, Karen; Röcker, Carlheinz; Wolff, Michael; Heilker, Ralf; Nienhaus, G. Ulrich; Wiedenmann, Jörg

2009-01-01

A monomeric variant of the red fluorescent protein eqFP611, mRuby, is described. With excitation and emission maxima at 558 nm and 605 nm, respectively, and a large Stokes shift of 47 nm, mRuby appears particularly useful for imaging applications. The protein shows an exceptional resistance to denaturation at pH extremes. Moreover, mRuby is about ten-fold brighter compared to EGFP when being targeted to the endoplasmic reticulum. The engineering process of eqFP611 revealed that the C-terminal tail of the protein acts as a natural peroxisomal targeting signal (PTS). Using an mRuby variant carrying the eqFP611-PTS, we discovered that ordered inheritance of peroxisomes is widespread during mitosis of different mammalian cell types. The ordered partitioning is realized by the formation of peroxisome clusters around the poles of the mitotic spindle and ensures that equal numbers of the organelle are inherited by the daughter cells. The unique spectral properties make mRuby the marker of choice for a multitude of cell biological applications. Moreover, the use of mRuby has allowed novel insights in the biology of organelles responsible for severe human diseases. PMID:19194514

Enhancing Natural Attenuation Through Bioaugmentation with Aerobic Bacteria that Degrade Cis-1,2-Dichloroethene

DTIC Science & Technology

2008-04-01

have genes that encode enzymes of the Calvin-Benson cycle, specifically for the key enzyme ribulose 1,5-bisphosphate carboxylase ( RubisCO ) which...Closer examination of the gene sequence annotated as RubisCO revealed that is more closely related to RubisCO -like (Hanson and Tabita 2001) proteins than...to RubisCO and is likely not involved in the Calvin-Benson cycle. Ionic Strength A recent paper (Müller, Walter et al. 2006) explored the

RubisCO selection using the vigorously aerobic and metabolically versatile bacterium Ralstonia eutropha.

PubMed

Satagopan, Sriram; Tabita, F Robert

2016-08-01

Recapturing atmospheric CO2 is key to reducing global warming and increasing biological carbon availability. Ralstonia eutropha is a biotechnologically useful aerobic bacterium that uses the Calvin-Benson-Bassham (CBB) cycle and the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) for CO2 utilization, suggesting that it may be a useful host to bioselect RubisCO molecules with improved CO2 -capture capabilities. A host strain of R. eutropha was constructed for this purpose after deleting endogenous genes encoding two related RubisCOs. This strain could be complemented for CO2 -dependent growth by introducing native or heterologous RubisCO genes. Mutagenesis and suppressor selection identified amino acid substitutions in a hydrophobic region that specifically influences RubisCO's interaction with its substrates, particularly O2 , which competes with CO2 at the active site. Unlike most RubisCOs, the R. eutropha enzyme has evolved to retain optimal CO2 -fixation rates in a fast-growing host, despite the presence of high levels of competing O2 . Yet its structure-function properties resemble those of several commonly found RubisCOs, including the higher plant enzymes, allowing strategies to engineer analogous enzymes. Because R. eutropha can be cultured rapidly under harsh environmental conditions (e.g., with toxic industrial flue gas), in the presence of near saturation levels of oxygen, artificial selection and directed evolution studies in this organism could potentially impact efforts toward improving RubisCO-dependent biological CO2 utilization in aerobic environments. d-ribulose 1,5-bisphosphate carboxylase/oxygenase, EC 4.1.1.39; phosphoribulokinase, EC 2.7.1.19. © 2016 Federation of European Biochemical Societies.

Self-induced laser line sweeping and self-pulsing in double-clad fiber lasers in Fabry-Perot and unidirectional ring cavities

NASA Astrophysics Data System (ADS)

Peterka, Pavel; Navrátil, Petr; Dussardier, Bernard; Slavík, Radan; Honzátko, Pavel; Kubecek, Václav

2012-06-01

Rare-earth doped fiber lasers are subject to instabilities and various self-pulsed regimes that can lead to catastrophic damage of their components. An interesting self-pulsing regime accompanied with laser wavelength drift with time is the so called self-induced laser line sweeping (SLLS). Despite the early observations of the SLLS in solid-state ruby lasers, in fiber lasers it was first time mentioned in literature only in 2009 where such a laser wavelength drift with time was observed in a relatively broad range of about 1076 -1084 nm in ring ytterbium-doped fiber laser (YDFL). The main characteristic of the SLLS is the scanning of the laser wavelength from shorter to longer wavelength, spanning over large interval of several nanometers, and instantaneous bounce backward. The period of this sweeping is usually quite long, of the order of seconds. This spectacular effect was attributed to spatial-hole burning caused by standing-wave in the laser cavity. In this paper we present experimental investigation of the SLLS in YDFLs in Fabry-Perot cavity and ring cavities. The SLLS was observed also in erbium-doped fiber laser around 1560 nm. We present for the first time observation of the laser wavelength sweep in reverse direction, i.e., from longer towards shorter wavelengths. It was observed in YDFL around 1080 nm.

Effects of pressure characteristics on transfection efficiency in laser-induced stress wave-mediated gene delivery

NASA Astrophysics Data System (ADS)

Ando, Takahiro; Sato, Shunichi; Ashida, Hiroshi; Obara, Minoru

2013-07-01

Laser-induced stress waves (LISWs) generated by irradiating a light-absorbing medium with a pulsed laser can transiently increase the permeability of cell membranes for gene delivery. In this study, we investigated the effects of pressure characteristics of LISWs upon gene transfection efficiency using lasers with different pulse durations: a 6-ns pulsed Nd:YAG laser and 20-ns and 200-µs pulsed ruby lasers. LISWs were generated by irradiating a black rubber disk, on which a transparent plastic sheet was adhered for confinement of the laser-produced plasma. Rat dorsal skin was injected with plasmid DNA coding for luciferase, to which LISWs were applied. With nanosecond laser pulses, transfection efficiency increased linearly with increasing positive peak pressure in the range of 35 to 145 MPa, the corresponding impulse ranging from 10 to 40 Paṡs. With 200-µs laser pulses, on the other hand, efficient gene expression was observed by the application of LISWs even with a 10-fold-lower peak pressure (˜5 MPa), the corresponding impulse being as large as 430 Paṡs. These results indicate that even at low peak pressures, efficient transfection can be achieved by extending the pressure duration and hence by increasing the impulse of LISWs, while the averaged expression efficiencies were relatively low.

Improving brightness and photostability of green and red fluorescent proteins for live cell imaging and FRET reporting.

PubMed

Bajar, Bryce T; Wang, Emily S; Lam, Amy J; Kim, Bongjae B; Jacobs, Conor L; Howe, Elizabeth S; Davidson, Michael W; Lin, Michael Z; Chu, Jun

2016-02-16

Many genetically encoded biosensors use Förster resonance energy transfer (FRET) to dynamically report biomolecular activities. While pairs of cyan and yellow fluorescent proteins (FPs) are most commonly used as FRET partner fluorophores, respectively, green and red FPs offer distinct advantages for FRET, such as greater spectral separation, less phototoxicity, and lower autofluorescence. We previously developed the green-red FRET pair Clover and mRuby2, which improves responsiveness in intramolecular FRET reporters with different designs. Here we report the engineering of brighter and more photostable variants, mClover3 and mRuby3. mClover3 improves photostability by 60% and mRuby3 by 200% over the previous generation of fluorophores. Notably, mRuby3 is also 35% brighter than mRuby2, making it both the brightest and most photostable monomeric red FP yet characterized. Furthermore, we developed a standardized methodology for assessing FP performance in mammalian cells as stand-alone markers and as FRET partners. We found that mClover3 or mRuby3 expression in mammalian cells provides the highest fluorescence signals of all jellyfish GFP or coral RFP derivatives, respectively. Finally, using mClover3 and mRuby3, we engineered an improved version of the CaMKIIα reporter Camuiα with a larger response amplitude.

Stimulated low-frequency Raman scattering in aqueous suspension of nanoparticles

NASA Astrophysics Data System (ADS)

Averyushkin, Anatolii S.; Baranov, Anatoly N.; Bulychev, Nikolay A.; Kazaryan, Mishik A.; Kudryavtseva, Anna D.; Shevchenko, Mikhail A.; Strokov, Maxim A.; Tcherniega, Nikolay V.; Zemskov, Konstantin I.

2018-04-01

The low-frequency acoustic mode in nanoparticles of different nature in aqueous suspension has been studied by stimulated low-frequency Raman scattering (SLFRS). Nanoparticles investigated (CuO, Ag, Au, ZnS) had different dimensions and different vibrational properties. Synthesis of cupric oxide nanoparticles in acoustoplasma discharge is described in details. SLFRS has been excited by nanosecond pulses of ruby laser. Spectra of the scattered light had been registered with the help of Fabry-Perot interferometer. SLFRS conversion efficiency, threshold and frequency shift of the scattered light are measured.

Ion beam analysis of rubies and their simulants

NASA Astrophysics Data System (ADS)

Juncomma, U.; Intarasiri, S.; Bootkul, D.; Tippawan, U.

2014-07-01

Ion beam analysis (IBA) is a set of well known powerful analytical techniques which use energetic particle beam as a probe. Among them, two techniques are suitable for gemological analysis, i.e., Particle Induced X-rays Emission (PIXE) and Ionoluminescence (IL). We combine these two techniques for the investigations of rubies and their simulants. The main objective is to find a reference fingerprint of these gemstones. The data are collected from several natural rubies, synthetic rubies, red spinels, almandine garnets and rubellite which very much resemble and are difficult to distinguish with the gemologist loupe. From our measurements, due to their different crystal structures and compositions, can be clearly distinguished by the IL and PIXE techniques. The results show that the PIXE spectra consist of a few dominant lines of the host matrix elements of each gemstone and some weaker lines due to trace elements of transition metals. PIXE can easily differentiate rubies from other stones by evaluating their chemical compositions. It is noticed that synthetic rubies generally contain fewer impurities, lower iron and higher chromium than the natural ones. Moreover, the IL spectrum of ruby is unique and different from those of others stones. The typical spectrum of ruby is centered at 694 nm, with small sidebands that can be ascribed to a Cr3+ emission spectrum which is dominated by an R-line at the extreme red end of the visible part of the electromagnetic spectrum. Although the spectrum of synthetic ruby is centered at the same wavelength, the peak is stronger due to higher concentration of Cr and lower concentration of Fe than for natural rubies. For spinel, the IL spectrum shows strong deformation where the R-line is split due to the presence of MgO. For rubellite, the peak center is shifted to 692 nm which might be caused by the replacement of Mn3+ at the Al3+ site of the host structure. It is noticed that almandine garnet is not luminescent due to the idiochromatic nature of the stone.

Marble-hosted ruby deposits of the Morogoro Region, Tanzania

NASA Astrophysics Data System (ADS)

Balmer, Walter A.; Hauzenberger, Christoph A.; Fritz, Harald; Sutthirat, Chakkaphan

2017-10-01

The ruby deposits of the Uluguru and Mahenge Mts, Morogoro Region, are related to marbles which represent the cover sequence of the Eastern Granulites in Tanzania. In both localities the cover sequences define a tectonic unit which is present as a nappe structure thrusted onto the gneissic basement in a north-western direction. Based on structural geological observations the ruby deposits are bound to mica-rich boudins in fold hinges where fluids interacted with the marble-host rock in zones of higher permeability. Petrographic observations revealed that the Uluguru Mts deposits occur within calcite-dominated marbles whereas deposits in the Mahenge Mts are found in dolomite-dominated marbles. The mineral assemblage describing the marble-hosted ruby deposit in the Uluguru Mts is characterised by corundum-dolomite-phlogopite ± spinel, calcite, pargasite, scapolite, plagioclase, margarite, chlorite, tourmaline whereas the assemblage corundum-calcite-plagioclase-phlogopite ± dolomite, pargasite, sapphirine, titanite, tourmaline is present in samples from the Mahenge Mts. Although slightly different in mineral assemblage it was possible to draw a similar ruby formation history for both localities. Two ruby forming events were distinguished by textural differences, which could also be modeled by thermodynamic T-XCO2 calculations using non-ideal mixing models of essential minerals. A first formation of ruby appears to have taken place during the prograde path (M1) either by the breakdown of diaspore which was present in the original sedimentary precursor rock or by the breakdown of margarite to corundum and plagioclase. The conditions for M1 metamorphism was estimated at ∼750 °C at 10 kbar, which represents granulite facies conditions. A change in fluid composition towards a CO2 dominated fluid triggered a second ruby generation to form. Subsequently, the examined units underwent a late greenschist facies overprint. In the framework of the East African Orogen we assume that the prograde ruby formation occurred at the commonly observed metamorphic event around 620 Ma. At the peak or during beginning of retrogression the fluid composition changed triggering a second ruby generation. The late stage greenschist facies overprint could have occurred at the waning stage of this metamorphic episode which is in the range of ∼580 Ma.

Industrial lasers in Japan

NASA Astrophysics Data System (ADS)

Karube, Norio

1991-03-01

I am to report on some aspects of industrial lasers in Japan. Mostly centering on the market. In Japan, the history of laser developnent is rather profound. And long. Ever since the first invention of the laser in this country in 1960. This is partly because of the fact that in Japan the spectroscopic studies of the ruby was very popular in the late 1950's. Ever since niost of the work has been done in the research laboratories of the industry, not in the universities or not in the governmental laboratories. And since that time our first activity was mainly centering on the basic research, but after that time we have the evolution of the technology. One of the features in Japan is that the activity of developement and research of laser technology from the very basic phase up to the present commercialization has been done by the same group of people, including ine. We had a national project which ended about six years ago which was sponsored by MITI. MITI is Ministry of International Trade and Industry in Japan. And because of this national project, the effect of this project had a very enlightening effect in Japan. And after that our Japanese laser market became very flourishing.

Optical hair removal.

PubMed

Ort, R J; Anderson, R R

1999-06-01

Traditional methods of hair removal have proven unsatisfactory for many individuals with excessive or unwanted hair. In the last few years, several lasers and xenon flashlamps have been developed that promise to fulfill the need for a practical, safe, and long-lasting method of hair removal. Aggressive marketing of these has contributed to their popularity among patients and physicians. However, significant controversy and confusion surrounds this field. This article provides a detailed explanation of the scientific underpinnings for optical hair removal and explores the advantages and disadvantages of the various devices currently available (Nd:YAG, ruby, alexandrite, diode lasers, and xenon flashlamp). Treatment and safety guidelines are provided to assist the practitioner in the use of these devices. Although the field of optical hair removal is still in its infancy, initial reports of long-term efficacy are encouraging.

Dual photon effects in nitrogen dioxide photolysis

NASA Technical Reports Server (NTRS)

Hakala, D.; Harteck, P.; Reeves, R. R.

1974-01-01

A previous study demonstrated two-photon consecutive absorption as being the most probable mechanism for the photodissociation of NO2 using a pulsed ruby laser at 6943 A. Additional data discussed here confirmed this and also examined an associated phenomenon, that of multiphoton induced fluorescence. The dissociation of NO2 by ON-O bond cleavage requires 3.4 eV, while the laser energy corresponds to 1.785 eV. The pooling of the energy of two photons would give more than enough energy to dissociate the NO2 into NO + O. Several mechanisms including (1) simultaneous absorption of two photons; (2) reaction of two singly excited NO2; (3) reaction of a singly excited NO2 with a ground state NO2; and (4) consecutive absorption of two photons were examined.

Maria Rubies I Garrofe (1932-1993)

ERIC Educational Resources Information Center

Baste, Carme Amoros

2004-01-01

This article profiles educator Maria Rubies I Garrofe. Rubies was a woman committed to education and the reconstruction of her country, Spain, equipped solely with the force of her convictions and her faith in dialogue. It is difficult to separate her personal commitment from her educational, social and political commitment. From the very outset…

Spin-lattice relaxation and the calculation of gain, pump power, and noise temperature in ruby

NASA Technical Reports Server (NTRS)

Lyons, J. R.

1989-01-01

The use of a quantitative analysis of the dominant source of relaxation in ruby spin systems to make predictions of key maser amplifier parameters is described. The spin-lattice Hamiltonian which describes the interaction of the electron spins with the thermal vibrations of the surrounding lattice is obtained from the literature. Taking into account the vibrational anisotropy of ruby, Fermi's rule is used to calculate the spin transition rates between the maser energy levels. The spin population rate equations are solved for the spin transition relaxation times, and a comparison with previous calculations is made. Predictions of ruby gain, inversion ratio, and noise temperature as a function of physical temperature are made for 8.4-GHz and 32-GHz maser pumping schemes. The theory predicts that ruby oriented at 90 deg will have approximately 50 percent higher gain in dB and slightly lower noise temperature than a 54.7-deg ruby at 32 GHz (assuming pump saturation). A specific calculation relating pump power to inversion ratio is given for a single channel of the 32-GHz reflected wave maser.

Aesthetic value improvement of the ruby stone using heat treatment and its synergetic surface study

NASA Astrophysics Data System (ADS)

Sahoo, Rakesh K.; Mohapatra, Birendra K.; Singh, Saroj K.; Mishra, Barada K.

2015-02-01

The surface behavior of the natural ruby stones before and after heat treatment with metal oxide additives like: zinc oxide (ZnO) and lead oxide (PbO) have been studied. The surface appearance of the ruby stones processed with the metal oxides changed whereas the bulk densities of the stones remained within the range of 3.9-4.0 g/cm3. The cracks healing and pores filling by the metal oxides on the surface of the ruby have been examined using scanning electron microscopy. The chemical compositions based on the XPS survey scans are in good agreement with the expected composition. The phase and crystallinity of the ruby stones original and heat-treated were obtained from their X-ray diffraction patterns. The change in peak separation between R1 and R2 - peaks in photoluminescence spectra and the contrary binding energy shift of the Al 2p peaks in the X-ray photoelectron spectra have been explicated. Moreover, in this work we describe the change in surface chemical and physical characteristics of the ruby stone before and after heat treatment.

Art in the Service of Science

NASA Astrophysics Data System (ADS)

Asmus, J. F.

In fields such as studio art, art conservation, archaeology, anthropology, music, and architecture it is often understood that many of the advances emerge from the introduction of new developments from science and technology. Scientific research is often justified on the basis of its past as well as potential future fallout into other endeavors as diverse as medicine, manufacturing, and the humanities. The diffusion of scientific innovation into the practice of art conservation has been punctuated by the introduction of a series of diverse technologies. Trace element and isotopic analyses, infrared imaging, ultraviolet fluorescence inspection, advanced coatings and adhesives, scanning electron microscopy, and photon/electron microprobes are notable examples. For the past thirty years various laser technologies have demonstrated utility in the practice of art conservation, as well. These include photon cleaning and divestment, holographic display and nondestructive analysis, surface characterization through laser fluorescence, radiation scattering and absorption, as well as laser-induced ultrasound. At the dawn of laser technology's introduction into the art conservation field (1972-74) the Center for Art/Science Studies (CASS) was established at the University of California, San Diego (UCSD) with the hope of accelerating and broadening the diffusion of scientific developments into art conservation practice. Surprisingly, one of the first events in the CASS/UCSD transpired when a Visual Arts Department student employed a primitive laser statue cleaner to "correct" a silk-screen print. In the course of maintaining her laser this art student discovered a dramatically improved method for aligning the complex optical beam train by utilizing her artistic training. A few months later another CASS/UCSD student in the Photographic Arts Program (while modifying a ruby laser to experiment with theater-lighting special effects) discovered an improved laser beam-profile diagnostic technique. These two, seemingly trite, examples of scientific serendipity "in reverse" are not isolated anomalies. History is replete with instances of art coming to the aid of science and technology. Examples include Samuel Morse's drawing upon his skill as a painter in support of his electrical engineering research, the collaboration of Michele Besso and Albert Einstein in the formulation of Special Relativity, Picasso's vision of wave-function collapse in Quantum Electrodynamics, and Jay DeFeo's depiction of Big Bangs and Black Holes while cosmologists were focusing on Fred Hoyle's steady-state continuum theory of the universe.

Path toward a high-energy solid-state laser

NASA Astrophysics Data System (ADS)

Wood, Gary L.; Merkle, Larry D.; Dubinskii, Mark; Zandi, Bahram

2004-04-01

Lasers have come a long way since the first demonstration by Maiman of a ruby crystal laser in 1960. Lasers are used as scientific tools as well as for a wide variety of applications for both commercial industry and the military. Today lasers come in all types, shapes and sizes depending on their application. The solid-state laser has some distinct advantages in that it can be rugged, compact, and self contained, making it reliable over long periods of time. With the advent of diode laser pumping a ten times increase in overall laser efficiency has been realized. This significant event, and others, is changing the way solid-state lasers are applied and allows new possibilities. One of those new areas of exploration is the high energy laser. Solid-state lasers for welding are already developed and yield energies in the 0.5 to 6 kilojoule range. These lasers are at the forefront of what is possible in terms of high energy solid-state lasers. It is possible to achieve energies of greater than 100 kJ. These sorts of energies would allow applications, in addition to welding, such as directed energy weapons, extremely remote sensing, power transfer, propulsion, biological and chemical agent neutralization and unexploded and mine neutralization. This article will review these new advances in solid-state lasers and the different paths toward achieving a high energy laser. The advantages and challenges of each approach will be highlighted.

Trace element fingerprinting of jewellery rubies by external beam PIXE

NASA Astrophysics Data System (ADS)

Calligaro, T.; Poirot, J.-P.; Querré, G.

1999-04-01

External beam PIXE analysis allows the non-destructive in situ characterisation of gemstones mounted on jewellery pieces. This technique was used for the determination of the geographical origin of 64 rubies set on a high-valued necklace. The trace element content of these gemstones was measured and compared to that of a set of rubies of known sources. Multivariate statistical processing of the results allowed us to infer the provenance of rubies : one comes from Thailand/Cambodia deposit while the remaining are attributed to Burma. This highlights the complementary capabilities of PIXE and conventional gemological observations.

Performance evaluation of the Abbott CELL-DYN Ruby and the Sysmex XT-2000i haematology analysers.

PubMed

Leers, M P G; Goertz, H; Feller, A; Hoffmann, J J M L

2011-02-01

Two mid-range haematology analysers (Abbott CELL-DYN Ruby and Sysmex XT-2000i) were evaluated to determine their analytical performance and workflow efficiency in the haematology laboratory. In total 418 samples were processed for determining equivalence of complete blood count (CBC) measurements, and 100 for reticulocyte comparison. Blood smears served for assessing the agreement of the differential counts. Inter-instrument agreement for most parameters was good although small numbers of discrepancies were observed. Systematic biases were found for mean cell volume, reticulocytes, platelets and mean platelet volume. CELL-DYN Ruby WBC differentials were obtained with all samples while the XT-2000i suppressed differentials partially or completely in 13 samples (3.1%). WBC subpopulation counts were otherwise in good agreement with no major outliers. Following first-pass CBC/differential analysis, 88 (21%) of XT-2000i samples required further analyser processing compared to 18 (4.3%) for the CELL-DYN Ruby. Smear referrals for suspected WBC/nucleated red blood cells and platelet abnormalities were indicated for 106 (25.4%) and 95 (22.7%) of the XT-2000i and CELL-DYN Ruby samples respectively. Flagging efficiencies for both analysers were found to be similar. The Sysmex XT-2000i and Abbott CELL-DYN Ruby analysers have broadly comparable analytical performance, but the CELL-DYN Ruby showed superior first-pass efficiency. © 2010 Blackwell Publishing Ltd.

Improving brightness and photostability of green and red fluorescent proteins for live cell imaging and FRET reporting

PubMed Central

Bajar, Bryce T.; Wang, Emily S.; Lam, Amy J.; Kim, Bongjae B.; Jacobs, Conor L.; Howe, Elizabeth S.; Davidson, Michael W.; Lin, Michael Z.; Chu, Jun

2016-01-01

Many genetically encoded biosensors use Förster resonance energy transfer (FRET) to dynamically report biomolecular activities. While pairs of cyan and yellow fluorescent proteins (FPs) are most commonly used as FRET partner fluorophores, respectively, green and red FPs offer distinct advantages for FRET, such as greater spectral separation, less phototoxicity, and lower autofluorescence. We previously developed the green-red FRET pair Clover and mRuby2, which improves responsiveness in intramolecular FRET reporters with different designs. Here we report the engineering of brighter and more photostable variants, mClover3 and mRuby3. mClover3 improves photostability by 60% and mRuby3 by 200% over the previous generation of fluorophores. Notably, mRuby3 is also 35% brighter than mRuby2, making it both the brightest and most photostable monomeric red FP yet characterized. Furthermore, we developed a standardized methodology for assessing FP performance in mammalian cells as stand-alone markers and as FRET partners. We found that mClover3 or mRuby3 expression in mammalian cells provides the highest fluorescence signals of all jellyfish GFP or coral RFP derivatives, respectively. Finally, using mClover3 and mRuby3, we engineered an improved version of the CaMKIIα reporter Camuiα with a larger response amplitude. PMID:26879144

Functional metagenomic selection of RubisCOs from uncultivated bacteria

USGS Publications Warehouse

Varaljay, Vanessa A; Satagopan, Sriram; North, Justin A.; Witteveen, Briana; Dourado, Manuella N.; Anantharaman, Karthik; Arbing, Mark A.; McCann, Shelley; Oremland, Ronald S.; Banfield, Jillian F.; Wrighton, Kelly C.; Tabita, F. Robert

2016-01-01

Ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) is a critical yet severely inefficient enzyme that catalyses the fixation of virtually all of the carbon found on Earth. Here, we report a functional metagenomic selection that recovers physiologically active RubisCO molecules directly from uncultivated and largely unknown members of natural microbial communities. Selection is based on CO2-dependent growth in a host strain capable of expressing environmental deoxyribonucleic acid (DNA), precluding the need for pure cultures or screening of recombinant clones for enzymatic activity. Seventeen functional RubisCO-encoded sequences were selected using DNA extracted from soil and river autotrophic enrichments, a photosynthetic biofilm and a subsurface groundwater aquifer. Notably, three related form II RubisCOs were recovered which share high sequence similarity with metagenomic scaffolds from uncultivated members of theGallionellaceae family. One of the Gallionellaceae RubisCOs was purified and shown to possessCO2/O2 specificity typical of form II enzymes. X-ray crystallography determined that this enzyme is a hexamer, only the second form II multimer ever solved and the first RubisCO structure obtained from an uncultivated bacterium. Functional metagenomic selection leverages natural biological diversity and billions of years of evolution inherent in environmental communities, providing a new window into the discovery of CO2-fixing enzymes not previously characterized.

Standard guidelines of care: laser and IPL hair reduction.

PubMed

Buddhadev, Rajesh M

2008-01-01

Laser-assisted hair removal, Laser hair removal, Laser and light-assisted hair removal, Laser and light-assisted, long-term hair reduction, IPL photodepilation, LHE photodepilation; all these are acceptable synonyms. Laser (Ruby, Nd Yag, Alexandrite, Diode), intense pulse light, light and heat energy system are the different light-/Laser-based systems used for hair removal; each have its advantages and disadvantages. The word "LONG-TERM HAIR REDUCTION" should be used rather than permanent hair removal. Patient counseling is essential about the need for multiple sessions. PHYSICIANS' QUALIFICATIONS: Laser hair removal may be practiced by any dermatologist, who has received adequate background training during postgraduation or later at a centre that provides education and training in Lasers or in focused workshops providing such training. The dermatologist should have adequate knowledge of the machines, the parameters and aftercare. The physician may allow the actual procedure to be performed under his/her direct supervision by a trained nurse assistant/junior doctor. However, the final responsibility for the procedure would lie with the physician. The procedure may be performed in the physician's minor procedure room. Investigations to rule out any underlying cause for hair growth are important; concurrent drug therapy may be needed. Laser parameters vary with area, type of hair, and the machine used. Full knowledge about the machine and cooling system is important. Future maintenance treatments may be needed.

Electromagnetic Radiation: Final Range Environmental Assessment, Revision 1

DTIC Science & Technology

2009-12-03

scanning, research, and medical treatment and surgical procedures. There are many different types of lasing materials as identified below ( Indiana ...vapor (red) 0.627 Xenon chloride (Excimer-UV) 0.308 Helium neon (red) 0.633 Xenon fluoride (Excimer-UV) 0.351 Krypton (red) 0.647 Helium cadmium (UV...0.325 Rhodamine 6G dye (tunable) 0.570-0.650 Nitrogen (UV) 0.337 Ruby (CrAlO3) (red) 0.694 Helium cadmium (violet) 0.441 Gallium arsenide (diode

Treatment of melasma in Caucasian patients using a novel 694-nm Q-switched ruby fractional laser

PubMed Central

2013-01-01

Background Melasma is a common hypermelanosis of the face. The use of a classical Q-switched ruby laser (QSRL) to treat melasma is discussed controversially and is associated with frequent adverse effects, such as hyper- or hypopigmentation. Recently a fractional-mode (FRx) QSRL was developed to minimize the adverse effects of classical QSRL. The objective of this research was to evaluate the efficacy and safety of a novel FRx-QSRL in the treatment of melasma in Caucasian patients. Methods We performed a retrospective study of 25 Caucasian melasma patients (Fitzpatrick skin types I to III). Patients received one to three FRx-QSRL treatments (Tattoostar FRx, Asclepion Laser Technologies, Jena, Germany) at pulse energies of 4 to 8 J/cm2. Three blinded investigators independently evaluated the melasma area and severity index (MASI) score before treatment and at the four- to six-week follow-ups. At additional three-month follow-ups, patients evaluated subjective improvement, pain and over-all satisfaction with the treatment according to a numeric analogue score (NAS). Side effects were documented. Results At four to six weeks post laser treatment for a mean of 1.4 sessions, we observed a significant (P = 0.0001) reduction of the MASI score from 6.54 to 1.98 (72.3%). Patients rated the pain of the intervention at a mean 2.46 points (0 = no pain; 10 = maximum pain), the improvement at a mean 5.55 points (0 = no improvement; 10 = maximum improvement) and the overall satisfaction at a mean 4.66 points (0 = not satisfied; 10 = maximum satisfaction). After three months, post-inflammatory hyperpigmentation (PIH) and/or recurring melasma were observed in 7 (28%) and 11 (44%) patients, respectively. Conclusion The 694-nm FRx-QSRL is a safe and effective option for treating melasma in Caucasian patients. Over periods of >3 months, PIH and/or recurring melasma may develop at significant rates and may reduce patient satisfaction. Multiple treatment sessions with lower pulse energies and/or a post-interventional therapy with hypopigmenting ointments and UV protection may help to minimize these complications. PMID:24225160

Treatment of melasma in Caucasian patients using a novel 694-nm Q-switched ruby fractional laser.

PubMed

Hilton, Said; Heise, Heike; Buhren, Bettina Alexandra; Schrumpf, Holger; Bölke, Edwin; Gerber, Peter Arne

2013-11-14

Melasma is a common hypermelanosis of the face. The use of a classical Q-switched ruby laser (QSRL) to treat melasma is discussed controversially and is associated with frequent adverse effects, such as hyper- or hypopigmentation. Recently a fractional-mode (FRx) QSRL was developed to minimize the adverse effects of classical QSRL. The objective of this research was to evaluate the efficacy and safety of a novel FRx-QSRL in the treatment of melasma in Caucasian patients. We performed a retrospective study of 25 Caucasian melasma patients (Fitzpatrick skin types I to III). Patients received one to three FRx-QSRL treatments (Tattoostar FRx, Asclepion Laser Technologies, Jena, Germany) at pulse energies of 4 to 8 J/cm2. Three blinded investigators independently evaluated the melasma area and severity index (MASI) score before treatment and at the four- to six-week follow-ups. At additional three-month follow-ups, patients evaluated subjective improvement, pain and over-all satisfaction with the treatment according to a numeric analogue score (NAS). Side effects were documented. At four to six weeks post laser treatment for a mean of 1.4 sessions, we observed a significant (P=0.0001) reduction of the MASI score from 6.54 to 1.98 (72.3%). Patients rated the pain of the intervention at a mean 2.46 points (0=no pain; 10=maximum pain), the improvement at a mean 5.55 points (0=no improvement; 10=maximum improvement) and the overall satisfaction at a mean 4.66 points (0=not satisfied; 10=maximum satisfaction). After three months, post-inflammatory hyperpigmentation (PIH) and/or recurring melasma were observed in 7 (28%) and 11 (44%) patients, respectively. The 694-nm FRx-QSRL is a safe and effective option for treating melasma in Caucasian patients. Over periods of >3 months, PIH and/or recurring melasma may develop at significant rates and may reduce patient satisfaction. Multiple treatment sessions with lower pulse energies and/or a post-interventional therapy with hypopigmenting ointments and UV protection may help to minimize these complications.

Clinical dental application of Er:YAG laser for Class V cavity preparation.

PubMed

Matsumoto, K; Nakamura, Y; Mazeki, K; Kimura, Y

1996-06-01

Following the development of the ruby laser by Maiman in 1960, the Nd:YAG laser, the CO2 laser, the semiconductor laser, the He-Ne laser, excimer lasers, the argon laser, and finally the Er:YAG laser capable of cutting hard tissue easily were developed and have come to be applied clinically. In the present study, the Er:YAG laser emitting at a wavelength of 2.94 microns developed by Luxar was used for the clinical preparation of class V cavities. Parameters of 8 Hz and approx. 250 mJ/pulse maximum output were used for irradiation. Sixty teeth of 40 patients were used in this clinical study. The Er:YAG laser used in this study was found to be a system suitable for clinical application. No adverse reaction was observed in any of the cases. Class V cavity preparation was performed without inducing any pain in 48/60 cases (80%). All of the 12 cases that complained of mild or severe intraoperative pain had previously complained of cervical dentin hypersensibility during the preoperative examination. Cavity preparation was completed with this laser system in 58/60 cases (91.7%). No treatment-related clinical problems were observed during the follow-up period of approx. 30 days after cavity preparation and resin filling. Cavity preparation took between approx. 10 sec and 3 min and was related more or less to cavity size and depth. Overall clinical evaluation showed no safety problem with very good rating in 49 cases (81.7%).

Time dependence of the radiation-induced EPR signal in sucrose.

PubMed

Desrosiers, Marc; Wadley, Samara

2006-01-01

Sucrose and common household sugars (e.g. cane) have been studied as dosemeters for a wide variety of applications. However, previous studies of the post-irradiation time dependence of irradiated sugar did not include an electron paramagnetic resonance (EPR) reference material. This work employs synthetic ruby as an EPR reference material to remove significant spectrometer/environmental influences on the measured time-dependent changes in the EPR spectral amplitude of irradiated sucrose. As such, these more accurate measurements should replace the previously published data.

Biology of Symbioses between Marine Invertebrates and Intracellular Bacteria

DTIC Science & Technology

1990-01-30

bisphosphate carboxylase We designed from published sequence information oligonucleotide primers which are complementary to conserved regions on RubisCO ...large and small subunit genes. These primers were used successfully to amplify using polymerase chain reaction (PCR) specific regions of RubisCO ...for the large subunit of ribulose bisphosphate carboxylase/oxygenase ( RubisCO ) to symbiont DNA shows that the symbionts from both deep-sea and shallow

Development of mRuby2-Transfected C3H10T1/2 Fibroblasts for Musculoskeletal Tissue Engineering

PubMed Central

Yang, Yunzhi Peter

2015-01-01

Mouse C3H10T1/2 fibroblasts are multipotent, mesenchymal stem cell (MSC)-like progenitor cells that are widely used in musculoskeletal research. In this study, we have established a clonal population of C3H10T1/2 cells stably-transfected with mRuby2, an orange-red fluorescence reporter gene. Flow cytometry analysis and fluorescence imaging confirmed successful transfection of these cells. Cell counting studies showed that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells proliferated at similar rates. Adipogenic differentiation experiments demonstrated that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells stained positive for Oil Red O and showed increased expression of adipogenic genes including adiponectin and lipoprotein lipase. Chondrogenic differentiation experiments demonstrated that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells stained positive for Alcian Blue and showed increased expression of chondrogenic genes including aggrecan. Osteogenic differentiation experiments demonstrated that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells stained positive for alkaline phosphatase (ALP) as well as Alizarin Red and showed increased expression of osteogenic genes including alp, ocn and osf-1. When seeded on calcium phosphate-based ceramic scaffolds, mRuby2-transfected C3H10T1/2 cells maintained even fluorescence labeling and osteogenic differentiation. In summary, mRuby2-transfected C3H10T1/2 cells exhibit mRuby2 fluorescence and showed little-to-no difference in terms of cell proliferation and differentiation as untransfected C3H10T1/2 cells. These cells will be available from American Type Culture Collection (ATCC; CRL-3268™) and may be a valuable tool for preclinical studies. PMID:26407291

Development of mRuby2-Transfected C3H10T1/2 Fibroblasts for Musculoskeletal Tissue Engineering.

PubMed

Ker, Dai Fei Elmer; Sharma, Rashmi; Wang, Evelyna Tsi Hsin; Yang, Yunzhi Peter

2015-01-01

Mouse C3H10T1/2 fibroblasts are multipotent, mesenchymal stem cell (MSC)-like progenitor cells that are widely used in musculoskeletal research. In this study, we have established a clonal population of C3H10T1/2 cells stably-transfected with mRuby2, an orange-red fluorescence reporter gene. Flow cytometry analysis and fluorescence imaging confirmed successful transfection of these cells. Cell counting studies showed that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells proliferated at similar rates. Adipogenic differentiation experiments demonstrated that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells stained positive for Oil Red O and showed increased expression of adipogenic genes including adiponectin and lipoprotein lipase. Chondrogenic differentiation experiments demonstrated that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells stained positive for Alcian Blue and showed increased expression of chondrogenic genes including aggrecan. Osteogenic differentiation experiments demonstrated that untransfected C3H10T1/2 cells and mRuby2-transfected C3H10T1/2 cells stained positive for alkaline phosphatase (ALP) as well as Alizarin Red and showed increased expression of osteogenic genes including alp, ocn and osf-1. When seeded on calcium phosphate-based ceramic scaffolds, mRuby2-transfected C3H10T1/2 cells maintained even fluorescence labeling and osteogenic differentiation. In summary, mRuby2-transfected C3H10T1/2 cells exhibit mRuby2 fluorescence and showed little-to-no difference in terms of cell proliferation and differentiation as untransfected C3H10T1/2 cells. These cells will be available from American Type Culture Collection (ATCC; CRL-3268™) and may be a valuable tool for preclinical studies.

The Processing and Mechanical Properties of High Temperature/High Performance Composites. Book 7. In-Situ Measurements of Stress and Damage

DTIC Science & Technology

1994-04-01

Physics, Vol.72, No.12, 1992, pp.5535-5538. (12] Ragan, D.R., Gustavsen, R., and Schiferl , D., "Calibration of the Ruby R2 and R2 Fluorescence Shifts... Schiferl , D., "Pressure and Temperature Dependence of Laser-Induced Fluorescence of Sm:YAG to 100 kbar and 7000 C and an Empirical Model," Journal of...1964). IS. H. D’Amour. D. Schiferl , W. Denner, H. Schulz and 20. J. W. McCauley and G. V. Gibbs. Z. Knistallogr. 135, W, B. Holzapfel, J. appl. Phys. 49

Optical Production and Detection of Ultrasonic Waves in Metals for Nondestructive Testing

NASA Technical Reports Server (NTRS)

Morrison, R. A.

1972-01-01

Ultrasonic waves were produced by striking the surface of a metal with the focused one-joule pulse of a Q-switched ruby laser. Rayleigh (surface) waves and longitudinal waves were detected with conventional transducers. Optical methods of detection were tested and developed. Rayleigh waves were produced with an oscillator and transducer. They were optically detected on curved polished surfaces, and on unpolished surfaces. The technique uses a knife edge to detect small angle changes of the surface as the wave pulse passes the illuminated spot. Optical flaw detection using pulse echo and attenuation is demonstrated.

Light and laser treatment modalities for disseminated superficial actinic porokeratosis: a systematic review.

PubMed

Aird, Gregory A; Sitenga, Jenna L; Nguyen, Austin Huy; Vaudreuil, Adam; Huerter, Christopher J

2017-05-01

Treatment of disseminated superficial actinic porokeratosis (DSAP) is poorly standardized. The present review seeks to comprehensively discuss the potential for laser and light modalities in the treatment of DSAP. A systematic review of light and laser treatment modalities was conducted to include 26 cases of patients with DSAP. Systematic review resulted in 14 articles to be included. Photodynamic therapy (PDT) overall was the least successful treatment modality, with clinical improvement seen in a minority of patients (MAL-PDT: N = 9 patients, 33.3% showed improvement; ALA-PDT: N = 3 patients, 0% improvement; hypericin-PDT: N = 2 patients, 0% improvement) after numerous post-procedural side effects of hyperpigmentation, inflammation, erythema, and discomfort. Overall, in the available reports, PDT demonstrates poor outcomes with greater incidence of side effects. The response rates of DSAP lesions treated with lasers were as follows: (Q-switched ruby lasers: N = 2, 100%; CO 2 laser: N = 1, 100%; PDT and CO 2 combination therapy: N = 2, 0-50%; erbium and neodymium YAG lasers: N = 2, 100%; fractional 1927-nm thulium fiber lasers: N = 2, 100%; Grenz rays: N = 1, 100%; and fractional photothermolysis: N = 2, 100%). The side effects of laser therapy were minimal and included mild erythema, slight hyperpigmentation, and moderate edema. Laser therapy is a promising treatment option for DSAP with an excellent side effect profile. However, higher power studies are required to determine optimal guidelines for laser treatment of DSAP.

A Ruby API to query the Ensembl database for genomic features.

PubMed

Strozzi, Francesco; Aerts, Jan

2011-04-01

The Ensembl database makes genomic features available via its Genome Browser. It is also possible to access the underlying data through a Perl API for advanced querying. We have developed a full-featured Ruby API to the Ensembl databases, providing the same functionality as the Perl interface with additional features. A single Ruby API is used to access different releases of the Ensembl databases and is also able to query multi-species databases. Most functionality of the API is provided using the ActiveRecord pattern. The library depends on introspection to make it release independent. The API is available through the Rubygem system and can be installed with the command gem install ruby-ensembl-api.

Biogeochemical Cycling of Manganese at Hydrothermal Vents

DTIC Science & Technology

1990-01-01

from an anoxic basin) contain the gene for the large subunit of Ribulose- 1,5-bisphosphate Carboxylase Oxygenase ( RubisCO ) suggestive of autotrophy... RubisCO gene probing on the bacterial isolates obtained from the hydrothermal vent environments as part of an ongoing ONR contract. In addition, we have...to test the feasibility of using gene probes for Ribulose-l,5- bisphosphate Carboxylase Oxygenase ( RubisCO ) for identifying autotrophic Mn(II

Sand dune of Ruby, Arizona, an anthropogenically created biodiversity hotspot for wasps and their velvet ant parasitoids

Treesearch

Justin O. Schmidt

2013-01-01

A large artificial sand dune composed of finely crushed mine tailings was produced by deep mining operations at Ruby, Arizona. Today, the ghost town of Ruby is an important historical location and biodiversity refuge, with the newly formed dune forming the core of the refuge. The dune provides ideal nesting habitat for at least 13 species of sand-loving wasps,...

Rapid middle Miocene extension and unroofing of the southern Ruby Mountains, Nevada

USGS Publications Warehouse

Colgan, Joseph P.; Howard, Keith A.; Fleck, Robert J.; Wooden, Joseph L.

2010-01-01

Paleozoic rocks in the northern Ruby Mountains were metamorphosed during Mesozoic crustal shortening and Cenozoic magmatism, but equivalent strata in the southern Ruby Mountains were never buried deeper than stratigraphic depths prior to exhumation in the footwall of a west dipping brittle normal fault. In the southern Ruby Mountains, Miocene sedimentary rocks in the hanging wall of this fault date from 15.2 to 11.6 Ma and contain abundant detritus from the Paleozoic section. Apatite fission track and (U-Th)/He samples of the Eocene Harrison Pass pluton record rapid cooling that peaked ca. 17–15 Ma, while apatite fission track data from Jurassic plutons east and west of the southern Ruby Mountains indicate near-surface temperatures (<60°C) since the Cretaceous. We interpret these data to record rapid unroofing of the southern Ruby Mountains during slip on the west dipping brittle detachment between 17–16 and 10–12 Ma, followed by minor high-angle faulting. We interpret published Oligocene to early Miocene K-Ar biotite and zircon fission track dates from the Harrison Pass pluton to be partially reset rather than to directly record fault slip. Our new data, together with published data on the distribution and composition of Miocene basin fill, suggest that rapid middle Miocene slip took place on the west dipping brittle detachment that bounds the Ruby Mountains and East Humboldt Range for 150 km along strike. This fault was thus active during a period of rapid extension (ca. 17–15 to 12–10 Ma) documented widely across the northern Basin and Range Province.

Comparison between sequentional treatment with diode and alexandrite lasers versus alexandrite laser alone in the treatment of hirsutism.

PubMed

Nilforoushzadeh, Mohammad Ali; Naieni, Farahnaz Fatemi; Siadat, Amir Hossein; Rad, Leila

2011-11-01

Laser systems that are commonly used for the treatment of hirsutism include the ruby laser (694 nm), the diode laser (800 nm), the alexandrite laser (755 nm) and the Nd:YAG laser (1084 nm). The diode laser and alexandrite laser are considered effective in treatment of hirsutism in dark-skinned patients. The response of hairs to these laser systems is variable and not complete. In this study, we compared the efficacy of these two laser systems for permanent hair removal. This was a randomized, controlled clinical trial that was performed with women of the age range 15-45 years old. After obtaining informed consent, the samples were randomized into two groups using random allocation software. The first group was treated with alexandrite laser alone (four sessions, two months apart). The second group was treated sequentially with diode laser for the first two sessions and alexandrite laser for the next two sessions. Overall, 111 patients (57 patients in the alexandrite laser group and 54 patients in the sequential diode-alexandrite laser group) were evaluated. There was no significant difference regarding mean of hair reduction between the two groups during the courses of treatment. Except for the first session, there was no significant difference regarding percent of patient satisfaction between the two groups (P value >0.05). Comparison between the two groups showed no significant difference one month, three months and six months after the last treatment (P value >0.05). Regarding the results of our study, there is no significant difference between sequential treatment with diode and alexandrite lasers versus alexandrite laser alone in the treatment of hirsutism. We suggest that in further studies, the efficacy of sequential treatment with other laser systems is evaluated against single treatment methods.

Lasers for Frontier Spectroscopy

NASA Astrophysics Data System (ADS)

Baldacchini, Giuseppe

The first laser has been invented in 1960 by using the red light from a ruby crystal, and since then the laser field exploded almost exponentially, and thousands of different materials, in the state of solids, liquids, vapors, gases, plasmas, and elementary particles have lased up to now from less than I Å to more than 1 mm. Many of them have been used with outstanding results both in basic science, and in industrial and commercial applications, by changing for ever the same lifestyle of humankind. As far as spectroscopy is concerned, the laser light has started an unprecedented revolution because of its unique properties as monochromaticity, coherence, power, brightness and short-pulse regime, unrivaled by any other natural and artificial light source. Spectroscopy applications increased qualitatively and quantitatively with the laser sources themselves, and they are still proceeding in parallel with the moving of the laser field towards new territories. Apart the opening up of new regions of the electromagnetic spectrum, like the terahertz gap, and the outstanding increase of the output power which is giving rise to completely new spectroscopic effects, the improvement of laser sources and auxiliary equipment is producing a growth of traditional laser spectroscopy with superior resolution and sensitivity. Moreover, spectroscopic techniques and laser light contributed to the development of new chemical and physical processes which have been used to fabricate photonic materials with new spectroscopic properties enriching the laser field itself, in a virtuous cycle spectroscopy→aser→material and back to spectroscopy with no end in sight.

Mr.CAS-A minimalistic (pure) Ruby CAS for fast prototyping and code generation

NASA Astrophysics Data System (ADS)

Ragni, Matteo

There are Computer Algebra System (CAS) systems on the market with complete solutions for manipulation of analytical models. But exporting a model that implements specific algorithms on specific platforms, for target languages or for particular numerical library, is often a rigid procedure that requires manual post-processing. This work presents a Ruby library that exposes core CAS capabilities, i.e. simplification, substitution, evaluation, etc. The library aims at programmers that need to rapidly prototype and generate numerical code for different target languages, while keeping separated mathematical expression from the code generation rules, where best practices for numerical conditioning are implemented. The library is written in pure Ruby language and is compatible with most Ruby interpreters.

Synthetic CO2-fixation enzyme cascades immobilized on self-assembled nanostructures that enhance CO2/O2 selectivity of RubisCO.

PubMed

Satagopan, Sriram; Sun, Yuan; Parquette, Jon R; Tabita, F Robert

2017-01-01

With increasing concerns over global warming and depletion of fossil-fuel reserves, it is attractive to develop innovative strategies to assimilate CO 2 , a greenhouse gas, into usable organic carbon. Cell-free systems can be designed to operate as catalytic platforms with enzymes that offer exceptional selectivity and efficiency, without the need to support ancillary reactions of metabolic pathways operating in intact cells. Such systems are yet to be exploited for applications involving CO 2 utilization and subsequent conversion to valuable products, including biofuels. The Calvin-Benson-Bassham (CBB) cycle and the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) play a pivotal role in global CO 2 fixation. We hereby demonstrate the co-assembly of two RubisCO-associated multienzyme cascades with self-assembled synthetic amphiphilic peptide nanostructures. The immobilized enzyme cascades sequentially convert either ribose-5-phosphate (R-5-P) or glucose, a simpler substrate, to ribulose 1,5-bisphosphate (RuBP), the acceptor for incoming CO 2 in the carboxylation reaction catalyzed by RubisCO. Protection from proteolytic degradation was observed in nanostructures associated with the small dimeric form of RubisCO and ancillary enzymes. Furthermore, nanostructures associated with a larger variant of RubisCO resulted in a significant enhancement of the enzyme's selectivity towards CO 2 , without adversely affecting the catalytic activity. The ability to assemble a cascade of enzymes for CO 2 capture using self-assembling nanostructure scaffolds with functional enhancements show promise for potentially engineering entire pathways (with RubisCO or other CO 2 -fixing enzymes) to redirect carbon from industrial effluents into useful bioproducts.

Biology of Symbioses between Marine Invertebrates and Intracellular Bacteria

DTIC Science & Technology

1991-01-21

bisphosphate carboxylase ( RubisCO ) from symbiotic bacteria of various origins, b) To continue methods development for 16S rRNA sequencing from symbionts in...frozen and badly preserved specimens, and c) To use these new techniques to sequence 16s DNA from a variety of symbionts a) RubisCO We have cloned the...gene coding for RubisCO from the sulfur oxidixing symbiont of the gastropod Alvinochoncha hessleri. Nucleotide sequence analysis of the cloned fragment

Cyanobacterial-based approaches to improving photosynthesis in plants.

PubMed

Zarzycki, Jan; Axen, Seth D; Kinney, James N; Kerfeld, Cheryl A

2013-01-01

Plants rely on the Calvin-Benson (CB) cycle for CO(2) fixation. The key carboxylase of the CB cycle is ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). Efforts to enhance carbon fixation in plants have traditionally focused on RubisCO or on approaches that can help to remedy RubisCO's undesirable traits: its low catalytic efficiency and photorespiration. Towards reaching the goal of improving plant photosynthesis, cyanobacteria may be instrumental. Because of their evolutionary relationship to chloroplasts, they represent ideal model organisms for photosynthesis research. Furthermore, the molecular understanding of cyanobacterial carbon fixation provides a rich source of strategies that can be exploited for the bioengineering of chloroplasts. These strategies include the cyanobacterial carbon concentrating mechanism (CCM), which consists of active and passive transporter systems for inorganic carbon and a specialized organelle, the carboxysome. The carboxysome encapsulates RubisCO together with carbonic anhydrase in a protein shell, resulting in an elevated CO(2) concentration around RubisCO. Moreover, cyanobacteria differ from plants in the isoenzymes involved in the CB cycle and the photorespiratory pathways as well as in mechanisms that can affect the activity of RubisCO. In addition, newly available cyanobacterial genome sequence data from the CyanoGEBA project, which has more than doubled the amount of genomic information available for cyanobacteria, increases our knowledge on the CCM and the occurrence and distribution of genes of interest.

Fluorescent cooling of objects exposed to sunlight – The ruby example

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berdahl, Paul; Chen, Sharon S.; Destaillats, Hugo

Various pigments are used to formulate desirable non-white colors that stay cooler in the sun than alternatives, which is particularly useful for hot climate areas. These cool pigments provide a high near-infrared (NIR) reflectance in the solar infrared range of 700-2500 nm, and also a color specified by a reflectance spectrum in the 400-700 nm visible range. Still cooler materials can be formulated by also utilizing the phenomenon of fluorescence (photoluminescence). Ruby, Al 2O 3 :Cr, is a prime example, with efficient emission in the deep red (~694 nm) and near infrared (700-800 nm). A layer of synthetic ruby crystalsmore » on a white surface having an attractive red color can remain cooler in the sun than conventional red materials. Ruby particles can also be used as a red/pink pigment. Increasing the Cr:Al ratio produces a stronger (darker) pigment but doping above ~3 wt% Cr 2O 3 causes concentration quenching of the fluorescence. The system quantum efficiency for lightly doped ruby-pigmented coatings over white is high, 0.83 ± 0.10.« less

Ruby-Helix: an implementation of helical image processing based on object-oriented scripting language.

PubMed

Metlagel, Zoltan; Kikkawa, Yayoi S; Kikkawa, Masahide

2007-01-01

Helical image analysis in combination with electron microscopy has been used to study three-dimensional structures of various biological filaments or tubes, such as microtubules, actin filaments, and bacterial flagella. A number of packages have been developed to carry out helical image analysis. Some biological specimens, however, have a symmetry break (seam) in their three-dimensional structure, even though their subunits are mostly arranged in a helical manner. We refer to these objects as "asymmetric helices". All the existing packages are designed for helically symmetric specimens, and do not allow analysis of asymmetric helical objects, such as microtubules with seams. Here, we describe Ruby-Helix, a new set of programs for the analysis of "helical" objects with or without a seam. Ruby-Helix is built on top of the Ruby programming language and is the first implementation of asymmetric helical reconstruction for practical image analysis. It also allows easier and semi-automated analysis, performing iterative unbending and accurate determination of the repeat length. As a result, Ruby-Helix enables us to analyze motor-microtubule complexes with higher throughput to higher resolution.

Holographic studies of shock waves within transonic fan rotors

NASA Technical Reports Server (NTRS)

Benser, W. A.; Bailey, E. E.; Gelder, T. F.

1974-01-01

NASA has funded two separate contracts to apply pulsed laser holographic interferometry to the detection of shock patterns in the outer span regions of high tip speed transonic rotors. The first holographic approach used ruby laser light reflected from a portion of the centerbody just ahead of the rotor. These holograms showed the bow wave patterns upstream of the rotor and the shock patterns just inside the blade row near the tip. The second holographic approach, on a different rotor, used light transmitted diagonally across the inlet annulus past the centerbody. This approach gave a more extensive view of the region bounded by the blade leading and trailing edges, by the part span shroud and by the blade tip. These holograms showed the passage shock emanating from the blade leading edge and a moderately strong conical shock originating at the intersection of the part span shroud leading edge and the blade suction surface.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); Tang, Shoou-Yu (Inventor); O'Brien, Martin J. (Inventor)

2009-01-01

A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Tang, Shoou-Yu (Inventor)

2011-01-01

A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Application Of Pulsed Laser Holography To Nondestructive Testing Of Aircraft Structures

NASA Astrophysics Data System (ADS)

Fagot, Hubert; Smigielski, Paul; Arnaud, Jean-Louis

1983-03-01

Subsequently to laboratory tests, experiments were conducted on an aircraft undergoing maintenance in order to assess the possible uses of holographic interferometry for non-destructive testing of large aircraft structures. A double ruby laser was used delivering two pulses with a duration of 20 ns each. The two pulses are separated by an arbitrary time interval At which is determined as a function of both the amplitude and frequency of the surface displacement. Shocks of the order of 100 mJ cause the structure under investigation to vibrate, the time interval At thereby ranging from 10 to 100 ps for a delay of a few ms after shock initiation. The method used is relatively insensitive to environmental disturbances. Although the laser delivers pulses of light of less than 100 mJ in energy, it is possible to visualize a field of 0.5 x1 m. Some results will be reported which have been obtained at the lower surface of an aerofoil, on a wheel well and on an air-brake. Finally a brief review will be made on the improvements envisaged on both the laser and the recording method in order to obtain an operational system for holographic non-destructive testing.

Alexandrite as a high-temperature pressure calibrant, and implications for the ruby-fluorescence scale

NASA Technical Reports Server (NTRS)

Jahren, A. H.; Kruger, M. B.; Jeanloz, Raymond

1992-01-01

The wavelength shifts of the R1 and R2 fluorescence lines of alexandrite (BeAl2O4:Cr(+3)) have been experimentally calibrated against the ruby-fluorescence scale as a function of both hydrostatic and nonhydrostatic pressures between 0 and 50 GPa, and simultaneously as a function of temperatures between 290 and 550 K. It is found that the pressure-temperature cross derivative of the fluorescence wavelength shifts are negligible for both ruby and alexandrite.

DOE Office of Scientific and Technical Information (OSTI.GOV)

The open source Project Haystack initiative defines meta data and communication standards related to data from buildings and intelligent devices. The Project Haystack REST API defines standard formats and operations for exchanging Haystack tagged data over HTTP. The HaystackRuby gem wraps calls to this REST API to enable Ruby application to easily integrate data hosted on a Project Haystack compliant server. The HaystackRuby gem was developed at the National Renewable Energy Lab to support applications related to campus energy. We hope that this tool may be useful to others.

MAP-oriented research in the People's Republic of China

NASA Technical Reports Server (NTRS)

Lu, D.

1985-01-01

A brief accounting of MAP oriented research in the Republic of China is given. A stratosphere balloon launching facility and its capabilities are reviewed. Observations of the stratospheric aerosols with a balloon-borne aerosol computer were made. Long term monitoring of stratospheric aerosols induced by volcanic eruptions are made with a ruby lidar. The main parameters of an ST radar system are given. The ionospheric D region is investigated with the method of ionospheric absorption. And photochemical modeling and radiation parameterization of the middle atmosphere are made.

Long term productivity of canvasbacks (Aythya valisineria) in a snowpack-driven desert marsh

USGS Publications Warehouse

Kruse, Kammie L.; Lovvorn, James R.; Takekawa, John Y.; Mackay, Jeffrey

2003-01-01

Ruby Lake, Nevada, is a large palustrine wetland that hosts the southern-most major breeding population of Canvasbacks (Aythya valisineria). That arid marsh, fed by springs derived from mountain snowpack, differs in climate and hydrology from glaciated potholes of the northern prairies where most Canvasbacks breed. Fourteen years of nesting data on Canvasbacks over a 31 year period (1970–2000) were analyzed to determine factors affecting breeding performance at Ruby Lake and whether they differed from those in the prairies. Long-term Mayfield nest success at Ruby Lake (50% of all nests) was in the range of that in the northern prairies (21–65%). Of all Canvasback nests, 73% were parasitized (mostly by Redheads [Aythya americana]) as compared to 83–97% in a large Manitoba marsh and 57–65% in Manitoba potholes. However, as in the northern prairies, nest parasitism generally had little or no effect on either nest success or percentage of host eggs that hatched. In Manitoba potholes, nest success was unrelated to habitat variables measured; but successful nests at Ruby Lake were over shallower water, farther from shore, in wider bands of emergent vegetation, and surrounded by lower stem densities than unsuccessful nests. Water level is the key factor in breeding performance of Canvasbacks at both Ruby Lake and the northern prairies; however, the source of water differs (mountain snowpack at Ruby Lake, direct precipitation in the prairies) and effects of water-level variations are reversed. In small prairie potholes (mostly <0.4 ha) with many mammalian predators, productivity of Canvasbacks (which build floating nests) is increased by high water that floods the emergent fringe. At Ruby Lake, a very large marsh (2,830 ha) with mostly avian predators, Canvasback productivity is decreased by high water that floods interior emergent stands too deeply. Water level at Ruby Lake was highly correlated (multiple R2 = 0.91) with mountain snowpack up to three years earlier, emphasizing the strong effect of climatic variations on wetland birds in that arid region.

What's a Nice Hummingbird Like You Doing at an AGU Meeting Like This? (or, Operation RubyThroat Meets The GLOBE Program)

NASA Astrophysics Data System (ADS)

Hilton, B.

2003-12-01

"Operation RubyThroat: The Hummingbird Project" is an international cross-disciplinary initiative that uses Ruby-throated Hummingbirds (Archilochus colubris) as a hook to excite K-12 students (and adults) about science learning. In 2002, Operation RubyThroat affiliated with The GLOBE Program as the first GLOBE protocol that involves animal behavior. Through Operation RubyThroat, students make observations about hummingbird phenology, behavior, and ecology and correlate their data against traditional GLOBE observations of atmosphere, climate, land cover, soils, hydrology, and phenology. Although Ruby-throated Hummingbirds (RTHUs) breed throughout the eastern half of the United States and southern Canada and may be the most common and most widely distributed of all 338 hummingbird species, little is known about how abiotic environmental factors affect their migration, nesting activities, and everyday behavior. Operation RubyThroat participants in the U.S. and Canada log early arrival dates of RTHUs during spring migration, note their presence throughout the breeding season, and report the last date RTHUs are seen in autumn. Conversely, participants in Mexico and all seven Central American countries (the region in which RTHUs spend their non-breeding months) watch for early arrivals in fall and late departures in spring. Participants also attempt to estimate numbers of RTHUs in local populations by counting the number of visits hummingbirds make to feeders and/or flowers in a 45-minute time block. Optional activities include observations of RTHU nesting behaviors and determining RTHU preferences for various species of native and exotic nectar sources. Participating schools are encouraged to establish Schoolyard Hummingbird Habitats in which to make their observations, but data may be collected in backyards or at local parks, nature centers, botanical gardens, and other sites where RTHUs occur. Adults not affiliated with K-12 schools are invited to become certified in the hummingbird protocols and to submit Operation RubyThroat data to GLOBE. Participants report sightings of any RTHUs that are banded and color-marked with dye or that have unusual plumage (albinistic, leucistic, etc.). Participants in the eastern U.S. and Canada also report the occurrence of "winter vagrant" hummingbirds, i.e., species from the western U. S. and Mexico that from August through March seem to be wandering more frequently into the region. These unusual movements by western hummingbird species, as well as migration timing and winter occurrences of RTHUs, are correlated against GLOBE data to determine possible effects of atmosphere, climate, and land use, including the impact of global warming. As a new GLOBE protocol, Operation RubyThroat is just beginning to generate data for analysis. Operation RubyThroat's collaboration with GLOBE is funded by a grant from the National Science Foundation. Support for other aspects of the project comes from, among others, Agilent Technologies, ConocoPhillips (through National Fish and Wildlife Foundation), The Christensen Fund, and individual donors. Operation RubyThroat is an education, research, and conservation initiative of Hilton Pond Center for Piedmont Natural History (www.hiltonpond.org) in York, South Carolina USA.

Theoretical comparison of maser materials for a 32-GHz maser amplifier

NASA Technical Reports Server (NTRS)

Lyons, James R.

1988-01-01

The computational results of a comparison of maser materials for a 32 GHz maser amplifier are presented. The search for a better maser material is prompted by the relatively large amount of pump power required to sustain a population inversion in ruby at frequencies on the order of 30 GHz and above. The general requirements of a maser material and the specific problems with ruby are outlined. The spin Hamiltonian is used to calculate energy levels and transition probabilities for ruby and twelve other materials. A table is compiled of several attractive operating points for each of the materials analyzed. All the materials analyzed possess operating points that could be superior to ruby. To complete the evaluation of the materials, measurements of inversion ratio and pump power requirements must be made in the future.

Experimental investigation of self-induced transparency and pulse delay in ruby.

NASA Technical Reports Server (NTRS)

Asher, I. M.

1972-01-01

We have investigated the self-induced transparency effect in ruby over a range of input energies which range from linear absorption to full transparency. The transmission, pulse delay, and pulse broadening were studied as a function of input energy. The transition region is narrower than that found in similar studies of the CO2/SF6 system; this is consistent with predictions based on ensembles of two-level systems. Included are the first pulse-delay and pulse-broadening curves to be obtained for the ruby system.

16 CFR 23.23 - Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone,” “birthstone,” “gemstone,” etc.

Code of Federal Regulations, 2011 CFR

2011-01-01

... PEWTER INDUSTRIES § 23.23 Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone...,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone to describe any product that... “ruby,” “sapphire,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone, or the...

16 CFR 23.23 - Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone,” “birthstone,” “gemstone,” etc.

Code of Federal Regulations, 2013 CFR

2013-01-01

... PEWTER INDUSTRIES § 23.23 Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone...,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone to describe any product that... “ruby,” “sapphire,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone, or the...

16 CFR 23.23 - Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone,” “birthstone,” “gemstone,” etc.

Code of Federal Regulations, 2010 CFR

2010-01-01

... PEWTER INDUSTRIES § 23.23 Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone...,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone to describe any product that... “ruby,” “sapphire,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone, or the...

16 CFR 23.23 - Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone,” “birthstone,” “gemstone,” etc.

Code of Federal Regulations, 2012 CFR

2012-01-01

... PEWTER INDUSTRIES § 23.23 Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone...,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone to describe any product that... “ruby,” “sapphire,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone, or the...

16 CFR 23.23 - Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone,” “birthstone,” “gemstone,” etc.

Code of Federal Regulations, 2014 CFR

2014-01-01

... PEWTER INDUSTRIES § 23.23 Misuse of the words “ruby,” “sapphire,” “emerald,” “topaz,” “stone...,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone to describe any product that... “ruby,” “sapphire,” “emerald,” “topaz,” or the name of any other precious or semi-precious stone, or the...

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Spatial distribution of laser radiation scattered in a plasma formed by optical breakdown of a gas

NASA Astrophysics Data System (ADS)

Bufetov, Igor'A.; Bufetova, G. A.; Fyodorov, V. B.

1994-12-01

Spatial distributions of laser radiation scattered by a laser spark were determined at different laser radiation wavelengths (λ = 1060, 530, 353, and 265 nm) and gas pressures (air at 10-760 Torr). An interference structure of the cone of the scattered radiation behind the spark was detected for the first time. The structure was attributed to interference of the radiation scattered in two or more self-focusing centres in the laser-spark plasma in air. The dependences of the maximum scattering angle on the gas pressure and on the laser radiation wavelength were determined experimentally.

Effect of wavelength on cutaneous pigment using pulsed irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherwood, K.A.; Murray, S.; Kurban, A.K.

Several reports have been published over the last two decades describing the successful removal of benign cutaneous pigmented lesions such as lentigines, cafe au lait macules' nevi, nevus of Ota, and lentigo maligna by a variety of lasers such as the excimer (351 nm), argon (488,514 nm), ruby (694 nm), Nd:YAG (1060 nm), and CO/sub 2/ (10,600 nm). Laser treatment has been applied to lesions with a range of pigment depths from superficial lentigines in the epidermis to the nevus of Ota in the reticular dermis. Widely divergent laser parameters of wavelength, pulse duration, energy density, and spotsizes have beenmore » used, but the laser parameters used to treat this range of lesions have been arbitrary, with little effort focused on defining optimal laser parameters for removal of each type. In this study, miniature black pig skin was exposed to five wavelengths (504, 590, 694, 720, and 750 nm) covering the absorption spectrum of melanin. At each wavelength, a range of energy densities was examined. Skin biopsies taken from laser-exposed sites were examined histologically in an attempt to establish whether optimal laser parameters exist for destroying pigment cells in skin. Of the five wavelengths examined, 504 nm produced the most pigment specific injury; this specificity being maintained even at the highest energy density of 7.0 J/cm2. Thus, for the destruction of melanin-containing cells in the epidermal compartment, 504 nm wavelength appears optimal.« less

Publications - GMC 191 | Alaska Division of Geological & Geophysical

Science.gov Websites

(3,489'-3,511') from the Union Oil Co. of California Ruby State #1 well Authors: Unknown Publication Date the Union Oil Co. of California Ruby State #1 well: Alaska Division of Geological & Geophysical

An introduction to scripting in Ruby for biologists.

PubMed

Aerts, Jan; Law, Andy

2009-07-16

The Ruby programming language has a lot to offer to any scientist with electronic data to process. Not only is the initial learning curve very shallow, but its reflection and meta-programming capabilities allow for the rapid creation of relatively complex applications while still keeping the code short and readable. This paper provides a gentle introduction to this scripting language for researchers without formal informatics training such as many wet-lab scientists. We hope this will provide such researchers an idea of how powerful a tool Ruby can be for their data management tasks and encourage them to learn more about it.

Defective pigment granule biogenesis and aberrant behavior caused by mutations in the Drosophila AP-3beta adaptin gene ruby.

PubMed Central

Kretzschmar, D; Poeck, B; Roth, H; Ernst, R; Keller, A; Porsch, M; Strauss, R; Pflugfelder, G O

2000-01-01

Lysosomal protein trafficking is a fundamental process conserved from yeast to humans. This conservation extends to lysosome-like organelles such as mammalian melanosomes and insect eye pigment granules. Recently, eye and coat color mutations in mouse (mocha and pearl) and Drosophila (garnet and carmine) were shown to affect subunits of the heterotetrameric adaptor protein complex AP-3 involved in vesicle trafficking. Here we demonstrate that the Drosophila eye color mutant ruby is defective in the AP-3beta subunit gene. ruby expression was found in retinal pigment and photoreceptor cells and in the developing central nervous system. ruby mutations lead to a decreased number and altered size of pigment granules in various cell types in and adjacent to the retina. Humans with lesions in the related AP-3betaA gene suffer from Hermansky-Pudlak syndrome, which is caused by defects in a number of lysosome-related organelles. Hermansky-Pudlak patients have a reduced skin pigmentation and suffer from internal bleeding, pulmonary fibrosis, and visual system malfunction. The Drosophila AP-3beta adaptin also appears to be involved in processes other than eye pigment granule biogenesis because all ruby allele combinations tested exhibited defective behavior in a visual fixation paradigm. PMID:10790396

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kreel, Nathan E.; Tabita, F. Robert; Berg, Ivan

Archaeal ribulose 1, 5-bisphospate carboxylase/oxygenase (RubisCO) is differentiated from other RubisCO enzymes and is classified as a form III enzyme, as opposed to the form I and form II RubisCOs typical of chemoautotrophic bacteria and prokaryotic and eukaryotic phototrophs. The form III enzyme from archaea is particularly interesting as several of these proteins exhibit unusual and reversible sensitivity to molecular oxygen, including the enzyme from Archaeoglobus fulgidus. Previous studies with A. fulgidus RbcL2 had shown the importance of Met-295 in oxygen sensitivity and pointed towards the potential significance of another residue (Ser-363) found in a hydrophobic pocket that is conservedmore » in all RubisCO proteins. In the current study, further structure/function studies have been performed focusing on Ser-363 of A. fulgidus RbcL2; various changes in this and other residues of the hydrophobic pocket point to and definitively establish the importance of Ser-363 with respect to interactions with oxygen. In addition, previous findings had indicated discrepant CO 2/O 2 specificity determinations of the Thermococcus kodakaraensis RubisCO, a close homolog of A. fulgidus RbcL2. As a result, it is shown here that the T. kodakaraensis enzyme exhibits a similar substrate specificity as the A. fulgidus enzyme and is also oxygen sensitive, with equivalent residues involved in oxygen interactions.« less

Changes in Anthocyanin Production during Domestication of Citrus1[OPEN

PubMed Central

Garcia-Lor, Andrés; Licciardello, Concetta; Las Casas, Giuseppina; Ramadugu, Chandrika; Krueger, Robert; Fanciullino, Anne-Laure; Froelicher, Yann

2017-01-01

Mandarin (Citrus reticulata), citron (Citrus medica), and pummelo (Citrus maxima) are important species of the genus Citrus and parents of the interspecific hybrids that constitute the most familiar commercial varieties of Citrus: sweet orange, sour orange, clementine, lemon, lime, and grapefruit. Citron produces anthocyanins in its young leaves and flowers, as do species in genera closely related to Citrus, but mandarins do not, and pummelo varieties that produce anthocyanins have not been reported. We investigated the activity of the Ruby gene, which encodes a MYB transcription factor controlling anthocyanin biosynthesis, in different accessions of a range of Citrus species and in domesticated cultivars. A white mutant of lemon lacks functional alleles of Ruby, demonstrating that Ruby plays an essential role in anthocyanin production in Citrus. Almost all the natural variation in pigmentation by anthocyanins in Citrus species can be explained by differences in activity of the Ruby gene, caused by point mutations and deletions and insertions of transposable elements. Comparison of the allelic constitution of Ruby in different species and cultivars also helps to clarify many of the taxonomic relationships in different species of Citrus, confirms the derivation of commercial varieties during domestication, elucidates the relationships within the subgenus Papeda, and allows a new genetic classification of mandarins. PMID:28196843

Changes in Anthocyanin Production during Domestication of Citrus.

PubMed

Butelli, Eugenio; Garcia-Lor, Andrés; Licciardello, Concetta; Las Casas, Giuseppina; Hill, Lionel; Recupero, Giuseppe Reforgiato; Keremane, Manjunath L; Ramadugu, Chandrika; Krueger, Robert; Xu, Qiang; Deng, Xiuxin; Fanciullino, Anne-Laure; Froelicher, Yann; Navarro, Luis; Martin, Cathie

2017-04-01

Mandarin ( Citrus reticulata ), citron ( Citrus medica ), and pummelo ( Citrus maxima ) are important species of the genus Citrus and parents of the interspecific hybrids that constitute the most familiar commercial varieties of Citrus : sweet orange, sour orange, clementine, lemon, lime, and grapefruit. Citron produces anthocyanins in its young leaves and flowers, as do species in genera closely related to Citrus , but mandarins do not, and pummelo varieties that produce anthocyanins have not been reported. We investigated the activity of the Ruby gene, which encodes a MYB transcription factor controlling anthocyanin biosynthesis, in different accessions of a range of Citrus species and in domesticated cultivars. A white mutant of lemon lacks functional alleles of Ruby , demonstrating that Ruby plays an essential role in anthocyanin production in Citrus Almost all the natural variation in pigmentation by anthocyanins in Citrus species can be explained by differences in activity of the Ruby gene, caused by point mutations and deletions and insertions of transposable elements. Comparison of the allelic constitution of Ruby in different species and cultivars also helps to clarify many of the taxonomic relationships in different species of Citrus , confirms the derivation of commercial varieties during domestication, elucidates the relationships within the subgenus Papeda , and allows a new genetic classification of mandarins. © 2017 American Society of Plant Biologists. All Rights Reserved.

Bidirectional light-scattering image processing method for high-concentration jet sprays

NASA Astrophysics Data System (ADS)

Shimizu, I.; Emori, Y.; Yang, W.-J.; Shimoda, M.; Suzuki, T.

1985-01-01

In order to study the distributions of droplet size and volume density in high-concentration jet sprays, a new technique is developed, which combines the forward and backward light scattering method and an image processing method. A pulsed ruby laser is used as the light source. The Mie scattering theory is applied to the results obtained from image processing on the scattering photographs. The time history is obtained for the droplet size and volume density distributions, and the method is demonstrated by diesel fuel sprays under various injecting conditions. The validity of the technique is verified by a good agreement in the injected fuel volume distributions obtained by the present method and by injection rate measurements.

Lasers as an approach for promoting drug delivery via skin.

PubMed

Lin, Chih-Hung; Aljuffali, Ibrahim A; Fang, Jia-You

2014-04-01

Using lasers can be an effective drug permeation-enhancement approach for facilitating drug delivery into or across the skin. The controlled disruption and ablation of the stratum corneum (SC), the predominant barrier for drug delivery, is achieved by the use of lasers. The possible mechanisms of laser-assisted drug permeation are the direct ablation of the skin barrier, optical breakdown by a photomechanical wave and a photothermal effect. It has been demonstrated that ablative approaches for enhancing drug transport provide some advantages, including increased bioavailability, fast treatment time, quick recovery of SC integrity and the fact that skin surface contact is not needed. In recent years, the concept of using laser techniques to treat the skin has attracted increasing attention. This review describes recent developments in using nonablative and ablative lasers for drug absorption enhancement. This review systematically introduces the concepts and enhancement mechanisms of lasers, highlighting the potential of this technique for greatly increasing drug absorption via the skin. Lasers with different wavelengths and types are employed to increase drug permeation. These include the ruby laser, the erbium:yttrium-gallium-garnet laser, the neodymium-doped yttrium-aluminum-garnet laser and the CO2 laser. Fractional modality is a novel concept for promoting topical/transdermal drug delivery. The laser is useful in enhancing the permeation of a wide variety of permeants, such as small-molecule drugs, macromolecules and nanoparticles. This potential use of the laser affords a new treatment for topical/transdermal application with significant efficacy. Further studies using a large group of humans or patients are needed to confirm and clarify the findings in animal studies. Although the laser fluence or output energy used for enhancing drug absorption is much lower than for treatment of skin disorders and rejuvenation, the safety of using lasers is still an issue. Caution should be used in optimizing the feasible conditions of the lasers in balancing the effectiveness of permeation enhancement and skin damage.

Dichromatic laser radiation effects on DNA of Escherichia coli and plasmids

NASA Astrophysics Data System (ADS)

Martins, W. A.; Polignano, G. A. C.; Guimarães, O. R.; Geller, M.; Paoli, F.; Fonseca, A. S.

2015-04-01

Dichromatic and consecutive laser radiations have attracted increased attention for clinical applications as offering new tools for the treatment of dysfunctional tissues in situations where monochromatic radiation is not effective. This work evaluated the survival, filamentation and morphology of Escherichia coli cells, and the induction of DNA lesions, in plasmid DNA exposed to low-intensity consecutive dichromatic laser radiation. Exponential and stationary wild type and formamidopyrimidine DNA glycosylase/MutM protein deficient E. coli cultures were exposed to consecutive low-intensity dichromatic laser radiation (infrared laser immediately after red laser) to study the survival, filamentation and morphology of bacterial cells. Plasmid DNA samples were exposed to dichromatic radiation to study DNA lesions by electrophoretic profile. Dichromatic laser radiation affects the survival, filamentation and morphology of E. coli cultures depending on the growth phase and the functional repair mechanism of oxidizing lesions in DNA, but does not induce single/double strands breaks or alkali-labile DNA lesions. Results show that low-intensity consecutive dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation, suggesting that other therapeutic effects could be obtained using dichromatic radiation.

Vibration Analysis Of Automotive Structures Using Holographic Interferometry

NASA Astrophysics Data System (ADS)

Brown, G. M.; Wales, R. R.

1983-10-01

Since 1979, Ford Motor Company has been developing holographic interferometry to supplement more conventional test methods to measure vehicle component vibrations. An Apollo PHK-1 Double Pulse Holographic Laser System was employed to visualize a variety of complex vibration modes, primarily on current production and prototype powertrain components. Design improvements to reduce powertrain response to problem excitations have been deter-mined through pulsed laser holography, and have, in several cases, been put into production in Ford vehicles. Whole-field definition of vibration related deflections provide continuity of information missed by accelerometer/modal analysis techniaues. Certain opera-tional problems, common among pulsed ruby holographic lasers, have reauired ongoing hardware and electronics improvements to minimize system downtime. Real-time, time-averaged and stroboscopic C. W. laser holographic techniques are being developed at Ford to complement the double pulse capabilities and provide rapid identification of modal frequencies and nodal lines for analysis of powertrain structures. Methods for mounting and exciting powertrains to minimize rigid body motions are discussed. Work at Ford will continue toward development of C. W. holographic techniques to provide refined test methodology dedicated to noise and vibration diagnostics with particular emphasis on semi-automated methods for quantifying displacement and relative phase using high resolution digitized video and computers. Continued use of refined pulsed and CW laser holographic interferometry for the analysis of complex structure vibrations seems assured.

Characteristics of laser-induced shock wave injury to the inner ear of rats

NASA Astrophysics Data System (ADS)

Kurioka, Takaomi; Matsunobu, Takeshi; Niwa, Katsuki; Tamura, Atsushi; Kawauchi, Satoko; Satoh, Yasushi; Sato, Shunichi; Shiotani, Akihiro

2014-12-01

Recently, the number of blast injuries of the inner ear has increased in the general population. In blast-induced inner ear injury, a shock wave (SW) component in the blast wave is considered to play an important role in sensorineural hearing loss. However, the mechanisms by which an SW affects inner ear tissue remain largely unknown. We aimed to establish a new animal model for SW-induced inner ear injury by using laser-induced SWs (LISWs) on rats. The LISWs were generated by irradiating an elastic laser target with 694-nm nanosecond pulses of a ruby laser. After LISW application to the cochlea through bone conduction, auditory measurements revealed the presence of inner ear dysfunction, the extent of which depended on LISW overpressure. A significantly lower survival rate of hair cells and spiral ganglion neurons, as well as severe oxidative damage, were observed in the inner ear exposed to an LISW. Although considerable differences in the pressure characteristics exist between LISWs and SWs in real blast waves, the functional and morphological changes shown by the present LISW-based model were similar to those observed in real blast-induced injury. Thus, our animal model is expected to be useful for laboratory-based research of blast-induced inner ear injury.

Defect Detection on Carbon Fibre Reinforced Plastics (cfrp) with Laser Generated Lamb Waves

NASA Astrophysics Data System (ADS)

Focke, O.; Huke, P.; Hildebrandt, A.

2011-06-01

Standard ultrasound methods using a phased-array or a single transducer are commonly used for non-destructive evaluation (NDE) during manufacturing of carbon fiber reinforced plastics (CFRP) parts and certificated testing schemes were developed for individual parts and geometries. However, most testing methods need direct contact, matching gels and remain therefore time consuming. Laser-Ultrasonics is advantageous due to the contactless measurement technology and high accessibility even on complex parts. Despite the non-destructive testing with body waves, we show that the NDE can be expanded using two-dimensional surface (Lamb) waves for detection of delaminations close to the surface or small deteriorations caused by e.g. impacts. Lamb waves have been excited with a single transducer and with a short-pulse Laser with additionally producing A0-and S0-Lamb waves. The waves were detected with a shearography setup that allows for measuring two-dimensionally the displacement of a surface. Short integration times of the camera were realized using a pulsed ruby laser for illumination. As a consequence to the anisotropy the propagation in different directions exhibits individual characteristics like amplitude, damping and velocity. This has motivated to build up models for the propagation of Lamb waves and to compare them with experimental results.

Characteristics of laser-induced shock wave injury to the inner ear of rats.

PubMed

Kurioka, Takaomi; Matsunobu, Takeshi; Niwa, Katsuki; Tamura, Atsushi; Kawauchi, Satoko; Satoh, Yasushi; Sato, Shunichi; Shiotani, Akihiro

2014-12-01

Recently, the number of blast injuries of the inner ear has increased in the general population. In blast-induced inner ear injury, a shock wave (SW) component in the blast wave is considered to play an important role in sensorineural hearing loss. However, the mechanisms by which an SW affects inner ear tissue remain largely unknown. We aimed to establish a new animal model for SW-induced inner ear injury by using laser-induced SWs (LISWs) on rats. The LISWs were generated by irradiating an elastic laser target with 694-nm nanosecond pulses of a ruby laser. After LISW application to the cochlea through bone conduction, auditory measurements revealed the presence of inner ear dysfunction, the extent of which depended on LISW overpressure. A significantly lower survival rate of hair cells and spiral ganglion neurons, as well as severe oxidative damage, were observed in the inner ear exposed to an LISW. Although considerable differences in the pressure characteristics exist between LISWs and SWs in real blast waves, the functional and morphological changes shown by the present LISW-based model were similar to those observed in real blast-induced injury. Thus, our animal model is expected to be useful for laboratory-based research of blast-induced inner ear injury.

Geochemistry and geochronology of carbonate-hosted base metal deposits in the southern Brooks Range, Alaska: temporal association with VMS deposits and metallogenic implications

USGS Publications Warehouse

Kelly, Karen; Slack, John; Selby, David

2009-01-01

The Brooks Range contains enormous accumulations of zinc and copper, either as VMS or sediment-hosted deposits. The Ruby Creek and Omar deposits are Cu-Co stratabound deposits associated with dolomitic breccias. Numerous volcanogenic Cu-Zn (+/-Ag, Au) deposits are situated ~20 km north of the Ruby Creek deposit. The carbonate-hosted deposits consist of chalcopyrite and bornite that fill open spaces, replace the matrix of the breccias, and occur in later cross-cutting veins. Cobaltiferous pyrite, chalcocite, minor tennantite-tetrahedrite, galena, and sphalerite are also present. At Ruby Creek, phases such as carrollite, renierite, and germanite occur rarely. The deposits have undergone post-depositional metamorphism (Ruby Creek, low greenschist facies; Omar, blueschist facies). The unusual geochemical signature includes Cu-Co +/- Ag, As, Au, Bi, Ge, Hg, Sb, and U with sporadic high Re concentrations (up to 2.7 ppm). New Re-Os data were obtained for chalcopyrite, bornite, and pyrite from the Ruby Creek deposit (analyses of sulfides from Omar are in progress). The data show extremely high Re abundances (hundreds of ppb, low ppm) and contain essentially no common Os. The Re-Os data provide the first absolute ages of ore formation for the Ruby Creek deposit and demonstrate that the Re-Os systematics of pyrite, chalcopyrite, and bornite are unaffected by greenschist metamorphism. The Re-Os data show that the main phase of Cu mineralization occurred at 384 +/-4.2 Ma, which coincides with zircon U-Pb ages from igneous rocks that are spatially and genetically associated with VMS deposits. This suggests a temporal link between regional magmatism and hydrothermal mineralization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Gauri S; Romagnoli, Simona; Verberkmoes, Nathan C

Rhodopseudomonas palustris is unique among characterized nonsulfur purple bacteria because of its capacity for anaerobic photoheterotrophic growth using aromatic acids. Like growth with other reduced electron donors, this growth typically requires the presence of bicarbonate/CO{sub 2} or some other added electron acceptor in the growth medium. Proteomic studies indicated that there was specific accumulation of form I ribulose 1, 5-bisphosphate carboxylase/oxygenase (RubisCO) subunit proteins (CbbL and CbbS), as well as the CbbX protein, in cells grown on benzoate without added bicarbonate; such cells used the small amounts of dissolved CO{sub 2} in the medium to support growth. These proteins weremore » not observed in extracts from cells grown in the presence of high levels (10 mM) of added bicarbonate. To confirm the results of the proteomics studies, it was shown that the total RubisCO activity levels were significantly higher (five- to sevenfold higher) in wild-type (CGA010) cells grown on benzoate with a low level (0.5 mM) of added bicarbonate. Immunoblots indicated that the increase in RubisCO activity levels was due to a specific increase in the amount of form I RubisCO (CbbLS) and not in the amount of form II RubisCO (CbbM), which was constitutively expressed. Deletion of the main transcriptional regulator gene, cbbR, resulted in impaired growth on benzoate-containing low-bicarbonate media, and it was established that form I RubisCO synthesis was absolutely and specifically dependent on CbbR. To understand the regulatory role of the CbbRRS two-component system, strains with nonpolar deletions of the cbbRRS genes were grown on benzoate. Distinct from the results obtained with photoautotrophic growth conditions, the results of studies with various CbbRRS mutant strains indicated that this two-component system did not affect the observed enhanced synthesis of form I RubisCO under benzoate growth conditions. These studies indicate that diverse growth conditions differentially affect the ability of the CbbRRS two-component system to influence cbb transcription.« less

Standard Reference Material (SRM 1990) for Single Crystal Diffractometer Alignment

USGS Publications Warehouse

Wong-Ng, W.; Siegrist, T.; DeTitta, G.T.; Finger, L.W.; Evans, H.T.; Gabe, E.J.; Enright, G.D.; Armstrong, J.T.; Levenson, M.; Cook, L.P.; Hubbard, C.R.

2001-01-01

An international project was successfully completed which involved two major undertakings: (1) a round-robin to demonstrate the viability of the selected standard and (2) the certification of the lattice parameters of the SRM 1990, a Standard Reference Material?? for single crystal diffractometer alignment. This SRM is a set of ???3500 units of Cr-doped Al2O3, or ruby spheres [(0 420.011 mole fraction % Cr (expanded uncertainty)]. The round-robin consisted of determination of lattice parameters of a pair of crystals' the ruby sphere as a standard, and a zeolite reference to serve as an unknown. Fifty pairs of crystals were dispatched from Hauptman-Woodward Medical Research Institute to volunteers in x-ray laboratories world-wide. A total of 45 sets of data was received from 32 laboratories. The mean unit cell parameters of the ruby spheres was found to be a=4.7608 A?? ?? 0.0062 A??, and c=12.9979 A?? ?? 0.020 A?? (95 % intervals of the laboratory means). The source of errors of outlier data was identified. The SRM project involved the certification of lattice parameters using four well-aligned single crystal diffractometers at (Bell Laboratories) Lucent Technologies and at NRC of Canada (39 ruby spheres), the quantification of the Cr content using a combined microprobe and SEM/EDS technique, and the evaluation of the mosaicity of the ruby spheres using a double-crystal spectrometry method. A confirmation of the lattice parameters was also conducted using a Guinier-Ha??gg camera. Systematic corrections of thermal expansion and refraction corrections were applied. These rubies_ are rhombohedral, with space group R3c. The certified mean unit cell parameters are a=4.76080 ?? 0.00029 A??, and c=12 99568 A?? ?? 0.00087 A?? (expanded uncertainty). These certified lattice parameters fall well within the results of those obtained from the international round-robin study. The Guinier-Ha??gg transmission measurements on five samples of powdered rubies (a=4.7610 A?? ?? 0.0013 A??, and c=12.9954 A?? ?? 0.0034 A??) agreed well with the values obtained from the single crystal spheres.

An introduction to scripting in Ruby for biologists

PubMed Central

Aerts, Jan; Law, Andy

2009-01-01

The Ruby programming language has a lot to offer to any scientist with electronic data to process. Not only is the initial learning curve very shallow, but its reflection and meta-programming capabilities allow for the rapid creation of relatively complex applications while still keeping the code short and readable. This paper provides a gentle introduction to this scripting language for researchers without formal informatics training such as many wet-lab scientists. We hope this will provide such researchers an idea of how powerful a tool Ruby can be for their data management tasks and encourage them to learn more about it. PMID:19607723

EFFECTS OF LASER RADIATION ON MATTER: Spectrum of the barium atom in a laser radiation field

NASA Astrophysics Data System (ADS)

Bondar', I. I.; Suran, V. V.

1990-08-01

An experimental investigation was made of the influence of a laser radiation field on the spectrum of barium atoms. The investigation was carried out by the method of three-photon ionization spectroscopy using dye laser radiation (ω = 14 800-18 700 cm - 1). The electric field intensity of the laser radiation was 103-106 V/cm. This laser radiation field had a strong influence on a number of bound and autoionizing states. The nature of this influence depended on the ratio of the excitation frequencies of bound and autoionizing states.

75 FR 3221 - Ruby Pipeline, L.L.C.; Notice of Availability of the Final Environmental Impact Statement for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-20

... effects of the construction and operation of the following project facilities: About 675.2 miles of 42... any of the following methods: Web site: http://www.blm.gov/nv/st/en/info/nepa/ruby_pipeline_project...

Calcium rubies: a family of red-emitting functionalizable indicators suitable for two-photon Ca2+ imaging.

PubMed

Collot, Mayeul; Loukou, Christina; Yakovlev, Aleksey V; Wilms, Christian D; Li, Dongdong; Evrard, Alexis; Zamaleeva, Alsu; Bourdieu, Laurent; Léger, Jean-François; Ropert, Nicole; Eilers, Jens; Oheim, Martin; Feltz, Anne; Mallet, Jean-Maurice

2012-09-12

We designed Calcium Rubies, a family of functionalizable BAPTA-based red-fluorescent calcium (Ca(2+)) indicators as new tools for biological Ca(2+) imaging. The specificity of this Ca(2+)-indicator family is its side arm, attached on the ethylene glycol bridge that allows coupling the indicator to various groups while leaving open the possibility of aromatic substitutions on the BAPTA core for tuning the Ca(2+)-binding affinity. Using this possibility we now synthesize and characterize three different CaRubies with affinities between 3 and 22 μM. Their long excitation and emission wavelengths (peaks at 586/604 nm) allow their use in otherwise challenging multicolor experiments, e.g., when combining Ca(2+) uncaging or optogenetic stimulation with Ca(2+) imaging in cells expressing fluorescent proteins. We illustrate this capacity by the detection of Ca(2+) transients evoked by blue light in cultured astrocytes expressing CatCh, a light-sensitive Ca(2+)-translocating channelrhodopsin linked to yellow fluorescent protein. Using time-correlated single-photon counting, we measured fluorescence lifetimes for all CaRubies and demonstrate a 10-fold increase in the average lifetime upon Ca(2+) chelation. Since only the fluorescence quantum yield but not the absorbance of the CaRubies is Ca(2+)-dependent, calibrated two-photon fluorescence excitation measurements of absolute Ca(2+) concentrations are feasible.

Optical Diagnostics on HIT-SI3

NASA Astrophysics Data System (ADS)

Everson, Christopher; Jarboe, Thomas; Morgan, Kyle

2016-10-01

Interferometry and Thomson Scattering are implemented on the HIT-SI3 (Helicity Injected Torus - Steady Inductive 3) device to provide time resolved measurements of electron density and spatially resolved measurements of electron temperature, respectively. HIT-SI3 is a modification of the original HIT-SI apparatus that uses three injectors instead of two. The scientific aim of HIT-SI3 is to develop a deeper understanding of how injector behavior and interactions influence current drive and spheromak stability. The interferometer system makes use of an intermediate frequency between two parallel 184.3 μm Far-Infrared (FIR) laser cavities which are optically pumped by a CO2 laser. The phase shift in this beat frequency due to the plasma index of refraction is used to calculate the line-integrated electron density. To measure the electron temperature, Thomson Scattered light from a 20 J (1 GW pulse) Ruby laser off of free electrons in the HIT-SI3 plasma is measured simultaneously at four locations across the spheromak (nominally 23 cm minor radius). Polychromators bin the collected light into 3 spectral bands to detect the relative level of scattering. Work supported by the D.O.E.

Instrument to synchronize Thomson scattering diagnostic measurements with MHD acitivity in a tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wintenberg, A.L.

1985-04-01

An instrument to synchronize the firing of a ruby laser for a Thomson scattering diagnostic with plasma oscillations was designed, developed, and evaluated. The instrument will fire the laser at a user-selected phase of an input sine or sawtooth wave with an accuracy of +-15/sup 0/. Allowable frequencies range from 20 to 500 Hz for a sawtooth and from 1 to 30 kHz for a sine wave. The instrument also allows synchronization with a sine wave to be enabled by a preselected sawtooth phase. The instrument uses analog signal processing circuits to separate the signal components, remove unwanted components, andmore » produce zero-phase synchronization pulses. The instrument measures the period between zero-phase pulses in order to produce phase synchronization pulses delayed a fraction of the period from the zero-phase pulses. The laser is fired by the phase synchronization pulse. Unwanted signal components are attenuated by bandpass filters. A digitally controlled self-adjusting bandpass filter for sine processing. The instrument was used to investigate the variation of the electron temperature profile with the phase of the x-ray signal from an Impurity Studies Experiment (ISX-B) plasma exhibiting magnetohydrodynamic (MHD) activity.« less

Comparison of the ablation ability of nucleus pulposus after 1,064 nm Nd:YAG laser and 980 nm diode laser radiation.

PubMed

Yin, Jian; Han, Zhengfeng; Guo, Baofeng; Guo, Han; Zhang, Tongtong; Zeng, Yanjun; Ren, Longxi

2015-07-01

To compare the ablation ability of nucleus pulposus after 1,064 nm Nd:YAG laser and 980 nm diode laser radiation. Goat spine specimen (GSS) was radiated using Nd:YAG laser and 980 nm diode laser and then divided into five groups based on the final energy--200, 400, 600, 800 and 1,000 J groups. The ablation quality of nucleus pulposus after radiation was recorded. The ablation quality of GSS was greater at higher radiation energies in both lasers. When compared at the same energy level, the ablation quality of GSS was greater in 980 nm diode laser than in 1,064 nm Nd:YAG laser. Statistical significance was observed in 200 and 400 J groups (P < 0.05) and in 600, 800 and 1,000 J groups (P < 0.01). Radiation with 980 nm diode laser showed better ablation ability than 1,064 nm Nd:YAG laser.

EFFECTS OF LASER RADIATION ON MATTER: Influence of the ambient air pressure on short-wavelength radiation from a laser plasma

NASA Astrophysics Data System (ADS)

Golovin, A. F.; Zemtsov, S. S.; Fedyushin, B. T.

1991-12-01

A detailed experimental investigation was made of the radiation from a plasma created on an aluminum target by a pulsed CO2 laser at different ambient gas pressures. Measurements were made of the energy and angular distribution of the radiation and of the efficiency of conversion of laser energy into reemitted plasma radiation. The intensity of this radiation was found to exhibit pressure-dependent pulsations. The maximum reflection of the laser radiation from the plasma was recorded at a pressure of ~ 40 Torr. An interpretation is given of the experimental data.

Whole genome sequences of the raspberry and strawberry pathogens Phytophthora rubi and P. fragariae

USDA-ARS?s Scientific Manuscript database

Phytophthora rubi and P. fragariae are two closely related oomycete plant pathogens that exhibit strong morphological and physiological similarities, but are specialized to infect different hosts of economic importance, namely raspberry and strawberry. Here, we report the draft genome sequences of t...

Origin of the different color of ruby and emerald

NASA Astrophysics Data System (ADS)

García-Lastra, J. M.; Barriuso, M. T.; Aramburu, J. A.; Moreno, M.

2005-09-01

The different color exhibited by ruby and emerald is a fundamental but still unsolved question. According to recent EXAFS measurements, such a difference can hardly be explained on the basis of a different average distance between Cr3+ and the six oxygen ligands. The puzzling difference in color between the two gemstones is shown in this work to arise essentially from the distinct electrostatic potential imposed by the rest of lattice ions upon the active electrons of the CrO69- unit. Main effects are shown to come from the electric field generated in the neighborhood of the Cr3+ site in ruby which is absent in the case of emerald due to symmetry.

The DV-Xα Calculations of Optical Spectra and Their Pressure-Induced Shifts for Ruby

NASA Astrophysics Data System (ADS)

Ma, Dongping; Ellis, D. E.; Liu, Yanyun; Chen, Jurong

1997-10-01

The R line and U band at normal pressure and their pressure-induced shifts of ruby have been calculated by making use of the SCF embedded-cluster discrete variational (DV-Xα) method. The calculated results of the spectral pressure-induced shifts of ruby by making use of the crystal-field theory have also been given. The results of the first-principle calculations are in very good agreement with the experimental data and the calculated results by using crystal-field theory. The results of local lattice relaxations around the Cr3+ ion are obtained by the DV-Xα calculations. The project supported by National Natural Science Foundation of China

Current and long-term technologies of laser therapy

NASA Astrophysics Data System (ADS)

Ulashcyk, Vladimir S.; Volotovskaya, Anna V.

2007-06-01

Laser therapy, using low-energy laser radiation, is being more and more applied. The most applied technology is transcutaneous radiation of tissues by laser radiation. Originally, a direct action on a pathological site was mostly used, but recently more attention is given to reflexogenic areas, acupuncture points, and endocrine organ projection sites. The development of light-conductive engineering made it possible to practically apply intraorgan laser therapy. This technology is widely spread in gynecology, otorhinolaryngology, urology, gastroenterology, etc. Close to it are different versions of intratissue laser therapy (intraosteal, periosteal, myofascial). A special kind of laser therapy is laser hemotherapy. Depending on the techniques and protocol of its application, there are extracorporeal, intravascular, and supravenous ways of action. According to our comparative investigations, supravenous hemotherapy by its therapeutic efficacy and major medicinal effects can be well compared with intravascular laser hemotherapy. With good prospects and efficiency is laser therapy as a combination of laser and other physical factors. Magnetolaser therapy has been scientifically substantiated and practically applied so far. Theoretically and experimentally substantiated is a combined application of laser radiation and physical factors such as ultrasound, direct current field, vacuum, cryotherapy, etc. Experimental research and few so far clinical observations are indicative of prospects of a complex application of laser radiation and drugs. To improve light absorption, laser radiation is combined with different dyes. Photodynamic therapy, originally used in oncology, is applied today in treating different diseases. We showed a possibility of using a number of drugs possessing simultaneously photosensitizing properties to this end. Laser radiation significantly influences pharmacokinetics and pharmacodynamics of drugs, which gives reason to practically implement laser technologies, based on pharmacomodulating action of laser radiation, to practical medicine.

Reconstruction of a three-dimensional, transonic rotor flow field from holographic interferogram data

NASA Technical Reports Server (NTRS)

Kittleson, John K.; Yu, Yung H.

1987-01-01

Holographic interferometry and computerized aided tomography (CAT) are used to determine the transonic velocity field of a model rotor blade in hover. A pulsed ruby laser recorded 40 interferograms with a 2 ft dia view field near the model rotor blade tip operating at a tip Mach number of 0.90. After digitizing the interferograms and extracting the fringe order functions, the data are transferred to a CAT code. The CAT code then calculates the perturbation velocity in several planes above the blade surface. The values from the holography-CAT method compare favorably with previously obtained numerical computations in most locations near the blade tip. The results demonstrate the technique's potential for three dimensional transonic rotor flow studies.

Optical radiation hazards of laser welding processes. Part 1: Neodymium-YAG laser.

PubMed

Rockwell, R J; Moss, C E

1983-08-01

High power laser devices are being used for numerous metalworking processes such as welding, cutting and heat treating. Such laser devices are totally enclosed either by the manufacturer or the end-user. When this is done, the total laser system is usually certified by the manufacturer following the federal requirements of the Code of Federal Regulations (CFR) 1040.10 and 10.40.11 as a Class I laser system. Similarly, the end-user may also reclassify an enclosed high-power laser into the Class I category following the requirements of the American National Standards Institute (ANSI) Z-136.1 (1980) standard. There are, however, numerous industrial laser applications where Class IV systems are required to be used in an unenclosed manner. In such applications, there is concern for both ocular and skin hazards caused by direct and scattered laser radiation, as well as potential hazards caused by the optical radiation created by the laser beam's interaction with the metal (i.e. the plume radiation). Radiant energy measurements are reported for both the scattered laser radiation and the resultant plume radiations which were produced during typical unenclosed Class IV Neodymium-YAG laser welding processes. Evaluation of the plume radiation was done with both radiometric and spectroradiometric measurement equipment. The data obtained were compared to applicable safety standards.

Teaching Financial Literacy with Max and Ruby

ERIC Educational Resources Information Center

Brown, Natalya; Ferguson, Kristen

2017-01-01

Teaching financial literacy is important at all stages of life, but is often neglected with elementary students. In this article, the authors describe a strategy for teaching financial literacy using the books about Max and Ruby by Rosemary Wells. These books can help introduce the five key concepts of financial literacy: scarcity, exchange,…

78 FR 40496 - Notice of Availability of the Draft Supplemental Environmental Impact Statement for the Ruby...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-05

...; MO 4500051040; TAS: 14X5017] Notice of Availability of the Draft Supplemental Environmental Impact... Availability. SUMMARY: In accordance with the National Environmental Policy Act of 1969, as amended (NEPA), and...) has prepared a Draft Supplemental Environmental Impact Statement (EIS) for the Ruby Pipeline Project...

75 FR 13676 - Prohibitions and Conditions for Importation of Burmese and Non-Burmese Covered Articles of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-23

... non- Burmese covered articles, affirming that an established system of verified controls from the mine... Importation of Burmese and Non- Burmese Covered Articles of Jadeite, Rubies, and Articles of Jewelry... importation of Burmese and non-Burmese covered articles of jadeite, rubies, and articles of jewelry containing...

Using ruby on rails to develop a web interface: a research-based exemplar with a computerized physical activity reporter.

PubMed

Blaz, Jacquelyn W; Pearce, Patricia F

2009-01-01

The world is becoming increasingly web-based. Health care institutions are utilizing the web for personal health records, surveillance, communication, and education; health care researchers are finding value in using the web for research subject recruitment, data collection, and follow-up. Programming languages, such as Java, require knowledge and experience usually found only in software engineers and consultants. The purpose of this paper is to demonstrate Ruby on Rails as a feasible alternative for programming questionnaires for use on the web. Ruby on Rails was specifically designed for the development, deployment, and maintenance of database-backed web applications. It is flexible, customizable, and easy to learn. With a relatively little initial training, a novice programmer can create a robust web application in a small amount of time, without the need of a software consultant. The translation of the Children's Computerized Physical Activity Reporter (C-CPAR) from a local installation in Microsoft Access to a web-based format utilizing Ruby on Rails is given as an example.

Numerical Investigation of Radiative Heat Transfer in Laser Induced Air Plasmas

NASA Technical Reports Server (NTRS)

Liu, J.; Chen, Y. S.; Wang, T. S.; Turner, James E. (Technical Monitor)

2001-01-01

Radiative heat transfer is one of the most important phenomena in the laser induced plasmas. This study is intended to develop accurate and efficient methods for predicting laser radiation absorption and plasma radiative heat transfer, and investigate the plasma radiation effects in laser propelled vehicles. To model laser radiation absorption, a ray tracing method along with the Beer's law is adopted. To solve the radiative transfer equation in the air plasmas, the discrete transfer method (DTM) is selected and explained. The air plasma radiative properties are predicted by the LORAN code. To validate the present nonequilibrium radiation model, several benchmark problems are examined and the present results are found to match the available solutions. To investigate the effects of plasma radiation in laser propelled vehicles, the present radiation code is coupled into a plasma aerodynamics code and a selected problem is considered. Comparisons of results at different cases show that plasma radiation plays a role of cooling plasma and it lowers the plasma temperature by about 10%. This change in temperature also results in a reduction of the coupling coefficient by about 10-20%. The present study indicates that plasma radiation modeling is very important for accurate modeling of aerodynamics in a laser propelled vehicle.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Microwave generation in an optical breakdown plasma created by modulated laser radiation

NASA Astrophysics Data System (ADS)

Antipov, A. A.; Grasyuk, Arkadii Z.; Losev, Leonid L.; Soskov, V. I.

1990-06-01

It was established that when laser radiation, intensity modulated at a frequency of 2.2 GHz, interacted with an optical breakdown plasma which it had created, a microwave component appeared in the thermal emf of the plasma. The amplitude of the microwave thermal emf reached 0.7 V for a laser radiation intensity of 6 GW/cm2. Laser radiation with λL = 1.06 μm was converted to the microwave range with λmω = 13 cm in the optical breakdown plasma. A microwave signal power of ~ 0.5 W was obtained from a laser power of ~ 5 MW.

Thermomechanical effect of pulse-periodic laser radiation on cartilaginous and eye tissues

NASA Astrophysics Data System (ADS)

Baum, O. I.; Zheltov, G. I.; Omelchenko, A. I.; Romanov, G. S.; Romanov, O. G.; Sobol, E. N.

2013-08-01

This paper is devoted to theoretical and experimental studies into the thermomechanical action of laser radiation on biological tissues. The thermal stresses and strains developing in biological tissues under the effect of pulse-periodic laser radiation are theoretically modeled for a wide range of laser pulse durations. The models constructed allow one to calculate the magnitude of pressures developing in cartilaginous and eye tissues exposed to laser radiation and predict the evolution of cavitation phenomena occurring therein. The calculation results agree well with experimental data on the growth of pressure and deformations, as well as the dynamics of formation of gas bubbles, in the laser-affected tissues. Experiments on the effect of laser radiation on the trabecular region of the eye in minipigs demonstrated that there existed optimal laser irradiation regimens causing a substantial increase in the hydraulic permeability of the radiation-exposed tissue, which can be used to develop a novel glaucoma treatment method.

Kinematics of the mosquito terrane, Coldfoot Area, Alaska: Keys to Brooks Range tectonics: Final report, Project No. 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harms, T.A.; Coney, P.J.

1988-04-01

Within the large-scale geometry of the Brooks Range, the Angayucham terrane occurs as a vast overthrust sheet. From the north flank of the Ruby terrane it underlies the Koyukuk basin and stretches north as the roof thrust to the various nappe terranes of the Brooks Range. The tectonic relationship of the Ruby terrane to the south flank of the Brooks Range lies largely obscured beneath the Angayucham in the eastern apex of the Koyukuk basin. The Mosquito terrane occurs as a window through the Angayucham at this juncture. The composition and structures of the Mosquito terrane reveal that is themore » result of shear along a sub-horizontal step or flange within the prominent, through-going dextral strike-slip fault system which cuts across the eastern Koyukuk basin and southeastern Brooks Range. Units of the Mosquito were derived from both the Angayucham and Ruby terranes. A consistent tectonic fabric imposed upon them is kinematically linked to the strike-slip system and indicates a northeasterly direction of transport across the terrane. The presence of Ruby-correlative units within the Mosquito suggests the Ruby underlies the Angayucham and that it is in contact with terrances of the southern Brooks Range at that structural level along high-angle strike-slip faults. These relationships demonstrate that an episode of dextral transpression is the latest in the history of terrane accretion and tectonic evolution of the Brooks Range. 35 refs.« less

Serine 363 of a Hydrophobic Region of Archaeal Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from Archaeoglobus fulgidus and Thermococcus kodakaraensis Affects CO2/O2 Substrate Specificity and Oxygen Sensitivity.

PubMed

Kreel, Nathan E; Tabita, F Robert

2015-01-01

Archaeal ribulose 1, 5-bisphospate carboxylase/oxygenase (RubisCO) is differentiated from other RubisCO enzymes and is classified as a form III enzyme, as opposed to the form I and form II RubisCOs typical of chemoautotrophic bacteria and prokaryotic and eukaryotic phototrophs. The form III enzyme from archaea is particularly interesting as several of these proteins exhibit unusual and reversible sensitivity to molecular oxygen, including the enzyme from Archaeoglobus fulgidus. Previous studies with A. fulgidus RbcL2 had shown the importance of Met-295 in oxygen sensitivity and pointed towards the potential significance of another residue (Ser-363) found in a hydrophobic pocket that is conserved in all RubisCO proteins. In the current study, further structure/function studies have been performed focusing on Ser-363 of A. fulgidus RbcL2; various changes in this and other residues of the hydrophobic pocket point to and definitively establish the importance of Ser-363 with respect to interactions with oxygen. In addition, previous findings had indicated discrepant CO2/O2 specificity determinations of the Thermococcus kodakaraensis RubisCO, a close homolog of A. fulgidus RbcL2. It is shown here that the T. kodakaraensis enzyme exhibits a similar substrate specificity as the A. fulgidus enzyme and is also oxygen sensitive, with equivalent residues involved in oxygen interactions.

Serine 363 of a Hydrophobic Region of Archaeal Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from Archaeoglobus fulgidus and Thermococcus kodakaraensis Affects CO2/O2 Substrate Specificity and Oxygen Sensitivity

PubMed Central

Kreel, Nathan E.; Tabita, F. Robert

2015-01-01

Archaeal ribulose 1, 5-bisphospate carboxylase/oxygenase (RubisCO) is differentiated from other RubisCO enzymes and is classified as a form III enzyme, as opposed to the form I and form II RubisCOs typical of chemoautotrophic bacteria and prokaryotic and eukaryotic phototrophs. The form III enzyme from archaea is particularly interesting as several of these proteins exhibit unusual and reversible sensitivity to molecular oxygen, including the enzyme from Archaeoglobus fulgidus. Previous studies with A. fulgidus RbcL2 had shown the importance of Met-295 in oxygen sensitivity and pointed towards the potential significance of another residue (Ser-363) found in a hydrophobic pocket that is conserved in all RubisCO proteins. In the current study, further structure/function studies have been performed focusing on Ser-363 of A. fulgidus RbcL2; various changes in this and other residues of the hydrophobic pocket point to and definitively establish the importance of Ser-363 with respect to interactions with oxygen. In addition, previous findings had indicated discrepant CO2/O2 specificity determinations of the Thermococcus kodakaraensis RubisCO, a close homolog of A. fulgidus RbcL2. It is shown here that the T. kodakaraensis enzyme exhibits a similar substrate specificity as the A. fulgidus enzyme and is also oxygen sensitive, with equivalent residues involved in oxygen interactions. PMID:26381513

Serine 363 of a hydrophobic region of Archaeal ribulose 1,5-bisphosphate carboxylase/oxygenase from Archaeoglobus fulgidus and Thermococcus kodakaraensis affects CO 2/O 2 substrate specificity and oxygen sensitivity

DOE PAGES

Kreel, Nathan E.; Tabita, F. Robert; Berg, Ivan

2015-09-18

Archaeal ribulose 1, 5-bisphospate carboxylase/oxygenase (RubisCO) is differentiated from other RubisCO enzymes and is classified as a form III enzyme, as opposed to the form I and form II RubisCOs typical of chemoautotrophic bacteria and prokaryotic and eukaryotic phototrophs. The form III enzyme from archaea is particularly interesting as several of these proteins exhibit unusual and reversible sensitivity to molecular oxygen, including the enzyme from Archaeoglobus fulgidus. Previous studies with A. fulgidus RbcL2 had shown the importance of Met-295 in oxygen sensitivity and pointed towards the potential significance of another residue (Ser-363) found in a hydrophobic pocket that is conservedmore » in all RubisCO proteins. In the current study, further structure/function studies have been performed focusing on Ser-363 of A. fulgidus RbcL2; various changes in this and other residues of the hydrophobic pocket point to and definitively establish the importance of Ser-363 with respect to interactions with oxygen. In addition, previous findings had indicated discrepant CO 2/O 2 specificity determinations of the Thermococcus kodakaraensis RubisCO, a close homolog of A. fulgidus RbcL2. As a result, it is shown here that the T. kodakaraensis enzyme exhibits a similar substrate specificity as the A. fulgidus enzyme and is also oxygen sensitive, with equivalent residues involved in oxygen interactions.« less

Holographic Cinematography With The Help Of A Pulse YAG Laser

NASA Astrophysics Data System (ADS)

Smigielski, P.; Fagot, H.; Albe, F.

1985-02-01

For many years opticists have tried to achieve 3D-cinematography with the help of holography. The term "cineholography" has been introduced in 1965. At that time the method consisted in superimposing on the same photographic plate various holograms recorded at different times. The image separation was achieved by rotating either the plate in its plane or the reference beam during both the recording and reconstructing processes. The number of views was limited by the principle itself, but a high repetition rate (100 kHz) has been obtained with a pulsed ruby laser. Then other experiments have been conducted by different authors, mainly in the Soviet Unions and in the United States of America, by using the principle of classical cinematography in which the image separation is obtained by translating the film. With this method we have recorded the first French holographic movies on 35 mm Agfa films with the help of a pulsed YAG laser built in our laboratory. This frequency doubled laser (X = 0.532 pm) delivers pulses of 20 ns with an energy of 30 HO at a repetition rate of 24 Hz. The experimental arrangements are described and some images of diffuse moving objects are presented. The volume of the recording scene is greater than one cubic meter. The coherence length of the laser is higher than one meter and remains steady during the recording process. Results are discussed and an outlook on the future is given with special respect to high repetition rate techniques.

Laser and Light Treatments for Hair Reduction in Fitzpatrick Skin Types IV-VI: A Comprehensive Review of the Literature.

PubMed

Fayne, Rachel A; Perper, Marina; Eber, Ariel E; Aldahan, Adam S; Nouri, Keyvan

2018-04-01

Unwanted facial and body hair presents as a common finding in many patients, such as females with hirsutism. With advances in laser and light technology, a clinically significant reduction in hair can be achieved in patients with light skin. However, in patients with darker skin, Fitzpatrick skin types (FST) IV-VI, the higher melanin content of the skin interferes with the proposed mechanism of laser-induced selective photothermolysis, which is to target the melanin in the hair follicle to cause permanent destruction of hair bulge stem cells. Many prospective and retrospective studies have been conducted with laser and light hair-removal devices, but most exclude patients with darkly pigmented skin, considering them a high-risk group for unwanted side effects, including pigmentation changes, blisters, and crust formation. We reviewed the published literature to obtain studies that focused on hair reduction for darker skin types. The existing literature for this patient population identifies longer wavelengths as a key element of the treatment protocol and indicates neodymium-doped yttrium aluminum garnet (Nd:YAG), diode, alexandrite, and ruby lasers as well as certain intense pulsed light sources for safe hair reduction with minimal side effects in patients with FST IV-VI, so long as energy settings and wavelengths are appropriate. Based on the findings in this review, safe and effective hair reduction for patients with FST IV-VI is achievable under proper treatment protocols and energy settings.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); Tang, Shoou-yu (Inventor); O'Brien, Martin (Inventor)

2010-01-01

Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Weimer, Carl S. (Inventor); Nelson, Loren D. (Inventor)

2008-01-01

Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Weimer, Carl S. (Inventor); Nelson, Loren D. (Inventor)

2005-01-01

Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

Generation and use of high power 213 nm and 266 nm laser radiation and tunable 210-400 nm laser radiation with BBO crystal matrix array

DOEpatents

Gruen, Dieter M.

2000-01-01

A 213 nm laser beam is capable of single photon ablative photodecomposition for the removal of a polymer or biological material substrate. Breaking the molecular bonds and displacing the molecules away from the substrate in a very short time period results in most of the laser photon energy being carried away by the displaced molecules, thus minimizing thermal damage to the substrate. The incident laser beam may be unfocussed and is preferably produced by quintupling the 1064 nm radiation from a Nd:YAG solid state laser, i.e., at 213 nm. In one application, the 213 nm laser beam is expanded in cross section and directed through a plurality of small beta barium borate (BBO) crystals for increasing the energy per photon of the laser radiation directed onto the substrate. The BBO crystals are arranged in a crystal matrix array to provide a large laser beam transmission area capable of accommodating high energy laser radiation without damaging the BBO crystals. The BBO crystal matrix array may also be used with 266 nm laser radiation for carrying out single or multi photon ablative photodecomposition. The BBO crystal matrix array may also be used in an optical parametric oscillator mode to generate high power tunable laser radiation in the range of 210-400 nm.

Peddling Poverty for Profit: Elements of Oppression in Ruby Payne's Framework

ERIC Educational Resources Information Center

Gorski, Paul C.

2008-01-01

Ruby Payne, CEO of aha! Process, Inc., and author of "A Framework for Understanding Poverty" (2005), has become one of the most influential figures in the U.S. public education milieu. Payne's framework, built largely upon understanding the "culture" of poverty, instructs educators on the values and mindsets poor students carry into the classroom…

Pathogenicity, fungicide resistance, and genetic variability of Phytophthora rubi isolates from raspberry (Rubus idaeus) in the Western United States

USDA-ARS?s Scientific Manuscript database

Root rot of raspberry (Rubus idaeus), thought to be primarily caused by Phytophthora rubi, is an economically important disease in the western United States. The objectives of this study were to determine which Phytophthora species are involved in root rot, examine the efficacy of different isolatio...

A dual-cavity ruby maser for the Ka-band link experiment

NASA Technical Reports Server (NTRS)

Shell, J.; Quinn, R. B.

1994-01-01

A 33.68-GHz dual-cavity ruby maser was built to support the Ka-Band Link Experiment (KABLE) conducted with the Mars Observer spacecraft. It has 25 dB of net gain and a 3-dB bandwidth of 85 MHz. Its noise temperature in reference to the cooled feedhorn aperture is 5 K.

[The laser therapy of rheumatoid arthritis].

PubMed

Soroka, N F

1989-01-01

About 300 patients with rheumatoid arthritis (RA) underwent multimodality treatment including laser radiation of varying wavelengths. Use was made of helium-neon, infrared, argon and helium-cadmium lasers. A new method of combined laser therapy by radiation of helium-cadmium and helium-neon lasers is described. A scheme of optimal parameters and types of laser radiation recommended for the treatment of different clinical varieties of RA is provided.

X-ray laser system, x-ray laser and method

DOEpatents

London, Richard A.; Rosen, Mordecai D.; Strauss, Moshe

1992-01-01

Disclosed is an x-ray laser system comprising a laser containing generating means for emitting short wave length radiation, and means external to said laser for energizing said generating means, wherein when the laser is in an operative mode emitting radiation, the radiation has a transverse coherence length to width ratio of from about 0.05 to 1. Also disclosed is a method of adjusting the parameters of the laser to achieve the desired coherence length to laser width ratio.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Low-threshold generation of harmonics and hard x radiation in a laser plasma. 1. Single-peak generation

NASA Astrophysics Data System (ADS)

Apollonov, V. V.; Derzhavin, S. I.; Kazakov, K. Kh

1993-02-01

A source of hard x radiation based on a laser plasma has been studied under conditions such that parametric instabilities are driven in the plasma at low intensities of the pump radiation (below 10 GW/cm2). A qualitative interpretation of the observed effects is offered.

Photothermal and photochemical effects of laser light absorption by indocyanine green (ICG)

NASA Astrophysics Data System (ADS)

Yaseen, Mohammad A.; Diagaradjane, Parmeswaran; Pikkula, Brian M.; Yu, Jie; Wong, Michael S.; Anvari, Bahman

2005-04-01

Indocyanine Green (ICG) is clinically used as a fluorescent dye for imaging purposes. Its rapid circulation kinetics and minimal toxicity has prompted investigation into ICG's utility as a photosentitizer for therapeutic applications. Traditionally, optically mediated tumor therapy has focused on photodynamic therapy, which employs a photochemical mechanism resulting from the absorption of low intensity CW laser light by localized photosensitizers such as Photofrin II, Benzoporphyrin Derivative (BPD), ICG. Treatment of cutaneous vascular malformations such as port-wine stains, on the other hand, is based on a photothermal mechanism resulting from the absorption of high intensity pulsed laser light by hemoglobin. In this study, we compared the effectiveness of combining photochemical and photothermal mechanisms during application of ICG in conjunction with laser irradiation with the intention that the combined approach may lead to a reduction in the threshold dose of pulsed laser light required to treat hypervascular malformations. The blood vessels in rabbit ears were used as an in vivo model for targeted vasculature. Irradiation of the ears with IR light (λ=785 nm, Δτ = 3 min, Io = 120 mW) was used to elicit photochemical damage, while photothermal damage was brought about using pulses from a ruby laser (λ=694 nm, τ = 3 ms) with different fluences. For the combined modality, photochemical damage was induced first and followed by photothermal irradiation. This modality was compared with photothermal irradiation alone. The effectiveness of each irradiation scheme was assessed using histopathological analysis. We present preliminary data that suggests that pretreatment with photodynamic therapy before photothermal coagulation results in more severe vascular damage with lower photothermal fluence levels. The results of this study provide the foundation work for further exploration of the therapeutic potentials of photochemical and photothermal effects during application of ICG in conjunction with laser irradiation.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Feasibility of investigation of optical breakdown statistics using multifrequency lasers

NASA Astrophysics Data System (ADS)

Ulanov, S. F.

1990-06-01

A method proposed for investigating the statistics of bulk optical breakdown relies on multifrequency lasers, which eliminates the influence of the laser radiation intensity statistics. The method is based on preliminary recording of the peak intensity statistics of multifrequency laser radiation pulses at the caustic using the optical breakdown threshold of K8 glass. The probability density distribution function was obtained at the focus for the peak intensities of the radiation pulses of a multifrequency laser. This method may be used to study the self-interaction under conditions of bulk optical breakdown of transparent dielectrics.

LASER RADIATION CHARACTERISTICS (BRIEF COMMUNICATIONS): Conversion of KrCl and XeCl laser radiation to the visible spectral range by stimulated Raman scattering in lead vapor

NASA Astrophysics Data System (ADS)

Evtushenko, Gennadii S.; Mel'chenko, S. V.; Panchenko, Aleksei N.; Tarasenko, Viktor F.

1990-04-01

Conversion of KrCl and XeCl laser radiation by stimulated Raman scattering was achieved in lead vapor. The KrCl laser radiation was converted into three lines in the visible region at λ = 406, 590, and 723 nm by transitions from both the ground and first excited levels of the lead atom. The conversion efficiency of XeCl laser radiation of low spatial coherence was found to be limited by the activation of a competing nonlinear process.

Laser radiation frequency doubling in a single-crystal fibre based on a stoichiometric LiNbO3 crystal

NASA Astrophysics Data System (ADS)

Kashin, V. V.; Nikolaev, D. A.; Rusanov, S. Ya; Tsvetkov, V. B.

2015-01-01

We demonstrate the employment of single-crystal optical fibres based on lithium niobate for doubling the laser radiation frequency. The measured characteristics of the fibre confirm its high quality and spatial homogeneity. Parameters of the frequency doublers for neodymium laser radiation (λ = 1 mm) based on fibre and bulk single crystals are compared. Single crystals are grown by the method of laser-heated pedestal growing with heating by radiation of a CO2 laser (LHPG-method).

[Phylogenetic and diversity analysis of Acidithiobacillus spp. based on 16S rRNA and RubisCO genes homologues].

PubMed

Liu, Minrui; Lin, Pengwu; Qi, Xing'e; Ni, Yongqing

2016-04-14

The purpose of the study was to reveal geographic region-related Acidithiobacillus spp. distribution and allopatric speciation. Phylogenetic and diversity analysis was done to expand our knowledge on microbial phylogeography, diversity-maintaining mechanisms and molecular biogeography. We amplified 16S rRNA gene and RubisCO genes to construct corresponding phylogenetic trees based on the sequence homology and analyzed genetic diversity of Acidithiobacillus spp.. Thirty-five strains were isolated from three different regions in China (Yunnan, Hubei, Xinjiang). The whole isolates were classified into five groups. Four strains were identified as A. ferrivorans, six as A. ferridurans, YNTR4-15 Leptspirillum ferrooxidans and HBDY3-31 as Leptospirillum ferrodiazotrophum. The remaining strains were identified as A. ferrooxidans. Analysis of cbbL and cbbM genes sequences of representative 26 strains indicated that cbbL gene of 19 were two copies (cbbL1 and cbbL2) and 7 possessed only cbbL1. cbbM gene was single copy. In nucleotide-based trees, cbbL1 gene sequences of strains were separated into three sequence types, and the cbbL2 was similar to cbbL1 with three types. Codon bias of RubisCO genes was not obvious in Acidithiobacillus spp.. Strains isolated from three different regions in China indicated a great genetic diversity in Acidithiobacillus spp. and their 16S rRNA/RubisCO genes sequence was of significant difference. Phylogenetic tree based on 16S rRNA genes and RubisCO genes was different in Acidithiobacillus spp..

Stability-activity tradeoffs constrain the adaptive evolution of RubisCO.

PubMed

Studer, Romain A; Christin, Pascal-Antoine; Williams, Mark A; Orengo, Christine A

2014-02-11

A well-known case of evolutionary adaptation is that of ribulose-1,5-bisphosphate carboxylase (RubisCO), the enzyme responsible for fixation of CO2 during photosynthesis. Although the majority of plants use the ancestral C3 photosynthetic pathway, many flowering plants have evolved a derived pathway named C4 photosynthesis. The latter concentrates CO2, and C4 RubisCOs consequently have lower specificity for, and faster turnover of, CO2. The C4 forms result from convergent evolution in multiple clades, with substitutions at a small number of sites under positive selection. To understand the physical constraints on these evolutionary changes, we reconstructed in silico ancestral sequences and 3D structures of RubisCO from a large group of related C3 and C4 species. We were able to precisely track their past evolutionary trajectories, identify mutations on each branch of the phylogeny, and evaluate their stability effect. We show that RubisCO evolution has been constrained by stability-activity tradeoffs similar in character to those previously identified in laboratory-based experiments. The C4 properties require a subset of several ancestral destabilizing mutations, which from their location in the structure are inferred to mainly be involved in enhancing conformational flexibility of the open-closed transition in the catalytic cycle. These mutations are near, but not in, the active site or at intersubunit interfaces. The C3 to C4 transition is preceded by a sustained period in which stability of the enzyme is increased, creating the capacity to accept the functionally necessary destabilizing mutations, and is immediately followed by compensatory mutations that restore global stability.

A compact tunable polarized X-ray source based on laser-plasma helical undulators

PubMed Central

Luo, J.; Chen, M.; Zeng, M.; Vieira, J.; Yu, L. L.; Weng, S. M.; Silva, L. O.; Jaroszynski, D. A.; Sheng, Z. M.; Zhang, J.

2016-01-01

Laser wakefield accelerators have great potential as the basis for next generation compact radiation sources because of their extremely high accelerating gradients. However, X-ray radiation from such devices still lacks tunability, especially of the intensity and polarization distributions. Here we propose a tunable polarized radiation source based on a helical plasma undulator in a plasma channel guided wakefield accelerator. When a laser pulse is initially incident with a skew angle relative to the channel axis, the laser and accelerated electrons experience collective spiral motions, which leads to elliptically polarized synchrotron-like radiation with flexible tunability on radiation intensity, spectra and polarization. We demonstrate that a radiation source with millimeter size and peak brilliance of 2 × 1019 photons/s/mm2/mrad2/0.1% bandwidth can be made with moderate laser and electron beam parameters. This brilliance is comparable with third generation synchrotron radiation facilities running at similar photon energies, suggesting that laser plasma based radiation sources are promising for advanced applications. PMID:27377126

Response to Laser Treatment of Café au Lait Macules Based on Morphologic Features.

PubMed

Belkin, Daniel A; Neckman, Julia P; Jeon, Hana; Friedman, Paul; Geronemus, Roy G

2017-11-01

Response to laser treatment for café au lait macules (CALMs) is inconsistent and difficult to predict. To test the hypothesis that irregularly bordered CALMs of the "coast of Maine" subtype respond better to treatment than those of the smooth-bordered "coast of California" subtype. This retrospective case series included patients from 2 multiple-clinician US practices treated from 2005 through 2016. All patients had a clinical diagnosis of CALM and were treated with a Q-switched or picosecond laser. A total of 51 consecutive patients were eligible, 6 of whom were excluded owing to ambiguous lesion subtype. Observers were blinded to final patient groupings. Treatment with 755-nm alexandrite picosecond laser, Q-switched ruby laser, Q-switched alexandrite laser, or Q-switched 1064-nm Nd:YAG laser. Main outcome was grade in a visual analog scale (VAS) consisting of 4 levels of treatment response: poor (grade 1, 0%-25% improvement), fair (grade 2, 26%-50% improvement), good (grade 3, 51%-75% improvement), and excellent (grade 4, 76%-100% improvement). Forty-five patients were included in the series, 19 with smooth-bordered lesions and 26 with irregularly bordered lesions. Thirty-four (76%) of the participants were female; 33 (73%) were white; and the mean age at the time of laser treatment was 14.5 years (range, 0-44 years). Smooth-bordered lesions received a mean VAS score of 1.76, corresponding to a fair response on average (26%-50% pigmentary clearance). Irregularly bordered lesions received a mean VAS score of 3.67, corresponding to an excellent response on average (76%-100% clearance) (P < .001). CALMs with jagged or ill-defined borders of the coast of Maine subtype tend to respond well to laser treatment, whereas those with smooth and well-defined borders of the coast of California subtype tend to have poor response. Clinicians using Q-switched or picosecond lasers to treat CALMs can use morphologic characteristics to help predict response and more effectively manage patient expectations.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Spaeth, Lisa G. (Inventor); O'Brien, Martin (Inventor); Tang, Shoou-yu (Inventor); Acott, Phillip E. (Inventor); Caldwell, Loren M. (Inventor)

2011-01-01

Systems and methods for sensing air includes at least one, and in some embodiments three, transceivers for projecting the laser energy as laser radiation to the air. The transceivers are scanned or aligned along several different axes. Each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines air temperatures, wind speeds, and wind directions based on the scattered laser radiation. Applications of the system to wind power site evaluation, wind turbine control, traffic safety, general meteorological monitoring and airport safety are presented.

Publications - GMC 353 | Alaska Division of Geological & Geophysical

Science.gov Websites

and Facilities Staff Seismic and Well Data Data Reports Contact Us Frequently Asked Questions Ask a Umiat (Blend, unknown well number) and from US Navy Umiat Ruby #1 (renamed Umiat Test Well #4); both Samples from US Navy Umiat (Blend, unknown well number) and from US Navy Umiat Ruby #1 (renamed Umiat Test

An Interface Transformation Strategy for AF-IPPS

DTIC Science & Technology

2012-12-01

Representational State Transfer (REST) and Java Enterprise Edition ( Java EE) to implement a reusable “translation service.” For SOAP and REST protocols, XML and...of best-of-breed open source software. The product baseline is summarized in the following table: Product Function Description Java Language...Compiler & Runtime JBoss Application Server Applications, Messaging, Translation Java EE Application Server Ruby on Rails Applications Ruby Web

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Formation of amplified spontaneous radiation in an expanding laser plasma allowing for refraction

NASA Astrophysics Data System (ADS)

Gulov, A. V.; Derzhiev, V. I.; Zhidkov, A. G.; Terskikh, A. O.; Yakovlenko, Sergei I.

1990-06-01

Calculations are made of the divergence of amplified spontaneous radiation in a laser plasma allowing for refraction by free electrons. An analysis is made of the divergence of the radiation generated due to a 3p→3s' transition in neon-like ions. Calculations are made of the divergence of the radiation due to the 4→3 transition in the O VIII ion allowing for refraction during expansion of a Formvar plasma.

Electron beam physical vapor deposition of thin ruby films for remote temperature sensing

NASA Astrophysics Data System (ADS)

Li, Wei; Coppens, Zachary J.; Greg Walker, D.; Valentine, Jason G.

2013-04-01

Thermographic phosphors (TGPs) possessing temperature-dependent photoluminescence properties have a wide range of uses in thermometry due to their remote access and large temperature sensitivity range. However, in most cases, phosphors are synthesized in powder form, which prevents their use in high resolution micro and nanoscale thermal microscopy. In the present study, we investigate the use of electron beam physical vapor deposition to fabricate thin films of chromium-doped aluminum oxide (Cr-Al2O3, ruby) thermographic phosphors. Although as-deposited films were amorphous and exhibited weak photoluminescence, the films regained the stoichiometry and α-Al2O3 crystal structure of the combustion synthesized source powder after thermal annealing. As a consequence, the annealed films exhibit both strong photoluminescence and a temperature-dependent lifetime that decreases from 2.9 ms at 298 K to 2.1 ms at 370 K. Ruby films were also deposited on multiple substrates. To ensure a continuous film with smooth surface morphology and strong photoluminescence, we use a sapphire substrate, which is thermal expansion coefficient and lattice matched to the film. These thin ruby films can potentially be used as remote temperature sensors for probing the local temperatures of micro and nanoscale structures.

Proteome Analysis for Understanding Abiotic Stress (Salinity and Drought) Tolerance in Date Palm (Phoenix dactylifera L.).

PubMed

El Rabey, Haddad A; Al-Malki, Abdulrahman L; Abulnaja, Khalid O; Rohde, Wolfgang

2015-01-01

This study was carried out to study the proteome of date palm under salinity and drought stress conditions to possibly identify proteins involved in stress tolerance. For this purpose, three-month-old seedlings of date palm cultivar "Sagie" were subjected to drought (27.5 g/L polyethylene glycol 6000) and salinity stress conditions (16 g/L NaCl) for one month. DIGE analysis of protein extracts identified 47 differentially expressed proteins in leaves of salt- and drought-treated palm seedlings. Mass spectrometric analysis identified 12 proteins; three out of them were significantly changed under both salt and drought stress, while the other nine were significantly changed only in salt-stressed plants. The levels of ATP synthase alpha and beta subunits, an unknown protein and some of RubisCO fragments were significantly changed under both salt and drought stress conditions. Changes in abundance of superoxide dismutase, chlorophyll A-B binding protein, light-harvesting complex1 protein Lhca1, RubisCO activase, phosphoglycerate kinase, chloroplast light-harvesting chlorophyll a/b-binding protein, phosphoribulokinase, transketolase, RubisCO, and some of RubisCO fragments were significant only for salt stress.

Biochemical Studies Of The Effect Of Two Laser Radiation Wavelengths On The Khapra Beetle Trogoderma Granarium Everts (Coleoptera : Dermestidae)

NASA Astrophysics Data System (ADS)

Abdel-Kader, Mahmoud H.; El-Nozahy, Adel M.; Ahmed, Salwa M. S.; Khalifa, Ibtesam A.

2007-02-01

The present work was carried out to evaluate the actual effect of subleathal dosage of LD30 of two different lasers (Argon-ion and CO2 lasers) on the main metabolites, phosphatases enzymes, transaminases, acetylcholinestrase and peroxidases in the one day adult stage of Trogoderma granarium treated as 2-3 days old pupae. Our results clearly indicated that two different wavelengths of laser radiation increased significantly the total proteins content, whereas no significant changes occurred in the total lipids for the two laser radiation wavelenghts. On the other hand the total carbohydrates were significantly decreased when irradiating using CO2 laser wavelength which is not the case for the Argon-ion laser radiation. Significant changes of phosphatases occurred for both wavelengths. Inhibition of transaminases GOT (glutamic oxaloacetic transaminases) and insignificant changes of GPT (glutamic pyruvic oxaloacetic transaminases) was observed for both laser wavelengths. Significant inhibition of acetyl cholinestrase was observed using CO2 laser and insignificant changes were recorded for Argon ion laser radiation where as insignificant decrease of peroxideses was observed for both lasers.

Investigation of temperature feedback signal parameters during neoplasms treatment by diode laser radiation

NASA Astrophysics Data System (ADS)

Belikov, Andrey V.; Gelfond, Mark L.; Shatilova, Ksenia V.; Semyashkina, Yulia V.

2016-04-01

Dynamics of temperature signal in operation area and laser power at nevus, papilloma, and keratoma in vivo removal by a 980+/-10 nm diode laser with "blackened" tip operating in continuous (CW) mode and with temperature feedback (APC) mode are presented. Feedback allows maintaining temperature in the area of laser treatment at a preset level by regulating power of diode laser radiation (automatic power control). Temperature in the area of laser treatment was controlled by measuring the amplitude of thermal radiation, which occurs when tissue is heated by laser radiation. Removal of neoplasm was carried out in CW mode with laser radiation average power of 12.5+/-0.5 W; mean temperature in the area of laser treatment was 900+/-10°C for nevus, 800+/-15°C for papilloma, and 850+/-20°C for keratoma. The same laser radiation maximal power (12.5 W) and targeted temperature (900°C) were set for nevus removal in APC mode. The results of investigation are real time oscillograms of the laser power and temperature in the area of laser treatment at neoplasms removal in two described above modes. Simultaneously with the measurement of laser power and the temperature in the area of laser treatment video recording of surgeon manipulations was carried out. We discuss the correlation between the power of the laser radiation, the temperature in the area of laser treatment and consistency of surgeon manipulation. It is shown that the method of removal (excision with or without traction, scanning) influences the temperature in the area of laser treatment. It was found, that at removal of nevus with temperature feedback (APC) mode to achieve comparable with CW mode temperature in the area of laser treatment (900+/-10°C) 20-50% less laser power is required. Consequently, removing these neoplasms in temperature feedback mode can be less traumatic than the removal in CW mode.

Tunable, rare earth-doped solid state lasers

DOEpatents

Emmett, John L.; Jacobs, Ralph R.; Krupke, William F.; Weber, Marvin J.

1980-01-01

Laser apparatus comprising combinations of an excimer pump laser and a rare earth-doped solid matrix, utilizing the 5d-4f radiative transition in a rare earth ion to produce visible and ultra-violet laser radiation with high overall efficiency in selected cases and relatively long radiative lifetimes.

Solar Pumped, Alkali Vapor Laser.

DTIC Science & Technology

1987-09-04

convert the solar radiation to electricity or longer wavelength blackbody radiation which is then used to power the laser. A directly pumped solar laser...wavelength blackbody radiation which is then used to power the laser. A directly pumped solar laser would utilize a portion of the solar spectrum to directly...sodium dimer (near the upper laser state) and a second body. *, I will review the method we used for measuring these rates and present preliminary

[The combined laser therapy of rheumatoid arthritis].

PubMed

Sidorov, V D; Mamiliaeva, D R; Derevnina, N A; Reformatskaia, S Iu

2000-01-01

Low-intensity infrared laser radiation to the tympanic vessels was studied as one of the hemophysiotherapeutic methods and as a component of combined treatment in which it accompanies local transcutaneous laser radiation of the affected joints. It is shown that immunomodulation is feasible under noninvasive interauricular laser effect on hemostasis. Indications for both laser regimens are formulated. Joint exposure to transcutaneous laser radiation is contraindicated if the affected joints have an exudative component of inflammation.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Conversion of the energy of fast electrons to thermal plasma radiation

NASA Astrophysics Data System (ADS)

Vergunova, G. A.; Rozanov, Vladislav B.

1992-01-01

An analysis is made of the conversion of the energy of highly energetic fast electrons, generated by the action of CO2 laser radiation on a target, into characteristic radiation emitted by a plasma formed from shell targets which, for instance, may be present inside targets irradiated by the CO2 laser. Analytical formulas are obtained for the temperature of the converted radiation. The results show that it is possible to control this radiation by choosing the parameters of the target and of the fast electron flux. The efficiency of conversion into characteristic thermal radiation is found numerically to be 95%. This method of conversion is more favorable than direct interaction of CO2 laser radiation with a target since the emitting region is localized in the target mass. When a laser interacts with a target the mass of this region increases with time and so the temperature of the emitted radiation is lower than in the case when fast electrons act on the target.

Ruby on Rails Applications

NASA Technical Reports Server (NTRS)

Hochstadt, Jake

2011-01-01

Ruby on Rails is an open source web application framework for the Ruby programming language. The first application I built was a web application to manage and authenticate other applications. One of the main requirements for this application was a single sign-on service. This allowed authentication to be built in one location and be implemented in many different applications. For example, users would be able to login using their existing credentials, and be able to access other NASA applications without authenticating again. The second application I worked on was an internal qualification plan app. Previously, the viewing of employee qualifications was managed through Excel spread sheets. I built a database driven application to streamline the process of managing qualifications. Employees would be able to login securely to view, edit and update their personal qualifications.

A ruby-colored Pseudobaeospora species is described as new from material collected on the island of Hawaii.

PubMed

Desjardin, Dennis E; Hemmes, Don E; Perry, Brian A

2014-01-01

Pseudobaeospora wipapatiae is described as new based on material collected in alien wet habitats on the island of Hawaii. Unique features of this beautiful species include deep ruby-colored basidiomes with two-spored basidia, amyloid cheilocystidia and a hymeniderm pileipellis with abundant pileocystidia that is initially deep ruby in KOH then changes to lilac gray. Phylogenetic analysis of nuclear large ribosomal subunit sequence data suggest a close relationship between Pseudobaeospora and Tricholoma. BLAST comparisons of internal transcribed spacer and 5.8S nuclear ribosomal subunit regions sequence data reveal greatest similarity with existing sequences of Pseudobaeospora species. A comprehensive description, color photograph, illustrations of salient micromorphological features and comparisons with phenetically similar taxa are provided. © 2014 by The Mycological Society of America.

Apparatus and method for generating continuous wave 16. mu. m laser radiation using gaseous CF/sub 4/

DOEpatents

Telle, J.M.

1984-05-01

Apparatus and method for generating continuous wave 16 ..mu..m laser radiation using gaseous CF/sub 4/. Laser radiation at 16 ..mu..m has been observed in a cooled static cell containing low pressure CF/sub 4/ optically pumped by an approximately 3 W output power c-w CO/sub 2/ laser. The laser cavity employed was a multiple-pass off-axis-path two spherical mirror ring resonator. Unidirectional CF/sub 4/ laser output power at 615 cm/sup -1/ exceeded 2 mW. Computer calculations indicate that for modest pump powers of about 40 W, approximately 1 W of emitted laser radiation at 16 ..mu..m might be obtained.

Apparatus and method for generating continuous wave 16 .mu.m laser radiation using gaseous CF.sub.4

DOEpatents

Telle, John M.

1986-01-01

Apparatus and method for generating continuous wave 16 .mu.m laser radiation using gaseous CF.sub.4. Laser radiation at 16 .mu.m has been observed in a cooled static cell containing low pressure CF.sub.4 optically pumped by an approximately 3 W output power cw CO.sub.2 laser. The laser cavity employed was a multiple-pass off-axis-path two spherical mirror ring resonator. Unidirectional CF.sub.4 laser output power at 615 cm.sup.-1 exceeded 2 mW. Computer calculations indicate that for modest pump powers of about 40 W, approximately 1 W of emitted laser radiation at 16 .mu.m might be obtained.

Holographic studies of shock waves within transonic fan rotors

NASA Technical Reports Server (NTRS)

Benser, W. A.; Bailey, E. E.; Gelder, T. F.

1973-01-01

Pulsed laser holographic interferometry has been applied to the detection of shock patterns in the outer span regions of high tip speed transonic rotors. The first holographic approach used ruby laser light reflected from a portion of the centerbody just ahead of the rotor. These holograms showed the bow wave patterns upstream of the rotor and the shock patterns just inside the blade row near the tip. Much of the region of interest was in the shadow of the blade leading edge and could not be visualized. The second holographic approach, on a different rotor, used light transmitted diagonally across the inlet annulus past the centerbody. This approach gave a more extensive view of the region bounded by the blade leading and trailing edges, by the part span shroud and by the blade tip. These holograms showed the passage shock emanating from the blade leading edge and a moderately strong conical shock originating at the intersection of the part span shroud leading edge and the blade suction surface. Reasonable details of the shock patterns were obtained from holograms which were made without extensive rig modifications.

Measurement of non-Maxwellian electron velocity distributions in a reflex discharge

NASA Technical Reports Server (NTRS)

Phipps, C. R., Jr.; Bershader, D.

1978-01-01

The results of a ruby laser Thomson scattering study of the space and time-resolved electron velocity distributions in a pulsed Penning discharge in hydrogen are presented. Electron densities were to the order of 10 to the 13th/cu cm and temperatures were roughly 3 eV. This point is just prior to the cessation of the discharge ohmic heating pulse. For magnetic strengths less than 200 G, Maxwellian distributions were found over an energy range six times thermal energy. Temperatures agreed with Langmuir probe data. For fields of 450 G, chaotic plasma potentials were observed to be unstable and the Thomson scattering showed that the electron velocity distributions had central temperatures of 2 eV and wing temperatures of 15-12 eV.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Temporal and thermodynamic characteristics of plasma formation

NASA Astrophysics Data System (ADS)

Ignatavichyus, M. V.; Kazakyavichyus, É.; Orshevski, G.; Danyunas, V.

1991-11-01

An investigation was made of plasma formation accompanying the interaction with aluminum, iron, and VK-6 alloy targets of nanosecond radiation from a YAG:Nd3+ laser (Emax = 50 mJ, τ = 3-8 ns). The duration of the plasma formation process depended weakly on the laser radiation parameters [the power density was varied in the range 1-3 GW/cm2, the pulse rise time in the range 2-8 ns, or the rate of rise of the power density in the range (1-8) × 108 W · cm - 2 · ns -1]. A study was made of the establishment of a local thermodynamic equilibrium in a plasma jet excited by radiation from nanosecond and picosecond (E = 30 mJ, τ = 40 ps) lasers. The maximum of the luminescence from an aluminum plasma excited by picosecond laser radiation was found to correspond to a local thermodynamic equilibrium. A local thermodynamic equilibrium could be absent in the case of excitation by nanosecond laser radiation.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Optimal two-mirror system for laser radiation focusing

NASA Astrophysics Data System (ADS)

Gitin, Andrey V.

2009-10-01

An optical system for laser radiation focusing, which consists of parabolic and elliptic mirrors, is considered. It is shown by the method of elementary reflections that the maximum concentration of laser radiation on the target can be achieved at a certain position of these mirrors.

Dichromatic and monochromatic laser radiation effects on survival and morphology of Pantoea agglomerans

NASA Astrophysics Data System (ADS)

Thomé, A. M. C.; Souza, B. P.; Mendes, J. P. M.; Soares, L. C.; Trajano, E. T. L.; Fonseca, A. S.

2017-05-01

Despite the beneficial effects of low-level lasers on wound healing, their application for treatment of infected injuries is controversial because low-level lasers could stimulate bacterial growth exacerbating the infectious process. Thus, the aim of this work was to evaluate in vitro effects of low-level lasers on survival, morphology and cell aggregation of Pantoea agglomerans. P. agglomerans samples were isolated from human pressure injuries and cultures were exposed to low-level monochromatic and simultaneous dichromatic laser radiation to study the survival, cell aggregation, filamentation and morphology of bacterial cells in exponential and stationary growth phases. Fluence, wavelength and emission mode were those used in therapeutic protocols for wound healing. Data show no changes in morphology and cell aggregation, but dichromatic laser radiation decreased bacterial survival in exponential growth phase and monochromatic red and infrared lasers increased bacterial survival at the same fluence. Simultaneous dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation and simultaneous dichromatic laser could be the option for treatment of infected pressure injuries by Pantoea agglomerans.

X-ray lasers. Citations from the International Aerospace Abstracts data base

NASA Technical Reports Server (NTRS)

Mauk, S. C.

1980-01-01

Various aspects of X-ray lasers are discussed in approximately 122 citations. Included are laser plasmas and outputs, plasma radiation, far ultraviolet radiation, gamma rays, optical pumping, optical resonators, and electron transitions. Laser applications, laser materials, and laser fusion are also included.

Late summer disease symptoms in western Washington red raspberry fields associated with co-occurrence of Phytophthora rubi, Verticillium dahliae, and Pratylenchus penetrans, but not Raspberry bushy dwarf virus

USDA-ARS?s Scientific Manuscript database

60% of the $109 million processed by the U.S. red raspberry industry is in northern Washington. In 2012, late summer disease symptoms were observed in many raspberry fields. These symptoms were initially attributed to Verticillium dahliae, but other soilborne pathogens (Phytophthora rubi, Pratylench...

Assault on Kids: How Hyper-Accountability, Corporatization, Deficit Ideologies, and Ruby Payne Are Destroying Our Schools. Counterpoints: Studies in the Postmodern Theory of Education, Volume 402

ERIC Educational Resources Information Center

Ahlquist, Roberta, Ed.; Gorski, Paul C., Ed.; Montano, Theresa, Ed.

2011-01-01

Hyper-accountability, corporatization, deficit ideology, and Ruby Payne's preparation of teachers to comply with these and other atrocities are not merely markers of philosophical shifts in education. They are manifestations of a neoliberal remaking of public schooling into a private and corporate enterprise. Collectively, these trends are seen…

Standard Reference Material (SRM 1990) For Single Crystal Diffractometer Alignment

PubMed Central

Wong-Ng, W.; Siegrist, T.; DeTitta, G. T.; Finger, L. W.; Evans, H. T.; Gabe, E. J.; Enright, G. D.; Armstrong, J. T.; Levenson, M.; Cook, L. P.; Hubbard, C. R.

2001-01-01

An international project was successfully completed which involved two major undertakings: (1) a round-robin to demonstrate the viability of the selected standard and (2) the certification of the lattice parameters of the SRM 1990, a Standard Reference Material® for single crystal diffractometer alignment. This SRM is a set of ≈3500 units of Cr-doped Al2O3, or ruby spheres [(0.420.011 mole fraction % Cr (expanded uncertainty)]. The round-robin consisted of determination of lattice parameters of a pair of crystals: the ruby sphere as a standard, and a zeolite reference to serve as an unknown. Fifty pairs of crystals were dispatched from Hauptman-Woodward Medical Research Institute to volunteers in x-ray laboratories world-wide. A total of 45 sets of data was received from 32 laboratories. The mean unit cell parameters of the ruby spheres was found to be a=4.7608 ű0.0062 Å, and c=12.9979 ű0.020 Å (95 % intervals of the laboratory means). The source of errors of outlier data was identified. The SRM project involved the certification of lattice parameters using four well-aligned single crystal diffractometers at (Bell Laboratories) Lucent Technologies and at NRC of Canada (39 ruby spheres), the quantification of the Cr content using a combined microprobe and SEM/EDS technique, and the evaluation of the mosaicity of the ruby spheres using a double-crystal spectrometry method. A confirmation of the lattice parameters was also conducted using a Guinier-Hägg camera. Systematic corrections of thermal expansion and refraction corrections were applied. These rubies– are rhombohedral, with space group R3¯c. The certified mean unit cell parameters are a=4.76080±0.00029 Å, and c=12.99568 ű0.00087 Å (expanded uncertainty). These certified lattice parameters fall well within the results of those obtained from the international round-robin study. The Guinier-Hägg transmission measurements on five samples of powdered rubies (a=4.7610 ű0.0013 Å, and c = 12.9954 ű0.0034 Å) agreed well with the values obtained from the single crystal spheres. PMID:27500067

[Induced thymus aging: radiation model and application perspective for low intensive laser radiation].

PubMed

Sevost'ianova, N N; Trofimov, A V; Lin'kova, N S; Poliakova, V O; Kvetnoĭ, I M

2010-01-01

The influence of gamma-radiation on morphofunctional state of thymus is rather like as natural thymus aging. However gamma-radiation model of thymus aging widely used to investigate geroprotectors has many shortcomings and limitations. Gamma-radiation can induce irreversible changes in thymus very often. These changes are more intensive in comparison with changes, which can be observed at natural thymus aging. Low intensive laser radiation can not destroy structure of thymus and its effects are rather like as natural thymus aging in comparison with gamma-radiation effects. There are many parameters of low intensive laser radiation, which can be changed to improve morphofunctional thymus characteristics in aging model. Using low intensive laser radiation in thymus aging model can be very perspective for investigations of aging immune system.

Ophthalmic laser system integrated with speckle variance optical coherence tomography for real-time temperature monitoring

NASA Astrophysics Data System (ADS)

Lee, Soohyun; Lee, Changho; Cheon, Gyeongwoo; Kim, Jongmin; Jo, Dongki; Lee, Jihoon; Kang, Jin U.

2018-02-01

A commercial ophthalmic laser system (R;GEN, Lutronic Corp) was integrated with a swept-source optical coherence tomography (OCT) imaging system for real-time tissue temperature monitoring. M-scan OCT images were acquired during laser-pulse radiation, and speckle variance OCT (svOCT) images were analyzed to deduce temporal signal variations related to tissue temperature change from laser-pulse radiation. A phantom study shows that svOCT magnitude increases abruptly after laser pulse radiation and recovered exponentially, and the peak intensity of svOCT image was linearly dependent on pulse laser energy until it saturates. A study using bovine iris also showed signal variation dependence on the laser pulse radiation, and the variation was more distinctive with higher energy level.

Qualification and Testing of Quantum Cascade Lasers for Harsh Environments

NASA Astrophysics Data System (ADS)

Brauer, C. S.; Myers, T. L.; Cannon, B. D.; Anderson, C. G.; Crowther, B. G.; Hansen, S.

2014-12-01

Quantum cascade lasers (QCLs) offer the potential for the development of novel, laser-based instruments for both terrestrial and space applications. In order to withstand harsh conditions encountered in these environments, lasers must be robust, and rigorous testing is required before new systems can be utilized. A particular concern for space applications is the potential damage to laser performance caused by radiation exposure. While the effects of radiation exposure in diode lasers have been studied extensively, the effect on QCLs, which are fundamentally different from diode lasers, is not well known. We thus present work to quantify the performance of QCLs after exposure to moderate and high levels of radiation from different sources, including protons and gamma rays, to determine the effects of radiation damage.

Protein and Genetic Composition of Four Chromatin Types in Drosophila melanogaster Cell Lines.

PubMed

Boldyreva, Lidiya V; Goncharov, Fyodor P; Demakova, Olga V; Zykova, Tatyana Yu; Levitsky, Victor G; Kolesnikov, Nikolay N; Pindyurin, Alexey V; Semeshin, Valeriy F; Zhimulev, Igor F

2017-04-01

Recently, we analyzed genome-wide protein binding data for the Drosophila cell lines S2, Kc, BG3 and Cl.8 (modENCODE Consortium) and identified a set of 12 proteins enriched in the regions corresponding to interbands of salivary gland polytene chromosomes. Using these data, we developed a bioinformatic pipeline that partitioned the Drosophila genome into four chromatin types that we hereby refer to as aquamarine, lazurite, malachite and ruby. Here, we describe the properties of these chromatin types across different cell lines. We show that aquamarine chromatin tends to harbor transcription start sites (TSSs) and 5' untranslated regions (5'UTRs) of the genes, is enriched in diverse "open" chromatin proteins, histone modifications, nucleosome remodeling complexes and transcription factors. It encompasses most of the tRNA genes and shows enrichment for non-coding RNAs and miRNA genes. Lazurite chromatin typically encompasses gene bodies. It is rich in proteins involved in transcription elongation. Frequency of both point mutations and natural deletion breakpoints is elevated within lazurite chromatin. Malachite chromatin shows higher frequency of insertions of natural transposons. Finally, ruby chromatin is enriched for proteins and histone modifications typical for the "closed" chromatin. Ruby chromatin has a relatively low frequency of point mutations and is essentially devoid of miRNA and tRNA genes. Aquamarine and ruby chromatin types are highly stable across cell lines and have contrasting properties. Lazurite and malachite chromatin types also display characteristic protein composition, as well as enrichment for specific genomic features. We found that two types of chromatin, aquamarine and ruby, retain their complementary protein patterns in four Drosophila cell lines.

IV INTERNATIONAL CONFERENCE ON ATOM AND MOLECULAR PULSED LASERS (AMPL'99): Radiative and photochemical properties of organic compounds excited by high-power XeCl laser radiation

NASA Astrophysics Data System (ADS)

Kopylova, T. N.; Kuznetsova, Rimma T.; Svetlichnyi, Valerii A.; Sergeev, A. K.; Tel'minov, E. N.; Filinov, D. N.

2000-06-01

Radiative and photochemical properties of a number of laser dyes excited by focused radiation of a XeCl laser with intensity up to 200 MW cm-2 were studied. A method for measuring the gain of organic molecules under high-power excitation is proposed. The dependence of the dye transmittance for the pump radiation on its intensity was studied. It is shown that changes in energy, spectral, and time characteristics of radiation and the photostability of compounds under high-power excitation are associated with the formation of superluminescence.

Fluorescence of Pentavalent Chromium in SiO2 Sol-Gel Glasses

NASA Technical Reports Server (NTRS)

Jia, Weiyi; Castro, Lymari; Wang, Yanyun; Liu, Huimin

1998-01-01

Chromium ions are very attractive to optical spectroscopy and laser physics. It is well known that the first laser in the history is a ruby laser activated with Cr(3+). It was found in early nineties that Cr(4+) was also an interesting lasing ion in the near infrared, and various Cr(4+) lasers have been developed. Very recently, it was reported that Cr(2+) doped in CdSe crystals showed lasing action in the infrared. The above achievement have stimulated an interest in searching for Cr(5+) and investigating its optical properties. Cr(5+) is isoelectronic with Ti(3+) and V(4+), having electron configuration 3d1. Ti(3+) is the active center of commercial cw and femtosecond sapphire lasers, tunable in the range 680-1100 nm. V(4+) doped in YAlO3 and Al2O3 showed broad band emission near 635 nm. Although EPR results of Cr(5+) were reported, the optical properties were less studied. Herren et al. reported an observation of luminescence from Cr doped in SiO2 sol-gel glass. The luminescence spectrum was assigned to pentavalent ions in their first paper, and later it was identified to be the emission from the charge transfer transition of Cr(6+). The first observation of photoluminescence from octahedrally coordinated Cr(5+) in BaCaMg aluminate glasses was reported very recently. In this work, we report luminescence results of Cr doped SiO2 sol-gel glasses. The fluorescence spectra are very different from Herrens' results, and we believe it originates from pentavalent Cr.

Laser-heated thruster

NASA Technical Reports Server (NTRS)

Kemp, N. H.; Lewis, P. F.

1980-01-01

The development of a computer program for the design of the thrust chamber for a CW laser heated thruster was examined. Hydrodgen was employed as the propellant gas and high temperature absorber. The laser absorption coefficient of the mixture/laser radiation combination is given in temperature and species densities. Radiative and absorptive properties are given to determine radiation from such gas mixtures. A computer code for calculating the axisymmetric channel flow of a gas mixture in chemical equilibrium, and laser energy absorption and convective and radiative heating is described. It is concluded that: (1) small amounts of cesium seed substantially increase the absorption coefficient of hydrogen; (2) cesium is a strong radiator and contributes greatly to radiation of cesium seeded hydrogen; (3) water vapor is a poor absorber; and (4) for 5.3mcm radiation, both H2O/CO and NO/CO seeded hydrogen mixtures are good absorbers.

Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005

USGS Publications Warehouse

Yager, Thomas R.; Menzie, W. David; Olson, Donald W.

2008-01-01

Comparisons of the weight and the value of production of a type of gemstone between countries may differ considerably. Whereas east African countries dominate the weight production of rubies, Burma (Myanmar) is widely thought to have the highest value of ruby production. Data on the value of gemstone production are even more difficult to estimate than is the weight of production. Value of production is dependent upon both the quality and the sizes of the stones produced. Such data are not readily available and are difficult to estimate; therefore this report does not present tables of values of production. Instead, the report briefly discusses the forms in which gemstones are sold, the systems used to value the gemstones, and selected data that illustrate the variability of value of gemstones of a particular type.

FIBER OPTICS. ACOUSTOOPTICS: Amplification of semiconductor laser radiation in the wavelength range 1.24-1.3 μm by stimulated Raman scattering in an optical fiber

NASA Astrophysics Data System (ADS)

Belotitskiĭ, V. I.; Kuzin, E. A.; Ovsyannikov, D. V.; Petrov, Mikhail P.

1990-07-01

An investigation was made of the influence of weak semiconductor laser radiation on the spectrum of stimulated Raman scattering in a single-mode optical waveguide pumped by a YAG:Nd3+ laser emitting at 1.06 μm. The scattered radiation power increased by a factor exceeding 10 at the semiconductor laser wavelength. A small-signal dynamic gain reached 47 dB. Simultaneous amplification was observed of several modes of multimode semiconductor laser radiation with an intermode spectral interval of 1.3 nm.

Experience of laser radiation for treatment of oral mucous lesions of different etiologies

NASA Astrophysics Data System (ADS)

Mosesyants, Elvira N.; Zazulevskaya, Lidiya Y.; Shevtsova, Elena

1997-05-01

Laser irradiation use for treatment of different manifestations of oral mucous diseases during the last 10 years. The aim of this research was study of the results of use He-Ne laser radiation in combination with main therapy for treatment of oral mucous lesions of different aetiology. He-Ne laser irradiation use for radiation of lesions were caused by different aetiology reasons. Under the observation was 116 patients 20 - 64 years old, who had and hadn't background pathology. There were biochemical, immunological controls. Data of research confirmed positive effect of use He-Ne laser radiation.

Luminescent light source for laser pumping and laser system containing same

DOEpatents

Hamil, Roy A.; Ashley, Carol S.; Brinker, C. Jeffrey; Reed, Scott; Walko, Robert J.

1994-01-01

The invention relates to a pumping lamp for use with lasers comprising a porous substrate loaded with a component capable of emitting light upon interaction of the component with exciting radiation and a source of exciting radiation. Preferably, the pumping lamp comprises a source of exciting radiation, such as an electron beam, and an aerogel or xerogel substrate loaded with a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce light, e.g., visible light, of a suitable band width and of a sufficient intensity to generate a laser beam from a laser material.

Laser-irradiated drug chromatographic analysis and laser injection of drugs to treat staphyloccocal lesions of skin

NASA Astrophysics Data System (ADS)

Zharov, Vladimir P.; Latyshev, Alexei S.; Kovsh, Anna I.; Razumova, Svetlana A.; Masyukova, Svetlana A.; Volnukhin, Vladimir A.

2001-05-01

This article deals with further development of laser drug delivery methods. In order to estimate the effect of laser- drug interactions, we carried out the chromatographic fractionation of dexamethasone, hydrocortisone, and gentamicine, both prior to and after irradiating them by pulsed Er:YAG laser radiation. The laser radiation parameters were as follows: the wavelength, pulse energy, and pulse duration were, respectively, 2.94 micrometers , 0.7 J, and 100 microsecond(s) . The total laser radiation dose administered to a 100 (mu) l sample of these drug preparations amounted to 150 J. A chromatographic analysis revealed that drug samples exposed to Er:YAG laser radiation did not show any change. The results obtained made it possible to employ pulsed Er:YAG laser radiation to perform laser-acoustic injection of the above-mentioned drug preparations to study the treatment of staphylococcal lesions in 30 guinea pigs. The perforated channel depth was measured and the injected drug solution volume was calculated. It was found that laser injection enabled one to introduce therapeutic doses of drugs, and that it expedited the healing of lesions by 3 to 4 days, as compared to the control group that received the topical application of drugs without laser irradiation.

Response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings exposed to UV-B.

PubMed

Chen, Yi-Ping

2009-07-01

To determine the response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings, Isatis indigotica seedlings were subjected to UV-B radiation (10.08 kJ m(-2)) for 8 h day(-1) for 8 days (PAR, 220 micromol m(-2) s(-1)) and then exposed to He-Ne laser radiation (633 nm; 5.23 mW mm(-2); beam diameter: 1.5 mm) for 5 min each day without ambient light radiation. Changes in free radical elimination systems were measured, the results indicate that: (1) UV-B radiation enhanced the concentration of Malondialdahyde (MDA) and decreased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in seedlings compared with the control. The concentration of MDA was decreased and the activities of SOD, CAT and POD were increased when seedlings were subjected to elevated UV-B damage followed by laser; (2) the concentration of UV absorbing compounds and proline were increased progressively with UV-B irradiation, laser irradiation and He-Ne laser irradiation plus UV-B irradiation compared with the control. These results suggest that laser radiation has an active function in repairing UV-B-induced lesions in seedlings.

Environmentally Clean Mitigation of Undesirable Plant Life Using Lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubenchik, A M; McGrann, T J; Yamamoto, R M

This concept comprises a method for environmentally clean destruction of undesirable plant life using visible or infrared radiation. We believe that during the blossom stage, plant life is very sensitive to electromagnetic radiation, with an enhanced sensitivity to specific spectral ranges. Small doses of irradiation can arrest further plant growth, cause flower destruction or promote plant death. Surrounding plants, which are not in the blossoming stage, should not be affected. Our proposed mechanism to initiate this effect is radiation produced by a laser. Tender parts of the blossom possess enhanced absorptivity in some spectral ranges. This absorption can increase themore » local tissue temperature by several degrees, which is sufficient to induce bio-tissue damage. In some instances, the radiation may actually stimulate plant growth, as an alternative for use in increased crop production. This would be dependent on factors such as plant type, the wavelength of the laser radiation being used and the amount of the radiation dose. Practical, economically viable realization of this concept is possible today with the advent of high efficiency, compact and powerful laser diodes. The laser diodes provide an efficient, environmentally clean source of radiation at a variety of power levels and radiation wavelengths. Figure 1 shows the overall concept, with the laser diodes mounted on a movable platform, traversing and directing the laser radiation over a field of opium poppies.« less

Ruby lidar observations and trajectory analysis of stratospheric aerosols injected by the volcanic eruptions of El Chichon

NASA Technical Reports Server (NTRS)

Uchino, O.; Tabata, T.; Akita, I.; Okada, Y.; Naito, K.

1985-01-01

Large amounts of aerosol particles and gases were injected into the lower stratosphere by the violet volcanic eruptions of El Chichon on March 28, and April 3 and 4, 1982. Observational results obtained by a ruby lidar at Tsukuba (36.1 deg N, 140.1 deg E) are shown, and some points of latitude dispersion processes of aerosols are discussed.

Scientific communications: Re-Os sulfide (bornite, chalcopyrite, and pyrite) systematics of the carbonate-hosted copper deposits at ruby creek, southern brooks range, Alaska

USGS Publications Warehouse

Selby, D.; Kelley, K.D.; Hitzman, M.W.; Zieg, J.

2009-01-01

New Re-Os data for chalcopyrite, bornite, and pyrite from the carbonate-hosted Cu deposit at Ruby Creek (Bornite), Alaska, show extremely high Re abundances (hundreds of ppb, low ppm) and contain essentially no common Os. The Re-Os data provide the first absolute ages of ore formation for the carbonate-hosted Ruby Creek Cu-(Co) deposit and demonstrate that the Re-Os systematics of pyrite, chalcopyrite, and bornite are unaffected by greenschist metamorphism. The Re-Os data show that the main phase of Cu mineralization pre dominantly occurred at 384 ?? 4.2 Ma, with an earlier phase possibly at ???400 Ma. The Re-Os data are consistent with the observed paragenetic sequence and coincide with zircon U-Pb ages from igneous rocks within the Ambler metallogenic belt, some of which are spatially and genetically associated with regional volcanogenic massive sulfide deposits. The latter may suggest a temporal link between regional magmatism and hydrothermal mineralization in the Ambler district. The utility of bornite and chalcopyrite, in addition to pyrite, contributes to a new understanding of Re-Os geochronology and permits a refinement of the genetic model for the Ruby Creek deposit. ?? 2009 Society of Economices Geologists, Inc.

Absorption and scattering of laser radiation by the diffusion flame of aviation kerosene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gvozdev, S V; Glova, A F; Dubrovskii, V Yu

2012-04-30

The absorption coefficient of the radiation of a repetitively pulsed Nd : YAG laser with an average output power up to 6 W and of a cw ytterbium optical fibre laser with an output power up to 3 kW was measured in the diffusion flame of aviation kerosene burning on a free surface in the atmospheric air. The absorption coefficient as a function of flame length, radiation power, and radiation intensity, which was varied in the {approx}10{sup 3} - 5 Multiplication-Sign 10{sup 4} W cm{sup -2} range, was obtained for two distances (1 and 2 cm) between the laser beammore » axis and the surface. The coefficient of radiation absorption by kerosene flame was compared with that in ethanol and kerosene - ethanol mixture flames. The radiation power scattered by a small segment of the kerosene flame irradiated by Nd : YAG laser radiation was measured as a function of longitudinal and azimuthal coordinates. An estimate was made of the total scattered radiation power.« less

Absorption and scattering of laser radiation by the diffusion flame of aviation kerosene

NASA Astrophysics Data System (ADS)

Gvozdev, S. V.; Glova, A. F.; Dubrovskii, V. Yu; Durmanov, S. T.; Krasyukov, A. G.; Lysikov, A. Yu; Smirnov, G. V.; Solomakhin, V. B.

2012-04-01

The absorption coefficient of the radiation of a repetitively pulsed Nd : YAG laser with an average output power up to 6 W and of a cw ytterbium optical fibre laser with an output power up to 3 kW was measured in the diffusion flame of aviation kerosene burning on a free surface in the atmospheric air. The absorption coefficient as a function of flame length, radiation power, and radiation intensity, which was varied in the ~103 — 5×104 W cm-2 range, was obtained for two distances (1 and 2 cm) between the laser beam axis and the surface. The coefficient of radiation absorption by kerosene flame was compared with that in ethanol and kerosene — ethanol mixture flames. The radiation power scattered by a small segment of the kerosene flame irradiated by Nd : YAG laser radiation was measured as a function of longitudinal and azimuthal coordinates. An estimate was made of the total scattered radiation power.

Effect of active-region “volume” on the radiative properties of laser heterostructures with radiation output through the substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nekorkin, S. M.; Zvonkov, B. N.; Baidus, N. V.

2017-01-15

The radiative properties of InGaAs/GaAs/InGaP laser structures with radiation output through the substrate depending on the number of quantum wells in the active region and laser diodes on their basis are investigated. It is established that the presence of six–eight quantum wells in the active region is optimum from the viewpoint of observable values of the threshold current and the output optical power of lasers.

Modelling of micromachining of human tooth enamel by erbium laser radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belikov, A V; Skrypnik, A V; Shatilova, K V

We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength betweenmore » the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained. (laser biophotonics)« less

Experimental comparison of laser energy losses in high-quality laser-oxygen cutting of low-carbon steel using radiation from fibre and CO{sub 2} lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golyshev, A A; Malikov, A G; Orishich, A M

We report a comparative experimental study of laseroxygen cutting of low-carbon steel using a fibre laser with a wavelength of 1.07 μm and a CO{sub 2} laser with a wavelength of 10.6 μm at the sheet thickness of 3 – 16 mm. For the two lasers we have measured the dependence of the cutting speed on the radiation power and determined the cutting speed at which the surface roughness is minimal. The coefficient of laser radiation absorption in the laser cutting process is measured for these lasers at different values of the cutting speed and radiation power. It is foundmore » that the minimal roughness of the cut surface is reached at the absorbed laser energy per unit volume of the removed material, equal to 11 – 13 J mm{sup -3}; this value is the same for the two lasers and does not depend on the sheet thickness. (laser technologies)« less

EFFECTS OF LASER RADIATION ON MATTER: Melting and thermocapillary convection under the action of pulsed laser radiation with an inhomogeneous spatial distribution

NASA Astrophysics Data System (ADS)

Uglov, A. A.; Smurov, I. Yu; Gus'kov, A. G.; Aksenov, L. V.

1990-08-01

A theoretical study is reported of melting and thermocapillary convection under the action of laser radiation with a nonmonotonic spatial distribution of the power density. An analysis is made of changes in the geometry of the molten bath with time. The transition from a nonmonotonic boundary of a melt, corresponding to the spatial distribution of the radiation, to a monotonic one occurs in a time of the order of 1 ms when the power density of laser radiation is 105 W/cm2. The vortex structure of the flow in the molten bath is governed by the spatial distribution of the laser radiation in such a way that each local power density maximum corresponds to two vortices with oppositely directed velocity components.

Comparison of contact and non-contact asphere surface metrology devices

NASA Astrophysics Data System (ADS)

DeFisher, Scott; Fess, Edward M.

2013-09-01

Metrology of asphere surfaces is critical in the precision optics industry. Surface metrology serves as feedback into deterministic grinding and polishing platforms. Many different techniques and devices are used to qualify an asphere surface during fabrication. A contact profilometer is one of the most common measurement technologies used in asphere manufacturing. A profilometer uses a fine stylus to drag a diamond or ruby tip over the surface, resulting in a high resolution curved profile. Coordinate measuring machines (CMM) apply a similar concept by touching the optic with a ruby or silicon carbine sphere. A CMM is able to move in three dimensions while collecting data points along the asphere surface. Optical interferometers use a helium-neon laser with transmission spheres to compare a reflected wavefront from an asphere surface to a reference spherical wavefront. Large departure aspheres can be measured when a computer generated hologram (CGH) is introduced between the interferometer and the optic. OptiPro Systems has developed a non-contact CMM called UltraSurf. It utilizes a single point non-contact sensor, and high accuracy air bearings. Several different commercial non-contact sensors have been integrated, allowing for the flexibility to measure a variety of surfaces and materials. Metrology of a sphere and an asphere using a profilometer, CMM, Interferometer with a CGH, and the UltraSurf will be presented. Cross-correlation of the measured surface error magnitude and shape will be demonstrated. Comparisons between the techniques and devices will be also presented with attention to accuracy, repeatability, and overall measurement time.

Laser Irradiated Foam Targets: Absorption and Radiative Properties

NASA Astrophysics Data System (ADS)

Salvadori, Martina; Luigi Andreoli, Pier; Cipriani, Mattia; Consoli, Fabrizio; Cristofari, Giuseppe; De Angelis, Riccardo; di Giorgio, Giorgio; Giulietti, Danilo; Ingenito, Francesco; Gus'kov, Sergey Yu.; Rupasov, Alexander A.

2018-01-01

An experimental campaign to characterize the laser radiation absorption of foam targets and the subsequent emission of radiation from the produced plasma was carried out in the ABC facility of the ENEA Research Center in Frascati (Rome). Different targets have been used: plastic in solid or foam state and aluminum targets. The activated different diagnostics allowed to evaluate the plasma temperature, the density distribution, the fast particle spectrum and the yield of the X-Ray radiation emitted by the plasma for the different targets. These results confirm the foam homogenization action on laser-plasma interaction, mainly attributable to the volume absorption of the laser radiation propagating in such structured materials. These results were compared with simulation absorption models of the laser propagating into a foam target.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Low-threshold generation of harmonics and hard x radiation in a laser plasma. 2. Multipeak generation

NASA Astrophysics Data System (ADS)

Apollonov, V. V.; Derzhavin, S. I.; Kazakov, K. Kh

1993-02-01

The conditions for the generation of hard x radiation with a multipeak structure in a plasma pumped by a long pulse from a free-running CO2 laser at a low intensity (q≲10 GW/cm2) have been studied. This x-ray generation had been observed in a previous study by the present authors. It is shown that this generation of hard x radiation with a multipeak structure leads to a more than tenfold increase in the yield of hard x radiation per laser pulse, under optimum conditions. This increase results from the additional peaks in the x-ray signal. An explanation of this effect is proposed.

Combined Impact of Gamma and Laser Radiation on Peripheral Blood of Rats in vivo

NASA Astrophysics Data System (ADS)

Zalesskaya, G. A.; Batay, L. E.; Koshlan, I. V.; Nasek, V. M.; Zilberman, R. D.; Milevich, T. I.; Govorun, R. D.; Koshlan, N. A.; Blaga, P.

2017-11-01

The impact of γ radiation of 137Cs (doses of 1 and 3 Gy), low-intensity laser radiation (λ = 670 nm, 5.3 or 10.6 J/cm2) as well as the influence of consecutive laser and γ radiation on peripheral blood and blood cells (erythrocytes, leukocytes, lymphocytes, granulocytes) were studied by analyzing the number of blood cells, blood absorption spectra, and activity of antioxidant defense enzymes. Two series of experiments were performed on four groups of rats. The rats of the control group (group 1) were not exposed to γ or laser radiation. In the experimental groups, single irradiation of the whole body of rats with γ radiation (group 2), three- or four-day over-vein irradiation of blood in the tail vein by low-intensity laser radiation (group 3), and successive three- or four-day irradiation of blood by laser and then a single irradiation of the whole body with γ radiation (group 4) were performed. It was shown that changes of the blood cell content in the experimental groups are accompanied by changes in the spectral characteristics of the blood and the activity of antioxidant defense enzymes. The radioprotective effect of low-intensity laser radiation is manifested as an increase in the average number of leukocytes and lymphocytes in the group as compared with the postradiation, as well as an increase in the activity of antioxidant protection enzymes. The possibility of using low-intensity optical radiation for correction of hematological disorders caused by ionizing radiation is discussed.

Nanoparticle-Enhanced Laser Induced Breakdown Spectroscopy for the noninvasive analysis of transparent samples and gemstones.

PubMed

Koral, C; Dell'Aglio, M; Gaudiuso, R; Alrifai, R; Torelli, M; De Giacomo, A

2018-05-15

In this paper, Nanoparticle-Enhanced Laser Induced Breakdown Spectroscopy is applied to transparent samples and gemstones with the aim to overcome the laser induced damage on the sample. We propose to deposit a layer of AuNPs on the sample surface by drying a colloidal solution before ablating the sample with a 532 nm pulsed laser beam. This procedure ensures that the most significant fraction of the beam, being in resonance with the AuNP surface plasmon, is mainly absorbed by the NP layer, which in turn results the breakdown to be induced on NPs rather than on the sample itself. The fast explosion of the NPs and the plasma induction allow the ablation and the transfer in the plasma phase of the portion of sample surface where the NPs were placed. The employed AuNPs are prepared in milliQ water without the use of any chemical stabilizers by Pulsed Laser Ablation in Liquids (PLAL), in order to obtain a strict control of composition and impurities, and to limit possible spectral interferences (except from Au emission lines). Therefore with this technique it is possible to obtain, together with the emission signal of Au (coming from atomized NPs), the emission spectrum of the sample, by limiting or avoiding the direct interaction of the laser pulse with the sample itself. This approach is extremely useful for the elemental analysis by laser ablation of high refractive index samples, where the laser pulse on an untreated surface can otherwise penetrate inside the sample, generate breakdown events below the superficial layer, and consequently cause cracks and other damage. The results obtained with NELIBS on high refractive index samples like glasses, tourmaline, aquamarine and ruby are very promising, and demonstrate the potentiality of this approach for precious gemstones analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

22 years of photodynamic therapy in China

NASA Astrophysics Data System (ADS)

Li, Jun-Heng

2005-07-01

The development of laser medicine in China is correlated with the development of laser science in China. The first Chinese ruby laser was created in 1961. Chinese pharmacists produced the Chinese HpD in 1981 and the first case of PDT was treated using Chinese HpD and Chinese laser equipment in the same year in Beijing. Its success brought attention establishing a research group supported by the government in 1982. A systemic research on PDT was then carried out and obvious results were achieved. The step taken for PDT also accelerated the researches on other kinds of laser medicine and surgery. Since 1982, thousands of patients of malignant tumors including tumors of the lung, esophagus, cardia, stomach, rectum, bladder, other urinary genital organs, face and mouth, eyes, ENT, head and neck, breast, and skin were treated using PDT in China. HpD fluorescence was examined in some centers. Except the superficial tumor cases, PDT procedures were done through the endoscopes. Since 1990"s, imaging guided percutaneous PDT was adopted in the organs cannot be reached by the endoscopes, such as liver cancer, peripheral lung cancer and others. PDT can be used for non-malignant cases such as occlusion of blood vessels, for example, we invented the treatment of port wine stains by PDT. Regular surgical operation combined with PDT for cerebral glioma showed to be a very good combination. HpD has been approved by the Chinese Government as a photosensitizer, so it is legal to be used in PDT. There are some second generation photosensitizers under studying in China, such as Hematoporphyrin monomethyl ether (HMME) etc. Lasers used for PDT now are mostly the diode laser of 630nm for the cancers. Research studies for PDT in China may be focalized on the aspects as new photosensitizers; the dosimetry in laser irradiation; atoptosis induced by PDT; preclinical and clinical studies for PDT new indications and new technologies.

Laser-plasma-based Space Radiation Reproduction in the Laboratory

PubMed Central

Hidding, B.; Karger, O.; Königstein, T.; Pretzler, G.; Manahan, G. G.; McKenna, P.; Gray, R.; Wilson, R.; Wiggins, S. M.; Welsh, G. H.; Beaton, A.; Delinikolas, P.; Jaroszynski, D. A.; Rosenzweig, J. B.; Karmakar, A.; Ferlet-Cavrois, V.; Costantino, A.; Muschitiello, M.; Daly, E.

2017-01-01

Space radiation is a great danger to electronics and astronauts onboard space vessels. The spectral flux of space electrons, protons and ions for example in the radiation belts is inherently broadband, but this is a feature hard to mimic with conventional radiation sources. Using laser-plasma-accelerators, we reproduced relativistic, broadband radiation belt flux in the laboratory, and used this man-made space radiation to test the radiation hardness of space electronics. Such close mimicking of space radiation in the lab builds on the inherent ability of laser-plasma-accelerators to directly produce broadband Maxwellian-type particle flux, akin to conditions in space. In combination with the established sources, utilisation of the growing number of ever more potent laser-plasma-accelerator facilities worldwide as complementary space radiation sources can help alleviate the shortage of available beamtime and may allow for development of advanced test procedures, paving the way towards higher reliability of space missions. PMID:28176862

Proceedings of the 1983 Scientific Conference on Obscuration and Aerosol Research

DTIC Science & Technology

1984-07-01

Aerosol Measurement Spheroids Laser Pulses Target Signatures Optical Pulses Pulse Propagation Clouds Laser Radiation Transport Analysis...Schematic diagram of apparatus used to make ATR measurements . (a) Top view of components. Solid line is path of laser radiation, broken line is path of...fabricated to measure the extinction properties of these materials for CO2 laser radiation. The selection process and preparation of the

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Spatial-temporal distribution of a mechanical load resulting from interaction of laser radiation with a barrier (analytic model)

NASA Astrophysics Data System (ADS)

Fedyushin, B. T.

1992-01-01

The concepts developed earlier are used to propose a simple analytic model describing the spatial-temporal distribution of a mechanical load (pressure, impulse) resulting from interaction of laser radiation with a planar barrier surrounded by air. The correctness of the model is supported by a comparison with experimental results.

Terahertz radiation generation by beating of two laser beams in a collisional plasma with oblique magnetic field

NASA Astrophysics Data System (ADS)

Hematizadeh, Ayoob; Jazayeri, Seyed Masud; Ghafary, Bijan

2018-02-01

A scheme for excitation of terahertz (THz) radiation is presented by photo mixing of two super-Gaussian laser beams in a rippled density collisional magnetized plasma. Lasers having different frequencies and wave numbers but the same electric fields create a ponderomotive force on the electrons of plasma in the beating frequency. Super-Gaussian laser beam has the exclusive features such as steep gradient in laser intensity distribution, wider cross-section in comparison with Gaussian profiles, which make stronger ponderomotive force and higher THz radiation. The magnetic field is considered oblique to laser beams propagation direction; in this case, depending on the phase matching conditions different mode waves can propagate in plasma. It is found that amplitude and efficiency of the emitted THz radiation not only are sensitive to the beating frequency, collision frequency, and magnetic field strength but to the angle between laser beams and static magnetic field. The efficiency of THz radiation can be optimized in a certain angle.

Modelling of micromachining of human tooth enamel by erbium laser radiation

NASA Astrophysics Data System (ADS)

Belikov, A. V.; Skrypnik, A. V.; Shatilova, K. V.

2014-08-01

We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength between the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained.

Bracket debonding by mid-infrared laser radiation

NASA Astrophysics Data System (ADS)

Jelínková, H.; Šulc, J.; Dostálová, T.; Koranda, P.; Němec, M.; Hofmanova, P.

2009-03-01

The purpose of the study was to determine the proper laser radiation for ceramic bracket debonding and the investigation of the tooth root temperature injury. The debonding was investigated by diode-pumped continuously running Tm:YAP and Nd:YAG lasers, and by GaAs laser diode generating radiation with the wavelengths 1.997 μm, 1.444 μm, and 0.808 μm, respectively. The possibility of brackets removal by laser radiation was investigated together with the tooth and, it specifically, root temperature rise. From the results it follows that continuously running diode pumped Tm:YAG or Nd:YAG laser generating wavelengths 1.997 μm or 1.444 μm, respectively, having the output power 1 W can be good candidates for ceramic brackets debonding.

INTERACTION OF LASER RADIATION WITH MATTER: Influence of surface breakdown on the process of drilling metals with pulsed CO2 laser radiation

NASA Astrophysics Data System (ADS)

Arutyunyan, R. V.; Baranov, V. Yu; Bobkov, I. V.; Bol'shov, Leonid A.; Dolgov, V. A.; Kanevskiĭ, M. F.; Malyuta, D. D.; Mezhevov, V. S.

1988-03-01

A report is given of the influence of low-threshold surface optical breakdown, occurring under the action of short (~ 5-μs) radiation pulses from a CO2 laser, on the process of the laser drilling of metals. Data are given on the difference between the interaction of radiation pulses having the same duration but differing in shape. A study was made of the influence of the pressure of the atmosphere surrounding a target on the results of laser drilling of metals. A theoretical explanation is given of the experimental results.

3D photomechanical model of tooth enamel ablation by Er-laser radiation

NASA Astrophysics Data System (ADS)

Belikov, Andrey V.; Shatilova, Ksenia V.; Skrypnik, Alexei V.

2014-02-01

The three-dimensional (3D) photomechanical model of human tooth enamel ablation is described. It takes into account: the structural peculiarities of enamel, Er-laser beam energy spatial distribution and laser radiation attenuation in the tissue. Dynamics change of enamel coefficient of absorption during ablation is also discussed. We consider the 3D photomechanical model of incomplete removal (modification) of the enamel rods by the pressure of water contained in the enamel pores and heated by laser radiation, and complete removal (ablation) of the enamel rods as result of hydroxyapatite heated by laser radiation and evaporation. Modeling results are in close agreement with the experimental results.

Generation of terahertz radiation by intense hollow Gaussian laser beam in magnetised plasma under relativistic-ponderomotive regime

NASA Astrophysics Data System (ADS)

Rawat, Priyanka; Rawat, Vinod; Gaur, Bineet; Purohit, Gunjan

2017-07-01

This paper explores the self-focusing of hollow Gaussian laser beam (HGLB) in collisionless magnetized plasma and its effect on the generation of THz radiation in the presence of relativistic-ponderomotive nonlinearity. The relativistic change of electron mass and electron density perturbation due to the ponderomotive force leads to self-focusing of the laser beam in plasma. Nonlinear coupling between the intense HGLB and electron plasma wave leads to generation of THz radiation in plasma. Resonant excitation of THz radiation at different frequencies of laser and electron plasma wave satisfies proper phase matching conditions. Appropriate expressions for the beam width parameter of the laser beam and the electric vector of the THz wave have been evaluated under the paraxial-ray and Wentzel-Kramers Brillouin approximations. It is found that the yield of THz amplitude depends on the focusing behaviour of laser beam, magnetic field, and background electron density. Numerical simulations have been carried out to investigate the effect of laser and plasma parameters on self-focusing of the laser beam and further its effect on the efficiency of the generated THz radiation.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Characteristics of the evolution of a plasma formed by cw and pulse-periodic CO2 laser radiation in various gases

NASA Astrophysics Data System (ADS)

Kanevskiĭ, M. F.; Stepanova, M. A.

1990-06-01

An investigation was made of the interaction between high-power cw and pulse-periodic CO2 laser radiation and a low-threshold optical breakdown plasma near a metal surface. Characteristics of the breakdown plasma were studied as a function of the experimental conditions. A qualitative analysis was made of the results using a simple one-dimensional model for laser combustion waves.

Numerical simulation of the shape of laser cut for fiber and CO2 lasers

NASA Astrophysics Data System (ADS)

Zaitsev, A. V.; Ermolaev, G. V.; Polyanskiy, T. A.; Gurin, A. M.

2017-10-01

The results of numerical modeling of steel plate laser cutting with nitrogen as assist gas with consideration of heat transfer into a bulk material are presented. In this work we studied a distribution of absorbed radiation energy inside cut kerf and the difference between CO2 and fiber laser radiation propagation and absorption. The influence of secondary absorption of reflected from the cut front radiation on stability of melt hydrodynamics is discussed for different laser types.

Activities report in quantum optics

NASA Astrophysics Data System (ADS)

1985-03-01

Soft X-ray radiation from laser plasmas, intense Planck radiation, X-ray spectroscopy with transmission gratings, simulation of laser-produced shock waves, self-similar expansion in vacuum, radiation hydrodynamics, electronic structure of highly compressed matter, and heavy-ion beams for inertial confinement were investigated, and a high power iodine laser was developed. Laser-spectroscopy experiments, as well as a gravitational wave experiments were conducted. The fundamentals of light-matter interaction and nonlinear dynamics were studied. Many-photon ionization of molecules; spectroscopy of shock pairs; interaction of excited molecules with surfaces; IR laser applications; organic photochemistry with UV lasers; theoretical chemistry; and a ClF laser were investigated. Thin layers, and a high-pressure CO2 laser were studied.

CPU Performance Counter-Based Problem Diagnosis for Software Systems

DTIC Science & Technology

2009-09-01

application servers and implementation techniques), this thesis only used the Enterprise Java Bean (EJB) SessionBean version of RUBiS. The PHP and Servlet ...collection statistics at the Java Virtual Machine (JVM) level can be reused for any Java application. Other examples of gray-box instrumentation include path...used gray-box approaches. For example, PinPoint [11, 14] and [29] use request tracing to diagnose Java exceptions, endless calls, and null calls in

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cannon, Gordon C.; Heinhorst, Sabine; Kerfeld, Cheryl A.

Cyanobacteria and some chemoautotrophic bacteria are able to grow in environments with limiting CO2 concentrations by employing a CO2-concentrating mechanism (CCM) that allows them to accumulate inorganic carbon in their cytoplasm to concentrations several orders of magnitude higher than that on the outside. The final step of this process takes place in polyhedral protein microcompartments known as carboxysomes, which contain the majority of the CO2-fixing enzyme, RubisCO. The efficiency of CO2 fixation by the sequestered RubisCO is enhanced by co-localization with a specialized carbonic anhydrase that catalyzes dehydration of the cytoplasmic bicarbonate and ensures saturation of RubisCO with its substrate,more » CO2. There are two genetically distinct carboxysome types that differ in their protein composition and in the carbonic anhydrase(s) they employ. Here we review the existing information concerning the genomics, structure and enzymology of these uniquely adapted carbonic anhydrases, which are of fundamental importance in the global carbon cycle.« less

Comparison of abundances of chemical elements in mineralized and unmineralized sandstone of the Brushy Basin Member of the Morrison Formation, Smith Lake District, Grants uranium region, New Mexico

USGS Publications Warehouse

Pierson, C.T.; Spirakis, C.S.; Robertson, J.F.

1983-01-01

Statistical treatment of analytical data from the Mariano Lake and Ruby uranium deposits in the Smith Lake district, New Mexico, indicates that organic carbon, arsenic, barium, calcium, cobalt, copper, gallium, iron, lead, manganese, molybdenum, nickel, selenium, strontium, sulfur, vanadium, yttrium, and zirconium are concentrated along with uranium in primary ore. Comparison of the Smith Lake data with information from other primary deposits in the Grants uranium region and elsewhere in the Morrison Formation of the Colorado Plateau suggests that these elements, with the possible exceptions of zirconium and gallium and with the probable addition of aluminum and magnesium, are typically associated with primary, tabular uranium deposits. Chemical differences between the Ruby and Mariano Lake deposits are consistent with the interpretation that the Ruby deposit has been more affected by post-mineralization oxidizing solutions than has the Mariano Lake deposit.

Micro-PIXE analysis of trace element concentrations of natural rubies from different locations in Myanmar

NASA Astrophysics Data System (ADS)

Sanchez, J. L.; Osipowicz, T.; Tang, S. M.; Tay, T. S.; Win, T. T.

1997-07-01

The trace element concentrations found in geological samples can shed light on the formation process. In the case of gemstones, which might be of artificial or natural origin, there is also considerable interest in the development of methods that provide identification of the origin of a sample. For rubies, trace element concentrations present in natural samples were shown previously to be significant indicators of the region of origin [S.M. Tang et al., Appl. Spectr. 42 (1988) 44, and 43 (1989) 219]. Here we report the results of micro-PIXE analyses of trace element (Ti, V, Cr, Fe, Cu and Ga) concentrations of a large set ( n = 130) of natural rough rubies from nine locations in Myanmar (Burma). The resulting concentrations are subjected to statistical analysis. Six of the nine groups form clusters when the data base is evaluated using tree clustering and principal component analysis.

Zeeman Effect in Ruby at High Pressures

NASA Astrophysics Data System (ADS)

Dan, Ioana

2012-02-01

We have developed a versatile fiber-coupled system for magneto-optical spectroscopy measurements at high pressure. The system is based on a miniature Cu-alloy Diamond Anvil Cell (from D'Anvils, Ltd) fitted with a custom-designed He gas-actuated membrane for in-situ pressure control, and coupled with a He transfer cryostat incorporating a superconducting magnet (from Quantum Designs). This system allows optical measurements (Raman, photoluminescence, reflectivity) within wide ranges of pressures (up to 100GPa), temperatures (4.2-300K) and magnetic fields (0-9T). We employ this system to examine the effect of pressure and non-hydrostatic stress on the Zeeman split d-d transitions of Cr^3+ in ruby (Al2O3: Cr^3+). We determine the effect of pressure and non-hydrostaticity on the trigonal crystal field in this material, and discuss the use of the Zeman-split ruby fluorescence as a possible probe for deviatoric stresses in diamond anvil cell experiments.

A Broadband Infrared Laser Source (2.5-17 μm) for Plasma Diagnostics

NASA Astrophysics Data System (ADS)

Ionin, A. A.; Kinyaevskii, I. O.; Klimachev, Yu. M.; Kozlov, A. Yu.; Kotkov, A. A.

2017-12-01

This paper presents the results of studies aimed at the creation of a hybrid laser system which is composed of a gas lasers and a nonlinear crystal and appreciably broadens and enriches the radiation spectrum of these lasers. A highly efficient conversion (37%) is attained when generating the second harmonic in a ZnGeP2 crystal owing to an increase in the peak power of CO laser radiation in the mode locking regime. The two-cascade conversion (generation of both sum and difference frequencies) of radiation of a broadband CO laser in the single sample of such nonlinear crystals as ZnGeP2 and AgGaSe2 is demonstrated. In this case, the radiation spectrum is broadened by nearly a factor of two, and the number of detected spectral lines grows by a factor of four. The use of a comparatively simple laser system of gas-discharge CO and CO2 lasers to conversion in AgGaSe2 results in laser radiation tunable over a set of narrow spectral lines within a range from 2.5 to 16.6 μm (more than two and a half octaves).

Experimental Evidence of Radiation Reaction in the Collision of a High-Intensity Laser Pulse with a Laser-Wakefield Accelerated Electron Beam

NASA Astrophysics Data System (ADS)

Cole, J. M.; Behm, K. T.; Gerstmayr, E.; Blackburn, T. G.; Wood, J. C.; Baird, C. D.; Duff, M. J.; Harvey, C.; Ilderton, A.; Joglekar, A. S.; Krushelnick, K.; Kuschel, S.; Marklund, M.; McKenna, P.; Murphy, C. D.; Poder, K.; Ridgers, C. P.; Samarin, G. M.; Sarri, G.; Symes, D. R.; Thomas, A. G. R.; Warwick, J.; Zepf, M.; Najmudin, Z.; Mangles, S. P. D.

2018-02-01

The dynamics of energetic particles in strong electromagnetic fields can be heavily influenced by the energy loss arising from the emission of radiation during acceleration, known as radiation reaction. When interacting with a high-energy electron beam, today's lasers are sufficiently intense to explore the transition between the classical and quantum radiation reaction regimes. We present evidence of radiation reaction in the collision of an ultrarelativistic electron beam generated by laser-wakefield acceleration (ɛ >500 MeV ) with an intense laser pulse (a0>10 ). We measure an energy loss in the postcollision electron spectrum that is correlated with the detected signal of hard photons (γ rays), consistent with a quantum description of radiation reaction. The generated γ rays have the highest energies yet reported from an all-optical inverse Compton scattering scheme, with critical energy ɛcrit>30 MeV .

3D Finite Element Model for Writing Long-Period Fiber Gratings by CO2 Laser Radiation

PubMed Central

Coelho, João M. P.; Nespereira, Marta; Abreu, Manuel; Rebordão, José

2013-01-01

In the last years, mid-infrared radiation emitted by CO2 lasers has become increasing popular as a tool in the development of long-period fiber gratings. However, although the development and characterization of the resulting sensing devices have progressed quickly, further research is still necessary to consolidate functional models, especially regarding the interaction between laser radiation and the fiber's material. In this paper, a 3D finite element model is presented to simulate the interaction between laser radiation and an optical fiber and to determine the resulting refractive index change. Dependence with temperature of the main parameters of the optical fiber materials (with special focus on the absorption of incident laser radiation) is considered, as well as convection and radiation losses. Thermal and residual stress analyses are made for a standard single mode fiber, and experimental results are presented. PMID:23941908

Probe And Enhancement Of SBS Based Phonons In Infrared Fibers Using Waveguide Coupled External Radiation

NASA Astrophysics Data System (ADS)

Yu, Chung; Chong, Yat C.; Fong, Chee K.

1989-06-01

Interaction of GHz and MHz radiation with CO2 laser propagation in a silver halide fiber using sBs based phonon coupling is furthet investigated. The external signal serves to both probe and enhance laser generated sBs phonons in the fiber. Efficient coupling of microwave radiation into the fiber is accomplished by placing the fiber in a hollow metallic waveguide, designed and constructed to transmit the dominant mode in the 0.9-2.0 GHz band. MHz radiation is conveniently coupled into the fiber using the guided microwave radiation as carrier. Phonon emissions from the fiber under CO2 laser pumping are first established on a spectrum analyzer; low frequency generators ale then tuned to match these frequencies and their maximum interaction recorded. Such interactions are systematically studied by monitoring the amplitude and waveform of the reflected and transmitted laser pulse at various power levels and frequencies of the externally coupled radiation. A plot of reflected laser power versus incident laser power reveals a distinct sBs generated phonon threshold. Variouslaunch directions of the GHz and MHz radiation with respect to the direction of laser propagation are realized to verify theory governing sBs interactions. The MHz radiation and its associated phonons in the fiber are convenient tools for probing sBs related phenomenon in infrared fibers.

Terahertz plasmonic laser radiating in an ultra-narrow beam

DOE PAGES

Wu, Chongzhao; Khanal, Sudeep; Reno, John L.; ...

2016-07-07

Plasmonic lasers (spasers) generate coherent surface plasmon polaritons (SPPs) and could be realized at subwavelength dimensions in metallic cavities for applications in nanoscale optics. Plasmonic cavities are also utilized for terahertz quantum-cascade lasers (QCLs), which are the brightest available solid-state sources of terahertz radiation. A long standing challenge for spasers that are utilized as nanoscale sources of radiation, is their poor coupling to the far-field radiation. Unlike conventional lasers that could produce directional beams, spasers have highly divergent radiation patterns due to their subwavelength apertures. Here, we theoretically and experimentally demonstrate a new technique for implementing distributed feedback (DFB) thatmore » is distinct from any other previously utilized DFB schemes for semiconductor lasers. The so-termed antenna-feedback scheme leads to single-mode operation in plasmonic lasers, couples the resonant SPP mode to a highly directional far-field radiation pattern, and integrates hybrid SPPs in surrounding medium into the operation of the DFB lasers. Experimentally, the antenna-feedback method, which does not require the phase matching to a well-defined effective index, is implemented for terahertz QCLs, and single-mode terahertz QCLs with a beam divergence as small as 4°×4° are demonstrated, which is the narrowest beam reported for any terahertz QCL to date. Moreover, in contrast to a negligible radiative field in conventional photonic band-edge lasers, in which the periodicity follows the integer multiple of half-wavelengths inside the active medium, antenna-feedback breaks this integer limit for the first time and enhances the radiative field of the lasing mode. Terahertz lasers with narrow-beam emission will find applications for integrated as well as standoff terahertz spectroscopy and sensing. Furthermore, the antenna-feedback scheme is generally applicable to any plasmonic laser with a Fabry–Perot cavity irrespective of its operating wavelength and could bring plasmonic lasers closer to practical applications.« less

First Octahedral Spherical Hohlraum Energetics Experiment at the SGIII Laser Facility

NASA Astrophysics Data System (ADS)

Huo, Wen Yi; Li, Zhichao; Chen, Yao-Hua; Xie, Xufei; Ren, Guoli; Cao, Hui; Li, Shu; Lan, Ke; Liu, Jie; Li, Yongsheng; Li, Sanwei; Guo, Liang; Liu, Yonggang; Yang, Dong; Jiang, Xiaohua; Hou, Lifei; Du, Huabing; Peng, Xiaoshi; Xu, Tao; Li, Chaoguang; Zhan, Xiayu; Wang, Zhebin; Deng, Keli; Wang, Qiangqiang; Deng, Bo; Wang, Feng; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Yuan, Guanghui; Zhang, Haijun; Jiang, Baibin; Zhang, Wei; Gu, Qianqian; He, Zhibing; Du, Kai; Deng, Xuewei; Zhou, Wei; Wang, Liquan; Huang, Xiaoxia; Wang, Yuancheng; Hu, Dongxia; Zheng, Kuixing; Zhu, Qihua; Ding, Yongkun

2018-04-01

The first octahedral spherical hohlraum energetics experiment is accomplished at the SGIII laser facility. For the first time, the 32 laser beams are injected into the octahedral spherical hohlraum through six laser entrance holes. Two techniques are used to diagnose the radiation field of the octahedral spherical hohlraum in order to obtain comprehensive experimental data. The radiation flux streaming out of laser entrance holes is measured by six flat-response x-ray detectors (FXRDs) and four M -band x-ray detectors, which are placed at different locations of the SGIII target chamber. The radiation temperature is derived from the measured flux of FXRD by using the blackbody assumption. The peak radiation temperature inside hohlraum is determined by the shock wave technique. The experimental results show that the octahedral spherical hohlraum radiation temperature is in the range of 170-182 eV with drive laser energies of 71 kJ to 84 kJ. The radiation temperature inside the hohlraum determined by the shock wave technique is about 175 eV at 71 kJ. For the flat-top laser pulse of 3 ns, the conversion efficiency of gas-filled octahedral spherical hohlraum from laser into soft x rays is about 80% according to the two-dimensional numerical simulation.

Pulse Holography: Review Of Applications

NASA Astrophysics Data System (ADS)

Smigielski, Paul

1990-04-01

Pulse Holography includes studies concerning time-varying phase objects as well as time-varying reflective objects involving the use of pulse ruby- and YAG-lasers. The paper is divided in two parts. One part concerns the direct use of 3-1) images reconstructed from holograms, i.e. applications to particle size analysis, 3-I) velocity measurements, 3-I) cinematography ... The second part describes applications using holographic interferometry in laboratory or in an industrial environment, i.e. applications to fluid mechanics, vibration analysis, non-destructive testing ... Recent developments including interferornetric cineholography, fiber optics, measurement of non-interferometric displacements ... , are also described. The future of holography depends to a great extent on data processing and interpretation of informations contained in holograms or holographic intericrograms. Therefore, we give the state of art in this field in Europe illustrated with some industrial applications.

Recycling of laser and plasma radiation energy for enhancement of extreme ultraviolet sources for nanolithography

NASA Astrophysics Data System (ADS)

Sizyuk, V.; Sizyuk, T.; Hassanein, A.; Johnson, K.

2018-01-01

We have developed comprehensive integrated models for detailed simulation of laser-produced plasma (LPP) and laser/target interaction, with potential recycling of the escaping laser and out-of-band plasma radiation. Recycling, i.e., returning the escaping laser and plasma radiation to the extreme ultraviolet (EUV) generation region using retroreflective mirrors, has the potential of increasing the EUV conversion efficiency (CE) by up to 60% according to our simulations. This would result in significantly reduced power consumption and/or increased EUV output. Based on our recently developed models, our High Energy Interaction with General Heterogeneous Target Systems (HEIGHTS) computer simulation package was upgraded for LPP devices to include various radiation recycling regimes and to estimate the potential CE enhancement. The upgraded HEIGHTS was used to study recycling of both laser and plasma-generated radiation and to predict possible gains in conversion efficiency compared to no-recycling LPP devices when using droplets of tin target. We considered three versions of the LPP system including a single CO2 laser, a single Nd:YAG laser, and a dual-pulse device combining both laser systems. The gains in generating EUV energy were predicted and compared for these systems. Overall, laser and radiation energy recycling showed the potential for significant enhancement in source efficiency of up to 60% for the dual-pulse system. Significantly higher CE gains might be possible with optimization of the pre-pulse and main pulse parameters and source size.

Self-mixing detection of backscattered radiation in a single-mode erbium fibre laser for Doppler spectroscopy and velocity measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dmitriev, A K; Konovalov, A N; Ul'yanov, V A

2014-04-28

We report an experimental study of the self-mixing effect in a single-mode multifrequency erbium fibre laser when radiation backscattered from an external moving object arrives at its cavity. To eliminate resulting chaotic pulsations in the laser, we have proposed a technique for suppressing backscattered radiation through the use of multimode fibre for radiation delivery. The multifrequency operation of the laser has been shown to lead to strong fluctuations of the amplitude of the Doppler signal and a nonmonotonic variation of the amplitude with distance to the scattering object. In spite of these features, the self-mixing signal was detected with amore » high signal-to-noise ratio (above 10{sup 2}) when the radiation was scattered by a rotating disc, and the Doppler frequency shift, evaluated as the centroid of its spectrum, had high stability (0.15%) and linearity relative to the rotation rate. We conclude that the self-mixing effect in this type of fibre laser can be used for measuring the velocity of scattering objects and in Doppler spectroscopy for monitoring the laser evaporation of materials and biological tissues. (control of laser radiation parameters)« less

CO2 lasers and applications II; Proceedings of the Third European Congress on Optics, The Hague, Netherlands, Mar. 12-14, 1990

NASA Technical Reports Server (NTRS)

Opower, Hans (Editor)

1990-01-01

Recent advances in CO2 laser technology and its applications are examined. Topics discussed include the excitation of CO2 lasers by microwave discharge, a compact RF-excited 12-kW CO2 laser, a robotic laser for three-dimensional cutting and welding, three-dimensional CO2-laser material processing with gantry machine systems, and a comparison of hollow metallic waveguides and optical fibers for transmitting CO2-laser radiation. Consideration is given to an aerodynamic window with a pump cavity and a supersonic jet, cutting and welding Al using a high-repetition-rate pulsed CO2 laser, speckle reduction in CO2 heterodyne laser radar systems, high-power-laser float-zone crystal growth, melt dynamics in surface processing with laser radiation, laser hardfacing, surface melting of AlSi10Mg with CO2 laser radiation, material processing with Cu-vapor lasers, light-induced flow at a metal surface, and absorption measurements in high-power CW CO2-laser processing of materials.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Emission of charged particles from the surface of a moving target acted on by cw CO2 laser radiation

NASA Astrophysics Data System (ADS)

Kuznetsov, S. I.; Petrov, A. L.; Shadrin, A. N.

1990-06-01

An experimental investigation was made of the emission of charged particles due to the irradiation of moving steel and graphite targets with cw CO2 laser radiation. The characteristics of the emission current signals were determined for different laser irradiation regimes. The maximum emission current density from the surface of a melt pool ( ~ 1.1 × 10 - 2 A/cm2) and the average temperature of the liquid metal (~ 2040 K) were measured for an incident radiation power density of 550 W and for horizontal and vertical target velocities of respectively ~ 1.5 mm/s and ~ 0.17 mm/s. The authors propose to utilize this phenomenon for monitoring the laser processing of materials.

Fibre Optic Temperature Sensors Using Fluorescent Phenomena.

NASA Astrophysics Data System (ADS)

Selli, Raman Kumar

Available from UMI in association with The British Library. A number of fibre optic sensors based on fluorescent phenomena using low cost electronic and optical filtering techniques, for temperature sensing applications are described and discussed. The initial device developed uses the absorption edge change of an optical glass to monitor changes in temperature with a second wavelength reference channel being generated from a fluorescent material, neodymium doped in glass. This device demonstrates the working of the self-referencing principle in a practical device tested over the temperature range of -60^circ C to 200^circC. This initial device was improved by incorporating a microprocessor and by modifying the processing electronic circuitry. An alternative probe was constructed which used a second fibre placed along-side the addressing fibre in contrast to the original device where the fibre is placed at the opposite end of the addressing fibre. A device based on the same principle but with different absorption glasses and a different fluorescent medium, crystalline ruby, was also examined. This device operated at a lower wavelength region compared to the infra -red working region of the first device. This work illustrated the need to make an appropriate choice of sensor absorption glass so that the cheaper indicator type LEDs, which operated at lower wavelengths, may be used. Ruby is a fluorescent material which is characterized by each emission wavelength having its own temperature characteristics. The integrated energy output over the complete emission spectrum is independent of temperature. This provided a means of generating a reference from the complete spectrum while a small frequency band gave a temperature dependent output. This characteristic of ruby was used to develop a temperature measuring device. A final system which utilises the temperature dependent decay-time emission properties of crystalline ruby was developed. In this case the ruby was excited by sinusoidally modulated light. This system employs a single indicator type green LED to excite the ruby sample and a single very sensitive silicon photodiode detector with an integral amplifier for low optical signal detection. Both of these components were inexpensive. The system yielded very high performance levels in terms of precision and resolution which has the potential for commercial exploitation. The different devices developed are compared and contrasted in the light of the commercial instruments on the market and other published data.

Red and infrared gas laser beam for therapy

NASA Astrophysics Data System (ADS)

Pascu, Mihail-Lucian; Ristici, Marin; Ristici, E.; Tivarus, Madalina-Elena

2000-06-01

For the low power laser therapy, the experiments show that better results are obtained when the laser beam is an overlapping of two radiations: one in the visible region of the spectrum and the other in IR region. Also, some experiments show that for good results in biostimulation it is important to have a high coherence length of laser beam; this is not the case of the laser diodes The He-Ne laser has the best coherence, being able to generate laser radiations in visible and IR. It has tow strong laser lines: 633 nm and 1.15 micrometers . Although their gains are about the same, the available power of the red radiation is 3-4 times higher because of its larger width, when they oscillate separately. Using special dichroic mirrors for simultaneous reflection of the both liens, the laser beam will consist of the two radiations, each of them having good coherence . A 420 mm active length, 1.8 mm inner diameter He-Ne laser tube and a special designed resonator has been developed. The mirrors reflect both radiations as follows: one reflects 99.9 percent and the other, the output mirror, reflects 98 percent. There is a competition between them because these lines have a common lower level. The output power of the laser beam as 6 mW for 633 nm and 4 mW for 1.15 micrometers , respectively.

Compact and highly efficient laser pump cavity

DOEpatents

Chang, Jim J.; Bass, Isaac L.; Zapata, Luis E.

1999-01-01

A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

Development of ultrashort x-ray/gamma-ray sources using ultrahigh power lasers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kim, Hyung Taek; Nakajima, Kazuhisa; Hojbota, Calin; Jeon, Jong Ho; Rhee, Yong-Joo; Lee, Kyung Hwan; Lee, Seong Ku; Sung, Jae Hee; Lee, Hwang Woon; Pathak, Vishwa B.; Pae, Ki Hong; Sebban, Stéphane; Tissandier, Fabien; Gautier, Julien; Ta Phuoc, Kim; Malka, Victor; Nam, Chang Hee

2017-05-01

Short-pulse x-ray/gamma-ray sources have become indispensable light sources for investigating material science, bio technology, and photo-nuclear physics. In past decades, rapid advancement of high intensity laser technology led extensive progresses in the field of radiation sources based on laser-plasma interactions - x-ray lasers, betatron radiation and Compton gamma-rays. Ever since the installation of a 100-TW laser in 2006, we have pursued the development of ultrashort x-ray/gamma-ray radiations, such as x-ray lasers, relativistic high-order harmonics, betatron radiation and all-optical Compton gamma-rays. With the construction of two PW Ti:Sapphire laser beamlines having peak powers of 1.0 PW and 1.5 PW in 2010 and 2012, respectively [1], we have investigated the generation of multi-GeV electron beams [2] and MeV betatron radiations. We plan to carry out the Compton backscattering to generate MeV gamma-rays from the interaction of a GeV electron beam and a PW laser beam. Here, we present the recent progress in the development of ultrashort x-ray/gamma-ray radiation sources based on laser plasma interactions and the plan for developing Compton gamma-ray sources driven by the PW lasers. In addition, we will present the applications of laser-plasma x-ray lasers to x-ray holography and coherent diffraction imaging. [references] 1. J. H. Sung, S. K. Lee, T. J. Yu, T. M. Jeong, and J. Lee, Opt. Lett. 35, 3021 (2010). 2. H. T. Kim, K. H. Pae, H. J. Cha, I J. Kim, T. J. Yu, J. H. Sung, S. K. Lee, T. M. Jeong, J. Lee, Phys. Rev. Lett. 111, 165002 (2013).

Multimode theory of plasmon excitation at a metal - photonic crystal interface

NASA Astrophysics Data System (ADS)

Kuznetsova, T. I.; Raspopov, N. A.

2017-12-01

Surface plasmon excitation at a photonic crystal - metal interface is studied taking into account multiple scattering of an initial light wave on a periodical crystal structure. The analysis is focused on calculating characteristics of the eigenwaves in a one-dimensional crystal, which comprise a set of harmonics with the wavevectors separated from each other by the value of the crystal lattice wavevector. Reflection from the crystal - metal interface binds the amplitudes of propagating and evanescent modes. Calculations show that for the dielectric characteristics of a synthetic opal and a substrate made of a real metal with a ruby laser radiation used as the initial wave, the fulfilment of plasmon resonance conditions leads to a local increase in the surface plasmon amplitude by a factor of 6.4 - 9 as compared to the average amplitude of the initial wave. As a rule, the effect can only be obtained for a single surface wave, all other waves being substantially weaker than the main plasmon. There is a specific case where the resonance condition holds for two modes simultaneously. In this case, two oppositely directed fluxes of equal intensity are generated at the interface. The resonance condition breaks at a small deviation of the incident angle of the initial wave θ from the normal direction (|θ| ⩾ 10-4 rad). In the latter case, the picture is asymmetric: at angles |θ| ⩾ 5 × 10-3 rad, only one plasmon remains intensive. The local density of electromagnetic energy at the photonic crystal - metal interface may exceed the corresponding value of the initial wave by a factor of 40 - 80.

Method and system for compact, multi-pass pulsed laser amplifier

DOEpatents

Erlandson, Alvin Charles

2014-11-25

A laser amplifier includes an input aperture operable to receive laser radiation having a first polarization, an output aperture coupled to the input aperture by an optical path, and a polarizer disposed along an optical path. A transmission axis of the polarizer is aligned with the first polarization. The laser amplifier also includes n optical switch disposed along the optical path. The optical switch is operable to pass the laser radiation when operated in a first state and to reflect the laser radiation when operated in a second state. The laser amplifier further includes an optical gain element disposed along the optical path and a polarization rotation device disposed along the optical path.

Preliminary Report on Floodplain Animals of the Upper Mississippi River and the Illinois Waterway Including Some Probable Impacts of Increased Commercial Traffic,

DTIC Science & Technology

1975-01-01

case of the canvasback, it is conceivable that a large oil spill in a concentration area during the peak migration period could destroy a substantial...winter crowned Lichtenstein secondary resident kinglet succession 123. Ruby-crowned Regulus calendula Statewide Statewide younger stand, C winter...Regulus calendula . Ruby-crowned Kinglet TV-c Family MOTACLLLIDAS - pipits Anthus spinoletta ’Water Pipit, TV-r Family BOHIYCILLIDAE - waxwings

[Agrobacterium rubi strains from blueberry plants are highly diverse].

PubMed

Abrahamovich, Eliana; López, Ana C; Alippi, Adriana M

2014-01-01

The diversity of a collection of Agrobacterium rubi strains isolated from blueberries from different regions of Argentina was studied by conventional microbiological tests and molecular techniques. Results from biochemical and physiological reactions, as well as from rep-PCR and RFLP analysis of PCR-amplified 23S rDNA showed high phenotypic and genotypic intraspecific variation. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.

Fiber optic coupling of a microlens conditioned, stacked semiconductor laser diode array

DOEpatents

Beach, Raymond J.; Benett, William J.; Mills, Steven T.

1997-01-01

The output radiation from the two-dimensional aperture of a semiconductor laser diode array is efficiently coupled into an optical fiber. The two-dimensional aperture is formed by stacking individual laser diode bars on top of another in a "rack and stack" configuration. Coupling into the fiber is then accomplished using individual microlenses to condition the output radiation of the laser diode bars. A lens that matches the divergence properties and wavefront characteristics of the laser light to the fiber optic is used to focus this conditioned radiation into the fiber.

The changes in the electronic spectra of ascorbic acid induced by laser radiation

NASA Astrophysics Data System (ADS)

Danyaeva, J. S.; Kutsenko, S. A.

2018-04-01

The results of research the changes in the absorption spectra of aqueous solutions of ascorbic acid under the influence of laser radiation are presented. The solutions were irradiated with the radiation of semiconductor lasers with wavelengths of 408 and 532 nm, YAG: Nd3+ laser with a wavelength of 1064 nm and a nitrogen laser with a wavelength of 337.1 nm. The photoinduced changes in the spectrum are revealed, which indicate the breakage of π -> π bonds in the molecule of ascorbic acid during its destruction.

Development of Technologies to Utilize Laser Plasma Radiations Sources for Radiation Effects Sciences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, J F

2007-01-31

This final report will cover work performed over the period of November 11, 2005 to September 30, 2006 on the contract to develop technologies using laser sources for radiation effects sciences. The report will discuss four topic areas; the laser source experiments on the Gekko Laser at Osaka, Japan, planning for the Charge State Freeze Out experiments to be performed in calendar year 2007, a review of previous xenon gasbags on the LANL Trident laser to provide planning support to the May-June 2007 HELEN experiments.

Optical Diagnostic System For Observation Of Laser-Produced Shock Waves

NASA Astrophysics Data System (ADS)

Wilke, Mark D.; Stone, Sidney N.

1980-11-01

Several standard plasma and gas dynamic diagnostic techniques have been integrated into a system for observing the formation and propagation of high-power Nd:glass-laser generated one- and two-dimensional shockwaves in air from 0.1 torr to atmospheric pres-sures. Diagnostics include either single-frame, two-wavelength holographic ruby-laser interferometry or single-frame, single-wavelength interferometry with ten frames of shadow-graphy. Streaks or ten frames of the early luminous shocked region also are taken on all shots, as well as time-resolved luminosity measurements using high-speed biplanar vacuum photodiodes with various wavelength interference filters. Shadowgraphy frames are 200-ns long at 1-μs intervals, while emission frames are variable with a maximum 10-ns exposure and 50-ns interval. Both the streak mode and emission measurements with the vacuum diode allow subnanosecond time resolution. The interferometry provides 20-ns exposures from 500 ns to late times. Methods for reducing and interpreting the data have been, or are currently being, developed. Interactive computer programs for digitizing the fringe patterns provide fringe-shift profiles for Abel inversion. This has provided neutral gas and electron density information in the spherical, one-dimensional cases. Diagrams and photographs of the experiment will be shown as well as examples of the data that have been taken. Methods for data reduction will be outlined and some of the results shown.

The laser radiation action on the crystal formation processes in the biological fluids

NASA Astrophysics Data System (ADS)

Malov, Alexander N.; Vaichas, Andrey A.; Novikova, Evgeniya A.

2016-11-01

The results of an experimental study of the laser radiation effect on the crystal`s formation in the volume of biological fluids that are complex multi-component solutions have been discussing. Are investigated white and natural bile in vitro. The qualitative changes were observed. Thus, at the bottom of the cell in which bile is not exposed to the laser radiation, the crystals are formed. In the irradiated bile gallstone has a thin layer of a homogeneous viscous colloidal liquid with very small, visible in polarized light crystalline formations was got. Irradiated laser bile's gallstone was covered evenly white deposit without surface defect unlike gallstone in bile without radiation exposure. A possible mechanism to explain the laser radiation action on the mineral formation in biological fluids and also practical application of this effect have been suggesting too.

Physical Approaches to Designing a Two-Cascade Terahertz Laser Generating Difference-Frequency Radiation in a Nonlinear Optical ZnGeP2 Crystal

NASA Astrophysics Data System (ADS)

Gribenyukov, A. I.; Dyomin, V. V.; Polovtsev, I. G.; Yudin, N. N.

2018-03-01

An optical layout of a two-cascade frequency converter of the mid-IR laser radiation into the terahertz (THz) radiation is proposed. In the first stage it is assumed to convert the Tm:YLF-laser frequency in a Cr+2:ZnSe polycrystal into the radiation with the wavelength 2-3 μm. The second cascade can be presented as a parametric conversion of the frequencies of two laser sources operating in the 2-3 μm range into the THz radiation via the difference-frequency mixing in a nonlinear optical ZnGeP2 crystal. The estimates of the terahertz output signal are reported.

Experimental and clinical standards, and evolution of lasers in neurosurgery.

PubMed

Devaux, B C; Roux, F X

1996-01-01

From initial experiments of ruby, argon and CO2 lasers on the nervous system so far, dramatic progress was made in delivery systems technology as well as in knowledge of laser-tissue interaction effects and hazards through various animal experiments and clinical experience. Most surgical effects of laser light on neural tissue and the central nervous system (CNS) are thermal lesions. Haemostasis, cutting and vaporization depend on laser emission parameters--wavelength, fluence and mode--and on the exposed tissues optical and thermal properties--water and haemoglobin content, thermal conductivity and specific heat. CO2 and Nd-YAG lasers have today a large place in the neurosurgical armamentarium, while new laser sources such as high power diode lasers will have one in the near future. Current applications of these lasers derive from their respective characteristics, and include CNS tumour and vascular malformation surgery, and stereotactic neurosurgery. Intracranial, spinal cord and intra-orbital meningiomas are the best lesions for laser use for haemostasis, dissection and tissue vaporization. Resection of acoustic neuromas, pituitary tumours, spinal cord neuromas, intracerebral gliomas and metastases may also benefit from lasers as accurate, haemostatic, non-contact instruments which reduce surgical trauma to the brain and eloquent structures such as brain stem and cranial nerves. Coagulative lasers (1.06 microns and 1.32 microns Nd-YAG, argon, or diode laser) will find an application for arteriovenous malformations and cavernomas. Any fiberoptic-guided laser will find a use during stereotactic neurosurgical procedures, including image-guided resection of tumours and vascular malformations and endoscopic tumour resection and cysts or entry into a ventricle. Besides these routine applications of lasers, laser interstitial thermotherapy (LITT) and photodynamic therapy (PDT) of brain tumours are still in the experimental stage. The choice of a laser in a neurosurgical operating room implies an evaluation of the laser use (applications, frequency), of the available budget and costs--including purchase, maintenance and staff training--, and material that will be necessary: unit, peripherals, safety devices and measures, training programme. Future applications of lasers in neurosurgery will come from technological advances and refined experimental applications. The availability of new wavelength, tunable, small sized and "smart" laser units, will enlarge the thermal and non-thermal interactions between laser energy and neural tissue leading to new surgical applications. Tissue photo-ablation, photohynamic therapy using second generation of photosensitizers, updated thermotherapy protocols, are current trends for further use of lasers in neurosurgery.

Solar-pumped CO laser

NASA Astrophysics Data System (ADS)

Treanor, Charles E.

This paper describes a method of converting thermal radiation directly into laser radiation at a wavelength of about 5 micrometers. The working fluid for the laser operation is a mixture of carbon monoxide and argon. The source of thermal radiation is assumed to be a solar oven or electrical oven operating in the range of 2000 to 2500 K. The use of carbon monoxide as the lasing material presents the advantage that the absorbing lines can be pressure broadened to permit efficient absorption of the thermal radiation without unacceptable increases in vibrational relaxation. Estimates of the efficiency, size, and power loading of such a laser are discussed.

NASA's Space Lidar Measurements of Earth and Planetary Surfaces

NASA Technical Reports Server (NTRS)

Abshire, James B.

2010-01-01

A lidar instrument on a spacecraft was first used to measure planetary surface height and topography on the Apollo 15 mission to the Moon in 1971, The lidar was based around a flashlamp-pumped ruby laser, and the Apollo 15-17 missions used them to make a few thousand measurements of lunar surface height from orbit. With the advent of diode pumped lasers in the late 1980s, the lifetime, efficiency, resolution and mass of lasers and space lidar all improved dramatically. These advances were utilized in NASA space missions to map the shape and surface topography of Mars with > 600 million measurements, demonstrate initial space measurements of the Earth's topography, and measured the detailed shape of asteroid. NASA's ICESat mission in Earth orbit just completed its polar ice measurement mission with almost 2 billion measurements of the Earth's surface and atmosphere, and demonstrated measurements to Antarctica and Greenland with a height resolution of a few em. Space missions presently in cruise phase and in operation include those to Mercury and a topographic mapping mission of the Moon. Orbital lidar also have been used in experiments to demonstrate laser ranging over planetary distances, including laser pulse transmission from Earth to Mars orbit. Based on the demonstrated value of the measurements, lidar is now the preferred measurement approach for many new scientific space missions. Some missions planned by NASA include a planetary mission to measure the shape and dynamics of Europa, and several Earth orbiting missions to continue monitoring ice sheet heights, measure vegetation heights, assess atmospheric CO2 concentrations, and to map the Earth surface topographic heights with 5 m spatial resolution. This presentation will give an overview of history, ongoing work, and plans for using space lidar for measurements of the surfaces of the Earth and planets.

Study on the electromagnetic radiation characteristics of discharging excimer laser system

NASA Astrophysics Data System (ADS)

Zhao, Duliang; Liang, Xu; Fang, Xiaodong; Wang, Qingsheng

2016-10-01

Excimer laser in condition of high voltage, large current and fast discharge will produce strong electromagnetic pulse radiation and electromagnetic interference on the around electrical equipment. The research on characteristics and distribution of excimer laser electromagnetic radiation could provide important basis for electromagnetic shielding and suppressing electromagnetic interference, and further improving the electromagnetic compatibility of system. Firstly, electromagnetic radiation source is analyzed according to the working principle of excimer laser. The key test points of the electromagnetic radiation, hydrogen thyratron, main discharge circuit and laser outlet, are determined by the mechanical structure and the theory of electromagnetic radiation. Secondly, characteristics of electromagnetic field were tested using a near field probe on the key positions of the vertical direction at 20, 50, and 80 cm, respectively. The main radiation frequencies and the radiation field characteristics in the near field are obtained. The experimental results show that the main radiation frequencies distribute in 47, 65, and 130 MHz for electric field and the main radiation frequencies distribute in 34, 100, and 165 MHz for magnetic field. The intensity of electromagnetic field decreases rapidly with the increase of test distance. The higher the frequency increases, the faster the amplitude attenuate. Finally, several electromagnetic interference suppression measurement methods are proposed from the perspective of electromagnetic compatibility according to the test results.

Qualification of quantum cascade lasers for space environments

NASA Astrophysics Data System (ADS)

Myers, Tanya L.; Cannon, Bret D.; Brauer, Carolyn S.; Crowther, Blake G.; Hansen, Stewart

2014-06-01

Laser-based instruments are enabling a new generation of scientific instruments for space environments such as those used in the exploration of Mars. The lasers must be robust and able to withstand the harsh environment of space, including radiation exposure. Quantum cascade lasers (QCLs), which are semiconductor lasers that emit in the infrared spectral region, offer the potential for the development of novel laser-based instruments for space applications. The performance of QCLs after radiation exposure, however, has not been reported. We report on work to quantify the performance of QCLs after exposure to two different radiation sources, 64 MeV protons and Cobalt-60 gamma rays, at radiation levels likely to be encountered during a typical space flight mission. No significant degradation in threshold current or slope efficiency is observed for any of the seven Fabry-Perot QCLs that are tested.

Laser radiation in active amplifying media treated as a transport problem - Transfer equation derived and exactly solved

NASA Astrophysics Data System (ADS)

Gupta, S. R. D.; Gupta, Santanu D.

1991-10-01

The flow of laser radiation in a plane-parallel cylindrical slab of active amplifying medium with axial symmetry is treated as a problem in radiative transfer. The appropriate one-dimensional transfer equation describing the transfer of laser radiation has been derived by an appeal to Einstein's A, B coefficients (describing the processes of stimulated line absorption, spontaneous line emission, and stimulated line emission sustained by population inversion in the medium) and considering the 'rate equations' to completely establish the rational of the transfer equation obtained. The equation is then exactly solved and the angular distribution of the emergent laser beam intensity is obtained; its numerically computed values are given in tables and plotted in graphs showing the nature of peaks of the emerging laser beam intensity about the axis of the laser cylinder.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Modification of biological objects in water media by CO2-laser radiation

NASA Astrophysics Data System (ADS)

Baranov, G. A.; Belyaev, A. A.; Onikienko, S. B.; Smirnov, S. A.; Khukharev, V. V.

2005-09-01

The modification of biological objects (polysaccharides and cells) by CO2-laser radiation in water added drop by drop into the interaction region is studied theoretically and experimentally. Calculations are performed by using the models describing gas-dynamic and heterogeneous processes caused by absorption of laser radiation by water drops. It is found experimentally that the laser modification of polysaccharides leads to the formation of low-molecular derivatives with immunostimulating properties. A dose of the product of laser activation of the yeast culture Saccharamyces cerevisiae prevented the development of a toxic emphysema in mice and protected them against lethal grippe and also prevented a decrease of survival rate, increased the average life, and prevented the development of metabolic and immune disorders in mice exposed to sublethal gamma-radiation doses.

EFFECTS OF LASER RADIATION ON MATTER: Efficient surface-erosion plasma formation in air due to the action of pulse-periodic laser radiation

NASA Astrophysics Data System (ADS)

Min'ko, L. Ya; Chumakou, A. N.; Bosak, N. A.

1990-11-01

A study was made of the interaction of a series of periodic laser (λ = 1.06 μm) pulses with a number of materials (aluminum, copper, graphite, ebonite) in air at laser radiation power densities q = 107-109 W/cm2 and repetition frequencies f<=50 kHz. The radiation was concentrated in spots of ~ 10 - 2 cm2 area. Efficient formation of plasma as a result of laser erosion (q > 2 × 108 W/cm2, f>=5 kHz) was observed. A screening layer of an air plasma created by the first pulse of the series was expelled from the interaction zone and this was followed by erosion plasma formation under conditions of slight screening of the target during the action of the subsequent laser pulses.

Soil temperature and water content drive microbial carbon fixation in grassland of permafrost area on the Tibetan plateau

NASA Astrophysics Data System (ADS)

Kong, W.; Guo, G.; Liu, J.

2014-12-01

Soil microbial communities underpin terrestrial biogeochemical cycles and are greatly influenced by global warming and global-warming-induced dryness. However, the response of soil microbial community function to global change remains largely uncertain, particularly in the ecologically vulnerable Tibetan plateau permafrost area with large carbon storage. With the concept of space for time substitution, we investigated the responses of soil CO2-fixing microbial community and its enzyme activity to climate change along an elevation gradient (4400-5100 m) of alpine grassland on the central Tibetan plateau. The elevation gradient in a south-facing hill slope leads to variation in climate and soil physicochemical parameters. The autotrophic microbial communities were characterized by quantitative PCR (qPCR), terminal restriction fragment length polymorphism analysis (T-RFLP) and cloning/sequencing targeting the CO2-fixing gene (RubisCO). The results demonstrated that the autotrophic microbial community abundance, structure and its enzyme activity were mainly driven by soil temperature and water content. Soil temperature increase and water decrease dramatically reduced the abundance of the outnumbered form IC RubisCO-containing microbes, and significantly changed the structure of form IC, IAB and ID RubisCO-containing microbial community. Structural equation model revealed that the RubisCO enzyme was directly derived from RubisCO-containing microbes and its activity was significantly reduced by soil temperature increase and water content decrease. Thus our results provide a novel positive feedback loop of climate warming and warming-induced dryness by that soil microbial carbon fixing potential will reduce by 3.77%-8.86% with the soil temperature increase of 1.94oC and water content decrease of 60%-70%. This positive feedback could be capable of amplifying the climate change given the significant contribution of soil microbial CO2-fixing up to 4.9% of total soil organic carbon.

Performance evaluation of Abbott CELL-DYN Ruby for routine use.

PubMed

Lehto, T; Hedberg, P

2008-10-01

CELL-DYN Ruby is a new automated hematology analyzer suitable for routine use in small laboratories and as a back-up or emergency analyzer in medium- to high-volume laboratories. The analyzer was evaluated by comparing the results from the CELL-DYN((R)) Ruby with the results obtained from CELL-DYN Sapphire . Precision, linearity, and carryover between patient samples were also assessed. Precision was good at all levels for the routine cell blood count (CBC) parameters, CV% being or= 0.98) with CELL-DYN Sapphire for the CBC parameters. For the absolute reticulocyte count, R(2) was 0.82. In the white blood cell (WBC) differentials, the between-days precision was good for all parameters (CV%: or= 0.97), and the correlation coefficient for absolute monocyte count and monocyte percentage were 0.91 and 0.87, respectively. For absolute basophil count and basophil percentage the correlations were weaker (R(2) = 0.46 and 0.34, respectively). Carryover was minimal for all the parameters studied. The linearities of WBC, red blood cell, PLTs, and hemoglobin were acceptable within the tested ranges. In conclusion, the results of the evaluation showed the performance of CELL-DYN Ruby to be good.

Estimates of evapotranspiration from the Ruby Lake National Wildlife Refuge area, Ruby Valley, northeastern Nevada, May 1999-October 2000

USGS Publications Warehouse

Berger, David L.; Johnson, Michael J.; Tumbusch, Mary L.; Mackay, Jeffrey

2001-01-01

The Ruby Lake National Wildlife Refuge in Ruby Valley, Nevada, contains the largest area of perennial wetlands in northeastern Nevada and provides habitat to a large number of migratory and nesting waterfowl. The long-term preservation of the refuge depends on the availability of sufficient water to maintain optimal habitat conditions. In the Ruby Valley water budget, evapotranspiration (ET) from the refuge is one of the largest components of natural outflow. To help determine the amount of inflow needed to maintain wetland habitat, estimates of ET for May 1999 through October 2000 were made at major habitats throughout the refuge. The Bowen-ratio method was used to estimate daily ET at four sites: over open water, in a moderate-to-dense cover of bulrush marsh, in a moderate cover of mixed phreatophytic shrubs, and in a desert-shrub upland. The eddy-correlation method was used to estimate daily ET for periods of 2 to 12 weeks at a meadow site and at four sites in a sparse-to-moderate cover of phreatophytic shrubs. Daily ET rates ranged from less than 0.010 inch per day at all of the sites to a maximum of 0.464 inch per day at the open-water site. Average daily ET rates estimated for open water and a bulrush marsh were about four to five times greater than in areas of mixed phreatophytic shrubs, where the depth to ground water is less than 5 feet. Based on the seasonal distribution of major habitats in the refuge and on winter and summer ET rates, an estimated total of about 89,000 acre-feet of water was consumed by ET during October 1999-September 2000 (2000 water year). Of this total, about 49,800 acre-feet was consumed by ET in areas of open water and bulrush marsh.

Under the Radar: The First Woman in Radio Astronomy, Ruby Payne-Scott

NASA Astrophysics Data System (ADS)

Miller Goss, W.

2012-05-01

Under the Radar, the First Woman in Radio Astronomy, Ruby Payne-Scott W. Miller Goss, NRAO Socorro NM Ruby Payne-Scott (1912-1981) was an eminent Australian scientist who made major contributions to the WWII radar effort (CSIR) from 1941 to 1945. In late 1945, she pioneered radio astronomy efforts at Dover Heights in Sydney, Australia at a beautiful cliff top overlooking the Tasman Sea. Again at Dover Heights, Payne-Scott carried out the first interferometry in radio astronomy using an Australian Army radar antenna as a radio telescope at sun-rise, 26 January 1946. She continued these ground breaking activities until 1951. Ruby Payne-Scott played a major role in discovering and elucidating the properties of Type III bursts from the sun, the most common of the five classes of transient phenomena from the solar corona. These bursts are one of the most intensively studied forms of radio emission in all of astronomy. She is also one of the inventors of aperture synthesis in radio astronomy. I examine her career at the University of Sydney and her conflicts with the CSIR hierarchy concerning the rights of women in the work place, specifically equal wages and the lack of permanent status for married women. I also explore her membership in the Communist Party of Australia as well as her partially released Australian Scientific Intelligence Organization file. Payne-Scott’s role as a major participant in the flourishing radio astronomy research of the post war era remains a remarkable story. She had a number of strong collaborations with the pioneers of early radio astronomy in Australia: Pawsey, Mills, Christiansen, Bolton and Little. I am currently working on a popular version of the Payne-Scott story; “Making Waves, The Story of Ruby Payne-Scott: Australian Pioneer Radio Astronomer” will be published in 2013 by Springer in the Astronomers’ Universe Series.

Dosimetry of laser emission

NASA Astrophysics Data System (ADS)

Kirillov, A. I.; Morskov, V. F.; Ustinov, N. D.

The basic criteria for dosimetric standards on photon, microwave, and ultraviolet emissions are reviewed. Attention is given to the biophysical effects of laser radiation, approaches to the evaluation of optical radiation hazard, and the effect of laser beams on the human eye. The fundamentals of the optical design of dosimeters are discussed, and an eye model is developed for a laser radiation meter. The discussion also covers the design of the electronic circuit of dosimeters and an evaluation of measurement errors.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Effect of compression of a laser plasma on the generation of harmonics and hard x radiation

NASA Astrophysics Data System (ADS)

Apollonov, V. V.; Derzhavin, S. I.; Kazakov, K. Kh

1993-02-01

A compression of a plasma produced at a conical target by a low-intensity beam (q≲10 GW/cm2) from a CO2 laser has been studied. The effect of this compression on the onset of the parametric instability responsible for the generation of harmonics and of hard x radiation has also been studied. A qualitative interpretation of the results is offered.

Efficacy of 694-nm fractional Q-switched ruby laser (QSRL) combined with sonophoresis on levorotatory vitamin C for treatment of melasma in Chinese patients.

PubMed

Zhou, H L; Hu, B; Zhang, C

2016-07-01

Melasma is a common acquired and distressing pigmentary disorder presenting to dermatology clinics. It is notably difficult to cure and has a tendency to relapse. The efficacy of classical Q-switched laser in treatment of melasma remains controversial. This study aims to investigate the efficacy and safety of 694-nm fractional QSRL combined with sonophoresis on levorotatory vitamin C for the treatment of melasma patients. Twenty-six patients with melasma were enrolled. Each patient received four to six fractional QSRL treatments at pulse energies of 2.5 to 4 J/cm(2) combined with sonophoresis on levorotatory vitamin C at 2-week intervals. The severity and the area of melasma were assessed by two investigators using the melasma area and severity index (MASI). Side effects were documented. Mean MASI score decreased from 15.51 ± 3.00 before treatment to 10.02 ± 4.39 3 months after the final treatment (P < 0.01). Side effects were few and transient. High-density coverage fractional QSRL combined with sonophoresis on levorotatory vitamin C is safe and effective for the treatment of melasma in Chinese patients.

Mathematical modeling of a photovoltaic-laser energy converter for iodine laser radiation

NASA Technical Reports Server (NTRS)

Walker, Gilbert H.; Heinbockel, John H.

1987-01-01

Space-based laser power systems will require converters to change laser radiation into electricity. Vertical junction photovoltaic converters are promising devices for this use. A promising laser for the laser power station is the t-C4F9I laser which emits radiation at a wavelength of 1.315 microns. This paper describes the results of mathematical modeling of a photovoltaic-laser energy converter for use with this laser. The material for this photovoltaic converter is Ga(53)In(47)As which has a bandgap energy of 0.94 eV, slightly below the energy of the laser photons (0.943 eV). Results of a study optimizing the converter parameters are presented. Calculated efficiency for a 1000 vertical junction converter is 42.5 percent at a power density of 1 x 10 to the 3d power w/sq cm.

Beam shaping of laser diode radiation by waveguides with arbitrary cladding geometry written with fs-laser radiation.

PubMed

Beckmann, Dennis; Schnitzler, Daniel; Schaefer, Dagmar; Gottmann, Jens; Kelbassa, Ingomar

2011-12-05

Waveguides with arbitrary cross sections are written in the volume of Al(2)O(3)-crystals using tightly focused femtosecond laser radiation. Utilizing a scanning system with large numerical aperture, complex cladding geometries are realized with a precision around 0.5 µm and a scanning speed up to 100 mm/s. Individual beam and mode shaping of laser diode radiation is demonstrated by varying the design of the waveguide cladding. The influence of the writing parameters on the waveguide properties are investigated resulting in a numerical aperture of the waveguides in the range of 0.1. This direct laser writing technique enables optical devices which could possibly replace bulky beam shaping setups with an integrated solution.

Choice of the laser wavelength for a herpetic keratitis treatment

NASA Astrophysics Data System (ADS)

Razhev, Alexander M.; Bagayev, Sergei N.; Chernikh, Valery V.; Kargapoltsev, Evgeny S.; Trunov, Alexander; Zhupikov, Andrey A.

2002-06-01

For the first time the effect of the UV laser radiation to human eye cornea with herpetic keratitis was experimentally investigated. In experiments the UV radiation of ArF (193 nm), KrCl (223 nm), KrF (248 nm) excimer lasers were used. Optimal laser radiation parameters for the treatment of the herpetic keratitis were determined. The immuno-biochemical investigations were carried out and the results of clinical trials are presented. The maximum ablation rate was obtained for the 248 nm radiation wavelength. The process of healing was successful but in some cases the haze on the surface of the cornea was observed. When used the 193 nm radiation wavelength the corneal surface was clear without any hazes but the epithelization process was slower than for 248 nm wavelength and in some cases the relapse was occurred. The best results for herpetic keratitis treatment have been achieved by utilizing the 223 nm radiation wavelength of the KrCl excimer laser. The use of the 223 nm radiation wavelength allows treating the herpetic keratitis with low traumatic process of ablation and provides high quality of corneal surface.

INTERACTION OF LASER RADIATION WITH MATTER: Influence of a target on operation of a pulsed CO2 laser emitting microsecond pulses

NASA Astrophysics Data System (ADS)

Baranov, V. Yu; Dolgov, V. A.; Malyuta, D. D.; Mezhevov, V. S.; Semak, V. V.

1987-12-01

The profile of pulses emitted by a TEA CO2 laser with an unstable resonator changed as a result of interaction of laser radiation with the surface of a metal in the presence of a breakdown plasma. This influence of a target on laser operation and its possible applications in laser processing of materials are analyzed.

Second NASA Conference on Laser Energy Conversion

NASA Technical Reports Server (NTRS)

Billman, K. W. (Editor)

1976-01-01

The possible transmission of high power laser beams over long distances and their conversion to thrust, electricity, or other useful forms of energy is considered. Specific topics discussed include: laser induced chemistry; developments in photovoltaics, including modification of the Schottky barrier devices and generation of high voltage emf'sby laser radiation of piezoelectric ceramics; the thermo electronic laser energy converter and the laser plasmadynamics converters; harmonic conversion of infrared laser radiation in molecular gases; and photon engines.

Biochemistry and control of the reductive tricarboxylic acid pathway of CO 2 fixation and physiological role of the Rubis CO-like protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tabita, F. Robert

2008-12-04

During the past years of this project we have made progress relative to the two major goals of the proposal: (1) to study the biochemistry and regulation of the reductive TCA cycle of CO 2 fixation and (2) to probe the physiological role of a RubisCO-like protein (RLP). Both studies primarily employ the green sulfur bacterium Chlorobium tepidum as well as other photosynthetic bacteria including Rhodospirillum rubrum and Rhodopseudomonas palustris.

Efficiently Distributing Component-based Applications Across Wide-Area Environments

DTIC Science & Technology

2002-01-01

a variety of sophisticated network-accessible services such as e-mail, banking, on-line shopping, entertainment, and serv - ing as a data exchange...product database Customer Serves as a façade to Order and Account Stateful Session Beans ShoppingCart Maintains list of items to be bought by customer...Pet Store tests; and JBoss 3.0.3 with Jetty 4.1.0, for the RUBiS tests) and a sin- gle database server ( Oracle 8.1.7 Enterprise Edition), each running

Efficiently Distributing Component-Based Applications Across Wide-Area Environments

DTIC Science & Technology

2002-01-01

Oracle 8.1.7 Enterprise Edition), each running on a dedicated 1GHz dual-processor Pentium III workstation. For the RUBiS tests, we used a MySQL 4.0.12...a variety of sophisticated network-accessible services such as e-mail, banking, on-line shopping, entertainment, and serv - ing as a data exchange...Beans Catalog Handles read-only queries to product database Customer Serves as a façade to Order and Account Stateful Session Beans ShoppingCart

Laser Radiation-Induced Air Breakdown And Plasma Shielding

NASA Astrophysics Data System (ADS)

Smith, David C.

1981-12-01

Gas breakdown, or the ionization of the air in the path of a high power laser, is a limit on the maximum intensity which can be propagated through the atmosphere. When the threshold for breakdown is exceeded, a high density, high temperature plasma is produced which is opaque to visible and infrared wavelengths and thus absorbs the laser radiation. The threshold in the atmosphere is significantly lower than in pure gases because of laser interaction and vaporization of aerosols. This aspect of air breakdown is discussed in detail. Parametric studies have revealed the scaling laws of breakdown as to wavelength and laser pulse duration, and these will be discussed and compared with existing models. A problem closely related to breakdown is the plasma produc-tion when a high intensity laser interacts with a surface. In this case, the plasma can be beneficial for coupling laser energy into shiny surfaces. The plasma absorbs the laser radiation and reradiates the energy at shorter wavelengths; this shorter wavelength radiation is absorbed by the surface, thus increasing the coupling of energy into the surface. The conditions for the enhancement of laser coupling into surfaces will be discussed, particularly for cw laser beams, an area of recent experimen-tal investigation.

Ultraviolet radiation induced discharge laser

DOEpatents

Gilson, Verle A.; Schriever, Richard L.; Shearer, James W.

1978-01-01

An ultraviolet radiation source associated with a suitable cathode-anode electrode structure, disposed in a gas-filled cavity of a high pressure pulsed laser, such as a transverse electric atmosphere (TEA) laser, to achieve free electron production in the gas by photoelectric interaction between ultraviolet radiation and the cathode prior to the gas-exciting cathode-to-anode electrical discharge, thereby providing volume ionization of the gas. The ultraviolet radiation is produced by a light source or by a spark discharge.

Argon laser phototherapy could eliminate the damage effects induced by the ionizing radiation "gamma radiation" in irradiated rabbits.

PubMed

Abdul-Aziz, Karolin Kamel; Tuorkey, M J

2010-04-02

The ionizing radiations could be taken in considerate as an integral part in our life, since, living organisms are actually exposed to a constant shower of ionizing radiations whether from the natural or artificial resources. The radio-protective efficiency of several chemicals has been confirmed in animal trails, whereas, due to their accumulative toxicity, their clinical utility is limited. Therefore, we aimed in the present work to investigate the possibility of using argon laser to recuperate the damaged tissues due to exposing to the ionizing radiation. The rabbits were used in this study, and they were designed as control, gamma irradiated, laser, and gamma plus laser groups. Lipid peroxidation, reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and glucose-6-phosphate dehydrogenase (G-6-PD) in blood and liver were evaluated. As well as, the level of protein thiol was evaluated in the plasma among each group. Results of this study revealed the potential therapeutic performance of the treatment by laser argon to decline the damaging effect of the ionized radiation whether at systematic or local levels. In conclusion, argon laser therapy appears propitious protective effect against the hazard effects of gamma radiation. Copyright 2010 Elsevier B.V. All rights reserved.

ARTICLES: Physical laws governing the interaction of pulse-periodic CO2 laser radiation with metals

NASA Astrophysics Data System (ADS)

Vedenov, A. A.; Gladush, G. G.; Drobyazko, S. V.; Pavlovich, Yu V.; Senatorov, Yu M.

1985-01-01

It is shown theoretically and experimentally that the efficiency of welding metals with a pulse-periodic CO2 laser beam of low duty ratio, at low velocities, can exceed that of welding with cw lasers and with electron beams. For the first time an investigation was made of the influence of the laser radiation parameters (energy and frequency) and of the welding velocity on the characteristics of the weld and on the shape of the weldpool. The influence of the laser radiation polarization on the efficiency of deep penetration was analyzed.

Fiber optic coupling of a microlens conditioned, stacked semiconductor laser diode array

DOEpatents

Beach, R.J.; Benett, W.J.; Mills, S.T.

1997-04-01

The output radiation from the two-dimensional aperture of a semiconductor laser diode array is efficiently coupled into an optical fiber. The two-dimensional aperture is formed by stacking individual laser diode bars on top of another in a ``rack and stack`` configuration. Coupling into the fiber is then accomplished using individual microlenses to condition the output radiation of the laser diode bars. A lens that matches the divergence properties and wavefront characteristics of the laser light to the fiber optic is used to focus this conditioned radiation into the fiber. 3 figs.

Design considerations for the use of laser-plasma accelerators for advanced space radiation studies

NASA Astrophysics Data System (ADS)

Königstein, T.; Karger, O.; Pretzler, G.; Rosenzweig, J. B.; Hidding, B.; Hidding

2012-08-01

We present design considerations for the use of laser-plasma accelerators for mimicking space radiation and testing space-grade electronics. This novel application takes advantage of the inherent ability of laser-plasma accelerators to produce particle beams with exponential energy distribution, which is a characteristic shared with the hazardous relativistic electron flux present in the radiation belts of planets such as Earth, Saturn and Jupiter. Fundamental issues regarding laser-plasma interaction parameters, beam propagation, flux development, and experimental setup are discussed.

Cytoplasmic molecular delivery with shock waves: importance of impulse.

PubMed Central

Kodama, T; Hamblin, M R; Doukas, A G

2000-01-01

Cell permeabilization using shock waves may be a way of introducing macromolecules and small polar molecules into the cytoplasm, and may have applications in gene therapy and anticancer drug delivery. The pressure profile of a shock wave indicates its energy content, and shock-wave propagation in tissue is associated with cellular displacement, leading to the development of cell deformation. In the present study, three different shock-wave sources were investigated; argon fluoride excimer laser, ruby laser, and shock tube. The duration of the pressure pulse of the shock tube was 100 times longer than the lasers. The uptake of two fluorophores, calcein (molecular weight: 622) and fluorescein isothiocyanate-dextran (molecular weight: 71,600), into HL-60 human promyelocytic leukemia cells was investigated. The intracellular fluorescence was measured by a spectrofluorometer, and the cells were examined by confocal fluorescence microscopy. A single shock wave generated by the shock tube delivered both fluorophores into approximately 50% of the cells (p < 0.01), whereas shock waves from the lasers did not. The cell survival fraction was >0.95. Confocal microscopy showed that, in the case of calcein, there was a uniform fluorescence throughout the cell, whereas, in the case of FITC-dextran, the fluorescence was sometimes in the nucleus and at other times not. We conclude that the impulse of the shock wave (i.e., the pressure integrated over time), rather than the peak pressure, was a dominant factor for causing fluorophore uptake into living cells, and that shock waves might have changed the permeability of the nuclear membrane and transferred molecules directly into the nucleus. PMID:11023888

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Phase locking of the radiation of ring waveguide CO2 lasers

NASA Astrophysics Data System (ADS)

Glova, A. F.; Lebedev, E. A.; Lysikov, A. Yu; Shchetnikov, S. B.

1999-12-01

Phase locking of the radiation of two ring waveguide CO2 lasers with a common cavity and unidirectional lasing was achieved for an output power of about 20 W. Measurements of the fringe visibility of the radiation intensity distributions in the far-field zone agreed qualitatively with the calculations for plane waves.

Influence of the finite linewidth of the laser radiation spectrum on the shape of the coherent population trapping resonance line in an optically dense medium with a buffer gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barantsev, K. A., E-mail: kostmann@yandex.ru; Popov, E. N.; Litvinov, A. N., E-mail: andrey.litvinov@mail.ru

2015-11-15

The theory of coherent population trapping resonance is developed for the finite linewidth of the laser radiation spectrum in an optically dense medium of Λ atoms in a cell with a buffer gas. Equations are derived for the atomic density matrix and laser emission spectrum transfer in a cell with working and buffer gases at a finite temperature. The dependence of the quality factor of coherent population trapping resonance on the linewidth of the laser radiation spectrum is studied by measuring transmitted radiation and fluorescence signals.

Gold-coated copper cone detector as a new standard detector for F2 laser radiation at 157 nm.

PubMed

Kück, Stefan; Brandt, Friedhelm; Taddeo, Mario

2005-04-20

A new standard detector for high-accuracy measurements of F2 laser radiation at 157 nm is presented. This gold-coated copper cone detector permits the measurement of average powers up to 2 W with an uncertainty of approximately 1%. To the best of our knowledge, this is the first highly accurate standard detector for F2 laser radiation for this power level. It is fully characterized according to Guide to the Expression of Uncertainty in Measurement of the International Organization for Standardization and is connected to the calibration chain for laser radiation established by the German National Metrology Institute.

Analytical model for electromagnetic radiation from a wakefield excited by intense short laser pulses in an unmagnetized plasma

NASA Astrophysics Data System (ADS)

Chen, Zi-Yu; Chen, Shi; Dan, Jia-Kun; Li, Jian-Feng; Peng, Qi-Xian

2011-10-01

A simple one-dimensional analytical model for electromagnetic emission from an unmagnetized wakefield excited by an intense short-pulse laser in the nonlinear regime has been developed in this paper. The expressions for the spectral and angular distributions of the radiation have been derived. The model suggests that the origin of the radiation can be attributed to the violent sudden acceleration of plasma electrons experiencing the accelerating potential of the laser wakefield. The radiation process could help to provide a qualitative interpretation of existing experimental results, and offers useful information for future laser wakefield experiments.

X-ray radiation from nonlinear Thomson scattering of an intense femtosecond laser on relativistic electrons in a helium plasma.

PubMed

Ta Phuoc, K; Rousse, A; Pittman, M; Rousseau, J P; Malka, V; Fritzler, S; Umstadter, D; Hulin, D

2003-11-07

We have generated x-ray radiation from the nonlinear Thomson scattering of a 30 fs/1.5 J laser beam on plasma electrons. A collimated x-ray radiation with a broad continuous spectrum peaked at 0.15 keV with a significant tail up to 2 keV has been observed. These characteristics are found to depend strongly on the laser strength parameter a(0). This radiative process is dominant for a(0) greater than unity at which point the relativistic scattering of the laser light originates from MeV energy electrons inside the plasma.

Qualification of quantum cascade lasers for space environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, Tanya L.; Cannon, Bret D.; Brauer, Carolyn S.

2014-06-11

Laser-based instruments are enabling a new generation of scientific instruments for space environments such as those used in the exploration of Mars. The lasers must be robust and able to withstand the harsh environment of space, including radiation exposure. Quantum cascade lasers (QCLs), which are semiconductor lasers that emit in the infrared spectral region, offer the potential for the development of novel laser-based instruments for space applications. The performance of QCLs after radiation exposure, however, has not been reported. We report on work to quantify the performance of QCLs after exposure to two different radiation sources, 64 MeV protons andmore » Cobalt-60 gamma rays, at radiation levels likely to be encountered during a typical space flight mission. No significant degradation in threshold current or slope efficiency is observed for any of the seven Fabry-Perot QCLs that are tested.« less

X-ray emission as a potential hazard during ultrashort pulse laser material processing

NASA Astrophysics Data System (ADS)

Legall, Herbert; Schwanke, Christoph; Pentzien, Simone; Dittmar, Günter; Bonse, Jörn; Krüger, Jörg

2018-06-01

In laser machining with ultrashort laser pulses unwanted X-ray radiation in the keV range can be generated when a critical laser intensity is exceeded. Even if the emitted X-ray dose per pulse is low, high laser repetition rates can lead to an accumulation of X-ray doses beyond exposure safety limits. For 925 fs pulse duration at a center wavelength of 1030 nm, the X-ray emission was investigated up to an intensity of 2.6 × 1014 W/cm2. The experiments were performed in air with a thin disk laser at a repetition rate of 400 kHz. X-ray spectra and doses were measured for various planar target materials covering a wide range of the periodic table from aluminum to tungsten. Without radiation shielding, the measured radiation doses at this high repetition rate clearly exceed the regulatory limits. Estimations for an adequate radiation shielding are provided.

Laser Radiation in Active Amplifying Media Treated as a Transport Problem - Transfer Equation Derived and Exactly Solved

NASA Astrophysics Data System (ADS)

Das Gupta, Santanu; Das Gupta, S. R.

1991-10-01

The flow of laser radiation in a plane-parallel cylindrical slab of active amplifying medium with axial symmetry is treated as a problem in radiative transfer. The appropriate one-dimensional transfer equation describing the transfer of laser radiation has been derived by an appeal to Einstein'sA, B coefficients (describing the processes of stimulated line absorption, spontaneous line emission, and stimulated line emission sustained by population inversion in the medium) and considering the ‘rate equations’ to completely establish the rational of the transfer equation obtained. The equation is then exactly solved and the angular distribution of the emergent laser beam intensity is obtained; its numerically computed values are given in tables and plotted in graphs showing the nature of peaks of the emerging laser beam intensity about the axis of the laser cylinder.

EFFECTS OF LASER RADIATION ON MATTER: Growth of periodic structures on the surface of germanium subjected to pulsed laser radiation

NASA Astrophysics Data System (ADS)

Barsukov, D. O.; Gusakov, G. M.; Frolov, A. I.

1991-12-01

An experimental investigation was made of the dynamics of growth of periodic surface structures due to the interaction with pulsed laser radiation. Samples of Ge were subjected to laser pulses (λ = 1.06 μm, τ = 70 ns) with energy densities in the range 0.5-5.5 J/cm2. An investigation was made of the dynamics of the first-order diffraction of probe (λ = 0.53 μm) laser pulses with a time resolution 4 ns when p- and s-polarized laser radiation was incident at angles close to normal. A strong nonlinearity of the growth of such periodic surface structures was observed. The energy density from which such growth began depended on the quality of the polished Ge surface. The parameters of the dynamics of the growth of these structures were estimated.

Energy exchange between a laser beam and charged particles using inverse transition radiation and method for its use

DOEpatents

Kimura, Wayne D.; Romea, Richard D.; Steinhauer, Loren C.

1998-01-01

A method and apparatus for exchanging energy between relativistic charged particles and laser radiation using inverse diffraction radiation or inverse transition radiation. The beam of laser light is directed onto a particle beam by means of two optical elements which have apertures or foils through which the particle beam passes. The two apertures or foils are spaced by a predetermined distance of separation and the angle of interaction between the laser beam and the particle beam is set at a specific angle. The separation and angle are a function of the wavelength of the laser light and the relativistic energy of the particle beam. In a diffraction embodiment, the interaction between the laser and particle beams is determined by the diffraction effect due to the apertures in the optical elements. In a transition embodiment, the interaction between the laser and particle beams is determined by the transition effect due to pieces of foil placed in the particle beam path.

Development of Mesospheric Sodium Laser Beacon for Atmospheric Adaptive Optics

NASA Technical Reports Server (NTRS)

Jeys, T. H.

1992-01-01

A solid-state source of long pulse length, sodium-resonance radiation was developed for the purpose of generating an artificial star in the earth's mesospheric sodium layer. This radiation is generated by sum-frequency mixing the output of a 1.064 micron Nd:YAG laser with the output of a 1.319-micron Nd:YAG laser. By operating these lasers at wavelengths very close to the peak of their tuning curves, it is possible to match the wavelength of the sum-frequency radiation to that of the sodium D2 adsorption wavelength. Two pulsed laser systems were constructed, one producing as much as 0.6 J of sodium resonance radiation at a 10-Hz repetition rate and another producing as much as 24 mJ at a 840-Hz repetition rate. In both laser systems, the 1.06-micron and 1.32-micron Nd:YAG lasers are configured as mode-locked master oscillators followed by power amplifiers. Other aspects of this project are presented.

[Research on cells ablation characters by laser plasma].

PubMed

Han, Jing-hua; Zhang, Xin-gang; Cai, Xiao-tang; Duan, Tao; Feng, Guo-ying; Yang, Li-ming; Zhang, Ya-jun; Wang, Shao-peng; Li, Shi-wen

2012-08-01

The study on the mechanism of laser ablated cells is of importance to laser surgery and killing harmful cells. Three radiation modes were researched on the ablation characteristics of onion epidermal cells under: laser direct irradiation, focused irradiation and the laser plasma radiation. Based on the thermodynamic properties of the laser irradiation, the cell temperature rise and phase change have been analyzed. The experiments show that the cells damage under direct irradiation is not obvious at all, but the focused irradiation can cause cells to split and moisture removal. The removal shape is circular with larger area and rough fracture edges. The theoretical analysis found out that the laser plasma effects play a key role in the laser ablation. The thermal effects, radiation ionization and shock waves can increase the deposition of laser pulses energy and impact peeling of the cells, which will greatly increase the scope and efficiency of cell killing and is suitable for the cell destruction.

New Experimental Setup for High-Pressure High-Temperature Gigahertz Ultrasonic Interferometry

NASA Astrophysics Data System (ADS)

Kantor, A. P.; Kantor, I. Y.; Dubrovinsky, L. S.; Jacobsen, S. D.

2005-12-01

The only direct information about Earth's interior comes from seismological observations of sound wave velocities. In order to create compositional and mineralogical model from seismological data knowledge of the elastic properties and crystal chemistry of minerals is necessary. Gigahertz ultrasonic interferometry (GUI) is a relatively new tool used to measure single-crystal compressional and shear-wave travel times, which are converted to sound velocities and elastic moduli for direct application to problems in geophysics. Although possibility of simultaneous high-pressure and high-temperature GUI measurements in diamond anvil cell was demonstrated before up to temperature of 250°C, in situ pressure measurements were not possible. We developed new experimental setup for simultaneous GUI and pressure determination using a ruby fluorescence gouge. A diamond anvil cell is equipped with a miniature internal resistive heater with thermocouple fixed at a very small distance from the sample chamber. DAC is mounted at the rotating stage with 5 degrees of freedom (XYZ and two tilting degrees), that can be fixed in three different positions: on top of a P-buffer rod for compressional wave velocities measurement, on top of S-buffer rod for shear wave velocities measurement and under the microscope, equipped with laser and portable high-resolution spectrometer for ruby fluorescence measurement. DAC under high temperature could be moved between these three positions, and independent pressure, temperature, S and P wave velocities measurements could be done simultaneously at each data point. In addition to single-crystal elasticity measurements, ability of GUI for elasticity measurements of liquids was demonstrated. Compressional wave velocities in liquid argon were measured at high pressures and temperatures, showing the ability of GUI for studies equation of state of a liquid.

Laser Materials and Laser Spectroscopy - A Satellite Meeting of IQEC '88

NASA Astrophysics Data System (ADS)

Wang, Zhijiang; Zhang, Zhiming

1989-03-01

The Table of Contents for the book is as follows: * Laser Materials * Laser Site Spectroscopy of Transition Metal Ions in Glass * Spectroscopy of Chromium Doped Tunable Laser Materials * Spectroscopic Properties of Nd3+ Ions in LaMgAl11O19 Crystal * Spectral Study and 2.938 μm Laser Emission of Er3+ in the Y3Al5O12 Crystal * Raman-infrared Spectra and Radiationless Relaxation of Laser Crystal NdAl3(BO3)4 * A Study on HB and FLN in BaFCl0.5Br0.5:Sm2+ at 77K * Pair-pumped Upconversion Solid State Lasers * CW Upconversion Laser Action in Neodymium and Erbium doped Solids * Ultra-high Sensitive Upconversion Fluorescence of YbF3 Doped with Trace Tm3+ and Er3+ * The Growth and Properties of NYAB and EYAB Multifunctional Crystal * Study on Fluorescence and Laser Light of Er3+ in Glass * Growth and Properties of Single Crystal Fibers for Laser Materials * A Study on the Quality of Sapphire, Ruby and Ti3+ Doped Sapphire Grown by Temperature Gradient Technique (TGT) and Czochralski Technique (CZ) * The Measurement of Output Property of Ti3+ Al2O3 Laser Crystal * An Xα Study of the Laser Crystal MgF2 : V2+ * Q-switched NAB Laser * Miniature YAG Lasers * Study of High Efficiency {LiF}:{F}^-_2 Color Center Crystals * Study on the Formation Conditions and Optical Properties of (F2+)H Color Center in NaCl:OH- Crystals * Novel Spectroscopic Properties of {LiF}:{F}^+_3 - {F}_2 Mixed Color Centers Laser Crystals * Terraced Substrate Visible GaAlAs Semiconductor Lasers with a Large Optical Cavity * The Temperature Dependence of Gain Spectra, Threshold Current and Auger Recombination in InGaAsP-InP Double Heterojunction Laser diode * Time-resolved Photoluminescence and Energy Transfer of Bound Excitons in GaP:N Crystals * Optical Limiting with Semiconductors * A Critical Review of High-efficiency Crystals for Tunable Lasers * Parametric Scattering in β - BaB2O4 Crystal Induced by Picosecond Pulses * Generation of Picosecond Pulses at 193 nm by Frequency Mixing in β - BaB2O4 * Mixing Frequency Generation of 271.0 - 291.5 nm in β - BaB2O4 * Low Temperature Absorption Steps Near Ultraviolet Intrinsic Edge in Beta Barium Metaborate * The Growth and Properties of BaTiO3 Crystals * High-order Phenomena Accompanied with Self-pumped Phase Conjugation in BaTiO * Growth and Laser Damage Estimation of Potassium Dihydrogen Phosphate Crystals for Laser Fusion * Noncritically Phase-matched KTP for Diode-pumped Lasers (400-700 nm) * Potassium Titanyl Phosphate (KTP): Properties and New Applications * A Kind of New Defect in KTP Crystal and its SHG Enhanced Effect * Nucleation and Growth of the Non-linear Optical Crystal Potassium Pentaborate Tetrahydrate * Quasi-periodic Oscillations in Photoinduced Conical Light Scattering from LiNbO3 : Fe Crystals * Laser Excited Photoreflectance of GaxIn1-xAs/InP Multiple Quantum Wells * Growth, Spectroscopic Properties and Applications of Doped LiNbO3 Crystals * Photorefractive and Photovoltaic Effect in Doped LiNbO3 * Recent Advances in Photorefractive Nonlinear Optics * Study on the Doubling-frequency and Anti-photorefractive Property of Heavily Magnesium-doped Lithium-rich Lithium Niobate Crystals * A New Technique for Increasing Two-wave Mixing Gain in Photorefractive Bi12SiO20 Crystals * Experimental Proof: There Existing Another Mechanism of Photorefractive Index in Crystal Ce-SBN * Effect of Crystal Annealing on Holographic Recording in Bismuth Silicon Oxide * Two Wave Coupling in KNbO3 Photorefractive Crystal * Photorefractive Effects in Nd-Doped Ferroelectric (KxNa1-x)0.4-(SryBa1-y)0.8 Nb2O6 Single Crystal * High Pressure Raman Spectra and the Effect of Pressure to the Ferroelastic Phase Transition in LnP5O15 * Time-delay Four-wave Mixing with Incoherent Light in Absorption Bands Treated as a Multi-level System * Pulsed Laser Induced Dislocation Structure in Lithium Fluoride Single Crystals * Laser Spectroscopy * Nonclassical Radiation from Single-atom Oscillators * Laser Spectroscopic Studies of Molecules in Highly Excited Vibrational State * Investigation of the Stark Effect in Xenon Autoionizing Rydberg Series with the Use of Coherent Tunable XUV Radiation * Laser Spectroscopy of Autoionising 5 dnf J = 4.5 Rydberg Series of Ba I * Resonance Photoionization Spectroscopy of Atoms: Autoionization and Highly Excited States of Kr and U * Stark Spectra of Strontium and Calcium Atoms * Observation of Bidirectional Stimulated Radiation at 330 nm, 364 nm and 718 nm with 660 nm Laser Pumping in Sodium Vapour * Study of Molecular Rydberg States and their Discriminations in Na2 * The Measurement of the High Excited Spectra of Samarium by using Stepwise Laser Excitation Method * Product Analysis in the Reaction of the Two-photon Excited Xe(5p56p) States with Freons * Photoionization Spectra of Ca and Sr Atoms above the Classical Field-ionization Threshold * Effect of Medium Background on the Hydrogen Spectrum * Photoemission and Photoelectron Spectra from Autoionizing Atoms in Strong Laser Field * Natural Radiative Lifetime Measurements of High-lying States of Samarium * Two-step Laser Excitation of nf Rydberg States in Neutral Al and Observation of Stark Effect * Measurements of Excited Spectra of the Refractory Metal Elements using Discharge Synchronized with the Laser Pulse * Multiphoton Ionization of Atomic Lead at 1.06μ * Kinetic Processes in the Electron-beam pumped KrF Laser * Laser-induced Fluorescence of Zn2 Excimer * Calculation of Transition Intensity in Heteronuclear Dimer NaK: Comparison with Experiment * Laser-induced Fluorescence of CCl2 Carbene * Study of Multiphoton Ionization Spectrum of Benzene and Two-photon Absorption Cross Section * Dicke Narrowing of N2O Linewidth Perturbed by N2 at 10 μm Band * Polyatomic Molecular Ions Studied by Laser Photodissociation Spectroscopy * Transverse-optically Pumped Ultraviolet S2 Laser * Multiphoton Ionization of Propanal by High Power Laser * UV MPI Mass Spectroscopy and Dynamics of Photodissociation of SO2 * Multiphoton Ionization-fragmentation Patterns of Ethylamine and Dimethylamine Isomers * Cars Measurements of SF6 Pumped by a CO2 Laser Pulse * Angular Dependence of Phase Conjugation of CO2 Laser on SF6 Gas * Resolution of Stretching-vibrational and Translational Raman Bands of Liquid Water by Means of Polarization Four-photon Spectroscopy * Laser-produced Plasma as an Effective Source for X-Ray Spectroscopy * Rotational Structure of the Low Lying Electronic States of Samarium Monoxide * Effects of Poling and Stretching on Second-harmonic Generation in Amorphous Vinylidene Cyanide/Vinyl Acetate Copolymer * Laser-induced Spectroscopy of Cardiovascular Tissues * Laser-excited Malignancy Autofluorescence for Tumour Malignancy Investigation and its Origin * A Study on Several Hematoporphyrin Derivatives by Time-resolved Spectroscopy * Research on Strong Field Processes with a Subpicosecond 400 GW Ultraviolet Source * Growth, Decay and Quenching of Stimulated Raman Scattering in Transparent Liquid Droplets * Layer Condensed Ammonia Studied by Photoacoustic Spectroscopy * High Efficiency Raman Conversion of XeCl Laser Radiation in Lead Vapor * Combined Effect of Stimulated Scattering and Phase Modulation on Generation of Supercontinum * Resonant Multiwave Mixing in Sodium Vapor * High Pressure Brillouin Scattering in Liquid Toluene * Optical Nonlinearities and Bistability in Gold Colloid * Sum-frequency Generation for Surface Vibrational Spectroscopy * Optical Studies of Molecule/Surface Interactions * Optical Second Harmonic Generation with Coupled Surface Plasmons from a Multi-layer Silver/Quartz Grating * Evidence of Silver Cluster and its Role in Surface Enhanced Raman Scattering (SERS) * Study on Cold-evaporated Silver Surfaces with Second-harmonic-generation * Study of Optical Second-harmonic-generation at Metal Surface with Polarization States * Spectroscopic Studies of J-Aggregates of Pseudoisocyanine in Molecular Monolayers in the Range 300 to 20 K * Study of Polymerization of Langmuir-Blodgett Monolayer by Surface Enhanced Raman Scattering * Dynamics of Laser-induced Etching of Si(III) Surface of Chlorine * Fourier Transform Heterodyne Spectroscopy of Liquid Interfaces * Generation of High Power UV Femtosecond Pulses * Femtosecond Photon Echoes * Transition Radiation of Femtosecond Optical Pulses * Observation of DFWN in a Saturable Absorber inside the CPM Ring Dye Laser Cavity * Study on the Induced Spectral Superbroadening of Ultrafast Laser Pulse in a Nonlinear Medium * Laser Cooling and Trapping of Atoms * Femtosecond Absorption Spectroscopy of Primary Processes in Bacterial Photosynthesis Reaction Centers * Observation of the Motion of Slow Atoms in a Standing Wave Field * The Interrelation between the Optical Properties and the MBE Growth Control of Quantum Well Structures * Ionic Excimers * Optical SHG Study on Polymerization of Langmuir-Blodgett Molecular Layers * Weak Localization of Light * Statistical Fragmentation Patterns of Metastable Ion: Comparison with Experiment * Oxygeneration Reaction of Cerium with XeCl Laser * Measurement of Verdet Coefficient and Magneto-optic Spectroscopy in terms of Beats * Study on Rhodamine 6G/Xylene and Red B Laser Dye Mixture System * Ultranarrow Absorption Resonances of Cold Particles and their Application in Spectroscopy and Optical Frequency Standards * The Dynamics of Ion Clouds in Paul Traps: Implications for Frequency Standard Applications * Frequency Stability Measurement of Zeeman Stabilized He-Ne Laser * Multi-wavelength CW He-Ne Laser and its Frequency Stabilization * Efficient Isotope Separation using Semiconductor Lasers * Multi-beam Circularly Polarized Holography * Ring Laser Opticity Meter * Improved Rademacher Functions and Rademacher Transform * Note

Infinite projected entangled-pair state algorithm for ruby and triangle-honeycomb lattices

NASA Astrophysics Data System (ADS)

Jahromi, Saeed S.; Orús, Román; Kargarian, Mehdi; Langari, Abdollah

2018-03-01

The infinite projected entangled-pair state (iPEPS) algorithm is one of the most efficient techniques for studying the ground-state properties of two-dimensional quantum lattice Hamiltonians in the thermodynamic limit. Here, we show how the algorithm can be adapted to explore nearest-neighbor local Hamiltonians on the ruby and triangle-honeycomb lattices, using the corner transfer matrix (CTM) renormalization group for 2D tensor network contraction. Additionally, we show how the CTM method can be used to calculate the ground-state fidelity per lattice site and the boundary density operator and entanglement entropy (EE) on an infinite cylinder. As a benchmark, we apply the iPEPS method to the ruby model with anisotropic interactions and explore the ground-state properties of the system. We further extract the phase diagram of the model in different regimes of the couplings by measuring two-point correlators, ground-state fidelity, and EE on an infinite cylinder. Our phase diagram is in agreement with previous studies of the model by exact diagonalization.

BioC implementations in Go, Perl, Python and Ruby

PubMed Central

Liu, Wanli; Islamaj Doğan, Rezarta; Kwon, Dongseop; Marques, Hernani; Rinaldi, Fabio; Wilbur, W. John; Comeau, Donald C.

2014-01-01

As part of a communitywide effort for evaluating text mining and information extraction systems applied to the biomedical domain, BioC is focused on the goal of interoperability, currently a major barrier to wide-scale adoption of text mining tools. BioC is a simple XML format, specified by DTD, for exchanging data for biomedical natural language processing. With initial implementations in C++ and Java, BioC provides libraries of code for reading and writing BioC text documents and annotations. We extend BioC to Perl, Python, Go and Ruby. We used SWIG to extend the C++ implementation for Perl and one Python implementation. A second Python implementation and the Ruby implementation use native data structures and libraries. BioC is also implemented in the Google language Go. BioC modules are functional in all of these languages, which can facilitate text mining tasks. BioC implementations are freely available through the BioC site: http://bioc.sourceforge.net. Database URL: http://bioc.sourceforge.net/ PMID:24961236

Dichromatic and monochromatic laser radiation effects on antibiotic resistance, biofilm formation, and division rate of Pantoea agglomerans

NASA Astrophysics Data System (ADS)

Thomé, A. M. C.; Souza, B. P.; Mendes, J. P. M.; Cardoso, A. F. R.; Soares, L. C.; Trajano, E. T. L.; Fonseca, A. S.

2018-06-01

Since infection is a common cause of delayed wound healing, it is important to understand the effect of low-level laser therapy (LLLT) in bacterial mechanisms. In this study we evaluated the effects of LLLT on antibiotic resistance, division rate, and biofilm formation of Pantoea agglomerans. P. agglomerans samples were isolated from human pressure injuries in humans and cultures were exposed to low-level monochromatic and simultaneous dichromatic laser radiation to study the susceptibility of an antimicrobial to ampicillin and piperacillin  +  tazobactam, quantification of areas of bacterial colonies, and biofilm formation of bacterial cells. Fluence, wavelength, and emission mode were used in the therapeutic protocols for wound healing. The data showed no changes in the areas of the colonies, but dichromatic laser radiation decreased biofilm formation, while a monochromatic red laser at low dose increased biofilm formation and infrared at high dose decreased antibiotic resistance to ampicillin. LLLT modulates antibiotic resistance and biofilm formation of P. agglomerans, but these depend on the laser irradiation parameters, since dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation. Thus, simultaneous dichromatic low-level red and infrared lasers could be a new option for the treatment of infected wounds, reducing biofilm formation, without altering antibiotic resistance and the division rate of P. agglomerans cultures.

Effects of clinical infrared laser on superficial radial nerve conduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greathouse, D.G.; Currier, D.P.; Gilmore, R.L.

The purposes of this study were to demonstrate the effects of infrared laser radiation on the sensory nerve conduction of a specified peripheral nerve in man and determine temperature changes in the tissue surrounding the treated nerve. Twenty healthy adults were divided into three groups: control (n = 5); experimental (n = 10), infrared laser radiation at 20 sec/cm2; and experimental (n = 5), infrared laser radiation treatment at 120 sec/cm2. Antidromic sensory nerve conduction studies were performed on the superficial radial nerve of each subject's right forearm. The infrared laser radiation was applied at a fixed intensity for fivemore » 1-cm2 segments. Latency, amplitude, and temperature measurements were recorded pretest; posttest; and posttest intervals of 1, 3, 5, 10, and 15 minutes. An analysis of variance with repeated measures was used to examine the data. No significant change was noted in the distal sensory latency or amplitude of the evoked sensory potential in either experimental or control groups as a result of the applications of the infrared laser radiation treatment. This study demonstrates that infrared laser used at clinically applied intensities does not alter conduction of sensory nerves nor does it elevate the subcutaneous temperature.« less

Nano material processing with lasers in combination with nearfield technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickmann, K.; Jersch, J.; Demming, F.

1996-12-31

Recent research work has shown, that focusing of laser radiation down to a few nanometer can be obtained by using lasers in combination with nearfield technology (known from Scanning Tunneling Microscope STM or Atomic Force Microscope AFM). Lateral external illumination of STM- or AFM-probe tips with laser radiation can cause tremendous intensity enhancement in the nearfield underneath the tip. This effect can be explained by various electrostatic as well as electrodynamic effects known from Surface Enhanced Raman Spectroscopy (SERS). This effect was utilized to concentrate laser radiation with high intensity between a tip and a substrate in the nearfield. FOLANT-techniquemore » (FOcusing of LAser radiation in the Nearfield of a Tip) enables intensity enhancement up to 10{sup 6} in a narrow localized zone underneath the tip. The interaction area with nanometer scale can be applied for material processing even down to atomic dimensions. Using STM-/ laser-combination, hillocks, pits and grooves with lateral dimensions down to 10 nm have been obtained on gold substrates. AFM-/ laser-combination enabled nanostructures down to 20 nm on dielectric materials as for example polycarbonate.« less

Advanced optic fabrication using ultrafast laser radiation

NASA Astrophysics Data System (ADS)

Taylor, Lauren L.; Qiao, Jun; Qiao, Jie

2016-03-01

Advanced fabrication and finishing techniques are desired for freeform optics and integrated photonics. Methods including grinding, polishing and magnetorheological finishing used for final figuring and polishing of such optics are time consuming, expensive, and may be unsuitable for complex surface features while common photonics fabrication techniques often limit devices to planar geometries. Laser processing has been investigated as an alternative method for optic forming, surface polishing, structure writing, and welding, as direct tuning of laser parameters and flexible beam delivery are advantageous for complex freeform or photonics elements and material-specific processing. Continuous wave and pulsed laser radiation down to the nanosecond regime have been implemented to achieve nanoscale surface finishes through localized material melting, but the temporal extent of the laser-material interaction often results in the formation of a sub-surface heat affected zone. The temporal brevity of ultrafast laser radiation can allow for the direct vaporization of rough surface asperities with minimal melting, offering the potential for smooth, final surface quality with negligible heat affected material. High intensities achieved in focused ultrafast laser radiation can easily induce phase changes in the bulk of materials for processing applications. We have experimentally tested the effectiveness of ultrafast laser radiation as an alternative laser source for surface processing of monocrystalline silicon. Simulation of material heating associated with ultrafast laser-material interaction has been performed and used to investigate optimized processing parameters including repetition rate. The parameter optimization process and results of experimental processing will be presented.

Simulation study of terahertz radiation generation by circularly polarized laser pulses propagating in axially magnetized plasma

NASA Astrophysics Data System (ADS)

Saroch, Akanksha; Jha, Pallavi

2017-12-01

This paper deals with a two-dimensional simulation study of terahertz radiation emission in the wake of circularly polarized laser pulses propagating in uniformly magnetized plasma, using the XOOPIC code. The external magnetic field is applied along the direction of propagation of the laser pulse. It is seen that linearly polarized terahertz radiation is emitted off-axis, along the propagation direction, in plasma. This emitted radiation is also seen to be transmitted in vacuum. Simulation studies reveal that no such radiation is generated on-axis for the given configuration.

Spectrum and Angular Distribution of γ-rays from Radiative Damping in Extremely Relativistic Laser-Plasma Interaction

NASA Astrophysics Data System (ADS)

Pandit, Rishi; Sentoku, Yasuhiko

2013-10-01

Effects of the radiative damping in the interaction of extremely intense laser (> 1022 W/cm2) with dense plasma is studied via a relativistic collisional particle-in-cell simulation, PICLS. When the laser intensity is getting close to 1024 W/cm2, the effect of quantum electrodynamics (QED) appears. We had calculated γ-rays from the radiative damping processes based on the classical model [1], but had taken into account the QED effect [2] in the spectrum calculation. In ultra-intense laser-plasma interaction, electrons are accelerated by the strong laser fields and emit γ-ray photons mainly via two processes, namely, Bremsstrahlung and radiative damping. Such relativistic γ-ray has wide range of frequencies and the angular distribution depends on the hot electron source. Comparing the details of γ-rays from the Bremsstrahlung and the radiative damping in simulations, we will discuss the laser parameters and the target conditions (geometry and material) to distinguish the photons from each process and also the QED effect in the γ-rays spectrum at the extremely relativistic intensity. Supported by US DOE DE-SC0008827.

Lidar determination of winds by aerosol inhomogeneities: motion velocity in the planetary boundary layer.

PubMed

Kolev, I; Parvanov, O; Kaprielov, B

1988-06-15

The paper presents results from lidar measurements of wind velocity in the planetary boundary layer using correlation data processing. Two lidars are used in our experiments: a ruby lidar operating along slant paths and a YAG:Nd lidar operating for near vertical sounding used by us for the first time. On the basis of our experience the optimal sizes of aerosol inhomogeneities (30-300 m), the duration of the experiments (2-10 min), and the repetition rate of laser shots (fractions of hertz to several hertz) are determined. The results are compared to independent data obtained from anemometer measurements, theodolite- and radar-tracked pilot balloons. The range of differences is ~1-2 m/s in speed and 10-15 degrees in direction. Preliminary results from the use of lidar data to remotely sound the wind speed for various atmospheric stratifications and synoptic situations are described as well.

X-Ray Laser

DTIC Science & Technology

1991-01-31

Reflection in Relativistic Electron Beam Channel Radiation Systems, IEEE Trans. on Plasma Science 16(5), 548 (1988). 3. M. Strauss, P. Amendt, N...Reduced Radiation Losses in a Channeled-Beam X-Ray Laser by Bragg Reflection Coupling, Phys. Rev. A 39(11), 5791 (1989). 6. M. Strauss and N. Rostoker... Radiation Guiding in Channeling Beam X-Ray Laser by Bragg Reflection Coupling, Phys. Rev. A 40(12), 7097 (1989). 91-00870111 llllltl

Transversely diode-pumped alkali metal vapour laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parkhomenko, A I; Shalagin, A M

2015-09-30

We have studied theoretically the operation of a transversely diode-pumped alkali metal vapour laser. For the case of high-intensity laser radiation, we have obtained an analytical solution to a complex system of differential equations describing the laser. This solution allows one to exhaustively determine all the energy characteristics of the laser and to find optimal parameters of the working medium and pump radiation (temperature, buffer gas pressure, and intensity and width of the pump spectrum). (lasers)

Analytical modeling of polarization transformation of laser radiation of various spectral ranges by birefringent structures

NASA Astrophysics Data System (ADS)

Motrich, A. V.; Ushenko, O. G.

2018-01-01

The results of statistical dependence and correlation structures of two-dimensional Mueller matrix elements in various spectral regions of laser radiation by changes in the distribution of orientations of optical axes and birefringence of protein crystals. Namely, a two-wave ("red-blue") approach - layer of biological tissues irradiated by He-Ne laser (λ1 = 0,63μm ) and He-Cd laser (λ1 = 0,41μm )was used Conducted analysis of polarimetric sensitivity was made, a state of polarization points that contain volumetric structures of biological objects to spectral region of laser radiation was detected.

Isotopic and trace element variations in the Ruby Batholith, Alaska, and the nature of the deep crust beneath the Ruby and Angayucham Terranes

USGS Publications Warehouse

Arth, Joseph G.; Zmuda, Clara C.; Foley, Nora K.; Criss, Robert E.; Patton, W.W.; Miller, T.P.

1989-01-01

Thirty-six samples from plutons of the Ruby batholith of central Alaska were collected and analyzed for 22 trace elements, and many were analyzed for the isotopic compositions of Sr, Nd, O, and Pb in order to delimit the processes that produced the diversity of granodioritic to granitic compositions, to deduce the nature of the source of magmas at about 110 Ma, and to characterize the deep crust beneath the Ruby and Angayucham terranes. Plutons of the batholith show a substantial range in initial 87Sr/86Sr (SIR) of 0.7055–0.7235 and a general decrease from southwest to northeast. Initial 143Nd/144Nd (NIR) have a range of 0.51150–0.51232 and generally increase from southwest to northeast. The δ18O values for most whole rocks have a range of +8.4 to +11.8 and an average of +10.3‰. Rb, Cs, U, and Th show large ranges of concentration, generally increase as SiO2 increases, and are higher in southwest than in northeast plutons. Sr, Ba, Zr, Hf, Ta, Sc, Cr, Co, and Zr show large ranges of concentration and generally decrease as SiO2 increases. Rare earth elements (REE) show fractionated patterns and negative Eu anomalies. REE concentrations and anomalies are larger in the southwest than in the northeast plutons. Uniformity of SIR and NIR in Sithylemenkat and Jim River plutons suggests a strong role for fractional crystallization or melting of uniform magma sources at depth. Isotopic variability in Melozitna, Ray Mountains, Hot Springs, and Kanuti plutons suggests complex magmatic processes such as magma mixing and assimilation, probably combined with fractional crystallization, or melting of a complex source at depth. The large variations in SIR and NIR in the batholith require a variation in source materials at depth. The southwestern plutons probably had dominantly siliceous sources composed of metamorphosed Proterozoic and Paleozoic upper crustal rocks. The northeastern plutons probably had Paleozoic sources that were mixtures of siliceous and intermediate to mafic crustal rocks. The inferred sources could well have been the higher-metamorphic-grade lithologic equivalents of the exposed Proterozoic(?) to Paleozoic schists, orthogneisses, and metavolcanic rocks of Ruby terrane, the silicic portions of which are quite radiogenic. The deeper crustal sources that gave rise to most of the batholithic magmas are inferred to be similar under both the Ruby metamorphic terrane and the Angayucham ophiolitic terrane.

A way to improve dose rate laser simulation adequacy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skorobogatov, P.K.; Nikiforov, A.Y.; Demidov, A.A.

1998-12-01

A method for improving laser simulation of dose rate radiation in silicon IC`s (Integrated Circuit) is analyzed based on the application of noncoherent laser radiation. Experimental validation was performed using test structures with up to 90% surface metallization coverage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bucksbaum, P.H.; Ceglio, N.M.

This volume contains the papers delivered at the conference which chronicle the major advances in short-wavelength laser physics and technology. It is divided into the following sections: Sources of Short-Wavelength Radiation; Applications of Short-Wavelength Radiation; High-Intensity Laser Sources; and High-Intensity Laser-Matter Interactions.

Improved Characteristics of Laser Source of Ions Using a Frequency Mode Laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khaydarov, R. T.

2008-04-07

We used a mass-spectrometric method to investigate the characteristics of laser-produced plasma ions depending on the nature of the target and on the parameters of the laser radiation. Experiments are carried out on porous Y{sub 2}O{sub 3} targets with different densities {rho}, subjected to a laser radiation, where the laser works in a frequency mode (v = l-12 Hz). We found that the laser frequency has a significant effect on the parameters of plasma ions: with increasing the frequency of the laser the charge, energy and intensity of ions increase for a given parameters of the target. This effect ismore » more pronounced for small densities of the target. We related these two effects to a non-linear ionization process in the plasma due to the formation of dense plasma volume inside the sample absorbing the laser radiation and to the change of the focusing conditions in the case of the frequency mode laser.« less

Unexpected impact of radiation friction: enhancing production of longitudinal plasma waves.

PubMed

Gelfer, Evgeny; Elkina, Nina; Fedotov, Alexander

2018-04-24

We study the penetration of ultra-intense (intensity I [Formula: see text] 10 23-24  W/cm 2 ) circularly polarized laser pulses into a thick subcritical plasma layer with accounting for radiation friction. We show that radiation pressure is enhanced due to radiation friction in the direction transverse to the laser pulse propagation, and that for stronger and longer laser pulses this mechanism dominates over the ordinary ponderomotive pressure, thus resulting in a substantionaly stronger charge separation than anticipated previously. We give estimates of the effect and compare them with the results of one and two dimensional particle-in-cell simulations. This effect can be important for laser-based acceleration schemes.

Calculating the radiation characteristics of accelerated electrons in laser-plasma interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, X. F.; Graduate School of Engineering, Utsunomiya University, 7-1-2 Yohtoh, Utsunomiya 321-8585; Yu, Q.

2016-03-15

In this paper, we studied the characteristics of radiation emitted by electrons accelerated in a laser–plasma interaction by using the Lienard–Wiechert field. In the interaction of a laser pulse with a underdense plasma, electrons are accelerated by two mechanisms: direct laser acceleration (DLA) and laser wakefield acceleration (LWFA). At the beginning of the process, the DLA electrons emit most of the radiation, and the DLA electrons emit a much higher peak photon energy than the LWFA electrons. As the laser–plasma interaction progresses, the LWFA electrons become the major radiation emitter; however, even at this stage, the contribution from DLA electronsmore » is significant, especially to the peak photon energy.« less

INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Spectroscopic investigation of thermodynamic parameters of a plasma plume formed by the action of cw CO2 laser radiation on a metal substrate

NASA Astrophysics Data System (ADS)

Vasil'chenko, Zh V.; Azharonok, V. V.; Filatova, I. I.; Shimanovich, V. D.; Golubev, V. S.; Zabelin, A. M.

1996-09-01

Emission spectroscopy methods were used in an investigation of thermodynamic parameters of a surface plasma formed by the action of cw CO2 laser radiation of (2-5)×106 W cm-2 intensity on stainless steel in a protective He or Ar atmosphere. The spatiotemporal structure and pulsation characteristics of the plasma plume were used to determine the fields of the plasma electron density and temperature.

INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Calculation of mass transfer in the remote cutting of metals by radiation of a high-power repetitively pulsed CO2 laser

NASA Astrophysics Data System (ADS)

Gladush, G. G.; Rodionov, N. B.

2002-01-01

The mechanism of remote cutting of steel plates by radiation of a high-power repetitively pulsed CO2 laser is theoretically studied. The models of melt removal by the gravity force and the recoil pressure of material vapour are proposed and the sufficient conditions for the initiation of cutting are determined. A numerical model of a thermally thin plate was employed to describe the cutting for large focal spots.

Collective effects in the Thomson back-scattering between a laser pulse and a relativistic electron beam

NASA Astrophysics Data System (ADS)

Bacci, A.; Maroli, C.; Petrillo, V.; Serafini, L.

2006-08-01

Collective effects in the radiation emission via Thomson back-scattering of an intense optical laser pulse by high brightness electron beams are analyzed. The micro-bunching of the electron beam on the scale of the wavelength of the emitted radiation and the consequent free-electron-laser instability may significantly enhance the number of photons emitted. Scaling-laws of the radiation properties, both in the collective and incoherent spontaneous regimes versus laser and electron beam parameters are discussed in the framework of the one-dimensional model.

LASER MEDICINE: Effect of laser radiation absorption in water and blood on the optimal wavelength for endovenous obliteration of varicose veins

NASA Astrophysics Data System (ADS)

Zhilin, K. M.; Minaev, V. P.; Sokolov, Aleksandr L.

2009-08-01

This work examines laser radiation absorption in water and blood at the wavelengths that are used in endovenous laser treatment (EVLT): 0.81-1.06, 1.32, 1.47, 1.5 and 1.56 μm. It is shown that the best EVLT conditions are ensured by 1.56-μm radiation. Analysis of published data suggests that even higher EVLT efficacy may be achieved at wavelengths of 1.68 and 1.7 μm.

Investigation of the vapour-plasma plume in the welding of titanium by high-power ytterbium fibre laser radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bykovskiy, D P; Petrovskii, V N; Uspenskiy, S A

2015-03-31

The vapour-plasma plume produced in the welding of 6-mm thick VT-23 titanium alloy plates by ytterbium fibre laser radiation of up to 10 kW power is studied in the protective Ar gas medium. High-speed video filming of the vapour-plasma plume is used to visualise the processes occurring during laser welding. The coefficient of inverse bremsstrahlung by the welding plasma plume is calculated from the data of the spectrometric study. (interaction of laser radiation with matter)

Demonstration of Ignition Radiation Temperatures in Indirect-Drive Inertial Confinement Fusion Hohlraums

NASA Astrophysics Data System (ADS)

Glenzer, S. H.; MacGowan, B. J.; Meezan, N. B.; Adams, P. A.; Alfonso, J. B.; Alger, E. T.; Alherz, Z.; Alvarez, L. F.; Alvarez, S. S.; Amick, P. V.; Andersson, K. S.; Andrews, S. D.; Antonini, G. J.; Arnold, P. A.; Atkinson, D. P.; Auyang, L.; Azevedo, S. G.; Balaoing, B. N. M.; Baltz, J. A.; Barbosa, F.; Bardsley, G. W.; Barker, D. A.; Barnes, A. I.; Baron, A.; Beeler, R. G.; Beeman, B. V.; Belk, L. R.; Bell, J. C.; Bell, P. M.; Berger, R. L.; Bergonia, M. A.; Bernardez, L. J.; Berzins, L. V.; Bettenhausen, R. C.; Bezerides, L.; Bhandarkar, S. D.; Bishop, C. L.; Bond, E. J.; Bopp, D. R.; Borgman, J. A.; Bower, J. R.; Bowers, G. A.; Bowers, M. W.; Boyle, D. T.; Bradley, D. K.; Bragg, J. L.; Braucht, J.; Brinkerhoff, D. L.; Browning, D. F.; Brunton, G. K.; Burkhart, S. C.; Burns, S. R.; Burns, K. E.; Burr, B.; Burrows, L. M.; Butlin, R. K.; Cahayag, N. J.; Callahan, D. A.; Cardinale, P. S.; Carey, R. W.; Carlson, J. W.; Casey, A. D.; Castro, C.; Celeste, J. R.; Chakicherla, A. Y.; Chambers, F. W.; Chan, C.; Chandrasekaran, H.; Chang, C.; Chapman, R. F.; Charron, K.; Chen, Y.; Christensen, M. J.; Churby, A. J.; Clancy, T. J.; Cline, B. D.; Clowdus, L. C.; Cocherell, D. G.; Coffield, F. E.; Cohen, S. J.; Costa, R. L.; Cox, J. R.; Curnow, G. M.; Dailey, M. J.; Danforth, P. M.; Darbee, R.; Datte, P. S.; Davis, J. A.; Deis, G. A.; Demaret, R. D.; Dewald, E. L.; di Nicola, P.; di Nicola, J. M.; Divol, L.; Dixit, S.; Dobson, D. B.; Doppner, T.; Driscoll, J. D.; Dugorepec, J.; Duncan, J. J.; Dupuy, P. C.; Dzenitis, E. G.; Eckart, M. J.; Edson, S. L.; Edwards, G. J.; Edwards, M. J.; Edwards, O. D.; Edwards, P. W.; Ellefson, J. C.; Ellerbee, C. H.; Erbert, G. V.; Estes, C. M.; Fabyan, W. J.; Fallejo, R. N.; Fedorov, M.; Felker, B.; Fink, J. T.; Finney, M. D.; Finnie, L. F.; Fischer, M. J.; Fisher, J. M.; Fishler, B. T.; Florio, J. W.; Forsman, A.; Foxworthy, C. B.; Franks, R. M.; Frazier, T.; Frieder, G.; Fung, T.; Gawinski, G. N.; Gibson, C. R.; Giraldez, E.; Glenn, S. M.; Golick, B. P.; Gonzales, H.; Gonzales, S. A.; Gonzalez, M. J.; Griffin, K. L.; Grippen, J.; Gross, S. M.; Gschweng, P. H.; Gururangan, G.; Gu, K.; Haan, S. W.; Hahn, S. R.; Haid, B. J.; Hamblen, J. E.; Hammel, B. A.; Hamza, A. V.; Hardy, D. L.; Hart, D. R.; Hartley, R. G.; Haynam, C. A.; Heestand, G. M.; Hermann, M. R.; Hermes, G. L.; Hey, D. S.; Hibbard, R. L.; Hicks, D. G.; Hinkel, D. E.; Hipple, D. L.; Hitchcock, J. D.; Hodtwalker, D. L.; Holder, J. P.; Hollis, J. D.; Holtmeier, G. M.; Huber, S. R.; Huey, A. W.; Hulsey, D. N.; Hunter, S. L.; Huppler, T. R.; Hutton, M. S.; Izumi, N.; Jackson, J. L.; Jackson, M. A.; Jancaitis, K. S.; Jedlovec, D. R.; Johnson, B.; Johnson, M. C.; Johnson, T.; Johnston, M. P.; Jones, O. S.; Kalantar, D. H.; Kamperschroer, J. H.; Kauffman, R. L.; Keating, G. A.; Kegelmeyer, L. M.; Kenitzer, S. L.; Kimbrough, J. R.; King, K.; Kirkwood, R. K.; Klingmann, J. L.; Knittel, K. M.; Kohut, T. R.; Koka, K. G.; Kramer, S. W.; Krammen, J. E.; Krauter, K. G.; Krauter, G. W.; Krieger, E. K.; Kroll, J. J.; La Fortune, K. N.; Lagin, L. J.; Lakamsani, V. K.; Landen, O. L.; Lane, S. W.; Langdon, A. B.; Langer, S. H.; Lao, N.; Larson, D. W.; Latray, D.; Lau, G. T.; Le Pape, S.; Lechleiter, B. L.; Lee, Y.; Lee, T. L.; Li, J.; Liebman, J. A.; Lindl, J. D.; Locke, S. F.; Loey, H. K.; London, R. A.; Lopez, F. J.; Lord, D. M.; Lowe-Webb, R. R.; Lown, J. G.; Ludwigsen, A. P.; Lum, N. W.; Lyons, R. R.; Ma, T.; MacKinnon, A. J.; Magat, M. D.; Maloy, D. T.; Malsbury, T. N.; Markham, G.; Marquez, R. M.; Marsh, A. A.; Marshall, C. D.; Marshall, S. R.; Maslennikov, I. L.; Mathisen, D. G.; Mauger, G. J.; Mauvais, M.-Y.; McBride, J. A.; McCarville, T.; McCloud, J. B.; McGrew, A.; McHale, B.; Macphee, A. G.; Meeker, J. F.; Merill, J. S.; Mertens, E. P.; Michel, P. A.; Miller, M. G.; Mills, T.; Milovich, J. L.; Miramontes, R.; Montesanti, R. C.; Montoya, M. M.; Moody, J.; Moody, J. D.; Moreno, K. A.; Morris, J.; Morriston, K. M.; Nelson, J. R.; Neto, M.; Neumann, J. D.; Ng, E.; Ngo, Q. M.; Olejniczak, B. L.; Olson, R. E.; Orsi, N. L.; Owens, M. W.; Padilla, E. H.; Pannell, T. M.; Parham, T. G.; Patterson, R. W., Jr.; Pavel, G.; Prasad, R. R.; Pendlton, D.; Penko, F. A.; Pepmeier, B. L.; Petersen, D. E.; Phillips, T. W.; Pigg, D.; Piston, K. W.; Pletcher, K. D.; Powell, C. L.; Radousky, H. B.; Raimondi, B. S.; Ralph, J. E.; Rampke, R. L.; Reed, R. K.; Reid, W. A.; Rekow, V. V.; Reynolds, J. L.; Rhodes, J. J.; Richardson, M. J.; Rinnert, R. J.; Riordan, B. P.; Rivenes, A. S.; Rivera, A. T.; Roberts, C. J.; Robinson, J. A.; Robinson, R. B.; Robison, S. R.; Rodriguez, O. R.; Rogers, S. P.; Rosen, M. D.; Ross, G. F.; Runkel, M.; Runtal, A. S.; Sacks, R. A.; Sailors, S. F.; Salmon, J. T.; Salmonson, J. D.; Saunders, R. L.; Schaffer, J. R.; Schindler, T. M.; Schmitt, M. J.; Schneider, M. B.; Segraves, K. S.; Shaw, M. J.; Sheldrick, M. E.; Shelton, R. T.; Shiflett, M. K.; Shiromizu, S. J.; Shor, M.; Silva, L. L.; Silva, S. A.; Skulina, K. M.; Smauley, D. A.; Smith, B. E.; Smith, L. K.; Solomon, A. L.; Sommer, S.; Soto, J. G.; Spafford, N. I.; Speck, D. E.; Springer, P. T.; Stadermann, M.; Stanley, F.; Stone, T. G.; Stout, E. A.; Stratton, P. L.; Strausser, R. J.; Suter, L. J.; Sweet, W.; Swisher, M. F.; Tappero, J. D.; Tassano, J. B.; Taylor, J. S.; Tekle, E. A.; Thai, C.; Thomas, C. A.; Thomas, A.; Throop, A. L.; Tietbohl, G. L.; Tillman, J. M.; Town, R. P. J.; Townsend, S. L.; Tribbey, K. L.; Trummer, D.; Truong, J.; Vaher, J.; Valadez, M.; van Arsdall, P.; van Prooyen, A. J.; Vergel de Dios, E. O.; Vergino, M. D.; Vernon, S. P.; Vickers, J. L.; Villanueva, G. T.; Vitalich, M. A.; Vonhof, S. A.; Wade, F. E.; Wallace, R. J.; Warren, C. T.; Warrick, A. L.; Watkins, J.; Weaver, S.; Wegner, P. J.; Weingart, M. A.; Wen, J.; White, K. S.; Whitman, P. K.; Widmann, K.; Widmayer, C. C.; Wilhelmsen, K.; Williams, E. A.; Williams, W. H.; Willis, L.; Wilson, E. F.; Wilson, B. A.; Witte, M. C.; Work, K.; Yang, P. S.; Young, B. K.; Youngblood, K. P.; Zacharias, R. A.; Zaleski, T.; Zapata, P. G.; Zhang, H.; Zielinski, J. S.; Kline, J. L.; Kyrala, G. A.; Niemann, C.; Kilkenny, J. D.; Nikroo, A.; van Wonterghem, B. M.; Atherton, L. J.; Moses, E. I.

2011-02-01

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of TRAD=300eV and a symmetric implosion to a 100μm diameter hot core.

X-ray lasers and methods utilizing two component driving illumination provided by optical laser means of relatively low energy and small physical size

DOEpatents

Rosen, Mordecai D.; Matthews, Dennis L.

1991-01-01

An X-ray laser (10), and related methodology, are disclosed wherein an X-ray laser target (12) is illuminated with a first pulse of optical laser radiation (14) of relatively long duration having scarcely enough energy to produce a narrow and linear cool plasma of uniform composition (38). A second, relatively short pulse of optical laser radiation (18) is uniformly swept across the length, from end to end, of the plasma (38), at about the speed of light, to consecutively illuminate continuously succeeding portions of the plasma (38) with optical laser radiation having scarcely enough energy to heat, ionize, and invert them into the continuously succeeding portions of an X-ray gain medium. This inventive double pulse technique results in a saving of more than two orders of magnitude in driving optical laser energy, when compared to the conventional single pulse approach.

Fast and broadband detector for laser radiation

NASA Astrophysics Data System (ADS)

Scorticati, Davide; Crapella, Giacomo; Pellegrino, Sergio

2018-02-01

We developed a fast detector (patent pending) based on the Laser Induced Transverse Voltage (LITV) effect. The advantage of detectors using the LITV effect over pyroelectric sensors and photodiodes for laser radiation measurements is the combination of an overall fast response time, broadband spectral acceptance, high saturation threshold to direct laser irradiation and the possibility to measure pulsed as well as cw-laser sources. The detector is capable of measuring the energy of single laser pulses with repetition frequencies up to the MHz range, adding the possibility to also measure the output power of cw-lasers. Moreover, the thermal nature of the sensor enables the capability to work in a broadband spectrum, from UV to THz as well as the possibility of operating in a broad-range (10-3-102 W/cm2 ) of incident average optical power densities of the laser radiation, without the need of adopting optical filters nor other precautions.

longitudinal space charge assisted echo seeding of a free electron laser

NASA Astrophysics Data System (ADS)

Hacker, Kirsten

2015-05-01

Seed lasers are employed to improve the temporal coherence of free-electron laser light. However, when seed pulses are short relative to the particle bunch, the noisy, temporally incoherent radiation from the un-seeded electrons can overwhelm the coherent, seeded radiation. In this paper a new seeding mechanism to improve the contrast between coherent and incoherent free electron laser radiation is employed together with a novel, simplified echo-seeding method. The concept relies on a combination of longitudinal space charge wakes and an echo-seeding technique to make a short, coherent pulse of FEL light together with noise background suppression. Several different simulation codes are used to illustrate the concept with conditions at the soft x-ray Free-electron LASer in Hamburg, FLASH. The impacts of coherent synchrotron radiation, intra beam scattering, and high peak current operation are investigated.

Nonlinear Thomson scattering of a relativistically strong tightly focused ultrashort laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vais, O. E.; Bochkarev, S. G., E-mail: bochkar@sci.lebedev.ru; Bychenkov, V. Yu.

The problem of nonlinear Thomson scattering of a relativistically strong linearly polarized ultrashort laser pulse tightly focused into a spot with a diameter of D{sub F} ≳ λ (where λ is the laser wavelength) is solved. The energy, spectral, and angular distributions of radiation generated due to Thomson scattering from test electrons located in the focal region are found. The characteristics of scattered radiation are studied as functions of the tightness of laser focusing and the initial position of test particles relative to the center of the focal region for a given laser pulse energy. It is demonstrated that themore » ultratight focusing is not optimal for obtaining the brightest and hardest source of secondary electromagnetic radiation. The hardest and shortest radiation pulse is generated when the beam waist diameter is ≃10λ.« less

LASERS: Excimer XeCl laser excited by microsecond megawatt microwave pulses from a commercial 3.07-GHz microwave oscillator

NASA Astrophysics Data System (ADS)

Vaulin, V. A.; Slinko, V. N.; Sulakshin, S. S.

1990-12-01

An excimer laser (λ approx 308 nm) utilizing an Ne-Xe-HCl mixture was excited by microwave (ν0 = 3.07 GHz) pulses of 2.8-μs duration and ~ 0.9 MW power delivered by a commercial microwave oscillator. A peak laser radiation power of 130 W was obtained in pulses of 280 ns duration. Laser radiation from along the center of a laser tube was recorded in addition to that from the skin layer.

Biological Effects of Laser Radiation. Volume I. Review of the Literature on Biological Effects of Laser Radiation-to 1965.

DTIC Science & Technology

1978-10-17

because of the rapid progress made in laser technology to date. The use of the Laser Microprobe in spectrochemical analysis of the elements is based on...spectroscopy to vaporize microscopic amounts of samples for elemental analysis . On the other hand, the intense, highly monochromatic laser beam is being...employed as a light source for Raman spectroscopy to study molecular structure. These two uses of lasers in spectroscopic analysis have been sucessful

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Physics of the plasma corona in the problem of laser controlled thermonuclear fusion

NASA Astrophysics Data System (ADS)

Andreev, N. E.; Gorbunov, Leonid M.; Tikhonchuk, Vladimir T.

1994-09-01

A brief analysis is made of the most important nonlinear processes which result from the interaction of laser radiation with thermonuclear targets. lt is shown that problems in the physics of the plasma corona should be an essential part of any programme of research on laser controlled thermonuclear fusion. A list is given of the problems that have to be solved first before going to the next level of laser energies.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Selective metallisation of diamonds with the aid of laser radiation

NASA Astrophysics Data System (ADS)

Shafeev, Georgii A.; Pimenov, S. M.; Lubnin, Evgenii N.; Smolin, A. A.; Konov, Vitalii I.; Laptev, V. A.

1995-02-01

An experimental investigation was made of laser activation of diamond surfaces (single crystals and polycrystalline diamond films) prior to electroless before catalytic deposition of metals from solutions. The activation was carried out by a copper vapour laser or a KrF excimer laser in two ways: decomposition of a thin film of palladium acetylacetonate and local laser stimulated modification of the diamond surface by laser evaporation. An ohmic contact (Cu or Ni) with an adhesive strength of 3 N mm-2 was formed and the spatial resolution achieved was 10 μm.

Laser absorption phenomena in flowing gas devices

NASA Technical Reports Server (NTRS)

Chapman, P. K.; Otis, J. H.

1976-01-01

A theoretical and experimental investigation is presented of inverse Bremsstrahlung absorption of CW CO2 laser radiation in flowing gases seeded with alkali metals. In order to motivate this development, some simple models are described of several space missions which could use laser powered rocket vehicles. Design considerations are given for a test call to be used with a welding laser, using a diamond window for admission of laser radiation at power levels in excess of 10 kW. A detailed analysis of absorption conditions in the test cell is included. The experimental apparatus and test setup are described and the results of experiments presented. Injection of alkali seedant and steady state absorption of the laser radiation were successfully demonstrated, but problems with the durability of the diamond windows at higher powers prevented operation of the test cell as an effective laser powered thruster.

Photonic crystal microchip laser

NASA Astrophysics Data System (ADS)

Gailevicius, D.; Koliadenko, V.; Purlys, V.; Peckus, M.; Taranenko, V.; Staliunas, K.

2017-02-01

The microchip lasers, being sources of coherent light, suffer from one serious drawback: low spatial quality of the beam, strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here we propose that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. We experimentally show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by factor of 2, and thus increase the brightness of radiation by a factor of 4. This comprises a new kind of laser, the "photonic crystal microchip laser", a very compact and efficient light source emitting high spatial high brightness radiation.

Photonic Crystal Microchip Laser.

PubMed

Gailevicius, Darius; Koliadenko, Volodymyr; Purlys, Vytautas; Peckus, Martynas; Taranenko, Victor; Staliunas, Kestutis

2016-09-29

The microchip lasers, being very compact and efficient sources of coherent light, suffer from one serious drawback: low spatial quality of the beam strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here it is proposed that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M 2 reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3. This comprises a new kind of laser, the "photonic crystal microchip laser", a very compact and efficient light source emitting high spatial quality high brightness radiation.

Picosecond excite-and-probe absorption measurement of the 4T2 state nonradiative lifetime in ruby

NASA Technical Reports Server (NTRS)

Gayen, S. K.; Wang, W. B.; Petricevic, V.; Dorsinville, R.; Alfano, R. R.

1985-01-01

In a picosecond excite-and-probe absorption measurement, a 527-nm picosecond pulse excites the 4T2 state of the Cr(3+) ion in ruby and a 3.4-micron picosecond probe pulse monitors the growth and decay of population in the 2E state as a function of pump-probe delay. From the growth of population in the metastable 2E state, an upper limit of 7 ps for the nonradiative lifetime of the 4T2 state is determined.

Reflectivity of the gyroid biophotonic crystals in the ventral wing scales of the Green Hairstreak butterfly, Callophrys rubi.

PubMed

Michielsen, K; De Raedt, H; Stavenga, D G

2010-05-06

We present a comparison of the computer simulation data of gyroid nanostructures with optical measurements (reflectivity spectra and scattering diagrams) of ventral wing scales of the Green Hairstreak butterfly, Callophrys rubi. We demonstrate that the omnidirectional green colour arises from the gyroid cuticular structure grown in the domains of different orientation. We also show that this three-dimensional structure, operating as a biophotonic crystal, gives rise to various polarization effects. We briefly discuss the possible biological utility of the green coloration and polarization effects.

Comment Comparison of the fluorescence lifetimes of Cr 3+ in crystals, glasses and glass ceramics and their use to interpret the effect of pressure on ruby

NASA Astrophysics Data System (ADS)

Champagnon, B.; Pilla, O.

1989-09-01

A correlation has been proposed by Urošević Panić Jovanić, Zeković and Savić between the lifetimes of Cr 3+ in various environments and the Dq parameter of ligand field theory. We show that these observed lifetimes depend on various factors such as multisite effects, reabsorption, thermal excitation or 2E 4T 2 mixing. The correlation between lifetimes and pressure on ruby has to consider these different effects.

An Improved Measurement Method for the Strength of Radiation of Reflective Beam in an Industrial Optical Sensor Based on Laser Displacement Meter.

PubMed

Bae, Youngchul

2016-05-23

An optical sensor such as a laser range finder (LRF) or laser displacement meter (LDM) uses reflected and returned laser beam from a target. The optical sensor has been mainly used to measure the distance between a launch position and the target. However, optical sensor based LRF and LDM have numerous and various errors such as statistical errors, drift errors, cyclic errors, alignment errors and slope errors. Among these errors, an alignment error that contains measurement error for the strength of radiation of returned laser beam from the target is the most serious error in industrial optical sensors. It is caused by the dependence of the measurement offset upon the strength of radiation of returned beam incident upon the focusing lens from the target. In this paper, in order to solve these problems, we propose a novel method for the measurement of the output of direct current (DC) voltage that is proportional to the strength of radiation of returned laser beam in the received avalanche photo diode (APD) circuit. We implemented a measuring circuit that is able to provide an exact measurement of reflected laser beam. By using the proposed method, we can measure the intensity or strength of radiation of laser beam in real time and with a high degree of precision.

An Improved Measurement Method for the Strength of Radiation of Reflective Beam in an Industrial Optical Sensor Based on Laser Displacement Meter

PubMed Central

Bae, Youngchul

2016-01-01

An optical sensor such as a laser range finder (LRF) or laser displacement meter (LDM) uses reflected and returned laser beam from a target. The optical sensor has been mainly used to measure the distance between a launch position and the target. However, optical sensor based LRF and LDM have numerous and various errors such as statistical errors, drift errors, cyclic errors, alignment errors and slope errors. Among these errors, an alignment error that contains measurement error for the strength of radiation of returned laser beam from the target is the most serious error in industrial optical sensors. It is caused by the dependence of the measurement offset upon the strength of radiation of returned beam incident upon the focusing lens from the target. In this paper, in order to solve these problems, we propose a novel method for the measurement of the output of direct current (DC) voltage that is proportional to the strength of radiation of returned laser beam in the received avalanche photo diode (APD) circuit. We implemented a measuring circuit that is able to provide an exact measurement of reflected laser beam. By using the proposed method, we can measure the intensity or strength of radiation of laser beam in real time and with a high degree of precision. PMID:27223291

Enhanced tunable narrow-band THz emission from laser-modulated electron beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiang, D.; Stupakov, G.; /SLAC

2009-06-19

We propose and analyze a scheme to generate enhanced narrow-band terahertz (THz) radiation through down-conversion of the frequency of optical lasers using laser-modulated electron beams. In the scheme the electron beam is first energy modulated by two lasers with wave numbers k{sub 1} and k2, respectively. After passing through a dispersion section, the energy modulation is converted to density modulation. Due to the nonlinear conversion process, the beam will have density modulation at wave number k = nk{sub 1} + mk{sub 2}, where n and m are positive or negative integers. By properly choosing the parameters for the lasers andmore » dispersion section, one can generate density modulation at THz frequency in the beam using optical lasers. This density-modulated beam can be used to generate powerful narrow-band THz radiation. Since the THz radiation is in tight synchronization with the lasers, it should provide a high temporal resolution for the optical-pump THz-probe experiments. The central frequency of the THz radiation can be easily tuned by varying the wavelength of the two lasers and the energy chirp of the electron beam. The proposed scheme is in principle able to generate intense narrow-band THz radiation covering the whole THz range and offers a promising way towards the tunable intense narrow-band THz sources.« less

Q-switched Er:YAG radiation transmission through an oxide glass fiber for medical applications

NASA Astrophysics Data System (ADS)

Papadopoulos, Dimitris N.; Papagiakoumou, Eirini; Serafetinides, Alexander A.

2002-09-01

In the last few years, there has been an increasing interest for the 3 μm laser radiation in various medical applications, as this wavelength is strongly absorbed by the water and the other components of soft and hard tissue. An intensive development effort is going on throughout the world, in order to develop reliable lasers emitting in the 3 μm wavelength range. Our laser development effort with the Q-switched Er:YAG laser is briefly described in this article. Additionally for medical applications there is a great demand for good flexible delivery systems, in the mid-IR wavelength region. In this work the radiation transmission of a Q-switched Er:YAG laser, emitting at 2.94 μm, through high power (HP) oxide glass fibers of 450 μm core diameter was studied. Attenuation measurements were obtained as a function of the laser energy input and as a function of curvature, at 90 °, 180° and 360° bending angle. The output beam quality was studied using a beam profiler. Experiments with the same delivery system transmitting free-running Er:YAG laser radiation, were performed for comparison. The results are promising for the delivery of Q-switched Er:YAG laser radiation, as the fibers exhibited attenuation of 0.7 dB/m, and no damage of them was observed.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Control of the angular distribution of the radiation emitted by phase-locked laser arrays

NASA Astrophysics Data System (ADS)

Kachurin, O. R.; Lebedev, F. V.; Napartovich, M. A.; Khlynov, M. E.

1991-03-01

A numerical investigation was made of the influence of the number and packing density of a linear array of periodically arranged coherent sources on the efficiency of redistributing the radiation power from the side lobes to the main lobe of the angular distribution of the emitted radiation by using a binary phase corrector mounted in the image-doubling plane. The results are given of experimental investigations of a new device for improving the radiation pattern of phase-locked laser arrays.

Radiation from particles moving in small-scale magnetic fields created in solid-density laser-plasma laboratory experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keenan, Brett D., E-mail: bdkeenan@ku.edu; Medvedev, Mikhail V.

2015-11-15

Plasmas created by high-intensity lasers are often subject to the formation of kinetic-streaming instabilities, such as the Weibel instability, which lead to the spontaneous generation of high-amplitude, tangled magnetic fields. These fields typically exist on small spatial scales, i.e., “sub-Larmor scales.” Radiation from charged particles moving through small-scale electromagnetic (EM) turbulence has spectral characteristics distinct from both synchrotron and cyclotron radiation, and it carries valuable information on the statistical properties of the EM field structure and evolution. Consequently, this radiation from laser-produced plasmas may offer insight into the underlying electromagnetic turbulence. Here, we investigate the prospects for, and demonstrate themore » feasibility of, such direct radiative diagnostics for mildly relativistic, solid-density laser plasmas produced in lab experiments.« less

System and method of infrared matrix-assisted laser desorption/ionization mass spectrometry in polyacrylamide gels

DOEpatents

Haglund, Jr., Richard F.; Ermer, David R.; Baltz-Knorr, Michelle Lee

2004-11-30

A system and method for desorption and ionization of analytes in an ablation medium. In one embodiment, the method includes the steps of preparing a sample having analytes in a medium including at least one component, freezing the sample at a sufficiently low temperature so that at least part of the sample has a phase transition, and irradiating the frozen sample with short-pulse radiation to cause medium ablation and desorption and ionization of the analytes. The method further includes the steps of selecting a resonant vibrational mode of at least one component of the medium and selecting an energy source tuned to emit radiation substantially at the wavelength of the selected resonant vibrational mode. The medium is an electrophoresis medium having polyacrylamide. In one embodiment, the energy source is a laser, where the laser can be a free electron laser tunable to generate short-pulse radiation. Alternatively, the laser can be a solid state laser tunable to generate short-pulse radiation. The laser can emit light at various ranges of wavelength.

UV and IR laser radiation's interaction with metal film and teflon surfaces

NASA Astrophysics Data System (ADS)

Fedenev, A. V.; Alekseev, S. B.; Goncharenko, I. M.; Koval', N. N.; Lipatov, E. I.; Orlovskii, V. M.; Shulepov, M. A.; Tarasenko, V. F.

2003-04-01

The interaction of Xe ([lambda] [similar] 1.73 [mu]m) and XeCl (0.308 [mu]m) laser radiation with surfaces of metal and TiN-ceramic coatings on glass and steel substrates has been studied. Correlation between parameters of surface erosion versus laser-specific energy was investigated. Monitoring of laser-induced erosion on smooth polished surfaces was performed using optical microscopy. The correlation has been revealed between characteristic zones of thin coatings damaged by irradiation and energy distribution over the laser beam cross section allowing evaluation of defects and adhesion of coatings. The interaction of pulsed periodical CO2 ([lambda] [similar] 10.6 [mu]m), and Xe ([lambda] [similar] 1.73 [mu]m) laser radiation with surfaces of teflon (polytetrafluoroethylene—PTFE) has been studied. Monitoring of erosion track on surfaces was performed through optical microscopy. It has been shown that at pulsed periodical CO2-radiation interaction with teflon the sputtering of polymer with formation of submicron-size particles occurs. Dependencies of particle sizes, form, and sputtering velocity on laser pulse duration and target temperature have been obtained.

Effects of femtosecond laser radiation on the skin

NASA Astrophysics Data System (ADS)

Rogov, P. Yu; Bespalov, V. G.

2016-08-01

A mathematical model of linear and nonlinear processes is presented occurring under the influence of femtosecond laser radiation on the skin. There was held an analysis and the numerical solution of an equation system describing the dynamics of the electron and phonon subsystems were received. The results can be used to determine the maximum permissible levels of energy generated by femtosecond laser systems and the establishment of Russian laser safety standards for femtosecond laser systems.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Hydrodynamic efficiency of laser-induced transfer of matter

NASA Astrophysics Data System (ADS)

Isakov, Vladimir A.; Kanavin, Andrey P.; Nasibov, A. S.

2007-04-01

A one-dimensional analytic hydrodynamic model of the direct laser-induced transfer of matter is considered. The efficiency of pulsed laser radiation energy conversion to the kinetic energy of the ejected matter is determined. It is shown that the hydrodynamic efficiency of the process for the layers of matter of thickness exceeding the laser radiation absorption depth is determined by the adiabatic index of the evaporated matter.

Critical analysis of active methods of ozone layer recovery

NASA Astrophysics Data System (ADS)

Bekker, S. Z.; Doronin, A. P.; Kozlov, S. I.

2017-09-01

A critical analysis is given for various methods for recovery of the ozone layer of the Earth: the emission of alkane gases, the destruction of freons by laser IR radiation and with microwave discharge, exposure to laser UV radiation and electric discharge in the atmosphere, the use of solar radiation, laser infrared radiation, and gamma rays, and the creation of an artificial formation at high altitudes that shields the solar radiation dissociating ozone. The optimal methods are discussed in terms of their effectiveness, economic costs, and environmental consequences. These include the use of gamma rays sources, electric discharge in the atmosphere, and microwave breakdown.

Thermal and optical modeling of "blackened" tips for diode laser surgery

NASA Astrophysics Data System (ADS)

Belikov, Andrey V.; Skrypnik, Alexei V.; Kurnyshev, Vadim Y.

2016-04-01

This paper presents the results of thermal and optical modeling of "blackened" tips (fiber-optic thermal converter) with different structures: film and volumetric. Film converter is created by laser radiation action on a cork or paper and it is a one-step process. As a result, a carbonized cork or paper adhered to the distal end of the optical fiber absorbs light that leads to heating of the distal end of the optical fiber. We considered the peculiarities of volumetric converters formed by sintering (second step) of the target material transferred to the tip, at irradiating the target with laser radiation (first step). We investigated the interaction between 980 nm laser radiation and converters in the air and water. As a result of experiments and modeling, it was obtain, that converter temperature and power of converter destruction depend on the environment in which it is placed. We found that film converter in the air at average power of laser radiation of 0.30+/-0.05 W is heated to 900+/-50°C and destructed, and volumetric converter in the air at average power of laser radiation of 1.0+/-0.1 W is heated to 1000+/-50°C and destructed at reaching of 4.0+/-0.1 W only. We found that film converter in the water at average power of laser radiation of 1.0+/-0.1 W is heated to 550+/-50°C and destructed at reaching of 4.0+/-0.1 W only. Volumetric converter at average power of laser radiation of4.0+/-0.1 W is heated to 450+/-50°C and is not destructed up to 7.5+/-0.1 W, it is heated to 500+/-50°C in this case. Thus, volumetric converter is more resistant to action of laser heating.

Cr:ZnSe laser pumped with Tm:YAP microchip laser

NASA Astrophysics Data System (ADS)

Koranda, Petr; Sulc, Jan; Doroshenko, Maxim; Jelinková, Helena; Basiev, Tasoltan T.; Osiko, Vjatcheslav; Badikov, V. V.; Badikov, D.

2010-02-01

Cr:ZnSe laser coherently longitudinally pumped with Tm:YAP microchip laser was realised. The pumping laser consisted of Tm:YAP crystal (3x3 mm) with resonator mirrors deposited directly on its faces (on rear face the dielectric layer with high reflectance for 1998 nm wavelength and high transmittance for 790 nm pumping radiation wavelength; on output face the dielectric layer with reflectance 97% at 1998 nm wavelength). The maximal output power was 5.5 W and the generated radiation wavelength was 1998 nm. The main advantage of this pumping was stable and still output without relaxation spikes (non-spiking). The Tm:YAP laser radiation was collimated and focused by the set of two CaF2 lenses. The pumping beam spot diameter inside the Cr:ZnSe crystal was 300 μm. The Cr:ZnSe laser resonator consisted of flat rear mirror (HT at 1998 nm and HR at 2100 - 2900 nm) and curved output coupler (r = -150 mm, R = 95% at 2100 - 2700 nm). The maximal output energy of stable radiation was 4 mJ (pulse duration 10 ms, repetition rate 10 Hz). For wavelength tuning the Lyott filter (quartz plate under Brewster angle) was placed between the Cr:ZnSe crystal and output coupler. The generated radiation wavelength was continuously tunable from 2246 - 2650 nm.

Laser-heated rocket studies

NASA Technical Reports Server (NTRS)

Kemp, N. H.; Root, R. G.; Wu., P. K. S.; Caledonia, G. E.; Pirri, A. N.

1976-01-01

CW laser heated rocket propulsion was investigated in both the flowing core and stationary core configurations. The laser radiation considered was 10.6 micrometers, and the working gas was unseeded hydrogen. The areas investigated included initiation of a hydrogen plasma capable of absorbing laser radiation, the radiation emission properties of hot, ionized hydrogen, the flow of hot hydrogen while absorbing and radiating, the heat losses from the gas and the rocket performance. The stationary core configuration was investigated qualitatively and semi-quantitatively. It was found that the flowing core rockets can have specific impulses between 1,500 and 3,300 sec. They are small devices, whose heating zone is only a millimeter to a few centimeters long, and millimeters to centimeters in radius, for laser power levels varying from 10 to 5,000 kW, and pressure levels of 3 to 10 atm. Heat protection of the walls is a vital necessity, though the fraction of laser power lost to the walls can be as low as 10% for larger powers, making the rockets thermally efficient.

Laser surgery: using the carbon dioxide laser.

PubMed Central

Wright, V. C.

1982-01-01

In 1917 Einstein theorized tha through an atomic process a unique kind of electromagnetic radiation could be produced by stimulated emission. When such radiation is in the optical or infrared spectrum it is termed laser (light amplification by stimulated emission of radiation) light. A laser, a high-intensity light source, emits a nearly parallel electromagnetic beam of energy at a given wavelength that can be captured by a lens and concentrated in the focal spot. The wavelength determines how the laser will be used. The carbon dioxide laser is now successfully employed for some surgical procedures in gynecology, otorhinolaryngology, neurosurgery, and plastic and general surgery. The CO2 laser beam is directed through the viewing system of an operating microscope or through a hand-held laser component. Its basic action in tissue is thermal vaporization; it causes minimal damage to adjacent tissues. Surgeons require special training in the basic methods and techniques of laser surgery, as well as in the safety standards that must be observed. Images FIG. 5 PMID:7074503

High energy XeBr electric discharge laser

DOEpatents

Sze, Robert C.; Scott, Peter B.

1981-01-01

A high energy XeBr laser for producing coherent radiation at 282 nm. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr is used as the halogen donor which undergoes harpooning reactions with Xe.sub.M * to form XeBr*.

Simulation of planetary entry radiative heating with a CO2 gasdynamic laser

NASA Technical Reports Server (NTRS)

Lundell, J. H.; Dickey, R. R.; Howe, J. T.

1975-01-01

Heating encountered during entry into the atmospheres of Jupiter, Saturn, and Uranus is described, followed by a discussion of the use of a CO2 gasdynamic laser to simulate the radiative component of the heating. Operation and performance of the laser is briefly described. Finally, results of laser tests of some candidate heat-shield materials are presented.

High energy XeBr electric discharge laser

DOEpatents

Sze, R.C.; Scott, P.B.

A high energy XeBr laser for producing coherent radiation at 282 nm is disclosed. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr, is used as the halogen donor which undergoes harpooning reactions with Xe/sub M/ to form XeBr.

50th anniversary of the laser

NASA Astrophysics Data System (ADS)

Bertolotti, M.

2010-09-01

On July, 7, 1960 a press conference at Huyghes announced that Maiman had assembled and put into operation the first laser. It was the very pulsed ruby laser that everybody knows today. The announcement came as a bomb. Nobody expected that in an unknown laboratory, new to the race to build a laser, this result could be obtained. It was such an unexpected result that many still today mantain that the true laser was discovered at Bell by Shawlow. This result was achieved through a long story which passed by the Townes maser and many tentative experiments and discussions both in the USA and Soviet Union. In this special issue we present a collection of papers which provide further information as to what happened after Einstein introduced the concept of stimulated emission. The first paper is a short paper by Townes on the development of the physics of microwaves following the creation of the maser. When the laser came on the stage one of its properties was the inherent coherence of the emitted light. Emil Wolf's contribution enlights the early days of coherence to which he so much contributed and the very timely first Rochester Conference which was held on June 27-29, 1960 a few days before the Times announcement of the Maiman achievement. Important contributions were given by Soviet Scientists and, Svetlana Lukishova's contributions helps us understand the work of Valentin Fabrikant which was mostly unknown to western scientists. At the end of his life, Maiman went to Vancouver in Canada and Andrew H. Rawicz gives his testimoniancy of his friendship there. Coherence and the statistical properties of laser light were much studied and we have two exceptional papers by Roy Pike and Jan Perina discussing these arguments. The issue also contains three more papers presenting some earlier achievements in the construction of multiquantumwell laser (M. L. Dotor, P. Huertas, P. A. Postigo, D. Golmayo and F. Briones), the first measurements on very short pulses (H. P. Weber and R. Dandliker) and spatial coherence (D. P. Barato and M. L. Calvo).

Strong terahertz radiation from relativistic laser interaction with solid density plasmas

NASA Astrophysics Data System (ADS)

Li, Y. T.; Li, C.; Zhou, M. L.; Wang, W. M.; Du, F.; Ding, W. J.; Lin, X. X.; Liu, F.; Sheng, Z. M.; Peng, X. Y.; Chen, L. M.; Ma, J. L.; Lu, X.; Wang, Z. H.; Wei, Z. Y.; Zhang, J.

2012-06-01

We report a plasma-based strong THz source generated in intense laser-solid interactions at relativistic intensities >1018 W/cm2. Energies up to 50 μJ/sr per THz pulse is observed when the laser pulses are incident onto a copper foil at 67.5°. The temporal properties of the THz radiation are measured by a single shot, electro-optic sampling method with a chirped laser pulse. The THz radiation is attributed to the self-organized transient fast electron currents formed along the target surface. Such a source allows potential applications in THz nonlinear physics and provides a diagnostic of transient currents generated in intense laser-solid interactions.

Fabrication of versatile cladding light strippers and fiber end-caps with CO2 laser radiation

NASA Astrophysics Data System (ADS)

Steinke, M.; Theeg, T.; Wysmolek, M.; Ottenhues, C.; Pulzer, T.; Neumann, J.; Kracht, D.

2018-02-01

We report on novel fabrication schemes of versatile cladding light strippers and end-caps via CO2 laser radiation. We integrated cladding light strippers in SMA-like connectors for reliable and stable fiber-coupling of high-power laser diodes. Moreover, the application of cladding light strippers in typical fiber geometries for high-power fiber lasers was evaluated. In addition, we also developed processes to fuse end-caps to fiber end faces via CO2 laser radiation and inscribe the fibers with cladding light strippers near the end-cap. Corresponding results indicate the great potential of such devices as a monolithic and low-cost alternative to SMA connectors.

Hollow-core photonic-crystal fibres for laser dentistry.

PubMed

Konorov, Stanislav O; Mitrokhin, Vladimir P; Fedotov, Andrei B; Sidorov-Biryukov, Dmitrii A; Beloglazov, Valentin I; Skibina, Nina B; Wintner, Ernst; Scalora, Michael; Zheltikov, Aleksei M

2004-04-07

Hollow-core photonic-crystal fibres (PCFs) for the delivery of high-fluence laser radiation capable of ablating tooth enamel are developed. Sequences of picosecond pulses of 1.06 microm Nd:YAG-laser radiation with a total energy of about 2 mJ are transmitted through a hollow-core photonic-crystal fibre with a core diameter of approximately 14 microm and are focused on a tooth surface in vitro to ablate dental tissue. The hollow-core PCF is shown to support the single-fundamental-mode regime for 1.06 microm laser radiation, serving as a spatial filter and allowing the laser beam quality to be substantially improved. The same fibre is used to transmit emission from plasmas produced by laser pulses on the tooth surface in the backward direction for detection and optical diagnostics.

Temperature and pressure dependence of dichloro-difluoromethane (CF2C12) absorption coefficients for CO2 waveguide laser radiation

NASA Technical Reports Server (NTRS)

Harward, C. N.

1977-01-01

Measurements were performed to determine the pressure and temperature dependence of CFM-12 absorption coefficients for CO2 waveguide laser radiation. The absorption coefficients of CFM-12 for CO2 waveguide laser radiation were found to have no spectral structure within small spectral bandwidths around the CO2 waveguide laser lines in the CO2 spectral band for pressures above 20 torr. All of the absorption coefficients for the CO2 laser lines studied are independent of pressure above 100 torr, except for the P(36) laser CO2 spectral band. The absorption coefficients associated with the P(42) line in the same band showed the greatest change with temperature, and it also has the largest value of all the lines studied.

Betatron x-ray radiation from laser-plasma accelerators driven by femtosecond and picosecond laser systems

NASA Astrophysics Data System (ADS)

Albert, F.; Lemos, N.; Shaw, J. L.; King, P. M.; Pollock, B. B.; Goyon, C.; Schumaker, W.; Saunders, A. M.; Marsh, K. A.; Pak, A.; Ralph, J. E.; Martins, J. L.; Amorim, L. D.; Falcone, R. W.; Glenzer, S. H.; Moody, J. D.; Joshi, C.

2018-05-01

A comparative experimental study of betatron x-ray radiation from laser wakefield acceleration in the blowout and self-modulated regimes is presented. Our experiments use picosecond duration laser pulses up to 150 J (self-modulated regime) and 60 fs duration laser pulses up to 10 J (blowout regime), for plasmas with electronic densities on the order of 1019 cm-3. In the self-modulated regime, where betatron radiation has been very little studied compared to the blowout regime, electrons accelerated in the wake of the laser pulse are subject to both the longitudinal plasma and transverse laser electrical fields. As a result, their motion within the wake is relatively complex; consequently, the experimental and theoretical properties of the x-ray source based on self-modulation differ from the blowout regime of laser wakefield acceleration. In our experimental configuration, electrons accelerated up to about 250 MeV and betatron x-ray spectra with critical energies of about 10-20 keV and photon fluxes between 108 and 1010 photons/eV Sr are reported. Our experiments open the prospect of using betatron x-ray radiation for applications, and the source is competitive with current x-ray backlighting methods on multi-kilojoule laser systems.

RUBI -a Reference mUltiscale Boiling Investigation for the Fluid Science Laboratory

NASA Astrophysics Data System (ADS)

Schweizer, Nils; Stelzer, Marco; Schoele-Schulz, Olaf; Picker, Gerold; Ranebo, Hans; Dettmann, Jan; Minster, Olivier; Toth, Balazs; Winter, Josef; Tadrist, Lounes; Stephan, Peter; Grassi, Walter; di Marco, Paolo; Colin, Catherine; Piero Celata, Gian; Thome, John; Kabov, Oleg

Boiling is a two-phase heat transfer process where large heat fluxes can be transferred with small driving temperature differences. The high performance of boiling makes the process very interesting for heat transfer applications and it is widely used in industry for example in power plants, refrigeration systems, and electronics cooling. Nevertheless, due to the large number of involved phenomena and their often highly dynamic nature a fundamental understanding and closed theoretical description is not yet accomplished. The design of systems incorporating the process is generally based on empirical correlations, which are commonly accompanied by large uncertainties and, thus, has to be verified by expensive test campaigns. Hence, strong efforts are currently made to develop applicable numerical tools for a reliable prediction of the boiling heat transfer performance and limits. In order to support and validate this development and, in particular as a precondition, to enhance the basic knowledge about boiling the comprehensive multi-scale experiment RUBI (Reference mUlti-scale Boiling Investigation) for the Fluid Science Laboratory on board the ISS is currently in preparation. The scientific objectives and requirements of RUBI have been defined by the members of the ESA topical team "Boiling and Multiphase Flow" and addresses fundamental aspects of boiling phenomena. The main objectives are the measurement of wall temperature and heat flux distribution underneath vapour bubbles with high spatial and tem-poral resolution by means of IR thermography accompanied by the synchronized high-speed observation of the bubble shapes. Furthermore, the fluid temperature in the vicinity and inside of the bubbles will be measured by a micro sensor array. Additional stimuli are the generation of an electric field above the heating surface and a shear flow created by a forced convection loop. The objective of these stimuli is to impose forces on the bubbles and investigate the resulting bubble behaviour such as bubble sliding on and detaching from the surface. The experiments benefits from the absence of vapour buoyancy and natural convection in the high quality and long-term microgravity of the ISS. Effects and phenomena like thermocapillary convection that are hardly observable in normal gravity conditions can be investigated. Clearly predefined conditions particularly of the thermal layer at the heating surface can be established without disturbances by natural convection. Vapour buoyancy as the main detaching force in normal gravity is missing. Hence, it is possible to study stationary, attached bubbles and alternative detaching forces. With RUBI a long history of boiling experiments is perpetuated that used microgravity as a tool for a deeper understanding of the fundamental phenomena. Several precursor experiments closely related to the RUBI project have already been conducted on parabolic flights. The subject of the paper is to provide an overview on the RUBI project, its scientific objectives and the corresponding experimental principle. The current design of the experiment container that is under development at ASTRIUM Space Transportation in Friedrichshafen will be introduced. Furthermore, results from the precursor experiments are presented. The industrial activities of the RUBI project are funded and the science team is supported by ESA.

Biological Effects of Laser Radiation. Volume II. Review of Our Studies on Biological Effects of Laser Radiation-1965-1971.

DTIC Science & Technology

1978-10-17

alter the immunological capability/virulence ratio of influenza virus ; gross and microscopic descriptions of lesions, their natural history, and...with Viruses 4 Chapter 4 Studies on Normal Animals 6 Chapter 5 Tumor-Related Laser Radiation Studies and Potential for Carcinogenesis 17 Chapter 6...affect the immunological capability/virulence ratio of influenza virus in order to explore facilitation of vaccine production; 5) extensive gross and

Dynamic laser-induced effects in nanocomposite systems based on the cadmium sulfide quantum dots in a silicate matrix.

PubMed

Voznesenskiy, S S; Sergeev, A A; Postnova, I V; Galkina, A N; Shchipunov, Yu A; Kulchin, Yu N

2015-02-23

In this paper we study the laser-induced modification of optical properties of nanocomposite based on cadmium sulphide quantum dots encapsulated into thiomalic acid shell which were embedded into a porous silica matrix. It was found that exposure to laser radiation at λ = 405.9 nm leads to modification of optical properties of nanocomposite. For this exposed area there is a significant amount of photodynamic changes under subsequent exposure to laser radiation at λ = 405.9 nm, namely photoabsorption and photorefraction which were studied at λ = 633 nm. The value of these effects dependent on the concentration of quantum dots and modifying radiation parameters. Moreover, it has dependence from polarization of exposure radiation.

Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

DOEpatents

Bischel, William K. [Menlo Park, CA; Jacobs, Ralph R. [Livermore, CA; Prosnitz, Donald [Hamden, CT; Rhodes, Charles K. [Palo Alto, CA; Kelly, Patrick J. [Fort Lewis, WA

1979-02-20

Method and apparatus for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH.sub.3) or methyl fluoride (CH.sub.3 F) is optically pumped by a pair of CO.sub.2 lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level.

Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

DOEpatents

Bischel, W.K.; Jacobs, R.R.; Prosnitz, D.P.; Rhodes, C.K.; Kelly, P.J.

1979-02-20

Method and apparatus are disclosed for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH[sub 3]) or methyl fluoride (CH[sub 3]F) is optically pumped by a pair of CO[sub 2] lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level. 3 figs.

Investigation of the cylindrical vacuum hohlraum energy in the first implosion experiment at the SGIII laser facility

NASA Astrophysics Data System (ADS)

Zhang, Huasen; Jiang, Wei; Ge, Fengjun; Song, Peng; Zou, Shiyang; Huang, Tianxuan; Li, Sanwei; Yang, Dong; Li, Zhichao; Hou, Lifei; Guo, Liang; Che, Xingsen; Du, Huabing; Xie, Xufei; He, Xiaoan; Li, Chaoguang; Zha, Weiyi; Xu, Tao; Liu, Yonggang; Wei, Huiyue; Liu, Xiangming; Chen, Zhongjing; Zhang, Xing; Yan, Ji; Pu, Yudong; Peng, Xiaoshi; Li, Yulong; Gu, Peijun; Zheng, Wudi; Liu, Jie; Ding, Yongkun; Zhu, Shaoping

2018-02-01

The cylindrical vacuum hohlraum energy at the SGIII laser facility [X. T. He and W. Y. Zhang, Eur. Phys. J. D 44, 227 (2007) and W. Zheng et al., High Power Laser Sci. Eng. 4, e21 (2016)] is investigated for the first time. The hohlraum size and the laser energy are intermediate between the Nova and NIF typical hohlraum experiments. It is found that the SGIII hohlraum exhibits an x-ray conversion efficiency of about 85%, which is more close to that of the NIF hohlraum. The LARED simulations of the SGIII hohlraum underestimate about 15% of the radiation flux measured from the laser entrance hole, while the capsule radiation drive inferred from the x-ray bangtime is roughly consistent with the experiments. The underestimation of the SGIII hohlraum radiation flux is mainly caused by the more enclosed laser entrance hole in the LARED simulation. The comparison between the SGIII and NIF hohlraum simulations by LARED indicates that the LARED generally underestimates the measured radiation flux by 15% for the high x-ray conversion efficiency hohlraums, while it can roughly predict the capsule radiation drive inside the hohlraum.

Spectral and angular distribution of photons via radiative damping in extreme ultra-intense laser-plasma interaction

NASA Astrophysics Data System (ADS)

Pandit, Rishi; Sentoku, Yasuhiko

2012-10-01

Spectral and angular distribution of photons produced in the interaction of extremely intense laser (> 10^22,/cm^2) with dense plasma are studied with a help of a collisional particle-in-cell simulation, PICLS. In ultra-intense laser-plasma interaction, electrons are accelerated by the strong laser fields and emit γ-ray photons mainly via two processes, namely, Bremsstrahlung and radiative damping. We had developed numerical models of these processes in PICLS and study the spectrum and the angular distribution of γ-rays produced in the relativistic laser regime. Such relativistic γ-rays have wide range of frequencies and the angular distribution depends on the hot electron source. From the power loss calculation in PICLS we found that the Bremsstrahlung will get saturated at I > 10^22,/cm^2 while the radiative damping will continuously increase. Comparing the details of γ-rays from the Bremsstrahlung and the radiative damping in simulations, we will discuss the laser parameters and the target conditions (geometry and material) to distinguish the photons from each process and how to catch the signature of the radiative damping in future experiments.

Laser system for natural gas detection. Phase 1: Laboratory feasibility studies

NASA Technical Reports Server (NTRS)

Grant, W. B.; Hinkley, E. D., Jr.

1982-01-01

This project demonstrated the feasibility of using laser remote sensing technology as a tool for leak survey work in natural gas distribution systems. A laboratory device was assembled using a pair of helium neon (HeNe) lasers to measure methane. One HeNe laser emits radiation at a wavelength of 3.3922 micrometers, which corresponds to a strong absorption feature of methane, while the other emits radiation at a wavelength of 3.3911 micrometers, which corresponds to a weak absorption by methane. As a particular area is scanned for leaks, the laser is pointed at convenient topographic targets within its operating range, about 25 m. A portion of the backscattered radiation is collected by a receiver and focused onto an indium antimonide (InSb) photodetector, cooled to 77K. Methane concentrations were determined from the differential absorption at the two wavelengths for the backscattered radiation.

Flying relativistic mirrors for nonlinear QED studies.

NASA Astrophysics Data System (ADS)

Bulanov, Stepan; Schroeder, Carl; Esarey, Eric; Leemans, Wim

2017-10-01

Recent progress in laser technology has led to a dramatic increase of laser power and intensity. As a result, the laser-matter interaction will happen in the radiation dominated regimes. In a strong electromagnetic field, electrons can be accelerated to such high velocities that the radiation reaction starts to play an important role. The radiation effects change drastically the laser-plasma interaction leading to fast energy losses. Moreover, previously unexplored regimes of the interaction will be entered into, in which quantum electrodynamics (QED) can occur. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail. In order to study different regimes of interaction as well as the transition from one into another the utilization of flying relativistic mirrors, which can generate electromagnetic pulses with varying frequency and intensity, is proposed. The scheme is demonstrated for multiphoton Compton scattering. Work supported by U.S. DOE under Contract No. DE-AC02-05CH11231.

Bond strengths evaluation of laser ceramic bracket debonding

NASA Astrophysics Data System (ADS)

Dostalová, T.; Jelinková, H.; Šulc, J.; Němec, M.; Fibrich, M.; Jelínek, M.; Michalík, P.; Bučková, M.

2012-09-01

Ceramic brackets often used for an orthodontic treatment can lead to problems such as enamel tear outs because of their low fracture resistance and high bond strengths. Therefore the aim of our study was to investigate the positive laser radiation effect on bracket debonding. Moreover, the influence of the enamel shape surface under the bracket and laser radiation power on the debonding strength was investigated. The source of the radiation was the longitudinally diode-pumped Tm:YAP laser operating at 1997 nm. To eliminate the tooth surface roughness the flat enamel surface was prepared artificially and the bracket was bonded on it. The debonding was accomplished by Tm:YAP laser radiation with different the power value while recording the temperature rise in the pulp. To simulate the debonding process in vivo the actual bond strength was measured by the digital force gauge. The results were analyzed by scanning electron microscope.

Comparison of the effect of UV laser radiation and of a radiomimetic substance on chromatin

NASA Astrophysics Data System (ADS)

Radulescu, Irina; Radu, Liliana; Serbanescu, Ruxandra; Nelea, V. D.; Martin, C.; Mihailescu, Ion N.

1998-07-01

The damages of the complex of deoxyribonucleic acid (DNA) and proteins from chromatin, produced by the UV laser radiation and/or by treatment with a radiomimetic substance, bleomycin, were compared. The laser radiation and bleomycin effects on chromatin structure were determined by the static and dynamic fluorimetry of chromatin complexes with the DNA specific ligand-- proflavine and by the analysis of tryptophan chromatin intrinsic fluorescence. Time resolved spectroscopy is a sensitive technique which allows to determine the excited state lifetimes of chromatin--proflavine complexes. Also, the percentage contributions to the fluorescence of proflavine, bound and unbound to chromatin DNA, were evaluated. The damages produced by the UV laser radiation on chromatin are similar with those of radiomimetic substance action and consists in DNA and proteins destruction. The DNA damage degree has been determined. The obtained results may constitute some indications in the laser utilization in radiochimiotherapy.

Attenuation of laser radiation by the flame of burning hydrocarbons and efficiency of remote cutting of metals

NASA Astrophysics Data System (ADS)

Gvozdev, S. V.; Glova, A. F.; Dubrovskii, V. Yu; Durmanov, S. T.; Krasyukov, A. G.; Lysikov, A. Yu; Smirnov, G. V.; Pleshkov, V. M.

2017-12-01

Mobile laser technological complex MLTC-20 with radiation power 20 kW and radiation wavelength 1.07 μm created in SRC RF TRINITI on the base of a three cw fiber Yb lasers is used successfully at remote cutting of the metalworks at carrying out of the emergency-reduction works on the out of control gas wells. In this work the results of the investigation of the possibility and the efficiency of laser radiation application for remote cutting of metals on the emergency oil wells have been presented. Measurements of the mean absorption coefficient of the radiation of a cw fiber Yb laser under its propagation in a flame of burning oil in dependence on radiation intensity have been carried out. It was shown that at the intensity ~104 W/cm2 the absorption coefficient traverses the maximum where its value is equal to ~0.1 cm-1, and at the intensity increasing to the values 105 - 106 W/cm2 it stabilizes on a small level ~5·10-3 - 10-2 cm-1. It is established that the maximal velocity and the efficiency of remote cutting of the steel plates with a thickness up to 10 mm by the radiation with the intensity 106 W/cm2 exceed these factors at the intensity 104 W/cm2. The possibility of the efficient remote cutting of steel plate with a thickness of 60 mm by laser radiation having the power 7.5 kW and the intensity 105 W/cm2 has been demonstrated.

Study to define behavior of liquid lubricants in an elastohydrodynamic contact

NASA Technical Reports Server (NTRS)

Lauer, J. L.

1974-01-01

The spectra of an ester and a saturated hydrocarbon polymer were obtained at pressures ranging from ambient to 2 GN/sq m (20 kilobar) and at temperatures between ambient and 180 C in absorption and between 150 C and 210 C in emission. To simulate contact conditions the fluids were contained in the tiny sample volume of a diamond cell, i.e., the hole in a metal spacer separating two diamonds pressed against each other in a nut crackerlike arrangement. Pressures could be deduced from bandshifts and states of aggregation from bandwidths in the fluorescence spectrum of a ruby crystal immersed in the fluids. An infrared Fourier transform spectrometer was used with attachments specially designed to analyze the radiation passed through the sample and both diamonds (absorption technique) or the radiation emanating from the heated sample and passing through only one diamond (emission technique). The latter technique is applicable to operating EHD contacts. Spectral changes pointing to possible glass transitions and composition changes were observed. Emission and absorption spectra were generally equivalent. Some emission bandshapes appear to be temperature sensitive enough to be useful as internal temperature probes.

Surface Features and Cathodoluminescence (CL) Characteristics of Corundum Gems from Eastern of Thailand

NASA Astrophysics Data System (ADS)

Boonsoong, A.

2017-12-01

Thailand has long been well known as a supplier of gemstones and also one of the world's color stone centers for decades. The principal gemstones are corundum, garnet and zircon. The corundum deposits of Chanthaburi-Trat Provinces form the most significant ruby-sapphire concentration in Thailand. Corundums are commonly found in secondary deposits (alluvium, elluvial, residual-soil and colluvium deposits as well as stream sediments) with the thickness of the gem-bearing layer varying from 10-100cm and the thickness of the overburden ranging up to 15m. A number of corundum samples were collected from each of the twenty-nine corundum deposits in the Chanthaburi-Trat gem fields, eastern of Thailand. Corundum varies in colour across the region with colours associated with three geographic zones; a western zone, characterized by blue, green and yellow sapphires; a middle zone with blue, green sapphires plus rubies; and an eastern zone yielding mainly rubies. This project has aim to study surface features and characterize the Cathodoluminescence (CL) of corundum gems in the Chanthaburi-Trat gem fields, Thailand. Surfaces of the corundums under a scanning electron microscope show triangular etch features and randomly oriented needle-like patterns. These reveal that the corundums have interacted with the magma during their ascent to the Earth's surface. Surface features attributable to transport and weathering processes are scratches, conchoidal fractures and a spongy surface appearance. Clay minerals and Fe-Ti oxide minerals deposited on the spongy surfaces of some corundums also indicate that these grains experienced chemical weathering or reacted with the soil solution while they were in the alluvium. Cathodoluminescence shows some blue sapphires to exhibit dull blue luminescence. The main cause of the CL appearance of sapphires is likely to be a quench centre, Fe2+ in their structure. The bright red luminescence in corundum reflects a high Cr3+ content and is always exhibited by the red, pink, violet and purple rubies. Some rubies may exhibit dull red luminescence because of Fe2+ quench centres.

Comparison of the effect of soft-core potentials and Coulombic potentials on bremsstrahlung during laser matter interaction

NASA Astrophysics Data System (ADS)

Pandit, Rishi R.; Becker, Valerie R.; Barrington, Kasey; Thurston, Jeremy; Ramunno, Lora; Ackad, Edward

2018-04-01

An intense, short laser pulse incident on rare-gas clusters can produce nano-plasmas containing energetic electrons. As these electrons undergo scattering, from both phonons and ions, they emit bremsstrahlung radiation. Here, we compare a theory of bremsstrahlung emission appropriate for the interaction of intense lasers with matter using soft-core potentials and Coulombic potentials. A new scaling for the radiation cross-section and the radiated power via bremsstrahlung is derived for a soft-core potential (which depends on the potential depth) and compared with the Coulomb potential. Calculations using the new scaling are performed for electrons in vacuum ultraviolet, infrared and mid-infrared laser pulses. The radiation cross-section and the radiation power via bremsstrahlung are found to increase rapidly with increases in the potential depth of up to around 200 eV and then become mostly saturated for larger depths while remaining constant for the Coulomb potential. In both cases, the radiation cross-section and the radiation power of bremsstrahlung decrease with increases in the laser wavelength. The ratio of the scattering amplitude for the soft-core potential and that for the Coulombic potential decreases exponentially with an increase in momentum transfer. The bremsstrahlung emission by electrons in plasmas may provide a broadband light source for diagnostics.

Nanomedical science and laser-driven particle acceleration: promising approaches in the prethermal regime

NASA Astrophysics Data System (ADS)

Gauduel, Y. A.

2017-05-01

A major challenge of spatio-temporal radiation biomedicine concerns the understanding of biophysical events triggered by an initial energy deposition inside confined ionization tracks. This contribution deals with an interdisciplinary approach that concerns cutting-edge advances in real-time radiation events, considering the potentialities of innovating strategies based on ultrafast laser science, from femtosecond photon sources to advanced techniques of ultrafast TW laser-plasma accelerator. Recent advances of powerful TW laser sources ( 1019 W cm-2) and laser-plasma interactions providing ultra-short relativistic particle beams in the energy domain 5-200 MeV open promising opportunities for the development of high energy radiation femtochemistry (HERF) in the prethermal regime of secondary low-energy electrons and for the real-time imaging of radiation-induced biomolecular alterations at the nanoscopic scale. New developments would permit to correlate early radiation events triggered by ultrashort radiation sources with a molecular approach of Relative Biological Effectiveness (RBE). These emerging research developments are crucial to understand simultaneously, at the sub-picosecond and nanometric scales, the early consequences of ultra-short-pulsed radiation on biomolecular environments or integrated biological entities. This innovating approach would be applied to biomedical relevant concepts such as the emerging domain of real-time nanodosimetry for targeted pro-drug activation and pulsed radio-chimiotherapy of cancers.

Evolution analysis of EUV radiation from laser-produced tin plasmas based on a radiation hydrodynamics model

PubMed Central

Su, M. G.; Min, Q.; Cao, S. Q.; Sun, D. X.; Hayden, P.; O’Sullivan, G.; Dong, C. Z.

2017-01-01

One of fundamental aims of extreme ultraviolet (EUV) lithography is to maximize brightness or conversion efficiency of laser energy to radiation at specific wavelengths from laser produced plasmas (LPPs) of specific elements for matching to available multilayer optical systems. Tin LPPs have been chosen for operation at a wavelength of 13.5 nm. For an investigation of EUV radiation of laser-produced tin plasmas, it is crucial to study the related atomic processes and their evolution so as to reliably predict the optimum plasma and experimental conditions. Here, we present a simplified radiation hydrodynamic model based on the fluid dynamic equations and the radiative transfer equation to rapidly investigate the evolution of radiation properties and dynamics in laser-produced tin plasmas. The self-absorption features of EUV spectra measured at an angle of 45° to the direction of plasma expansion have been successfully simulated and explained, and the evolution of some parameters, such as the plasma temperature, ion distribution and density, expansion size and velocity, have also been evaluated. Our results should be useful for further understanding of current research on extreme ultraviolet and soft X-ray source development for applications such as lithography, metrology and biological imaging. PMID:28332621

Features and dosimetry of laser-inflicted retina injuries induced by short laser pulses

NASA Astrophysics Data System (ADS)

Pustovalov, Victor K.

1996-04-01

Energy absorption, heat transfer, thermodenaturation under the action of laser radiation pulse on pigmented spherical granules in heterogeneous laminated biotissues are investigated on the base of mathematical simulation. The possibility of selective interaction between short radiation pulses and pigmented retina biotissues is noted which results in the formation of thermodenaturation microregions inside and near the melanosomes. These denaturation microregions can originate in the eye biotissue under laser radiation intensities less than about 2 - 4 times the threshold ones determined ophthalmoscopically. These microdamages can appear without being detected by the standard ophthalmoscopical methods.

A new Faraday rotator for high average power lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khazanov, E A

2001-04-30

The new design of a Faraday rotator is proposed which allows one to compensate partially the radiation depolarisation in magneto-optical elements induced by heating due to the laser radiation absorption. The new design is compared analytically and numerically with a conventional design for the cases of glass and crystal magneto-optical media. It is shown that a rotator, which provides the compensation for birefringence in active elements with the accuracy up to 1 % at the average laser radiation power of 1 kW in the rotator, can be created. (laser applications and other topics in quantum electronics)

Treatment of children with severe cases of yersiniosis

NASA Astrophysics Data System (ADS)

Gordeets, A. V.; Beniova, S. N.; Shapovalov, E. G.; Malashenkova, V. G.; Sedulina, O. F.

2001-04-01

A study is made of a low-intensity laser radiation technique to treat severe cases of yersiniosis. This technique was tested in 43 children affected by severe cases of pseudotuberculosis and in 32 children suffering from intestinal yersiniosis. Comparing laser therapy and a conventional treatment revealed that these approaches produced significantly different therapeutic and immunological effects. It was found that low-intensity laser radiation combined with drug therapy resulted in a reduction of intoxication duration, diarrhea, hospitalization time, and drug doses. Moreover, the combined application of laser radiation and rug preparations enabled an efficient recovery of the immune state.

Automatic control system of high precision welding of workpieces in mechanical engineering

NASA Astrophysics Data System (ADS)

Kuznetsov, I. N.; Zvezdin, V. V.; Israfilov, I. H.; Portnov, S. M.

2014-12-01

In this paper, based on the conducted patent research, the system of laser welding control with different geometry of weld and shapes of parts is developed. The method of monitoring the position of the spot of laser radiation in relation to the curved weld is worked out; it is based on the tracking the edges of the welded parts by low-power laser radiation reflected from the surface of the parts. It allows to make the positioning of the focus of laser radiation in relation to the juncture of the welded parts automatically.

Generation of continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling of a Ti:sapphire laser.

PubMed

Cha, Yong-Ho; Ko, Kwang-Hoon; Lim, Gwon; Han, Jae-Min; Park, Hyun-Min; Kim, Taek-Soo; Jeong, Do-Young

2010-03-20

We have generated continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling a high-power Ti:sapphire laser in an external enhancement cavity. An LBO crystal that is Brewster-cut and antireflection coated on both ends is used for a long-term stable frequency doubling. By optimizing the input coupler's reflectivity, we could generate 1.5 W 378 nm radiation from a 5 W 756 nm Ti:sapphire laser. According to our knowledge, this is the highest CW frequency-doubled power of a Ti:sapphire laser.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA Annealing of induced absorption in quartz glasses by ArF laser radiation

NASA Astrophysics Data System (ADS)

Sergeev, P. B.; Sergeev, A. P.

2010-11-01

Annealing of individual bands of electron-beam-induced absorption (IA) in the region of 150 — 400 nm in KS-4V, KU-1, and Corning 7980 (ArF Grade) quartz glasses by ArF laser radiation is studied. It is shown that the phototransformation of the IA spectra occurs mainly due to a significant decrease in the amplitudes of bands at λ = 183.5, 213, and 260 nm. The role played by interstitial oxygen, hydrogen, and chlorine in the formation and relaxation of glass defects is considered.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Characteristics of the scattering of neutral atoms by two counterpropagating pulsed optical fields

NASA Astrophysics Data System (ADS)

Grinchuk, V. A.; Grishina, I. A.; Kuzin, E. F.; Nagaeva, M. L.; Ryabenko, G. A.; Yakovlev, V. P.

1994-04-01

The scattering of neutral sodium atoms by a strong field of two counterpropagating (incident on and reflected from a mirror) short laser pulses was used in an experimental investigation of a stimulated radiation pressure. The reasons for the anomalous frequency structure in the scattering of atoms were identified. The oscillatory nature of the dependence of the scattering on the detuning from resonance was found to be significant in strong laser radiation fields. The oscillation period depended on the distance between the reflecting mirror and the atomic beam.

Optical radiation hazards of laser welding processes. Part II: CO2 laser.

PubMed

Rockwell, R J; Moss, C E

1989-08-01

There has been an extensive growth within the last five years in the use of high-powered lasers in various metalworking processes. The two types of lasers used most frequently for laser welding/cutting processes are the Neodymium-yttrium-aluminum-garnet (Nd:YAG) and the carbon dioxide (CO2) systems. When such lasers are operated in an open beam configuration, they are designated as a Class IV laser system. Class IV lasers are high-powered lasers that may present an eye and skin hazard under most common exposure conditions, either directly or when the beam has been diffusely scattered. Significant control measures are required for unenclosed (open beam), Class IV laser systems since workers may be exposed to scattered or reflected beams during the operation, maintenance, and service of these lasers. In addition to ocular and/or skin exposure hazards, such lasers also may present a multitude of nonlaser beam occupational concerns. Radiant energy measurements are reported for both the scattered laser radiation and the plasma-related plume radiations released during typical high-powered CO2 laser-target interactions. In addition, the application of the nominal hazard zone (NHZ) and other control measures also are discussed with special emphasis on Class IV industrial CO2 laser systems.

Efficient 'Foton' electric-discharge KrCl laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panchenko, Aleksei N; Tarasenko, Viktor F

The design of the 'Foton' electric-discharge laser, optimised for operation on the basis of KrCl* molecules, and its energy parameters were investigated. At {lambda} = 222 nm the radiation energy was up to 250 mJ per pulse. The specific output radiation energy was 2.5 J litre{sup -1} and the laser efficiency was in excess of 0.8%. The possibility of further improvement of the characteristics of electric-discharge KrCl lasers are discussed. (lasers)

Multidisciplinary approaches to radiation-balanced lasers (MARBLE): a MURI program by AFOSR (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sheik-Bahae, Mansoor

2017-02-01

An overview of the diverse research activities under the newly funded MURI project by AFOSR will be presented. The main goal is to advance the science of radiation-balanced lasers, also known as athermal lasers, in order to mitigate the thermal degradation of the high-power laser beams. The MARBLE project involves researchers from four universities and spans research activities in rare-earth doped crystals and fibers to semiconductor disc lasers.

Longitudinal space charge assisted echo seeding of a free-electron laser with laser-spoiler noise suppression

NASA Astrophysics Data System (ADS)

Hacker, Kirsten

2014-09-01

Seed lasers are employed to improve the temporal coherence of free-electron laser (FEL) light. However, when these seed pulses are short relative to the particle bunch, the noisy, temporally incoherent radiation from the unseeded electrons can overwhelm the coherent, seeded radiation. In this paper, a technique to seed a particle bunch with an external laser is presented in which a new mechanism to improve the contrast between coherent and incoherent free electron laser radiation is employed together with a novel, simplified echo-seeding method. The concept relies on a combination of longitudinal space charge wakes and an echo-seeding technique to make a short, coherent pulse of FEL light together with noise background suppression. Several different simulation codes are used to illustrate the concept with conditions at the soft x-ray free-electron laser in Hamburg, FLASH.

Tuned alexandrite laser for dentistry

NASA Astrophysics Data System (ADS)

Sulc, Jan; Jelinkova, Helena; Dostalova, Tatjana; Miyagi, Mitsunobu

1999-12-01

A tunable solid state laser system has been developed emitting visible light in the region from 710 to 775 nm, which can be used for medical applications. The laser head of this system is composed of alexandrite crystal rod, two dielectric mirrors, and a tuning element. The maximum reached output energy in the free running multimode regime was 400 mJ with the pulse duration of 70 micrometers . The output laser radiation was guided via a multimode quartz fiber or via a special fluorocarbon polymer-coated silver hollow glass waveguide. At first, this radiation with laser fluency of 2.5 J/cm2 was used for the ablation of dental calculus. Next, the laser radiation propagation in the root canal and its effect on bacteria was proved. The dissipated energy measurement was made inside and outside the tooth. Hence, the alexandrite laser could be useful for medical applications in dentistry.

Effect of fusion mixture treatment on the surface of low grade natural ruby

NASA Astrophysics Data System (ADS)

Sakthivel, R.; Pradhan, K. C.; Nayak, B. B.; Dash, Tapan; Sahu, R. K.; Mishra, B. K.

2017-05-01

Improvement in aesthetic look of low grade natural ruby (gemstone) surface was clearly evident after fusion mixture treatment. Surface impurities of the gemstone were significantly reduced to give it a face lift. The processing consists of heat treatment (1000 °C) of the raw gemstone with fusion mixture (sodium and potassium carbonates), followed by hydrochloric acid digestion (90 °C) and ultrasonic cleaning.Both the untreated and the treated gemstone were characterized by X-ray diffraction, UV-vis spectroscopy (diffuse reflectance),photoluminescence and X-ray photoelectron spectroscopy. The paper consolidates the results of these studies and presents the effect of the typical chemical treatment (stated above) on the low grade natural ruby. While X-ray diffraction study identifies the occurrence of alumina phase in both the treated and the untreated gemstones, the UV-vis spectra exhibit strong characteristic absorption of Cr3+at 400 and 550 nm wavelength for the treated gemstone in contrast to weak absorption observed for the untreated gemstone at such wavelengths, thus showing the beneficial effect of fusion mixture treatment. Peaks observed for the gemstone (for both treated and untreated samples) in the excitation spectra of photoluminescence show a good correlation with observed UV-vis (diffuse reflectance) spectra. Photoluminescence emission spectra of the untreated gemstone show characteristic emission at 695 nm for Cr3+ ion (as in alumina matrix), but its emission intensity significantly reduces after fusion mixture treatment. It is found that the surface of the fusion mixture treated ruby gemstone looks much brighter than the corresponding untreated surface.

The effect of MLS laser radiation on cell lipid membrane.

PubMed

Pasternak, Kamila; Wróbel, Dominika; Nowacka, Olga; Pieszyński, Ireneusz; Bryszewska, Maria; Kujawa, Jolanta

2018-03-14

Authors of numerous publications have proved the therapeutic effect of laser irradiation on biological material, but the mechanisms at cellular and subcellular level are not yet well understood. The aim of this study was to assess the effect of laser radiation emitted by the MLS M1 system (Multiwave Locked System) at two wavelengths (808 nm continuous and 905 nm pulsed) on the stability and fluidity of liposomes with a lipid composition similar to that of human erythrocyte membrane or made of phosphatidylocholine. Liposomes were exposed to low-energy laser radiation at surface densities 195 mW/cm² (frequency 1,000 Hz) and 230 mW/cm² (frequency 2,000 Hz). Different doses of radiation energy in the range 0-15 J were applied. The surface energy density was within the range 0.46 - 4.9 J/cm ². The fluidity and stability of liposomes subjected to such irradiation changed depending on the parameters of radiation used. Since MLS M1 laser radiation, depending on the parameters used, affects fluidity and stability of liposomes with the lipid content similar to erythrocyte membrane, it may also cause structural and functional changes in cell membranes.

Remote steering of laser beams by radar- and laser-induced refractive-index gradients in the atmosphere Remote steering of laser beams

NASA Astrophysics Data System (ADS)

Zheltikov, A. M.; Shneider, M. N.; Voronin, A. A.; Sokolov, A. V.; Scully, M. O.

2012-01-01

Refractive-index gradients induced in the atmospheric air by properly tailored laser and microwave fields are shown to enable a remote steering of laser beams. Heating-assisted modulation of the refractive index of the air by microwave radiation is shown to support small-angle laser-beam bending with bending angles on the order of 10-2. Ionization of the atmospheric air by dyads of femto- and nanosecond laser pulses, on the other hand, can provide beam deflection angles in excess of π/5, offering an attractive strategy for radiation transfer, free-space communications, and laser-based standoff detection.

Generation of 369.4 nm Radiation by Efficient Doubling of a Diode Laser

NASA Technical Reports Server (NTRS)

Williams, A.; Seidel, D. J.; Maleki, J.

1993-01-01

A resonant cavity second harmonic generation system has been developed to produce 369.4 nm radiation from a 738.8 nm diode laser with 10 mW nominal output power. This system utilizes a polarization technique to lock the cavity to the laser frequency. In this paper we report on an evaluation of the system using a Titanium:Sapphire laser as the input source, and preliminary results with a diode laser source. To our knowledge, this is the deepest uv light ever produced by frequency-doubling a diode laser.

Sapphire capillary interstitial irradiators for laser medicine

NASA Astrophysics Data System (ADS)

Shikunova, I. A.; Dolganova, I. N.; Dubyanskaya, E. N.; Mukhina, E. E.; Zaytsev, K. I.; Kurlov, V. N.

2018-04-01

In this paper, we demonstrate instruments for laser radiation delivery based on sapphire capillary needles. Such sapphire irradiators (introducers) can be used for various medical applications, such as photodynamic therapy, laser hyperthermia, laser interstitial thermal therapy, and ablation of tumors of various organs. Unique properties of sapphire allow for effective redistribution of the heat, generated in biological tissues during their exposure to laser radiation. This leads to homogeneous distribution of the laser irradiation around the needle, and lower possibility of formation of the overheating focuses, as well as the following non-transparent thrombi.

A blackbody radiation-pumped CO2 laser experiment

NASA Technical Reports Server (NTRS)

Christiansen, W. H.; Insuik, R. J.; Deyoung, R. J.

1982-01-01

Thermal radiation from a high temperature oven was used as an optical pump to achieve lasing from CO2 mixtures. Laser output as a function of blackbody temperature and gas conditions is described. This achievement represents the first blackbody cavity pumped laser and has potential for solar pumping.

BioC implementations in Go, Perl, Python and Ruby.

PubMed

Liu, Wanli; Islamaj Doğan, Rezarta; Kwon, Dongseop; Marques, Hernani; Rinaldi, Fabio; Wilbur, W John; Comeau, Donald C

2014-01-01

As part of a communitywide effort for evaluating text mining and information extraction systems applied to the biomedical domain, BioC is focused on the goal of interoperability, currently a major barrier to wide-scale adoption of text mining tools. BioC is a simple XML format, specified by DTD, for exchanging data for biomedical natural language processing. With initial implementations in C++ and Java, BioC provides libraries of code for reading and writing BioC text documents and annotations. We extend BioC to Perl, Python, Go and Ruby. We used SWIG to extend the C++ implementation for Perl and one Python implementation. A second Python implementation and the Ruby implementation use native data structures and libraries. BioC is also implemented in the Google language Go. BioC modules are functional in all of these languages, which can facilitate text mining tasks. BioC implementations are freely available through the BioC site: http://bioc.sourceforge.net. Database URL: http://bioc.sourceforge.net/ Published by Oxford University Press 2014. This work is written by US Government employees and is in the public domain in the US.

Evolution of basin and range structure in the Ruby Mountains and vicinity, Nevada

NASA Technical Reports Server (NTRS)

Blackwell, D. D.; Reese, N. M.; Kelley, S. A.

1985-01-01

Results from various age dating techniques, seismic reflection profiling hydrocarbon maturation studies, and structural analysis were used to evaluate the Cenozoic deformation in the Ruby Mountains and adjoining ranges (pinyon Range and Cortez Range) in Elko and Eureka Counties, Nevada. Age dating techniques used include potassium-argon ages of biotites from granites published by Kistler et al. (1981) and fission track ages from apatite and zircon. Fission track ages from apatite reflect a closing temperature of 100 plus or minus 20 deg C. Zircon fission track ages reflect a closing temperature of 175 plus or minus 25 deg C and potassium-argon ages from brotite reflect a closing temperature of 250 plus or minus 30 deg C. Thus these results allow a reasonably precise tracking of the evolution of the ranges during the Cenozoic. Seismic reflection data are available from Huntington Valley. Access to seismic reflection data directly to the west of the Harrison Pass Pluton in the central Ruby Mountains was obtained. In addition results are available from several deep exploration holes in Huntington Valley.

Betatron x-ray radiation in the self-modulated wakefield acceleration regime (Conference Presentation)

NASA Astrophysics Data System (ADS)

Albert, Felicie

2017-05-01

Betatron x-ray radiation, driven by electrons from laser-wakefield acceleration, has unique properties to probe high energy density (HED) plasmas and warm dense matter. Betatron radiation is produced when relativistic electrons oscillate in the plasma wake of a laser pulse. Its properties are similar to those of synchrotron radiation, with a 1000 fold shorter pulse. This presentation will focus on the experimental challenges and results related to the development of betatron radiation in the self modulated regime of laser wakefield acceleration. We observed multi keV Betatron x-rays from a self-modulated laser wakefield accelerator. The experiment was performed at the Jupiter Laser Facility, LLNL, by focusing the Titan short pulse beam (4-150 J, 1 ps) onto the edge of a Helium gas jet at electronic densities around 1019 cm-3. For the first time on this laser system, we used a long focal length optic, which produced a laser normalized potential a0 in the range 1-3. Under these conditions, electrons are accelerated by the plasma wave created in the wake of the light pulse. As a result, intense Raman satellites, which measured shifts depend on the electron plasma density, were observed on the laser spectrum transmitted through the target. Electrons with energies up to 200 MeV, as well as Betatron x-rays with critical energies around 20 keV, were measured. OSIRIS 2D PIC simulations confirm that the electrons gain energy both from the plasma wave and from their interaction with the laser field.

UV laser radiation alters the embryonic protein profile of adrenal-kidney-gonadal complex and gonadal differentiation in the lizard, Calotes Versicolor.

PubMed

Khodnapur, Bharati S; Inamdar, Laxmi S; Nindi, Robertraj S; Math, Shivkumar A; Mulimani, B G; Inamdar, Sanjeev R

2015-02-01

To examine the impact of ultraviolet (UV) laser radiation on the embryos of Calotes versicolor in terms of its effects on the protein profile of the adrenal-kidney-gonadal complex (AKG), sex determination and differentiation, embryonic development and hatching synchrony. The eggs of C. versicolor, during thermo-sensitive period (TSP), were exposed to third harmonic laser pulses at 355 nm from a Q-switched Nd:YAG laser for 180 sec. Subsequent to the exposure they were incubated at the male-producing temperature (MPT) of 25.5 ± 0.5°C. The AKG of hatchlings was subjected to protein analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and to histology. The UV laser radiation altered the expression of the protein banding pattern in the AKG complex of hatchlings and it also affected the gonadal sex differentiation. SDS-PAGE of AKG of one-day-old hatchlings revealed a total of nine protein bands in the control group whereas UV laser irradiated hatchlings expressed a total of seven protein bands only one of which had the same Rf as a control band. The UV laser treated hatchlings have an ovotestes kind of gonad exhibiting a tendency towards femaleness instead of the typical testes. It is inferred that 355 nm UV laser radiation during TSP induces changes in the expression of proteins as well as their secretions. UV laser radiation had an impact on the gonadal differentiation pathway but no morphological anomalies were noticed.

Laser-enhanced dynamics in molecular rate processes

NASA Technical Reports Server (NTRS)

George, T. F.; Zimmerman, I. H.; Devries, P. L.; Yuan, J.-M.; Lam, K.-S.; Bellum, J. C.; Lee, H.-W.; Slutsky, M. S.

1978-01-01

The present discussion deals with some theoretical aspects associated with the description of molecular rate processes in the presence of intense laser radiation, where the radiation actually interacts with the molecular dynamics. Whereas for weak and even moderately intense radiation, the absorption and stimulated emission of photons by a molecular system can be described by perturbative methods, for intense radiation, perturbation theory is usually not adequate. Limiting the analysis to the gas phase, an attempt is made to describe nonperturbative approaches applicable to the description of such processes (in the presence of intense laser radiation) as electronic energy transfer in molecular (in particular atom-atom) collisions; collision-induced ionization and emission; and unimolecular dissociation.

Thermal Investigation of Interaction between High-power CW-laser Radiation and a Water-jet

NASA Astrophysics Data System (ADS)

Brecher, Christian; Janssen, Henning; Eckert, Markus; Schmidt, Florian

The technology of a water guided laser beam has been industrially established for micro machining. Pulsed laser radiation is guided via a water jet (diameter: 25-250 μm) using total internal reflection. Due to the cylindrical jet shape the depth of field increases to above 50 mm, enabling parallel kerfs compared to conventional laser systems. However higher material thicknesses and macro geometries cannot be machined economically viable due to low average laser powers. Fraunhofer IPT has successfully combined a high-power continuous-wave (CW) fiber laser (6 kW) and water jet technology. The main challenge of guiding high-power laser radiation in water is the energy transferred to the jet by absorption, decreasing its stability. A model of laser water interaction in the water jet has been developed and validated experimentally. Based on the results an upscaling of system technology to 30 kW is discussed, enabling a high potential in cutting challenging materials at high qualities and high speeds.

Enhanced THz radiation generation by photo-mixing of tophat lasers in rippled density plasma with a planar magnetostatic wiggler and s-parameter

NASA Astrophysics Data System (ADS)

Abedi-Varaki, M.

2018-02-01

In this paper, the effects of planar magnetostatic wiggler and s-parameter on the terahertz (THz) radiation generation through rippled plasma have been investigated. Efficient THz radiation generation by photo-mixing of tophat lasers for rippled density plasma in the presence of the wiggler field has been presented. Fundamental equations for the analysis of the non-linear current density and THz radiation generation by wiggler magnetostatic field have been derived. It is shown that for the higher order of the tophat lasers, the values of THz amplitude are greater. In fact, the higher order of the tophat lasers has a sharp gradient in the intensity of lasers, which leads to a stronger nonlinear ponderomotive force and, consequently, a stronger current density. In addition, it is seen that by increasing s-parameter, the normalized transverse profile becomes more focused near the axis of y. Furthermore, it is observed that the normalized laser efficiency has a decreasing trend with increasing normalized THz frequency for different values of the wiggler field. Also, it is shown that by employing a greater order of the tophat lasers and a stronger wiggler field, the efficiency of order of 30% can be achieved. Moreover, it is found that we can control focus and intensity of THz radiation emitted in rippled plasma by choosing the appropriate order of the tophat lasers and tuning of the wiggler field.

Detachable microsphere scalpel tips for potential use in ophthalmic surgery with the erbium:YAG laser.

PubMed

Hutchens, Thomas C; Darafsheh, Arash; Fardad, Amir; Antoszyk, Andrew N; Ying, Howard S; Astratov, Vasily N; Fried, Nathaniel M

2014-01-01

Vitreoretinal surgery is performed using mechanical dissection that sometimes results in iatrogenic complications, including vitreous hemorrhage, retinal breaks, incomplete membrane delamination, retinal distortion, microscopic damage, etc. An ultraprecise laser probe would be an ideal tool for cutting away pathologic membranes; however, the depth of surgery should be precisely controlled to protect the sensitive underlying retina. The ultraprecise surgical microprobe formed by chains of dielectric spheres for use with the erbium:YAG laser source (λ=2940  nm), with extremely short optical penetration depth in tissue, was optimized. Numerical modeling demonstrated a potential advantage of five-sphere focusing chains of sapphire spheres with index n=1.71 for ablating the tissue with self-limited depth around 10 to 20 μm. Novel detachable microsphere scalpel tips formed by chains of 300 μm sapphire (or ruby) spheres were tested on ophthalmic tissues, ex vivo. Detachable scalpel tips could allow for reusability of expensive mid-infrared trunk fibers between procedures, and offer more surgical customization by interchanging various scalpel tip configurations. An innovative method for aiming beam integration into the microsphere scalpel to improve the illumination of the surgical site was also shown. Single Er:YAG pulses of 0.2 mJ and 75-μs duration produced ablation craters in cornea epithelium for one, three, and five sphere structures with the latter generating the smallest crater depth (10 μm) with the least amount of thermal damage depth (30 μm). Detachable microsphere laser scalpel tips may allow surgeons better precision and safety compared to mechanical scalpels when operating on delicate or sensitive areas like the retina.

Subsurface plasma in beam of continuous CO2-laser

NASA Astrophysics Data System (ADS)

Danytsikov, Y. V.; Dymshakov, V. A.; Lebedev, F. V.; Pismennyy, V. D.; Ryazanov, A. V.

1986-03-01

Experiments performed at the Institute of Atomic Energy established the conditions for formation of subsurface plasma in substances by laser radiation and its characteristics. A quasi-continuous CO2 laser emitting square pulses of 0.1 to 1.0 ms duration and 1 to 10 kW power as well as a continuous CO2 laser served as radiation sources. Radiation was focused on spots 0.1 to 0.5 mm in diameter and maintained at levels ensuring constant power density during the interaction time, while the temperature of the target surface was measured continuously. Metals, graphite and dielectric materials were tested with laser action taking place in air N2 + O2 mixtures, Ar or He atmosphere under pressures of 0.01 to 1.0 atm. Data on radiation intensity thresholds for evaporation and plasma formation were obtained. On the basis of these thresholds, combined with data on energy balance and the temperature profile in plasma layers, a universal state diagram was constructed for subsurface plasma with nonquantified surface temperature and radiation intensity coordinates.

Hard tooth tissue removal by short and long Er:YAG or Er,Cr:YSGG mid-infrared laser radiation

NASA Astrophysics Data System (ADS)

Jelínková, H.; Dostálová, T.; Remeš, M.; Šulc, J.; Němec, M.; Fibrich, M.

2017-02-01

Hard dental tissue removal by laser radiation is an alternative treatment to conventional dental-drilling procedures. The advantages of this therapy are fast and localized treatment of hard dental tissue and painlessness. The most effective systems for those purposes are Er-lasers generating radiation at wavelengths of around 3 μm. The aim of this study was qualitative and quantitative examination of human dentin and ivory tissue removal by pulsed free-running (FR) and Q-switched (QSW) Er:YAG and Er,Cr:YSGG laser radiations. From the obtained results it follows that generally Er:YAG laser has lower threshold for the tissue removal in both FR and QSW regimes. Furthermore, the FR Er:YAG and Er,Cr:YSGG radiation can be effective for both dentin and ivory ablation and can prepare smooth cavities without side effects. The QSW regime is useful preferably for precise ablation of a starting tooth defect and for the part of the tooth very close to the gum. This regime is excellent for micro-preparation or for tooth treatment of children.

Interaction of laser beams with magnetized substance in a strong magnetic field

NASA Astrophysics Data System (ADS)

Kuzenov, V. V.

2018-03-01

Laser-driven magneto-inertial fusion assumed plasma and magnetic flux compression by quasisymmetric laser-driven implosion of magnetized target. We develop a 2D radiation magnetohydrodynamic code and a formulation for the one-fluid two-temperature equations for simulating compressible non-equilibrium magnetized target plasma. Laser system with pulse radiation with 10 ns duration is considered for numerical experiments. A numerical study of a scheme of magnetized laser-driven implosion in the external magnetic field is carried out.

Laser Safety Manual for DREO

DTIC Science & Technology

1993-11-01

milieu de travail securitaire dans les laboratoires de recherche utilisant de la radiation laser. L ’"American National Standard for the Safe Use of...d6fense nationale de poursuites l ~gales. i~i. I I EXECUTIVE SUMMARY Laser beams are currently used for some R&D activities at DREO. As laser radiation...par un appared as described in CFAO 66-4. must be strictly observed, laser peut provoquer des br-tilures de la reline et de la peau . Les mesures de

Laser ablation of dental tissues with picosecond pulses of 1.06-microm radiation transmitted through a hollow-core photonic-crystal fiber.

PubMed

Konorov, Stanislav O; Mitrokhin, Vladimir P; Fedotov, Andrei B; Sidorov-Biryukov, Dmitrii A; Beloglazov, Valentin I; Skibina, Nina B; Shcherbakov, Andrei V; Wintner, Ernst; Scalora, Michael; Zheltikov, Aleksei M

2004-04-10

Sequences of picosecond pulses of 1.06-microm Nd:YAG laser radiation with a total energy of approximately 2 mJ are transmitted through a hollow-core photonic-crystal fiber with a core diameter of approximately 14 microm and are focused onto a tooth's surface in vitro to ablate dental tissue. The hollow-core photonic-crystal fiber is shown to support the single-fundamental-mode regime for 1.06-microm laser radiation, serving as a spatial filter and allowing the laser beam's quality to be substantially improved. The same fiber is used to transmit emission from plasmas produced by laser pulses onto the tooth's surface in the backward direction for detection and optical diagnostics.

The development of laser surgery and medicine in China

NASA Astrophysics Data System (ADS)

Chen, Mingzhe

2005-07-01

The first Chinese ruby laser was created in 1961 and it was adopted for the retina coagulation experiment in 1965. Since 1970's, lasers had been widely applied clinically including the diseases suitable to physical therapy or acupuncture. The Chinese HpD was first produced in 1981 and first case of PDT was treated using Chinese HpD and Chinese lasers in the same year. Its success brought attention establishing a research group supported by the government in 1982. A nationwide systemic research project on PDT was then carried out. The step taken for PDT also accelerated the development of various fields of laser medicine and surgery. Laser treatments had been commonly adopted in the clinics and hospitals for the diseases of the superficial lesions and the lesions can be reached by the endoscopes non-invasively in 1980's. Since 1990's, the interventional laser therapies adopted mainly were percutaneous laser angioplasty, laser treatments through laparoscope, thoracoscope, arthroscope, neuro-endoscope etc. Ultrasound guided percutaneous laser heat coagulation for small hepatic cancer revealed good results and ultrasound guided percutaneous PDT for advanced large liver cancer revealed unexpected results after five years follow-up. At present: There are more long-term follow-up patients in the clinical trial; more advanced commercial available lasers and new techniques are adopted. Since the popularization of scanning electron microscope, laser scanning confocal microscope, laser induced auto-fluorescence system, high sensitivity fluorescence microscopic imaging system etc. in the laboratories, the basic studies can be more advanced and some times, the sub-cellular level can be reached; ultra-structure histo-morphology and gene studies are involved. In dermatology, Q-switched Alexandrite laser and other Q-switched lasers are used mainly for the treatment of skin pigmentation and vascular diseases; pulsed dye laser, ultra-pulsed CO2 laser are used in resurfacing, facial acne scar, osmidrosis etc. For ophthalmology, excimer laser are used for myopia or hyperopia; argon green laser, krypton yellow laser are adopted in coagulation for retinal detachment and neovascularization etc. Lasers are often used for the canaliculoplasty in the lacrimal canal. Low level lasers had been used very often on the acupuncture points and for many chronic diseases. Intravascular low level laser irradiation adopting semiconductor lasers and He-Ne laser were reported to use for comatose patients, schizophrenia, vascular dementia, Alzeimer"s disease and coronary disease. Reports from laboratory studies in the field of low level laser demonstrated the stimulation effect on the cells and immunology system; inhibitory effect on proliferation; it improved the biomedical data in hemorrheology; promoted the spinal motor nerve cell function, axonal regeneration; increased epidermal Langerhams cell to improve the antigen function, increased myocardial capillary permeability. Intra-coronary low power red laser irradiation assisted coronary interventional therapy showed its prevention effect on restenosis. Studies about the effects of various kinds of lasers, their wavelength, power densities and doses on various kinds of tissues were reported.

Formation and dynamics of a plasma in superstrong laser fields including radiative and quantum electrodynamics effects

NASA Astrophysics Data System (ADS)

Artemenko, I. I.; Golovanov, A. A.; Kostyukov, I. Yu.; Kukushkina, T. M.; Lebedev, V. S.; Nerush, E. N.; Samsonov, A. S.; Serebryakov, D. A.

2016-12-01

Studies of phenomena accompanying the interaction of superstrong electromagnetic fields with matter, in particular, the generation of an electron-positron plasma, acceleration of electrons and ions, and the generation of hard electromagnetic radiation are briefly reviewed. The possibility of using thin films to initiate quantum electrodynamics cascades in the field of converging laser pulses is analyzed. A model is developed to describe the formation of a plasma cavity behind a laser pulse in the transversely inhomogeneous plasma and the generation of betatron radiation by electrons accelerated in this cavity. Features of the generation of gamma radiation, as well as the effect of quantum electrodynamics effects on the acceleration of ions, at the interaction of intense laser pulses with solid targets are studied.

Terahertz emission driven by two-color laser pulses at various frequency ratios

NASA Astrophysics Data System (ADS)

Wang, W.-M.; Sheng, Z.-M.; Li, Y.-T.; Zhang, Y.; Zhang, J.

2017-08-01

We present a simulation study of terahertz radiation from a gas driven by two-color laser pulses in a broad range of frequency ratios ω1/ω0 . Our particle-in-cell simulation results show that there are three series with ω1/ω0=2 n , n +1 /2 , n ±1 /3 (n is a positive integer) for high-efficiency and stable radiation generation. The radiation strength basically decreases with the increasing ω1 and scales linearly with the laser wavelength. These rules are broken when ω1/ω0<1 and much stronger radiation may be generated at any ω1/ω0 . These results can be explained with a model based on gas ionization by two linear-superposition laser fields, rather than a multiwave mixing model.

Counterpropagating Radiative Shock Experiments on the Orion Laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki-Vidal, F.; Clayson, T.; Stehlé, C.

We present new experiments to study the formation of radiative shocks and the interaction between two counterpropagating radiative shocks. The experiments are performed at the Orion laser facility, which is used to drive shocks in xenon inside large aspect ratio gas cells. The collision between the two shocks and their respective radiative precursors, combined with the formation of inherently three-dimensional shocks, provides a novel platform particularly suited for the benchmarking of numerical codes. The dynamics of the shocks before and after the collision are investigated using point-projection x-ray backlighting while, simultaneously, the electron density in the radiative precursor was measuredmore » via optical laser interferometry. Modeling of the experiments using the 2D radiation hydrodynamic codes nym and petra shows very good agreement with the experimental results.« less

Counterpropagating Radiative Shock Experiments on the Orion Laser.

PubMed

Suzuki-Vidal, F; Clayson, T; Stehlé, C; Swadling, G F; Foster, J M; Skidmore, J; Graham, P; Burdiak, G C; Lebedev, S V; Chaulagain, U; Singh, R L; Gumbrell, E T; Patankar, S; Spindloe, C; Larour, J; Kozlova, M; Rodriguez, R; Gil, J M; Espinosa, G; Velarde, P; Danson, C

2017-08-04

We present new experiments to study the formation of radiative shocks and the interaction between two counterpropagating radiative shocks. The experiments are performed at the Orion laser facility, which is used to drive shocks in xenon inside large aspect ratio gas cells. The collision between the two shocks and their respective radiative precursors, combined with the formation of inherently three-dimensional shocks, provides a novel platform particularly suited for the benchmarking of numerical codes. The dynamics of the shocks before and after the collision are investigated using point-projection x-ray backlighting while, simultaneously, the electron density in the radiative precursor was measured via optical laser interferometry. Modeling of the experiments using the 2D radiation hydrodynamic codes nym and petra shows very good agreement with the experimental results.

Counterpropagating Radiative Shock Experiments on the Orion Laser

DOE PAGES

Suzuki-Vidal, F.; Clayson, T.; Stehlé, C.; ...

2017-08-02

We present new experiments to study the formation of radiative shocks and the interaction between two counterpropagating radiative shocks. The experiments are performed at the Orion laser facility, which is used to drive shocks in xenon inside large aspect ratio gas cells. The collision between the two shocks and their respective radiative precursors, combined with the formation of inherently three-dimensional shocks, provides a novel platform particularly suited for the benchmarking of numerical codes. The dynamics of the shocks before and after the collision are investigated using point-projection x-ray backlighting while, simultaneously, the electron density in the radiative precursor was measuredmore » via optical laser interferometry. Modeling of the experiments using the 2D radiation hydrodynamic codes nym and petra shows very good agreement with the experimental results.« less

Numerical analysis of experiments on the generation of shock waves in aluminium under indirect (X-ray) action on the Iskra-5 facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bondarenko, S V; Dolgoleva, G V; Novikova, E A

The dynamics of laser and X-ray radiation fields in experiments with cylindrical converter boxes (illuminators), which had earlier been carried out on the Iskra-5 laser facility (the second harmonic of iodine laser radiation, {lambda} = 0.66 {mu}m) was investigated in a sector approximation using the SND-LIRA numerical technique. In these experiments, the X-ray radiation temperature in the box was determined by measuring the velocity of the shock wave generated in the sample under investigation, which was located at the end of the cylindrical illuminator. Through simulations were made using the SND-LIRA code, which took into account the absorption of lasermore » driver radiation at the box walls, the production of quasithermal radiation, as well as the formation and propagation of the shock wave in the sample under investigation. An analysis of the experiments permits determining the electron thermal flux limiter f: for f = 0.03 it is possible to match the experimental scaling data for X-ray in-box radiation temperature to the data of our simulations. The shock velocities obtained from the simulations are also consistent with experimental data. In particular, in the experiment with six laser beams (and a laser energy E{sub L} = 1380 J introduced into the box) the velocity of the shock front (determined from the position of a laser mark) after passage through a 50-{mu}m thick base aluminium layer was equal to 35{+-}1.6 km s{sup -1}, and in simulations to 36 km s{sup -1}. In the experiment with four laser beams (for E{sub L} = 850 J) the shock velocity (measured from the difference of transit times through the base aluminium layer and an additional thin aluminium platelet) was equal to 30{+-}3.6 km s{sup -1}, and in simulations to 30 km s{sup -1}. (interaction of laser radiation with matter)« less

Simulation study of enhancing laser-driven multi-keV line-radiation through application of external magnetic fields

NASA Astrophysics Data System (ADS)

Kemp, G. Elijah; Colvin, J. D.; Fournier, K. B.; May, M. J.; Barrios, M. A.; Patel, M. V.; Koning, J. M.; Scott, H. A.; Marinak, M. M.

2015-11-01

Laser-driven, spectrally tailored, high-flux x-ray sources have been developed over the past decade for testing the radiation hardness of materials used in various civilian, space and military applications. The optimal electron temperatures for these x-ray sources occur around twice the desired photon energy. At the National Ignition Facility (NIF) laser, the available energy can produce plasmas with ~ 10keV electron temperatures which result in highly-efficient ~ 5keV radiation but less than optimal emission from the > 10keV sources. In this work, we present a possible venue for enhancing multi-keV x-ray emission on existing laser platforms through the application of an external magnetic field. Preliminary radiation-hydrodynamics calculations with Hydra suggest as much as 2 - 14 × increases in laser-to-x-ray conversion efficiency for 22 - 68keV K-shell sources are possible on the NIF laser - without any changes in laser-drive conditions - through the application of an external axial 50 T field. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

The effect of laser radiation on the diffraction of X-rays in crystals

NASA Astrophysics Data System (ADS)

Trushin, V. N.; Chuprunov, E. V.; Khokhlov, A. F.

1988-10-01

The effect of laser radiation on the intensity of the X-ray diffraction peaks of KDP, ADP, and CuSO4-5H2O crystals was studied experimentally. This intensity was found to increase as a function of the laser beam power. This result suggests that it is possible to use laser beams to control X-ray intensity in the crystals considered.

LASERS IN MEDICINE: Structure of matrices for the transformation of laser radiation by biofractals

NASA Astrophysics Data System (ADS)

Angel'skii, O. V.; Ushenko, A. G.; Arkhelyuk, A. D.; Ermolenko, S. B.; Burkovets, D. N.

1999-12-01

The changes in the state of polarisation of laser radiation transformed by biofractal objects are examined. The orientational angular structure of the matrix elements of the operator representing the optical properties of biofractals with different morphological structures (mineralised collagen fibres and myosin bundles) is investigated. An optical model for the description of fractal laser fields under the conditions of single light scattering is proposed.

Efficient diode-pumped Tm:KYW 1.9-μm microchip laser with 1 W cw output power.

PubMed

Gaponenko, Maxim; Kuleshov, Nikolay; Südmeyer, Thomas

2014-05-19

We report on a diode-pumped Tm:KYW microchip laser generating 1 W continuous-wave output power. The laser operates at a wavelength of 1.94 μm in the fundamental TEM(00) mode with 71% slope efficiency relative to the absorbed pump radiation and 59% slope efficiency relative to the incident pump radiation. The optical-to-optical laser efficiency is 43%.

Calculation of the gain of a self-launched high-density free-electron laser by using a newly confirmed law stated as the impossibility of free-electron net stimulated radiation and modal analysis based on plasma hydrodynamics

NASA Astrophysics Data System (ADS)

Kim, S. H.

2017-05-01

We reason based on the concept of stationary plasma fluctuation that in the free-electron laser (FEL), the Coulomb force from the surrounding electrons and the Ampérian force arising from the beam current do not disrupt the density-deviation mode driven by the laser field in cooperation with the magnetic wiggler. We adopt the synchronization principle that in the state of a stationary plasma density-wave and laser wave, all electrons arriving at the same position can emit laser photons all together only at t = NT + t o , where N is an integer and T is the laser period. We find that in the FEL, the incident laser radiation acts as a dummy field in net stimulated radiation. Using these findings and noticing a previously-recognized concept that the radiation power from an electron is given by Δ E/T, where Δ E is the amplitude of the net work done by the electron during T [1], we derive the laser gain of a self-launched FEL. The thusly derived gain is in excellent agreement with the measured gain.

Generation of shock waves and formation of craters in a solid material irradiated by a short laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gus'kov, Sergei Yu; Borodziuk, S; Kasperczuk, A

2004-11-30

The results of investigations are presented which are concerned with laser radiation absorption in a target, the plasma state of its ablated material, the energy transfer to the solid target material, the characteristics of the shock wave and craters on the target surface. The investigation involved irradiation of a planar target by a subnanosecond plasma-producing laser pulse. The experiments were carried out with massive aluminium targets using the PALS iodine laser, whose pulse duration (0.4 ns) was much shorter than the shock wave attenuation and on-target crater formation times (50-200 ns). The investigations were conducted for a laser radiation energymore » of 100 J at two wavelengths of 0.438 and 1.315 {mu}m. For a given pulse energy, the irradiation intensity was varied in a broad range (10{sup 13}-10{sup 16} W cm{sup -2}) by varying the radius of the laser beam. The efficiency of laser radiation-to-shock energy transfer was determined as a function of the intensity and wavelength of laser radiation; also determined were the characteristics of the plasma plume and the shock wave propagating in the solid target, including the experimental conditions under which two-dimensional effects are highly significant. (invited paper)« less

Reflectivity of the gyroid biophotonic crystals in the ventral wing scales of the Green Hairstreak butterfly, Callophrys rubi

PubMed Central

Michielsen, K.; De Raedt, H.; Stavenga, D. G.

2010-01-01

We present a comparison of the computer simulation data of gyroid nanostructures with optical measurements (reflectivity spectra and scattering diagrams) of ventral wing scales of the Green Hairstreak butterfly, Callophrys rubi. We demonstrate that the omnidirectional green colour arises from the gyroid cuticular structure grown in the domains of different orientation. We also show that this three-dimensional structure, operating as a biophotonic crystal, gives rise to various polarization effects. We briefly discuss the possible biological utility of the green coloration and polarization effects. PMID:19828506