Science.gov

Sample records for laser na morfologia

  1. Optically pumped Na/sub 2/ laser

    SciTech Connect

    Kanorskii, S.I.; Kaslin, V.M.; Yakushev, O.F.

    1980-10-01

    A pulsed copper vapor laser emitting the 578.2 nm line was used as the pump source in achieving stimulated emission as a result of the electronic A/sup 1/..sigma../sup +//sub u/ to X/sup 1/..sigma../sup +//sub g/ transitions in the Na/sub 2/ molecule in the spectral range 0.765 to 0.804 ..mu... The average power of all the emission lines was 10 mW when the pulsed pump power was 150 W and the efficiency of conversion of the optical pump energy was about 3%. The pulse repetition frequency was 3.3 kHz. Violet diffuse radiation of the Na/sub 2/ molecules, generated by pumping with the copper vapor laser, was observed. The superradiance regime was found for some of the lines.

  2. Laser trapping of {sup 21}Na atoms

    SciTech Connect

    Lu, Zheng-Tian

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  3. Laser vaporized Li2, Na2, K2, and LiNa molecules observed by cavity ring-down spectroscopy

    NASA Astrophysics Data System (ADS)

    Labazan, I.; Milošević, S.

    2003-09-01

    Laser ablation of solid lithium, sodium, potassium, and lithium-sodium alloy was performed using a 308-nm excimer laser at fluences close to 1 J cm-2. Frequency and time resolved A-X and B-X electronic transitions of 6,7Li2, Na2, LiNa and K2 respectively, were observed. Lithium atom, dimer velocities, and influence of the background gas on dimer content of the plume have been measured. The origin of dimers at high densities, with subthermal internal energy, is discussed.

  4. Room-temperature diode-pumped Yb, Na: PbF2 laser.

    PubMed

    Yin, Jigang; Hang, Yin; He, Xiaoming; Zhang, Lianhan; Zhao, Chengchun; Gong, Juan

    2012-01-01

    Growth, spectroscopic properties, and laser performance of Yb, Na:PbF(2) crystals have been investigated. With a 2 mol.% Yb(3+)-doped sample we obtained 2.65 W output power at 1045 nm for 7.5 W of incident power at 976 nm. The laser wavelength could be tuned from 1017 to 1078 nm, showing the great potential of Yb, Na:PbF(2) as an amplifier medium for femtosecond pulses. PMID:22212807

  5. Low-NA fiber laser pumps powered by high-brightness single emitters

    NASA Astrophysics Data System (ADS)

    Yanson, Dan; Levy, Moshe; Peleg, Ophir; Rappaport, Noam; Shamay, Moshe; Dahan, Nir; Klumel, Genady; Berk, Yuri; Baskin, Ilya

    2015-03-01

    Fiber laser manufacturers demand high-brightness laser diode pumps delivering optical pump energy in both a compact fiber core and narrow angular content. A pump delivery fiber of a 105 μm core and 0.22 numerical aperture (NA) is typically used, where the fiber NA is under-filled to ease the launch of laser diode emission into the fiber and make the fiber tolerant to bending. At SCD, we have developed high-brightness NEON multi-emitter fiber-coupled pump modules that deliver 50 W output from a 105 μm, 0.15 NA fiber enabling low-NA power delivery to a customer's fiber laser network. Brightness-enhanced single emitters are engineered with ultra-low divergence for compatibility with the low-NA delivery fiber, with the latest emitters delivering 14 W with 95% of the slow-axis energy contained within an NA of 0.09. The reduced slow-axis divergence is achieved with an optimized epitaxial design, where the peak optical intensity is reduced to both lessen filamentation within the laser cavity and reduce the power density on the output facet thus increasing the emitter reliability. The low mode filling of the fiber allows it to be coiled with diameters down to 70 mm at full operating power despite the small NA and further eliminates the need for mode-stripping at fiber combiners and splices downstream from our pump modules. 50W fiber pump products at 915, 950 and 975 nm wavelengths are presented, including a wavelengthstabilized version at 976 nm.

  6. Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam

    SciTech Connect

    Ching, C.H.; Bailey, J.E.; Lake, P.W.; Filuk, A.B.; Adams, R.G.; McKenney, J.

    1996-06-01

    This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.

  7. Optically pumped gas laser using electronic transitions in the NaRb molecule

    SciTech Connect

    Kaslin, V.M.; Yakushev, O.F.

    1983-12-01

    Laser superradiance was achieved for the first time as a result of an electronic transition in a diatomic heteronuclear molecule as a result of direct optical pumping. This superradiance was observed in the region of 670 nm due to a transition to the ground state X/sup 1/..sigma../sup +/ of the intermetallic alkali molecule NaRb pumped by radiation from a pulsed copper vapor laser (lambda = 510.6 nm).

  8. Pulsed, room-temperature operation of a tunable NaCl color-center laser

    SciTech Connect

    Culpepper, C.F.; Carrig, T.J.; Pinto, J.F.; Georgiou, E.; Pollock, C.R.

    1987-11-01

    A room-temperature, pulsed, color-center laser using OH/sup : /-doped NaCl crystals is reported. Crystals were transversely pumped by a Q-switched Nd:YAG laser at 1.06 ..mu..m and produced output energies of 8.6 mJ in 20-nsec pulses. The tuning range extended from 1.37 to 1.77 ..mu..m. During 40 h of operation (>10/sup 6/ pulses), a gradual power fading was observed. Laser action is tentatively ascribed to F/sub 2//sup //sup +/ centers.

  9. Lasers: Cw and Q-switched Nd:NaLa(MoO4)2 laser noncritical to the temperature drift of the diode pump laser wavelength

    NASA Astrophysics Data System (ADS)

    Ushakov, S. N.; Romanyuk, V. A.; Ryabochkina, P. A.; Shestakova, I. A.; Lis, Denis A.; Subbotin, Kirill A.; Shestakov, A. V.; Zharikov, Evgeny V.

    2010-08-01

    Lasing in Nd:NaLa(MoO4)2 crystals is obtained without stabilisation of the diode pump wavelength. A dependence of the cw laser power (at a wavelength of 1059 nm) on the pump diode temperature is found within a range of 10—458C. It is shown that the variations in the diode temperature within this region change the lasing efficiency no more than by 30%. In the passive Q-switching regime, the experiments were performed under both pulsed and cw pumping. Upon pulsed pumping, the laser energy was 16 μJ at the output pulse duration of 11 ns. The laser wavelength was 1059 nm, as well as in the case of cw operation. Upon cw pumping with a power of 1.5 W, laser pulses were obtained with an energy of 15 μJ.

  10. Simple design for singlemode high power CW fiber laser using multimode high NA fiber

    NASA Astrophysics Data System (ADS)

    Morasse, Bertrand; Chatigny, Stéphane; Desrosiers, Cynthia; Gagnon, Éric; Lapointe, Marc-André; de Sandro, Jean-Philippe

    2009-02-01

    A large number of high power CW fiber lasers described in the literature use large mode area (LMA) double cladding fibers. These fibers have large core and low core numerical aperture (NA) to limit the number of supported modes and are typically operated under coiling to eliminate higher order modes. We describe here multimode (MM) high NA ytterbium doped fibers used in single mode output high power laser/amplifier configuration. Efficient single mode amplification is realized in the multimode doped fiber by matching the fundamental mode of the doped fiber to the LP01 mode of the fiber Bragg grating (FBG) and by selecting the upper V-number value that limits the overlap of the LP01 to the higher order modes. We show that negligible mode coupling is realized in the doped fiber, which ensures a stable power output over external perturbation without the use of tapers. Fundamental mode operation is maintained at all time without coiling through the use of FBG written in a single mode fiber. We show that such fiber is inherently more photosensitive and easier to splice than LMA fiber. We demonstrate an efficient 75W singlemode CW fiber laser using this configuration and predict that the power scaling to the kW level can be achieved, the design being more practical and resistant to photodarkening compared to conventional low NA LMA fiber.

  11. Flower-like Na2O nanotip synthesis via femtosecond laser ablation of glass

    PubMed Central

    2012-01-01

    The current state-of-the-art in nanotip synthesis relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. To realize their ultimate potential, synthesized nanotips require simpler fabrication techniques that allow for control over their final nano-morphology. We present a unique, dry, catalyst-free, and ambient condition method for creating densely clustered, flower-like, sodium oxide (Na2O) nanotips with controllable tip widths. Femtosecond laser ablation of a soda-lime glass substrate at a megahertz repetition rate, with nitrogen flow, was employed to generate nanotips with base and head widths as small as 100 and 20 nm respectively, and lengths as long as 10 μm. Control of the nanotip widths was demonstrated via laser dwell time with longer dwell times producing denser clusters of thinner nanotips. Energy dispersive X-ray analysis reveals that nanotip composition is Na2O. A new formation mechanism is proposed, involving an electrostatic effect between ionized nitrogen and polar Na2O. The synthesized nanotips may potentially be used in antibacterial and hydrogen storage applications. PMID:22809176

  12. [Joint Analyses of Na2SO4 Solution by Laser Induced Breakdown Spectroscopy and Raman Spectroscopy].

    PubMed

    Guo, Jin-jia; Lu, Yuan; Liu, Chun-hao; Zheng, Rong-er

    2016-01-01

    Spectroscopic sensor is becoming an important issue for the deep-sea exploration due to the advantages of multi-specie, multi-phases and stand-off detection. Different approach have been developing in recent years based on LIBS (Laser Induced Breakdown Spectroscopy) and Raman spectroscopy since Raman-LIBS are complementary techniques with the similar components and the capability of molecular and elementary analysis. In this work, we built a LIBS-Raman system and detected Na2SO4 in aqueous solution to evaluate the potential ocean application. With the same laser, spectrometer and detector, a hybrid of Raman and LIBS system was developed to realize the detection of anions and cations in the seawater. The optics was composed by two parts. Raman channel and LIBS channel, and the signal was collected by a Y type optical fiber bundle. The signal from two channels was separated by imaging on different arrays of the CCD detector. The Raman spectra of SO4(2-) and LIBS spectra of Na was successfully detected simultaneously when the pulse energy was above 3.6 mJ. However, due to the strong bremsstrahlung radiation of LIBS, the signal to noise ratio of Raman was significantly decreased as the laser energy increasing. The results manifested the great potential of Raman-LIBS combination for the underwater detection. PMID:27228778

  13. High-brightness power delivery for fiber laser pumping: simulation and measurement of low-NA fiber guiding

    NASA Astrophysics Data System (ADS)

    Yanson, Dan; Levy, Moshe; Peleg, Ophir; Rappaport, Noam; Shamay, Moshe; Dahan, Nir; Klumel, Genady; Berk, Yuri; Baskin, Ilya

    2015-02-01

    Fiber laser manufacturers demand high-brightness laser diode pumps delivering optical pump energy in both a compact fiber core and narrow angular content. A pump delivery fiber of a 105 μm core and 0.22 numerical aperture (NA) is typically used, where the fiber NA is under-filled to ease the launch of laser diode emission into the fiber and make the fiber tolerant to bending. At SCD, we have developed multi-emitter fiber-coupled pump modules that deliver 50 W output from a 105 μm, 0.15 NA fiber at 915, 950 and 976 nm wavelengths enabling low-NA power delivery to a customer's fiber laser network. In this work, we address the challenges of coupling and propagating high optical powers from laser diode sources in weakly guiding step-index multimode fibers. We present simulations of light propagation inside the low-NA multimode fiber for different launch conditions and fiber bend diameters using a ray-racing tool and demonstrate how these affect the injection of light into cladding-bounded modes. The mode filling at launch and source NA directly limit the bend radius at which the fiber can be coiled. Experimentally, we measure the fiber bend loss using our 50 W fiber-coupled module and establish a critical bend diameter in agreement with our simulation results. We also employ thermal imaging to investigate fiber heating caused by macro-bends and angled cleaving. The low mode filling of the 0.15 NA fiber by our brightness-enhanced laser diodes allows it to be coiled with diameters down to 70 mm at full operating power despite the low NA and further eliminates the need for mode-stripping at fiber combiners and splices downstream from our pump modules.

  14. Performance of a new high-NA scanned-laser mask lithography system

    NASA Astrophysics Data System (ADS)

    Hamaker, Henry Chris; Buck, Peter D.

    1997-02-01

    To meet the challenges of peak production of 0.25-micrometer design rule photomasks, a new generation of scanned-laser reticle writers has been developed. Based on the architecture of the ALTA 3000, the resolution and critical dimension (CD) control have been improved by integrating a new 33X, 0.8- NA reduction lens. The spot size of 0.27-micrometer FWHM represents a reduction by a factor of 0.6 relative to preceding scanned-laser products, thereby providing excellent CD linearity down to 0.5 micrometer. High throughput is maintained by reducing the number of averaging passes from eight to four. The sharper aerial image produced by the system limits the CD biasing which may be obtained using dose adjustment, so a dry etch process with zero etch bias must be used for optimal performance. Early characterization of the system indicates performance consistent with that required for 0.25 micrometer integrated circuits.

  15. Dissipative soliton operation of a diode pumped Yb:NaY(WO₄)₂ laser.

    PubMed

    Ma, Jie; Wang, Jun; Shen, Deyuan; Yu, Haohai; Zhang, Huaijin; Tang, Dingyuan

    2015-12-14

    We report on the dissipative soliton operation of a diode pumped Yb:NaY(WO₄)₂ (Yb:NYW) solid-state laser. The dissipative solitons and their features as the net cavity group velocity dispersion is changed from the normal to the anomalous dispersion regime are experimentally investigated. Taking advantage of the dissipative soliton shaping of the mode-locked pulses we have generated stable near transform-limited pulses as short as 54 fs. To our knowledge, this is so far the shortest pulse directly obtained from the mode-locked Yb:NYW oscillator. PMID:26699021

  16. Doubly passively Q-switched Yb:NaY(WO4)2 laser with dual-wavelength phenomenon

    NASA Astrophysics Data System (ADS)

    Lan, Ruijun

    2015-06-01

    A diode pumped doubly passively Q-switched \\text{Yb:NaY}≤ft(\\text{W}{{\\text{O}}4}\\right)2/\\text{C}{{\\text{r}}4+}\\text{:YAG}/\\text{GaAs} laser was realized for the first time to our knowledge. Compared with the singly passively Q-switched \\text{Yb:NaY}≤ft(\\text{W}{{\\text{O}}4}\\right)2/\\text{C}{{\\text{r}}4+}\\text{:YAG} laser, this laser can generate a higher repetition rate, and more symmetric and shorter pulses. The highest repetition rate and shortest pulse width was measured to be 82 kHz and 6 ns. At certain pump power, 1022 and 1026 nm dual-wavelength lasers were obtained, and the mechanism of this phenomenon was discussed.

  17. Synthesis and characterization of AgCl nanoparticles produced by laser ablation of Ag in NaCl solution

    NASA Astrophysics Data System (ADS)

    Mahmoodi, Afsaneh; Shoorshinie, Seyedeh Zahra; Dorranian, Davoud

    2016-04-01

    In this work, the structural and optical properties of silver chloride nanoparticles produced by laser ablation of Ag plate in NaCl solution were investigated. Five different concentrations of NaCl solution were used as the ablation environment. The beam of a Q-switched Nd:YAG laser of 1064 nm wavelength and 7 ns pulse width was employed to irradiate the Ag target in NaCl solutions. Fluence of laser pulse was 1.5 J/cm2, and repetition rate was 5 Hz. Samples were prepared using 1500 pulses. Produced nanoparticles were characterized using UV-visible-NIR absorption, and transmission spectrum, transmission electron microscopy, scanning electron microscopy, X-ray diffraction pattern, photoluminescence spectrum, and dynamic light scattering method. Results show that laser ablation is a promising method to produce AgCl nanoparticles. Size of nanoparticles, their lattice structure, and bandgap energy as well as the production rate may be controlled by the concentration of NaCl in the ablation environment.

  18. Applications of spectral analysis and filter design in laser frequency locking for Na Doppler lidars

    NASA Astrophysics Data System (ADS)

    Smith, John A.; Chu, Xinzhao; Huang, Wentao; Tan, Bo

    2009-10-01

    A dye ring laser is stabilized to a D2a Doppler-free feature of sodium vapor using a LabVIEW®-based, phase-sensitive servo. Locking precision and stability, at better than +/-1 MHz, are suitable for Na lidar applications. This performance was achieved with improved digital filtering and new approaches to the problem. The inverse (type II) Chebyshev discrete filter employed demonstrates superior filtering and computational efficiency plus improved flexibility. New approaches include the determination of optimum modulation frequency, laser-tuning sensitivity, and bandwidth requirements via spectral analyses of the noise spectrum, derivative scan, and modulated spectrum. This practice guides a user in selecting the system operation parameters and negotiating the trade-offs involved when expanding the filter's passband. Allan deviation plots provide a quantitative description of the short- and long-term frequency excursions. A comparison of Allan deviation plots before and after locking shows a substantial improvement in stability throughout time scales from 0.10 to 10 s.

  19. High brightness laser-diode device emitting 500 W from a 200 μm/NA0.22 fiber

    NASA Astrophysics Data System (ADS)

    Junhong, Yu; Linhui, Guo; Hualing, Wu; Zhao, Wang; Hao, Tan; Songxin, Gao; Deyong, Wu; Kai, Zhang

    2016-06-01

    A practical method of achieving high brightness and high power fiber-coupled laser-diode device is demonstrated both by experiment and ZEMAX software simulation, which is obtained by technologies of precision beam collimation, free space beam combining and polarization beam combining based on mini-bar diode laser chip. Using this method, fiber-coupled laser-diode module output power from the multimode fiber with 200 μm core diameter and 0.22 numerical aperture (NA) could reach 528 W, equalizing brightness is 11.0 MW/(cm2 sr) and electro-optical efficiency (defined as fiber output power divided by voltage and current of the module) is 43.0%. By this method, much wider applications of fiber-coupled laser-diode are anticipated.

  20. High brightness laser-diode device emitting 160 watts from a 100 μm/NA 0.22 fiber.

    PubMed

    Yu, Junhong; Guo, Linui; Wu, Hualing; Wang, Zhao; Tan, Hao; Gao, Songxin; Wu, Deyong; Zhang, Kai

    2015-11-10

    A practical method of achieving a high-brightness and high-power fiber-coupled laser-diode device is demonstrated both by experiment and ZEMAX software simulation, which is obtained by a beam transformation system, free-space beam combining, and polarization beam combining based on a mini-bar laser-diode chip. Using this method, fiber-coupled laser-diode module output power from the multimode fiber with 100 μm core diameter and 0.22 numerical aperture (NA) could reach 174 W, with equalizing brightness of 14.2  MW/(cm2·sr). By this method, much wider applications of fiber-coupled laser-diodes are anticipated. PMID:26560762

  1. Structural, spectroscopic, and tunable laser properties of Yb3+ -doped NaGd(WO4)2

    NASA Astrophysics Data System (ADS)

    Cascales, C.; Serrano, M. D.; Esteban-Betegón, F.; Zaldo, C.; Peters, R.; Petermann, K.; Huber, G.; Ackermann, L.; Rytz, D.; Dupré, C.; Rico, M.; Liu, J.; Griebner, U.; Petrov, V.

    2006-11-01

    Single crystals of Yb3+ -doped NaGd(WO4)2 with up to 20mol% ytterbium content have been grown by the Czochralski technique in air or in N2+O2 atmosphere and cooled to room temperature at different rates (4-250°C/h) . Only the noncentrosymmetric tetragonal space group I4¯ accounts for all reflections observed in the single crystal x-ray diffraction analysis. The distortion of this symmetry with respect to the centrosymmetric tetragonal space group I41/a is much lower for crystals cooled at a fast rate. Na+ , Gd3+ , and Yb3+ ions share the two nonequivalent 2b and 2d sites of the I4¯ structure, but Yb3+ (and Gd3+ ) ions are found preferentially in the 2b site. Optical spectroscopy at low (5K) temperature provides additional evidence of the existence of these two sites contributing to the line broadening. The comparison with the F7/22(n) and F5/22(n') Stark energy levels calculated using the crystallographic Yb-O bond distances allows to correlate the experimental optical bands with the 2b and 2d sites. As a novel uniaxial laser host for Yb3+ , NaGd(WO4)2 is characterized also with respect to its transparency, band-edge, refractive indices, and main optical phonons. Continuous-wave Yb3+ -laser operation is studied at room temperature both under Ti:sapphire and diode laser pumping. A maximum slope efficiency of 77% with respect to the absorbed power is achieved for the π polarization by Ti:sapphire laser pumping in a three-mirror cavity with Brewster geometry. The emission is tunable in the 1014-1079nm spectral range with an intracavity Lyot filter. Passive mode locking of this laser produces 120fs long pulses at 1037.5nm with an average power of 360mW at ≈97MHz repetition rate. Using uncoated samples of Yb:NaGd(WO4)2 at normal incidence in simple two-mirror cavities, output powers as high as 1.45W and slope efficiencies as high as 51% are achieved with different diode laser pump sources.

  2. Lasers.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1981-01-01

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

  3. Resonant infrared laser-induced desorption of methane condensed on NaCl(100): isotope mixture experiments.

    PubMed

    Redlich, Britta; Zacharias, Helmut; Meijer, Gerard; von Helden, Gert

    2006-01-28

    Resonantly enhanced infrared laser-induced desorption of methane condensed on a single-crystal NaCl(100) surface is observed after excitation with the widely tunable infrared laser output of the free-electron laser at the free-electron laser for infrared experiments facility using mass spectroscopic detection and time-of-flight analysis. Desorption of methane is observed only when the exciting light is in resonance with an internal vibrational mode of the molecule. Different intramolecular modes of the three methane isotopologues under study--CH(4), CD(4), and CD(3)H--are excited; the degenerate deformation mode nu(4) is observed for CH(4) and CD(4) at 7.69 and 10.11 microm, respectively, as well as the nu(2) and nu(4) modes of CD(3)H at 7.79, 9.75, and 9.98 microm. The desorption signals for the pure layers of these different methane isotopologues as well as for different mixtures of two of these are investigated as a function of the infrared wavelength and the laser fluence. The desorption behavior for pure and mixed layers is compared and the underlying desorption mechanism is discussed. PMID:16460197

  4. Fluorescence and laser photon counting: measurements of epithelial [Ca2+]i or [Na+]i with ciliary beat frequency.

    PubMed

    Mao, H; Wong, L B

    1998-01-01

    We describe a system we developed that enabled simultaneous measurements of either epithelial calcium ion concentration ([Ca2+]i) or sodium ion concentration ([Na+]i) with the ciliary beat frequency (CBF) in native ciliated epithelia using either Fura-2 (AM) or SBFI (AM) ratiometric fluorescence photon counting along with nonstationary laser light scattering. Studies were performed using native epithelial tissues obtained from ovine tracheae. The dynamic range of the laser light-scattering system was determined by a simulated light "beating" experiment. The nonstationary CBF was demonstrated by the time-frequency analysis of the raw photon count sequences of backscattered heterodyne photons from cultured and native epithelia. Calibrations of calcium and sodium ion concentrations were performed using the respective Fura-2 and SBFI impermanent salts as well as in native epithelia. The cumulative responses of 10(-6), 10(-5), and 10(-4) M nifedipine on [Ca2+]i together with the CBF as well as the cumulative responses of 10(-5), 10(-4), and 10(-3) M amiloride on [Na+]i together with the CBF were also determined. Nifedipine decreased [Ca2+]i but had no effect on CBF. Amiloride decreased [Na+]i and CBF. Stimulation of CBF corresponded with either an increase of [Na+]i or an increase of [Ca2+]i. Decreases of [Na+]i or substantial decreases of [Ca2+]i were associated with decreases in the CBF. These data demonstrate the utility of this system for investigating the regulatory mechanisms of intracellular ions dynamics and the CBF in native epithelia. PMID:9662158

  5. Alterações Induzidas Pelo Exercício no Número, Função e Morfologia de Monócitos de Ratos

    PubMed Central

    GUERESCHI, MARCIA G.; PRESTES, JONATO; DONATTO, FELIPE F.; DIAS, RODRIGO; FROLLINI, ANELENA B.; FERREIRA, CLÍLTON KO.; CAVAGLIERI, CLAUDIA R.; PALANCH, ADRIANNE C.

    2008-01-01

    O propósito desse estudo foi verificar as alterações histofisiológicas em monócitos e macrófagos induzidas por curtos períodos de exercícios. Ratos Wistar (idade = 2 meses, peso corporal = 200g) foram divididos em sete grupos (n=6 cada): controle sedentário (C), grupos exercitados (natação) na intensidade leve por 5 (5L), 10 (10L) e 15 minutos (15L), e grupos exercitados em intensidade moderada por 5 (5M), 10 (10M) e 15 minutes (15M). Na intensidade moderada os animais carregaram uma carga de 5% do peso corporal dos mesmos em seus respectivos dorsos. Os monócitos sangüíneos foram avaliados quanto à quantidade e morfologia e os macrófagos peritoneais foram analisados quanto à quantidade e atividade fagocitária. Os dados foram analisados usando ANOVA e Tukey’s post hoc test (p ≤ 0,05). Os grupos de intensidade leve e 5M apresentaram aumento nos níveis dos monócitos quando comparados com o controle. Foi observado aumento na área celular dos monócitos para os grupos 5L, 10L, 5M e 10M; a área nuclear aumentou para os grupos 10L, 5M e 10M em comparação com o controle. Houve aumento nos macrófagos peritoneais para os grupos 15L, 10M, 15M e diminuição no grupo 5M. A capacidade fagocitária dos macrófagos aumentou nos grupos de intensidade leve e para o grupo 10M. O exercício realizado por curtos períodos modulou o número e função dos macrófagos, assim como o número e morfologia dos monócitos, sendo tais alterações dependentes da intensidade. A soma das respostas agudas observadas nesse estudo pode exercer um efeito protetor contra doenças, podendo ser utilizada para a melhora da saúde e qualidade de vida.

  6. Thermal Characterization, Crystal Field Analysis and In-Band Pumped Laser Performance of Er Doped NaY(WO4)2 Disordered Laser Crystals

    PubMed Central

    Serrano, María Dolores; Cascales, Concepción; Han, Xiumei; Zaldo, Carlos; Jezowski, Andrzej; Stachowiak, Piotr; Ter-Gabrielyan, Nikolay; Fromzel, Viktor; Dubinskii, Mark

    2013-01-01

    Undoped and Er-doped NaY(WO4)2 disordered single crystals have been grown by the Czochralski technique. The specific heat and thermal conductivity (κ) of these crystals have been characterized from T = 4 K to 700 K and 360 K, respectively. It is shown that κ exhibits anisotropy characteristic of single crystals as well as a κ(T) behavior observed in glasses, with a saturation mean free phonon path of 3.6 Å and 4.5 Å for propagation along a and c crystal axes, respectively. The relative energy positions and irreducible representations of Stark Er3+ levels up to 4G7/2 multiplet have been determined by the combination of experimental low (<10 K) temperature optical absorption and photoluminescence measurements and simulations with a single-electron Hamiltonian including both free-ion and crystal field interactions. Absorption, emission and gain cross sections of the 4I13/2↔4I15/2 laser related transition have been determined at 77 K. The 4I13/2 Er3+ lifetime (τ) was measured in the temperature range of 77–300 K, and was found to change from τ (77K) ≈ 4.5 ms to τ (300K) ≈ 3.5 ms. Laser operation is demonstrated at 77 K and 300 K by resonantly pumping the 4I13/2 multiplet at λ≈1500 nm with a broadband (FWHM≈20 nm) diode laser source perfectly matching the 77 K crystal 4I15/2 → 4I13/2 absorption profile. At 77 K as much as 5.5 W of output power were obtained in π-polarized configuration with a slope efficiency versus absorbed pump power of 57%, the free running laser wavelength in air was λ≈1611 nm with the laser output bandwidth of 3.5 nm. The laser emission was tunable over 30.7 nm, from 1590.7 nm to 1621.4 nm, for the same π-polarized configuration. PMID:23555664

  7. High-NA high-throughput scanner compatible 2-kHz KrF excimer laser for DUV lithography

    NASA Astrophysics Data System (ADS)

    Nakarai, Hiroaki; Hisanaga, Naoto; Suzuki, Natsushi; Matsunaga, Takeshi; Asayama, Takeshi; Akita, Jun; Igarashi, Toru; Ariga, Tatsuya; Bushida, Satoru; Enami, Tatsuo; Nodomi, Ryoichi; Takabayashi, Yuichi; Sakanishi, Syouich; Suzuki, Takashi; Tomaru, Hitoshi; Nakao, Kiyoharu

    2000-07-01

    We have succeeded in the development of an excimer laser with ultra narrow bandwidth applicable to high N.A. scanners targeting on the 0.13micrometers -design rule. Key word of our solution for 0.13micrometers -design rule was 'extended technologies of currently available KrF excimer laser unit. As the result we could shorten development time remarkably. The narrower the laser spectrum, the less the influence of chromatic aberration on exposure projection lens; this is a well-known fact. We have developed the technologies to achieve spectral bandwidths less than 0.5pm, 20 percent narrower than our current model G20K. In order to attain this number, the major design change was made on line narrowing module, which was redesigned to minimize the dispersion of wavelength element. In addition gas condition was fine-tuned for the new line narrowing module. Integrated energy stability has been improved within +/- 0.35 percent with 35 pulses window by the introduction of a high efficiency pules power module and a faster gas circulation system. The rest of oscillation performances and durability equate with the base model G20K. The intelligent gas control system extended gas exchange interval up to 200 million pulses or 7 days. The G20K already passed through 10 billion-pulse test. Total energy loss was within 4mJ which is small enough to be compensated by gas injection and voltage change; it is a unique compensation system of Komatsu.

  8. Article on Trident Laser Facility for NA-11 Stockpile Stewardship Quarterly

    SciTech Connect

    Barnes, Cris W.

    2012-08-13

    The Trident Intermediate-Scale Laser Facility at Los Alamos National Laboratory is an extremely versatile Nd:glass laser system dedicated to high energy density laboratory physics and weapons physics research and fundamental laser-matter interactions. Trident is a three-beam, 200 J/beam at the second harmonic for glass (527 nm wavelength), facility with tremendous flexibility and high beam quality. Pulse durations varying over 6 orders of magnitude, from 0.5 picoseconds to 1.0 microsecs, can be directed to either of two different target chambers with changeable illumination geometries, including the ability to achieve near-diffraction limited focus. This provides a unique range of capability at one facility from sub-picosecond pulses (and high-intensity laser science) to nanosecond pulses (and LPI physics relevant to ICF) to microsecond pulses (and driving flyer plates for supported shock dynamic materials science.) When in short-pulse mode (less than picosecond pulse), a single beam can provide up to 200 TW of power with uniquely controllable and measured pre-pulse contrast of 10 orders of magnitude. A recent external capability review at Los Alamos concluded that 'Trident is generating excellent, cutting edge science and is a leading intermediate scale laser system worldwide.'

  9. Giant enhancement of upconversion in ultra-small Er3+/Yb3+:NaYF4 nanoparticles via laser annealing

    NASA Astrophysics Data System (ADS)

    Bednarkiewicz, A.; Wawrzynczyk, D.; Gagor, A.; Kepinski, L.; Kurnatowska, M.; Krajczyk, L.; Nyk, M.; Samoc, M.; Strek, W.

    2012-04-01

    Most of the synthesis routes of lanthanide-doped phosphors involve thermal processing which results in nanocrystallite growth, stabilization of the crystal structure and augmentation of luminescence intensity. It is of great interest to be able to transform the sample in a spatially localized manner, which may lead to many applications like 2D and 3D data storage, anti-counterfeiting protection, novel design bio-sensors and, potentially, to fabrication of metamaterials, 3D photonic crystals or plasmonic devices. Here we demonstrate irreversible spatially confined infrared-laser-induced annealing (LIA) achieved in a thin layer of dried colloidal solution of ultra-small ˜8 nm NaYF4 nanocrystals (NCs) co-doped with 2% Er3+ and 20% Yb3+ ions under a localized tightly focused beam from a continuous wave 976 nm medium power laser diode excitation. The LIA results from self-heating due to non-radiative relaxation accompanying the NIR laser energy upconversion in lanthanide ions. We notice that localized LIA appears at optical power densities as low as 15.5 kW cm-2 (˜354 ± 29 mW) threshold in spots of 54 ± 3 µm diameter obtained with a 10 × microscope objective. In the course of detailed studies, a complete recrystallization to different phases and giant 2-3 order enhancement in luminescence yield is found. Our results are highly encouraging and let us conclude that the upconverting ultra-small lanthanide-doped nanophosphors are particularly promising for direct laser writing applications.

  10. Thermoelectric conversion via laser-induced voltage in highly textured polycrystalline Na{sub x}CoO{sub 2} ceramic

    SciTech Connect

    Yan, G. W.; Wang, Y.; Zhang, H.; Yu, L.; Zhang, P. X.; Habermeier, H.-U.

    2011-11-15

    We have studied and analyzed the laser-induced voltage effect in highly c-axis-oriented polycrystalline Na{sub x}CoO{sub 2}. The textured and layered stacking Na{sub x}CoO{sub 2} (x {approx} 0.7) bulks were prepared by a solid-state reaction process. Under the irradiation on Na{sub 0.67}CoO{sub 2} bulk surface with pulsed laser ({lambda} = 248 nm), the induced voltage signals were observed on the inclined surface with rise time 30 ns-43 ns and peak voltage 200 mV-500 mV; the voltage peak values show a linear dependence of laser energy densities. The crystal grains orientation plays a critical role in voltage peak value whether in film or texture bulk. The transverse voltage signal brings the information of thermoelectric anisotropy. In Na{sub x}CoO{sub 2} band structure, the Fermi surface is different in the ab plane and along the c axis, leading to anisotropy of Seebeck coefficient. Additionally, the artificial structure of the inclined surface for highly textured bulk enables us to obtain a transverse voltage on inclined surface. These results demonstrated the layered textured bulk has potential applications in waste-heat conversion via transverse thermoelectric effect.

  11. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of {sup 21}Na with improved laser trapping techniques

    SciTech Connect

    Rowe, Mary A.

    1999-05-24

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive {sup 21}Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88in cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of {sup 21}Na to the experiment. Efficient manipulation of the {sup 21}Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of {sup 21}Na. She measured the 3S{sub 1/2}(F=1,m=0)-3S{sub 1/2}(F=2,m=0) atomic level splitting of {sup 21}Na to be 1,906,471,870{+-}200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms.

  12. Quantum electronic properties of the Na/sub 3/Ga/sub 2/Li/sub 3/F/sub 12/:Cr/sup 3+/ laser

    SciTech Connect

    Caird, J.A.; Payne, S.A.; Staver, P.R.; Ramponi, A.J.; Chase, L.L.; Krupke, W.F.

    1988-06-01

    Few of the existing Cr/sup 3+/ vibronic lasers have achieved the slope efficiency and tuning range expected based on their known spectroscopic properties. In order to discover the causes of this behavior, the performance of chromium doped gallium fluoride garnet, Na/sub 3/Ga/sub 2/Li/sub 3/F/sub 12/:Cr/sup 3+/, as a laser material has been investigated experimentally. The data reported here include absorption and emission spectra, emission rates, quantum efficiency, laser wavelength tuning range, laser output slope efficiencies, and excited state absorption spectra. Similar properties of the alexandrite laser material were studied for comparison. The results indicate that the performance of the gallium fluoride garnet laser is severely limited by Cr/sup 3+/ excited state absorption (ESA). A model is presented to account for the unexpected nature of the ESA, which appears to be a common problem for all Cr/sup 3+/ vibronic lasers. Criteria are suggested for choosing Cr/sup 3+/ hosts for which the effects of ESA will be minimized.

  13. Q-switching of an alexandrite laser by (F/sup +//sub 2/)/sub A/ color centers in NaF

    SciTech Connect

    Kolyago, S.S.; Matrosov, V.N.; Pestryakov, E.V.; Trunov, V.I.; Gusev, Y.L.; Shkadarevich, A.P.

    1985-12-01

    Investigations were made of the characteristics of (F/sup +//sub 2/)/sub A/ color centers in NaF and of the spectral and lasing properties of an alexandrite laser Q-switched by centers of this type. When a Lyot filter and a switch having an initial transmission of approx.70% were used in this laser resonator, pulses of 80--100 nsec duration with a spectral width of approx.0.1 cm/sup -1/ and a tuning range of 0.73--0.783 ..mu.. were obtained under pulse-periodic conditions (12.5 Hz).

  14. Interaction of Wide-Band-Gap Single Crystals with 248-nm Excimer Laser Irradiation: X. Laser-Induced Near-Surface Absorption in Single-Crystal NaCl

    SciTech Connect

    Nwe, K H.; Langford, Stephen C.; Dickinson, J T.; Hess, Wayne P.

    2005-02-15

    Ultraviolet laser-induced desorption of neutral atoms and molecules from nominally transparent, ionic materials can yield particle velocities consistent with surface temperatures of a few thousand Kelvin, even in the absence of visible surface damage. The origin of the laser required for this surface heating has been often overlooked. In this work, we report simultaneous neutral emission and laser transmission measurements on single crystal NaCl exposed to 248-nm excimer laser radiation. As much as 20% of the incident radiation at 248 nm must be absorbed in the near surface region to account for the observed particle velocities. We show that the laser absorption grows from low values over several pulses and saturates at values sufficient to account for the surface temperatures required to explain the observed particle velocity distributions. The growth of absorption in these early pulses is accompanied by a corresponding increase in the emission intensities. Diffuse reflectance spectra acquired after exposure suggest that near surface V-type centers are responsible for most of the absorption at 248 nm in single crystal NaCl.

  15. Interaction of wide-band-gap single crystals with 248-nm excimer laser irradiation. X. Laser-induced near-surface absorption in single-crystal NaCl

    SciTech Connect

    Nwe, K.H.; Langford, S.C.; Dickinson, J.T.; Hess, W.P.

    2005-02-15

    Ultraviolet laser-induced desorption of neutral atoms and molecules from nominally transparent, ionic materials can yield particle velocities consistent with surface temperatures of a few thousand kelvin even in the absence of visible surface damage. The origin of the laser absorption required for this surface heating has been often overlooked. In this work, we report simultaneous neutral emission and laser transmission measurements on single-crystal NaCl exposed to 248-nm excimer laser radiation. As much as 20% of the incident radiation at 248 nm must be absorbed in the near-surface region to account for the observed particle velocities. We show that the laser absorption grows from low values over several pulses and saturates at values sufficient to account for the surface temperatures required to explain the observed particle velocity distributions. The growth of absorption in these early pulses is accompanied by a corresponding increase in the emission intensities. The diffuse reflectance spectra acquired after exposure suggest that near-surface V-type centers are responsible for most of the absorption at 248 nm in single-crystal NaCl.

  16. Deep, high contrast microscopic cell imaging using three-photon luminescence of β-(NaYF4:Er3+/NaYF4) nanoprobe excited by 1480-nm CW laser of only 1.5-mW

    PubMed Central

    Liu, Jing; Wu, Ruitao; Li, Nana; Zhang, Xin; Zhan, Qiuqiang; He, Sailing

    2015-01-01

    It is challenging to achieve deep microscopic imaging for the strong scattering in biotissue. An efficient three-photon luminescence can effectively increase the penetration depth. Here we report that β-NaYF4: Er3+/NaYF4 UCNPs were excited by a 1480-nm CW-laser and emitted 543/653-nm light through a three-photon process. With the merit of the hexagonal crystal phase, sub-milliwatt laser power was utilized to excite the UCNP-probed cells to minimize the heating effect. The polymer-coated UCNPs were shown to be harmless to cells. The deep, high contrast in vitro microscopic imaging was implemented through an artificial phantom. Imaging depth of 800 μm was achieved using only 1.5 mW excitation and a 0.7 NA objective. The green/red emission intensities ratio after penetrating the phantom was studied, indicating that longer emission wavelength is preferred for deep multiphoton microscopy. The proposed and demonstrated β-UCNPs would have great potential in three-photon microscopy. PMID:26137385

  17. Deep, high contrast microscopic cell imaging using three-photon luminescence of β-(NaYF4:Er(3+)/NaYF4) nanoprobe excited by 1480-nm CW laser of only 1.5-mW.

    PubMed

    Liu, Jing; Wu, Ruitao; Li, Nana; Zhang, Xin; Zhan, Qiuqiang; He, Sailing

    2015-05-01

    It is challenging to achieve deep microscopic imaging for the strong scattering in biotissue. An efficient three-photon luminescence can effectively increase the penetration depth. Here we report that β-NaYF4: Er(3+)/NaYF4 UCNPs were excited by a 1480-nm CW-laser and emitted 543/653-nm light through a three-photon process. With the merit of the hexagonal crystal phase, sub-milliwatt laser power was utilized to excite the UCNP-probed cells to minimize the heating effect. The polymer-coated UCNPs were shown to be harmless to cells. The deep, high contrast in vitro microscopic imaging was implemented through an artificial phantom. Imaging depth of 800 μm was achieved using only 1.5 mW excitation and a 0.7 NA objective. The green/red emission intensities ratio after penetrating the phantom was studied, indicating that longer emission wavelength is preferred for deep multiphoton microscopy. The proposed and demonstrated β-UCNPs would have great potential in three-photon microscopy. PMID:26137385

  18. Fine tunable red-green upconversion luminescence from glass ceramic containing 5%Er{sup 3+}:NaYF{sub 4} nanocrystals under excitation of two near infrared femtosecond lasers

    SciTech Connect

    Shang, Xiaoying; Cheng, Wenjing; Zhou, Kan; Ma, Jing; Feng, Donghai; Zhang, Shian; Sun, Zhenrong; Jia, Tianqing; Chen, Ping; Qiu, Jianrong

    2014-08-14

    In this paper, we report fine tunable red-green upconversion luminescence of glass ceramic containing 5%Er{sup 3+}: NaYF{sub 4} nanocrystals excited simultaneously by two near infrared femtosecond lasers. When the glass ceramic was irradiated by 800 nm femtosecond laser, weak red emission centered at 670 nm was detected. Bright red light was observed when the fs laser wavelength was tuned to 1490 nm. However, when excited by the two fs lasers simultaneously, the sample emitted bright green light centered at 550 nm, while the red light kept the same intensity. The dependences of the red and the green light intensities on the two pump lasers are much different, which enables us to manipulate the color emission by adjusting the two pump laser intensities, respectively. We present a theoretical model of Er{sup 3+} ions interacting with two fs laser fields, and explain well the experimental results.

  19. Dynamics of electron excitations in densely packed plasmonic Ag/Na3AlF6 nanostructures under pulsed laser action

    NASA Astrophysics Data System (ADS)

    Buganov, O. V.; Zamkovets, A. D.; Ponyavina, A. N.; Tikhomirov, S. A.; Baran, L. V.

    2011-11-01

    Differential transient absorption spectra have been studied for planar densely packed Ag/Na3AlF6 nanostructures under ultrashort laser pulse excitation. The nanostructures were fabricated by sequential thermal evaporation of cryolite (Na3AlF6) and silver in vacuo onto glass and quartz substrates. A nonmonotonic variation in relaxation times of induced changes in a surface plasmon resonance band was observed with an increase in the metal surface density that resulted in nanoparticle size growth and structural modification of the densely packed layer. The tendency of the relaxation times to vary nonmonotonically is explained by both features of intrinsic size effects and electron-tunneling processes in plasmonic densely packed nanostructures of various topologies.

  20. INTERACTION OF LASER RADIATION WITH MATTER: Influence of Ca and Pb impurities on the bulk optical strength of ultrapure NaCl and KCl crystals

    NASA Astrophysics Data System (ADS)

    Vinogradov, An V.; Voszka, R.; Kovalev, Valerii I.; Faĭzullov, F. S.; Janszky, J.

    1987-06-01

    A significant increase (by a factor of about 3) of the bulk damage threshold in the case of interaction of CO2 laser radiation pulses with ultrapure NaCl and KCl crystals grown in a reactive atmosphere was observed on introduction of divalent metal ions Ca and Pb in concentrations of 10-5-10-6 mol/mol. Impurities were introduced in concentrations of 10-8-10-3 and 2×10-7-10-4 mol/mol into the melts of KCl and NaCl, respectively. The concentration of other impurities (including OH) did not exceed ~10-6 mol/mol. A physical model was developed to account for the observed dependence on the basis of an analogy between a system of colloidal particles and F centers in a crystal and a liquid-vapor system.

  1. Interaction of wide-band-gap single crystals with 248-nm excimer laser irradiation. IX. Photoinduced atomic desorption from cleaved NaCl(100) surfaces

    SciTech Connect

    Nwe, K.H.; Langford, S.C.; Dickinson, J.T.

    2005-07-01

    Neutral atomic sodium and chlorine emissions from cleaved, single-crystal NaCl(100) surfaces due to pulsed, 248-nm excimer laser irradiation have been characterized by time-resolved, quadrupole mass spectroscopy. At laser fluences below the threshold for optical breakdown, the resulting time-of-flight signals are consistent with particles emitted in thermal equilibrium with a laser-heated surface. Activation energy measurements made by varying the substrate temperature are consistent with F-H pair formation under UV excitation. By varying the laser fluence and estimating the effective surface temperature from the time-of-flight signals, additional activation energy measurements were made. The corresponding rate-limiting step is attributed to a thermally assisted, photoelectronic process involving atomic steps. Atomic force microscope images of surfaces irradiated at low fluences show monolayer islands that are created by the aggregation of material desorbed from steps. At somewhat higher fluences, monolayer pits due to F-center aggregation are also observed.

  2. Laser cooling of the vibrational motion of Na{sub 2} combining the effects of zero-width resonances and exceptional points

    SciTech Connect

    Lefebvre, R.; Jaouadi, A.; Dulieu, O.; Atabek, O.

    2011-10-15

    We propose various scenarios for molecular vibrational cooling combining the effects of two kinds of resonance states occurring during the photodissociation of Na{sub 2} taken as an illustrative example. Such resonances result from an appropriate sampling of laser parameters (wavelength and intensity): (a) For particular choices of intensity and wavelength, two resonance energies can be brought to complete coalescence, with their positions and widths becoming equal and leading to a so-called exceptional point (EP) in the parameter plane. Advantage can be taken from such points for very selective laser-controlled vibrational transfer strategies. (b) For specific intensities, far beyond the perturbation regime, some resonances can have a zero width (infinite lifetime). They are referred to as a zero-width resonance (ZWR) and may be used for vibrational purification purposes. We show how appropriately shaped, experimentally reachable laser pulses, encircling EPs or inducing ZWRs, may be used for a thorough and comprehensive control aiming at population transfer or purification schemes, which, starting from an initial field-free vibrational distribution, ends up in the ground vibrational level.

  3. Giant enhancement of upconversion in ultra-small Er³⁺/Yb³⁺:NaYF₄ nanoparticles via laser annealing.

    PubMed

    Bednarkiewicz, A; Wawrzynczyk, D; Gagor, A; Kepinski, L; Kurnatowska, M; Krajczyk, L; Nyk, M; Samoc, M; Strek, W

    2012-04-13

    Most of the synthesis routes of lanthanide-doped phosphors involve thermal processing which results in nanocrystallite growth, stabilization of the crystal structure and augmentation of luminescence intensity. It is of great interest to be able to transform the sample in a spatially localized manner, which may lead to many applications like 2D and 3D data storage, anti-counterfeiting protection, novel design bio-sensors and, potentially, to fabrication of metamaterials, 3D photonic crystals or plasmonic devices. Here we demonstrate irreversible spatially confined infrared-laser-induced annealing (LIA) achieved in a thin layer of dried colloidal solution of ultra-small ∼8 nm NaYF₄ nanocrystals (NCs) co-doped with 2% Er³⁺ and 20% Yb³⁺ ions under a localized tightly focused beam from a continuous wave 976 nm medium power laser diode excitation. The LIA results from self-heating due to non-radiative relaxation accompanying the NIR laser energy upconversion in lanthanide ions. We notice that localized LIA appears at optical power densities as low as 15.5 kW cm⁻² (∼354 ± 29 mW) threshold in spots of 54 ± 3 µm diameter obtained with a 10 × microscope objective. In the course of detailed studies, a complete recrystallization to different phases and giant 2-3 order enhancement in luminescence yield is found. Our results are highly encouraging and let us conclude that the upconverting ultra-small lanthanide-doped nanophosphors are particularly promising for direct laser writing applications. PMID:22433162

  4. Highly efficient Yb-free Er-La-Al doped ultra-low NA large mode area single-trench fiber laser.

    PubMed

    Jain, D; Alam, S; Jung, Y; Barua, P; Velazquez, M N; Sahu, J K

    2015-11-01

    We demonstrate a 60µm core diameter Yb free Er-La-Al doped single-trench fiber having a 0.038 ultra-low-NA, fabricated using conventional MCVD process in conjunction with solution doping technique. Numerical simulations predict an effective single mode operation with effective area varying from 1,820µm(2) to 1,960µm(2) (taking bend-induced modal distortion into account) for different thicknesses of trenches and resonant rings at a constant bend radius of 25cm. Moreover, all solid structure favors easy cleaving and splicing. Experimental measurements demonstrate a robust effective single mode operation. Furthermore, with a 4%-4% laser cavity, this fiber shows a record efficiency of 46% with respect to the absorbed pump power. PMID:26561099

  5. Experimental demonstration of intracavity solid-state laser cooling of Yb{sup 3+}:ZrF{sub 4}-BaF{sub 2}-LaF{sub 3}-AlF{sub 3}-NaF glass

    SciTech Connect

    Heeg, B.; Stone, M.D.; Khizhnyak, A.; DeBarber, P.A.; Rumbles, G.; Mills, G.

    2004-08-01

    We report an approach to bulk optical cooling of solid-state materials by placing the cooling medium inside a laser cavity. The laser system is a diode-pumped Yb{sup 3+}:KY(WO{sub 4}){sub 2} (KYW) laser, while the cooling medium is an uncoated sample of 2%-doped Yb{sup 3+}:ZrF{sub 4}-BaF{sub 2}-LaF{sub 3}-AlF{sub 3}-NaF (ZBLAN) glass. A typical drop of 6 K from ambient temperature was obtained from a noncontact temperature measurement based on the anti-Stokes luminescence profile, using diode pump power at the gain medium of 6 W, a laser wavelength of 1027 nm, and an absorbed power of 1.25 W.

  6. The vector behavior of aberrations in high numerical aperture (0.9 < NA < 3.1) laser focusing systems

    NASA Astrophysics Data System (ADS)

    Jo, Sseunhyeun

    This dissertation investigates vector behavior of aberrations for high numerical aperture optical systems using a solid immersion lens (SIL). In order to analyze the system, this dissertation introduces the illumination system transfer function (ISTF), which is a map in the space of the exit pupil that shows reflection and transmission properties of individual plane waves that are emitted from corresponding points in the exit pupil. A vector analysis using ISTF presents the role of propagating and evanescent energy in the SIL systems, where the boundary between the them is defined by total internal reflection. The behavior of third-order aberrations such as coma and astigmatism, are dramatically affected by polarization in high NA systems. The irradiance distribution exhibits significantly different characteristics, depending on how coma or astigmatism is aligned with the incident linear polarized light. Vector effects including diffraction, polarization, and aberration, are used to analyze tolerances along with a comparison to geometrical optics. Apodization in amplitude and phase of the angular spectrum is generated in high NA focusing systems due to the difference in vector transmission and reflection for each plane wave. The size of the incident gaussian beam is effectively reduced at the exit pupil by the amplitude apodization and causes a spot size increase in image space. The apodization in phase is called gap-induced aberration due to its dependence on the air gap. The gap- induced aberration does not come from lens surface imperfection, and it exhibits multiple orders of spherical aberration and astigmatism. The apodization in amplitude and phase is well characterized by separable supergaussian functions, where each function depends on the refractive index of the SIL n SIL and the air gap height h. The best defocus, based on characteristics of gap-induced aberration, is suggested to be a good compensator only for low nSIL and h. The system performance, as

  7. Demonstration of ultra-low NA rare-earth doped step index fiber for applications in high power fiber lasers.

    PubMed

    Jain, Deepak; Jung, Yongmin; Barua, Pranabesh; Alam, Shaiful; Sahu, Jayanta K

    2015-03-23

    In this paper, we report the mode area scaling of a rare-earth doped step index fiber by using low numerical aperture. Numerical simulations show the possibility of achieving an effective area of ~700 um² (including bend induced effective area reduction) at a bend diameter of 32 cm from a 35 μm core fiber with a numerical aperture of 0.038. An effective single mode operation is ensured following the criterion of the fundamental mode loss to be lower than 0.1 dB/m while ensuring the higher order modes loss to be higher than 10 dB/m at a wavelength of 1060 nm. Our optimized modified chemical vapor deposition process in conjunction with solution doping process allows fabrication of an Yb-doped step index fiber having an ultra-low numerical aperture of ~0.038. Experimental results confirm a Gaussian output beam from a 35 μm core fiber validating our simulation results. Fiber shows an excellent laser efficiency of ~81%and aM² less than 1.1. PMID:25837082

  8. Photofragmentation of Na

    SciTech Connect

    Assion, A.; Baumert, T.; Weichmann, U.; Gerber, G.

    2001-06-18

    Photofragmentation of Na{sup +}{sub 2} molecules in well prepared vibrational levels has been studied employing intense (10{sup 11}{endash}10{sup 14} W/cm{sup 2} ) and ultrashort (80fs) 790nm laser fields. Four fragmentation channels with different released kinetic energies are observed. Depending on the applied laser intensity, the fragmentation of Na{sup +}{sub 2} is governed by photodissociation on light-induced potentials and field ionization followed by Coulomb explosion. Below 1{times}10{sup 12} W /cm{sup 2} , only photodissociation on light-induced potentials is seen. For intermediate laser intensities, field ionization at large internuclear distances competes with photodissociation, thus preventing the observation of above threshold dissociation. Field ionization at small internuclear distances dominates for the highest laser intensities used.

  9. Enhanced 1.0 μm emission and simultaneously suppressed upconversion emission in Yb:PbF2 laser crystal codoped with NaF

    NASA Astrophysics Data System (ADS)

    Zhang, P. X.; Yin, J. G.; Hang, Y.; Yin, J. P.

    2013-04-01

    Na-codoped and only Yb-doped Yb:PbF2 crystals were successfully grown using the vertical Bridgman method. The influence of the ions codoped with Na+ on the distribution coefficients has been studied. Enhanced ˜1.0 μm emission and simultaneously suppressed upconversion emission was observed for Yb:PbF2 crystals codoped with 2 mol% NaF. A time-resolved spectroscopy study showed that the ions codoped with Na+ lengthen the fluorescence lifetime by 6%. Absorption spectra were also studied and showed that the ions codoped with Na+ can effectively suppress the formation of Yb2+ ions.

  10. Annual Scientific Report for DE-FG03-02NA00063 Coherent imaging of laser-plasma interactions using XUV high harmonic radiation

    SciTech Connect

    Prof. Henry C. Kapteyn

    2005-05-03

    In this project, we use coherent short-wavelength light generated using high-order harmonic generation as a probe of laser-plasma dynamics and phase transitions on femtosecond time-scales. The interaction of ultrashort laser pulses with materials and plasmas is relevant to stockpile stewardship, to understanding the equation of state of matter at high pressures and temperatures, and to plasma concepts such as the fast-ignitor ICF fusion concept and laser-based particle acceleration. Femtosecond laser technology makes it possible to use a small-scale setup to generate 20fs pulses with average power >10W at multiple kHz repetition rates, that can be focused to intensities in excess of 1017W/cm2. These lasers can be used either to rapidly heat materials to initiate phase transitions, or to create laser plasmas over a wide parameter space. These lasers can also be used to generate fully spatially coherent XUV beams with which to probe these materials and plasma systems. We are in process of implementing imaging studies of plasma hydrodynamics and warm, dense matter. The data will be compared with simulation codes of laser-plasma interactions, making it possible to refine and validate these codes.

  11. Na2ZnGe2S6: A New Infrared Nonlinear Optical Material with Good Balance between Large Second-Harmonic Generation Response and High Laser Damage Threshold.

    PubMed

    Li, Guangmao; Wu, Kui; Liu, Qiong; Yang, Zhihua; Pan, Shilie

    2016-06-15

    The development of frequency-conversion technology in the infrared region is in urgent need of new excellent infrared nonlinear optical (IR NLO) materials. How to achieve a good balance between laser damage threshold (LDT) and NLO coefficient (dij) for new IR NLO candidates is still a challenge. The combination of the highly electropositive alkali metal (Na) and Zn with d(10) electronic configuration into crystal structure affords one new IR NLO material, Na2ZnGe2S6. It exhibits excellent properties including a wide transparent region (0.38-22 μm), large band gap (3.25 eV), and especially a balance between a strong NLO coefficient (30-fold that of KDP) and a high LDT (6-fold that of AgGaS2), indicating a promising application in the IR region. Moreover, novel common-vertex-linked wavelike ∞[GeS3]n chains are interestingly discovered in Na2ZnGe2S6, which rarely exist in the reported thiogermanides containing alkali metals. In addition, calculated SHG density and dipole moment demonstrate that the large NLO response is mainly attributed to the cooperative effects of the [GeS4] and [ZnS4] units. PMID:27196357

  12. Enhanced ferroelectric and piezoelectric response in Mn-doped Bi0.5Na0.5TiO3-BaTiO3 lead-free film by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Jin, Chengchao; Wang, Feifei; Leung, Chung Ming; Yao, Qirong; Tang, Yanxue; Wang, Tao; Shi, Wangzhou

    2013-10-01

    Mn-doped Bi0.5Na0.5TiO3-BaTiO3 thin film with the composition around the morphotropic phase boundary was grown on Pt-electrodized Si substrate by pulsed laser deposition. Highly (1 0 0)-oriented film with pure perovskite structure was obtained through carefully controlling the growth conditions. Well-defined ferroelectric P-E loop was obtained with the average remnant polarization Pr and coercive field Ec of ∼11.3 μC/cm2 and ∼6.5 kV/mm, respectively. Polycrystalline structures and multidomain states were revealed by piezoresponse force microscopy and large local strain response was obtained with the normalized strain Smax/Emax up to 92 pm/V. The excellent global electrical properties make it quite promising in environmental-friendly ferroelectric and piezoelectric devices.

  13. Growth and electric properties of (100)-oriented Mn-doped (Bi0.5Na0.5)TiO3-BaTiO3 thin film by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Jin, Chengchao; Wang, Feifei; Leung, Chung Ming; Tang, Yanxue; Wang, Tao; Yao, Qirong; Shi, Wangzhou

    2014-06-01

    Mn-doped (Bi0.5Na0.5)TiO3-BaTiO3 (BNBMT) thin film with the composition near the morphotropic phase boundary was grown on (La0.6Sr0.4)CoO3-electroded SrTiO3 single-crystal substrate by using pulsed laser deposition method. Ascribed to the crystal structure and lattice similarity, (100)-oriented BNBMT film with pure single-phase perovskite structure was obtained through carefully controlling the growth conditions. Enhanced ferroelectric and dielectric properties were obtained with large remanent polarization P r of ˜21 μC/cm2, coercive field E c of ˜7.4 kV/mm and dielectric constant of ˜750 at 1 kHz. The excellent global electrical properties of the BNBMT film are promising for environmentally friendly ferroelectric devices.

  14. New laser materials for laser diode pumping

    NASA Technical Reports Server (NTRS)

    Jenssen, H. P.

    1990-01-01

    The potential advantages of laser diode pumped solid state lasers are many with high overall efficiency being the most important. In order to realize these advantages, the solid state laser material needs to be optimized for diode laser pumping and for the particular application. In the case of the Nd laser, materials with a longer upper level radiative lifetime are desirable. This is because the laser diode is fundamentally a cw source, and to obtain high energy storage, a long integration time is necessary. Fluoride crystals are investigated as host materials for the Nd laser and also for IR laser transitions in other rare earths, such as the 2 micron Ho laser and the 3 micron Er laser. The approach is to investigate both known crystals, such as BaY2F8, as well as new crystals such as NaYF8. Emphasis is on the growth and spectroscopy of BaY2F8. These two efforts are parallel efforts. The growth effort is aimed at establishing conditions for obtaining large, high quality boules for laser samples. This requires numerous experimental growth runs; however, from these runs, samples suitable for spectroscopy become available.

  15. Pulsed laser deposition of lead-free (Na0.5Bi0.5)1-xBaxTiO3 ferroelectric thin films with enhanced dielectric properties

    NASA Astrophysics Data System (ADS)

    Andrei, A.; Scarisoreanu, N. D.; Birjega, R.; Dinescu, M.; Stanciu, G.; Craciun, F.; Galassi, C.

    2013-08-01

    Ferroelectric lead-free (Na0.5Bi0.5)1-xBaxTiO3 thin films obtained by pulsed laser deposition have been structurally and electrically investigated for compositions, x = 0 and x = 0.06, in and out of the morphotropic phase boundary (MPB). Sodium bismuth titanate Na0.5Bi0.5TiO3 (NBT), pure or in solid solution with other materials (like BaTiO3), is considered to be the best candidate material for lead-free ferroelectric and piezoelectric applications such as actuators and nonvolatile memory devices. Bulk solid solutions with BaTiO3 (BT), (1-x)NBT-xBT (NBT-x%BT) have been investigated widely, also due to a morphotropic phase boundary (MPB) with enhanced dielectric and ferroelectric properties between a rhombohedral and a tetragonal ferroelectric phase, at x = 0.06. Nonetheless, to transpose bulk properties to NBT-BT thin films is a major achievement. XRD technique has been used for structural characterizations of NBT-BT films. Dielectric spectroscopy measurements were performed at room temperature in the frequency range 100 Hz-1 MHz. The best films show pure perovskite phase and good crystalline structure, as a function of specific deposition conditions. Unusual characteristics, especially dielectric constant values higher than those for bulk, have been found for films with specific crystallographic orientations.

  16. Nonlinear optical properties of pulsed laser deposited Gd2O3 and Dy2O3 doped K0.5Na0.5NbO3 thin films

    NASA Astrophysics Data System (ADS)

    Peddigari, Mahesh; Pattipaka, Srinivas; Bharti, Gyan Prakash; Khare, Alika; Dobbidi, Pamu

    2016-08-01

    We report the structural and nonlinear optical properties of Gd2O3 and Dy2O3 doped (K0.5Na0.5)NbO3 (KNN) lead-free thin films fabricated by pulsed laser deposition technique. The crystal structure of the films was analyzed by using Rietveld method. The higher tetragonality and improved surface morphology was observed for the rare-earth oxide doped films. The change in crystal structure and tetragonality with these dopants was explained in terms of change in the internal vibration modes of NbO6 octahedra. The nonlinear optical properties of the films were measured by using single beam Z-scan technique with a continuous wave He-Ne laser (λ = 632.8 nm). All the films have shown a large third-order nonlinear susceptibility and observed to be enhanced for rare-earth doped KNN thin films (|χ(3)| = 2.69 × 10-3 esu). The maximum nonlinear refractive index, n2 = 2.02 × 10-5 cm2/W, and nonlinear absorption coefficient, β = 3.48 cm/W, were obtained for Gd2O3, and Dy2O3 doped films respectively. These results indicate that rare-earth doped KNN thin films are potential candidates for nonlinear photonic applications.

  17. Final Scientific/Technical Report for DE-FG03-02NA00063 Coherent imaging of laser-plasma interactions using XUV high harmonic radiation

    SciTech Connect

    Henry Kapteyn

    2006-06-06

    The objective of this project was to develop experimental techniques for using coherent extreme-ultraviolet (EUV) radiation generated using the high-order harmonic generation technique, as an illumination source for studies of high-density plasmas relevant to the stockpile stewardship mission. In this project, we made considerable progress, including the first demonstration of imaging of dynamic processes using this coherent ultrashort pulse light. This work also stimulated considerable progress in the development of the required ultrashort EUV pulses, and in the development of new laser technologies that have been commercialized. We also demonstrated the first EUV sources that exhibit full intrinsic optical coherence. This work resulted in 12 publications.

  18. Highly-reproducible Raman scattering of NaYF4:Yb,Er@SiO2@Ag for methylamphetamine detection under near-infrared laser excitation.

    PubMed

    Ma, Yongmei; Liu, Honglin; Han, Zhenzhen; Yang, Liangbao; Liu, Jinhuai

    2015-08-01

    This study reported the significantly improved Raman enhancement ability of silver nanoparticles (Ag NPs) by decorating them on single NaYF4:Yb,Er@SiO2 core-shell particles (UC@SiO2@Ag) under a 785 nm excitation. The optimal thickness of the silica shell can be easily obtained by adjusting the amounts of TEOS, which is the crucial element to balance the upconversion and the formation of a hot spot by Ag NP aggregation. This substrate revealed highly reproducible properties, which is crucial to the practical application of SERS technology. This substrate exhibited an excellent sensitivity for methylamphetamine detection under near-infrared excitation. The advantages of NIR excitation in our SERS sensing open up a new application field of UC-noble metal composites, and also promise a new research direction for the synthesis and applications of SERS-active nanostructures. PMID:26090604

  19. Sol-gel synthesis and characterizations of crystalline NaGd(WO4)2 powder for anisotropic transparent ceramic laser application

    NASA Astrophysics Data System (ADS)

    Durairajan, A.; Thangaraju, D.; Balaji, D.; Moorthy Babu, S.

    2013-02-01

    NaGd(WO4)2 powders were synthesized at different pH (3.5, 4.5, 5.5, 6.5 and 7.5) values by conventional Pechini method. Sodium and gadolinium nitrate salts and ammonium paratungstate are used as starting precursors. Metal cations were chelated by citric acid and individual citrates were bound together with ethylene glycol. Synthesized gel was analyzed using differential thermal analysis (DTA), thermo gravimetric (TG) and FT-IR spectroscopy to understand the degradation of gel and formation of metal citrates. Calcined powders (250, 600, 700 and 800 °C) were characterized by powder XRD, FT-IR, Raman and FE-SEM analysis. The temperature dependent phase formation was examined by powder XRD. The morphological changes at different pH derived powders were observed with FE-SEM micrographs. Stepwise organic liberation with respect to temperature and presence of carbon content in the pre-fired powder were analyzed using FT-IR analysis. Raman spectrum reveals disordered tungstate vibrations in the NGW matrix.

  20. Electrical behaviors of c-axis textured 0.975Bi0.5Na0.5TiO3-0.025BiCoO3 thin films grown by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Guo, Feifei; Yang, Bin; Zhang, Shantao; Liu, Danqing; Wu, Fengmin; Wang, Dali; Cao, Wenwu

    2013-10-01

    The thin films of 0.975Bi0.5Na0.5TiO3-0.025BiCoO3 (BNT-BC) have been successfully deposited on (1 1 1) Pt/Ti/SiO2/Si (1 0 0) substrates by pulse laser deposition and their ferroelectric, dielectric, local piezoelectric properties and temperature dependent leakage current behaviors have been investigated systematically. X-ray diffraction indicates the films are single phased and c-axis oriented. The thin films exhibit ferroelectric polarization-electric field (P-E) hysteresis loop with a remnant polarization (Pr) of 10.0 μC/cm2 and an excellent fatigue resistance property up to 5 × 109 switching cycles. The dielectric constant and dielectric loss are 500 and 0.22 at 1 kHz, respectively. The tunability of the dielectric constant is about 12% at 20 kV/mm. The piezo-phase response hysteresis loop and piezo-amplitude response butterfly curve are observed by switching spectroscopy mode of piezoelectric force microscope (SS-PFM) and the piezoelectric coefficient d33 is about 19-63 pm/V, which is comparable to other reports. The dominant leakage current conduction mechanisms are ohmic conduction at low electric field and Schottky emission at high electric field, respectively. Our results may be helpful for further work on BNT-based thin films with improved electric properties.

  1. Electrical properties of (110) epitaxial lead-free ferroelectric Na0.5Bi0.5TiO3 thin films grown by pulsed laser deposition: Macroscopic and nanoscale data

    NASA Astrophysics Data System (ADS)

    Bousquet, M.; Duclère, J.-R.; Gautier, B.; Boulle, A.; Wu, A.; Députier, S.; Fasquelle, D.; Rémondière, F.; Albertini, D.; Champeaux, C.; Marchet, P.; Guilloux-Viry, M.; Vilarinho, P.

    2012-05-01

    We report the electrical properties, measured both at the macroscopic and nanometric scales, of epitaxial (110)-Na0.5Bi0.5TiO3 (NBT) thin films grown on (110)Pt/(110)SrTiO3 by pulsed laser deposition (PLD). The influence of the A-site composition (Na and/or Bi excess) on both the structural/microstructural characteristics and the electrical properties is discussed. Whatever the composition of the NBT target, the final layers are systematically epitaxially grown, with NBT crystallites mainly (110)-oriented, and as well (100)-oriented for some minor proportion. Atomic force microscopy (AFM) images reveal the coexistence of two kinds of grains presenting different shapes: namely flat and elongated grains, corresponding to (100)- and (110)-oriented NBT crystallites, respectively. The macroscopic ferroelectric properties were measured at room temperature. A rather well-defined shape of the hysteresis loops was obtained: the incorporation of a Bi excess in the target clearly improves the saturation of the loops. The ferroelectric performances are a remanent polarization (Pr) value, ranging from 7 to 14 μC/cm2, associated with a coercive field (Ec) in the range 68-85 kV/cm. In addition, at 105 Hz, the relative permittivity was about ɛr ˜ 255-410 and the dielectric losses (tan δ) were ˜6%-7%. Finally, the electrical properties at the local scale were investigated by coupling piezoresponse force microscopy (PFM) and tunneling AFM (TUNA) measurements. The collected data reveal that the two types of grains behave differently. The PFM amplitude signal of (110)-oriented grains is very contrasted and such grains are often divided in ferroelectric bi-domains of nanometric sizes, whereas the response of (100)-oriented grains is less contrasted and more homogeneous. The interpretation of the PFM signal is provided. The piezoloop recorded on a (110)NBT grain is strongly distorted and shifted along the vertical axis, in agreement with the vertical drift observed for macroscopic

  2. Laser Technology.

    ERIC Educational Resources Information Center

    Gauger, Robert

    1993-01-01

    Describes lasers and indicates that learning about laser technology and creating laser technology activities are among the teacher enhancement processes needed to strengthen technology education. (JOW)

  3. Understanding lasers

    SciTech Connect

    Gibilisco, S.

    1989-01-01

    Covering all different types of laser applications-Gibilisco offers an overview of this fascinating phenomenon of light. Here he describes what lasers are and how they work and examines in detail the different kinds of lasers in use today. Topics of particular interest include: the way lasers work; the different kinds of lasers; infrared, ultraviolet and x-ray lasers; use of lasers in industry and manufacturing; use of lasers for long-distance communications; fiberoptic communications; the way laser shows work; the reality of Star Wars; lasers in surgical and medical applications; and holography and the future of laser technology.

  4. Analysis of Laser Breakdown Data

    NASA Astrophysics Data System (ADS)

    Becker, Roger

    2009-03-01

    Experiments on laser breakdown for ns pulses of 532 nm or 1064 nm light in water and dozens of simple hydrocarbon liquids are analyzed and compared to widely-used models and other laser breakdown experiments reported in the literature. Particular attention is given to the curve for the probability of breakdown as a function of the laser fluence at the beam focus. Criticism is made of the na"ive forms of both ``avalanche'' breakdown and multi-photon breakdown. It appears that the process is complex and is intimately tied to the chemical group of the material. Difficulties with developing an accurate model of laser breakdown in liquids are outlined.

  5. Teradiode's high brightness semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

    2016-03-01

    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, <0.08 numerical aperture (NA) output fiber at a single center wavelength was demonstrated. Our TeraBlade industrial platform achieves world-record brightness levels for direct diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  6. Many-body perturbation theory calculations on the electronic states of Li 2, LiNa and Na 2

    NASA Astrophysics Data System (ADS)

    Davies, D. W.; Jones, G. J. R.

    1981-07-01

    Quasi-degenerate many-body perturbation theory with a multi-configuration reference space is used to obtain potential curves for the ground and excited electronic states of Li 2, LiNa and Na 2. Correlation contributions are analyzed and the effect of potential curve crossing on laser action is discussed.

  7. Diode-pumped CW molecular lasers

    NASA Astrophysics Data System (ADS)

    Wellegehausen, B.; Luhs, W.

    2016-05-01

    First continuous laser oscillation on many lines in the range of 533-635 nm on different transitions of Na2 and Te2 molecules has been obtained, optically pumped with common cw blue emitting InGaN diode lasers operating around 445 and 460 nm. Spectral narrowing of the diode laser is achieved with a beamsplitter and grating setup, allowing use of more than 50 % of the diode power. Operation conditions and properties of the laser systems are presented, and perspectives for the realization of compact low cost molecular lasers are discussed.

  8. Using short pulse lasers to drive X-ray lasers

    SciTech Connect

    Nilsen, J

    2009-07-27

    Nearly four decades ago H-like and He-like resonantly photo-pumped laser schemes were proposed for producing X-ray lasers. However, demonstrating these schemes in the laboratory has proved to be elusive. One challenge has been the difficulty of finding an adequate resonance between a strong pump line and a line in the laser plasma that drives the laser transition. Given a good resonance, a second challenge has been to create both the pump and laser plasma in close proximity so as to allow the pump line to transfer its energy to the laser material. With the advent of the X-FEL at LCLS we now have a tunable X-ray laser source that can be used to replace the pump line in previously proposed laser schemes and allow researchers to study the physics and feasibility of photo-pumped laser schemes. In this paper we model the Na-pumped Ne X-ray laser scheme that was proposed and studied many years ago by replacing the Na He-{alpha} pump line at 1127 eV with the X-FEL at LCLS. We predict gain on the 4f - 3d transition at 231 {angstrom}. We also examine the feasibility of photo-pumping He-like V and lasing on the 4f - 3d transition at 38.7 {angstrom}, which would be within the water-window. In addition we look at the possibility of photo-pumping Ne-like Fe and creating gain on the 4d - 3p transition at 53 {angstrom} and the 3p - 3s transition at 255 {angstrom}.

  9. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2002-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. The beam from the excitation light source is split with a portion of it going to the ignitor laser and a second portion of it being recombined with the first portion after a delay before injection into the ignitor laser. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones.

  10. Lasers of All Sizes

    NASA Astrophysics Data System (ADS)

    Balcou, Philippe; Forget, Sébastien Robert-Philip, Isabelle

    2015-10-01

    * Introduction * The Laser in All Its Forms * Gas lasers * Dye lasers * Solid-state lasers * Lasers for Every Taste * The rise of lasers * Lasers of all sizes * The colors of the rainbow... and beyond * Shorter and shorter lasers * Increasingly powerful lasers * Lasers: A Universal Tool? * Cutting, welding, and cleaning * Communicating * Treating illnesses * Measuring * Supplying energy? * Entertaining * Understanding * Conclusion

  11. Long-Lifetime Laser Materials For Effective Diode Pumping

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.

    1991-01-01

    Long quantum lifetimes reduce number of diodes required to pump. Pumping by laser diodes demonstrated with such common Nd laser materials as neodymium:yttrium aluminum garnet (Nd:YAG) and Nd:YLiF4, but such materials as Nd:LaF3, Nd:NaF.9YF3, and possibly Nd:YF3 more useful because of long lifetimes of their upper laser energy levels. Cost effectiveness primary advantage of solid-state laser materials having longer upper-laser-level lifetimes. Because cost of diodes outweighs cost of laser material by perhaps two orders of magnitude, cost reduced significantly.

  12. Laser therapy

    MedlinePlus

    ... be used for many medical purposes. Because the laser beam is so small and precise, it allows health care providers to safely treat tissue without injuring the surrounding area. Lasers are often used to: Treat varicose veins Improve ...

  13. Laser microphone

    DOEpatents

    Veligdan, James T.

    2000-11-14

    A microphone for detecting sound pressure waves includes a laser resonator having a laser gain material aligned coaxially between a pair of first and second mirrors for producing a laser beam. A reference cell is disposed between the laser material and one of the mirrors for transmitting a reference portion of the laser beam between the mirrors. A sensing cell is disposed between the laser material and one of the mirrors, and is laterally displaced from the reference cell for transmitting a signal portion of the laser beam, with the sensing cell being open for receiving the sound waves. A photodetector is disposed in optical communication with the first mirror for receiving the laser beam, and produces an acoustic signal therefrom for the sound waves.

  14. Nonablative lasers.

    PubMed

    Nouri, Keyvan; Rivas, Maria Patricia; Bouzari, Navid; Faghih, Sahar

    2006-06-01

    The trend toward minimally invasive rejuvenation techniques has led to the widespread use of nonablative lasers. Nonablative lasers can be classified in two groups based on their wavelengths: lasers emitting light in the visible range, and those emitting in the infrared range. In this review, different laser and intense pulsed light (IPL) systems are presented and critically discussed along with findings of the studies in the literature. PMID:17173583

  15. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2004-01-13

    Sequenced pulses of light from an excitation laser with at least two resonator cavities with separate output couplers are directed through a light modulator and a first polarzing analyzer. A portion of the light not rejected by the first polarizing analyzer is transported through a first optical fiber into a first ignitor laser rod in an ignitor laser. Another portion of the light is rejected by the first polarizing analyzer and directed through a halfwave plate into a second polarization analyzer. A first portion of the output of the second polarization analyzer passes through the second polarization analyzer to a second, oscillator, laser rod in the ignitor laser. A second portion of the output of the second polarization analyzer is redirected by the second polarization analyzer to a second optical fiber which delays the beam before the beam is combined with output of the first ignitor laser rod. Output of the second laser rod in the ignitor laser is directed into the first ignitor laser rod which was energized by light passing through the first polarizing analyzer. Combined output of the first ignitor laser rod and output of the second optical fiber is focused into a combustible fuel where the first short duration, high peak power pulse from the ignitor laser ignites the fuel and the second long duration, low peak power pulse directly from the excitation laser sustains the combustion.

  16. Laser driver

    SciTech Connect

    Culpepper, C.F.

    1989-03-14

    A laser driver for a laser diode is described, consisting of: an impedance matched input buffer amplifier to which a modulation signal is applied; and a current source coupled to the output of the impedance matched input buffer amplifier, the output of the current source providing an essentially constant amplitude a.c. current component coupled to drive the laser diode.

  17. CW laser pumped emerald laser

    SciTech Connect

    Shand, M.L.; Lai, S.T.

    1984-02-01

    A CW laser-pumped emerald laser is reported. A 34 percent output power slope efficiency is observed with longitudinal pumping by a krypton laser in a nearly concentric cavity. The laser has been tuned from 728.8 to 809.0 nm. Losses in emerald are larger than those of alexandrite determined in a similar cavity. The present data also indicate that the excited state absorption minimum is shifted from that of alexandrite. 13 references.

  18. Laser device

    DOEpatents

    Scott, Jill R.; Tremblay, Paul L.

    2004-11-23

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  19. Laser device

    DOEpatents

    Scott, Jill R.; Tremblay, Paul L.

    2007-07-10

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  20. Glass lasers.

    PubMed

    Snitzer, E

    1966-10-01

    After a general discussion of the merits of glass vs. crystals as host materials for laser ions, a summary is given of the various glass lasers. Because of its importance as an efficient, room temperature laser the properties of neodymium are considered in greater detail. This includes the nonlaser properties of Nd(3+) in glass, the spectral and temporal emission characteristics of Nd(3+) lasers, and Nd(3+) laser configurations. Separate sections deal with the other two room temperature lasers which use Yb(3+) or Er(3+). The problem of thermal stability of laser cavities is also discussed. Finally, a survey is given of the glasses that are useful as Faraday rotators. PMID:20057584

  1. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2003-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In a third embodiment, alternating short and long pulses of light from the excitation light source are directed into the ignitor laser. Each of the embodiments of the invention can be multiplexed so as to provide laser light energy sequentially to more than one ignitor laser.

  2. Effect of green laser irradiation on hydrogen production

    NASA Astrophysics Data System (ADS)

    Bidin, Noriah; Razak, Siti Noraiza A.; Radiana Azni, Siti; Nguroho, Waskito; Mohsin, Ali Kamel; Abdullah, Mundzir; Krishnan, Ganesan; Bakhtiar, Hazri

    2014-06-01

    The effect of green laser irradiation on hydrogen production via water electrolysis was investigated. Diode pumped solid-state laser operating in second harmonic generation was employed as a source of irradiation. The hydrogen production system was also irradiated by a conventional light, a halogen source, for comparison. The best catalyst was identified by mixing distilled water with two types of salt: NaCl and Na2SO4. Optimization of hydrogen production from water electrolysis was realized by using NaCl and green laser irradiation. The power of green laser irradiation and the concentration of NaCl in water contribute to hydrogen production. The hydrogen yield also depends on the distance and direction of the green beam to the electrode.

  3. Issue of data acquisition and processing using short range photogrammetry and terrestrial laser scanning for educational portals and virtual museums based on Wawel cathedral. (Polish Title: Problematyka pozyskiwania i przetwarzania danych fotogrametrycznych i z naziemnego skaningu laserowego na potrzeby tworzenia portali edukacyjnych i wirtualnych muzeów na przykładzie Katedry Wawelskiej)

    NASA Astrophysics Data System (ADS)

    Mitka, B.; Szelest, P.

    2013-12-01

    This paper presents the issues related to the acquisition and processing of terrestrial photogrammetry and laser scanning for building educational portals and virtual museums. Discusses the specific requirements of measurement technology and data processing for all kinds of objects, ranging from architecture through sculpture and architectural detail on the fabric and individual museum exhibits. Educational portals and virtual museums require a modern, high-quality visuals (3D models, virtual tours, animations, etc.) supplemented by descriptive content or audio commentary. Source for obtaining such materials are mostly terrestrial laser scanning and photogrammetry as technologies that provide complete information about the presented geometric objects. However, the performance requirements of web services impose severe restrictions on the presented content. It is necessary to use optimalization geometry process to streamline the way of its presentation. Equally important problem concerns the selection of appropriate technology and process measurement data processing presented for each type of objects. Only skillful selection of measuring equipment and data processing tools effectively ensure the achievement of a satisfactory end result. Both terrestrial laser scanning technology and digital close range photogrammetry has its strengths which should be used but also the limitations that must be taken into account in this kind of work. The key is choosing the right scanner for both the measured object and terrain such as pixel size in the performance of his photos.

  4. New nonlinear-laser properties of ferroelectric Nd{sup 3+}:Ba{sub 2}NaNb{sub 5}O{sub 15} - cw stimulated emission ({sup 4}F{sub 3/2} {yields} {sup 4}I{sub 11/2} and {sup 4}F{sub 3/2} {yields} {sup 4}I{sub 13/2} ), collinear and diffuse self-frequency doubling and summation

    SciTech Connect

    Kaminskii, Alexandr A; Jaque, D; Garsia, Sole J; Capmany, J; Bagayev, S N; Ueda, Ken-ichi

    1999-02-28

    A new cw laser with self-frequency doubling and summation of 1-{mu}m oscillation ({sup 4}F{sub 3/2} {yields} {sup 4}I{sub 11/2}) was constructed on the basis of an orthorhombic Nd{sup 3+}:Ba{sub 2}NaNb{sub 5}O{sub 15} crystal. The {sup 4}F{sub 3/2} {yields} {sup 4}I{sub 13/2} inter-Stark transition was used to excite cw 1.3-{mu}m stimulated emission from this ferroelectric. (letters to the editor)

  5. Semi-automated building extraction from airborne laser scanning data. (Polish Title: Półautomatyczne modelowanie brył budynków na podstawie danych z lotniczego skaningu laserowego)

    NASA Astrophysics Data System (ADS)

    Marjasiewicz, M.; Malej, T.

    2014-12-01

    The main idea of this project is to introduce a conception of semi - automated method for building model extraction from Airborne Laser Scanning data. The presented method is based on the RANSAC algorithm, which provides automatic collection planes for roofs model creation. In the case of Airborne Laser Scanning, the algorithm can process point clouds influenced with noise and erroneous measurement (gross errors). The RANSAC algorithm is based on the iterative processing of a set of points in order to estimate the geometric model. Research of u sing algorithm for ALS data was performed in available Cloud Compare and SketchUP software. An important aspect in this research was algorithm parameters selection, which was made on the basis of characteristics of point cloud and scanned objects. Analysis showed that the accuracy of plane extraction with RANSAC algorithm does not exceed 20 centimeters for point clouds of density 4 pts . /m 2 . RANSAC can be successfully used in buildings modelling based on ALS data. Roofs created by the presented method could be used in visualizations on a much better level than Level of Detail 2 by CityGML standard. If model is textured it can represent LoD3 standard.

  6. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2002-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In the embodiment of the invention claimed herein, the beam from the excitation light source is split with a portion of it going to the ignitor laser and a second portion of it being combined with either the first portion after a delay before injection into the ignitor laser.

  7. Evaporation of solids by pulsed laser irradiation

    NASA Astrophysics Data System (ADS)

    Stafast, H.; Von Przychowski, M.

    The focused beam of a KrF laser (248 nm) has been applied to irradiate targets of Al 2O 3, SiC, graphite, Pb, Ni, Cr, quartz, and NaCl at variable laser energy flux is the range 0-13 J/cm 2. The amount of target material ejected into the vacuum (background pressure about 8 × 10 -4 Torr) was determined from the target weight before and after laser irradiation. The average number of particles (formula weight) evaporated per laser pulse and per unit of irradiated target area is non-linearly dependent on the laser energy flux. The evaporation of Al 2O 3, SiC, and graphite is showing a well-defined flux threshold while the vaporization of Pb, Ni and Cr is rising smoothly with increasing flux. With both groups of materials laser evaporation is monotonically increasing with the laser energy flux. NaCl and quartz, on the other hand, are showing an intermediate maximum in the laser vaporization efficiency.

  8. Explosive vaporization of metallic sodium microparticles by CW resonant laser radiation.

    PubMed

    Atutov, S N; Baldini, W; Biancalana, V; Calabrese, R; Guidi, V; Mai, B; Mariotti, E; Mazzocca, G; Moi, L; Pod'yachev, S P; Tomassetti, L

    2001-11-19

    Explosive vaporization of metallic Na microparticles stimulated by resonant cw laser radiation has been observed in a glass cell. Vaporization occurs at low laser-power density. The effect consists in the generation of optically thick and sharply localized Na vapor clouds propagating in the cell against the laser beam. The effect is explained by laser excitation of Na atoms, which collide onto the surface of the microparticles and transfer their internal energy. This causes other atoms to be vaporized and to continue the avalanche process. PMID:11736344

  9. Laser pyrometry

    NASA Technical Reports Server (NTRS)

    Stein, Alexander

    1988-01-01

    A method of determining the emissivity of a hot target from a laser-based reflectance measurement which is conducted simultaneously with a measurement of the target radiance is described. Once the correct radiance and emissivity are determined, one calculates the true target temperature from these parameters via the Planck equations. The design and performance of a laser pyrometer is described. The accuracy of laser pyrometry and the effect of ambient radiance are addressed.

  10. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2002-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source capable of producing alternating beams of light having different wavelengths is used in tandem with one or more ignitor lasers to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using the single remote excitation light source for pumping one or more small lasers located proximate to one or more fuel combustion zones with alternating wavelengths of light.

  11. Biocavity Lasers

    SciTech Connect

    Gourley, P.L.; Gourley, M.F.

    2000-10-05

    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  12. Laser polishing

    NASA Astrophysics Data System (ADS)

    Temmler, A.; Willenborg, E.; Wissenbach, K.

    2012-03-01

    A new approach to polish metallic freeform surfaces is polishing by means of laser radiation. In this technology a thin surface layer is molten and the surface tension leads to a material flow from the peaks to the valleys. No material is removed but reallocated while molten. As the typical processing time is 1 min/cm2 laser polishing is up to 30 times faster than manual polishing. Reducing the roughness by laser polishing is achieved for several different materials such as hot work steels for the die and molding industries or titanium alloys for medical engineering. Enhancing the appearance of design surfaces is achieved by creating a dual-gloss effect by selective laser polishing (SLP). In comparison to conventional polishing processes laser polishing opens up the possibility of selective processing of small areas (< 0.1 mm2). A dual-gloss effect is based on a space-resolved change in surface roughness. In comparison to the initial surface the roughness of the laser polished surface is reduced significantly up to spatial wavelengths of 80 microns and therefore the gloss is raised considerably. The surface roughness is investigated by a spectral analysis which is achieved by a discrete convolution of the surface profile with a Gaussian loaded function. The surfaces roughness is split into discrete wavelength intervals and can be evaluated and optimized. Laser polishing is carried out by using a special tailored five-axis mechanical handling system, combined with a three axis laser scanning system and a fibre laser.

  13. Laser apparatus

    DOEpatents

    Lewis, Owen; Stogran, Edmund M.

    1980-01-01

    Laser apparatus is described wherein an active laser element, such as the disc of a face-pumped laser, is mounted in a housing such that the weight of the element is supported by glass spheres which fill a chamber defined in the housing between the walls of the housing and the edges of the laser element. The uniform support provided by the spheres enable the chamber and the pump side of the laser element to be sealed without affecting the alignment or other optical properties of the laser element. Cooling fluid may be circulated through the sealed region by way of the interstices between the spheres. The spheres, and if desired also the cooling fluid may contain material which absorbs radiation at the wavelength of parasitic emissions from the laser element. These parasitic emissions enter the spheres through the interface along the edge surface of the laser element and it is desirable that the index of refraction of the spheres and cooling fluid be near the index of refraction of the laser element. Thus support, cooling, and parasitic suppression functions are all accomplished through the use of the arrangement.

  14. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1990-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency, and provides spectral analysis of a laser beam.

  15. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1989-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

  16. Lasers in Cancer Treatment

    MedlinePlus

    ... Cancer Treatment On This Page What is laser light? What is laser therapy, and how is it ... future hold for laser therapy? What is laser light? The term “ laser ” stands for light amplification by ...

  17. Laser Therapy

    MedlinePlus

    ... Non-ablative Laser Rejuvenation Non-invasive Body Contouring Treatments Skin Cancer Skin Cancer Information Free Skin Cancer Screenings Skin ... Non-ablative Laser Rejuvenation Non-invasive Body Contouring Treatments Skin Cancer Skin Cancer Information Free Skin Cancer Screenings Skin ...

  18. Laser device

    DOEpatents

    Scott, Jill R.; Tremblay, Paul L.

    2008-08-19

    A laser device includes a virtual source configured to aim laser energy that originates from a true source. The virtual source has a vertical rotational axis during vertical motion of the virtual source and the vertical axis passes through an exit point from which the laser energy emanates independent of virtual source position. The emanating laser energy is collinear with an orientation line. The laser device includes a virtual source manipulation mechanism that positions the virtual source. The manipulation mechanism has a center of lateral pivot approximately coincident with a lateral index and a center of vertical pivot approximately coincident with a vertical index. The vertical index and lateral index intersect at an index origin. The virtual source and manipulation mechanism auto align the orientation line through the index origin during virtual source motion.

  19. Highly efficient Raman distributed feedback fibre lasers.

    PubMed

    Shi, Jindan; Alam, Shaif-ul; Ibsen, Morten

    2012-02-27

    We demonstrate highly efficient Raman distributed feedback (DFB) fibre lasers for the first time with up to 1.6 W of continuous wave (CW) output power. The DFB Bragg gratings are written directly into two types of commercially available passive germano-silica fibres. Two lasers of 30 cm length are pumped with up to 15 W of CW power at 1068 nm. The threshold power is ~2 W for a Raman-DFB (R-DFB) laser written in standard low-NA fibre, and only ~1 W for a laser written in a high-NA fibre, both of which oscillate in a narrow linewidth of <0.01 nm at ~1117 nm and ~1109 nm, respectively. The slope efficiencies are ~74% and ~93% with respect to absorbed pump power in the low-NA fibre and high-NA fibre respectively. Such high conversion efficiency suggests that very little energy is lost in the form of heat through inefficient energy transfer. Our results are supported by numerical simulations, and furthermore open up for the possibility of having narrow linewidth all-fibre laser sources in wavelength bands not traditionally covered by rare-earth doped silica fibres. Simulations also imply that this technology has the potential to produce even shorter R-DFB laser devices at the centimetre-level and with mW-level thresholds, if Bragg gratings formed in fibre materials with higher intrinsic Raman gain coefficient than silica are used. These materials include for example tellurite or chalcogenide glasses. Using glasses like these would also open up the possibility of having narrow linewidth fibre sources with DFB laser oscillating much further into the IR than what currently is possible with rare-earth doped silica glasses. PMID:22418313

  20. Autokeratomileusis Laser

    NASA Astrophysics Data System (ADS)

    Kern, Seymour P.

    1987-03-01

    Refractive defects such as myopia, hyperopia, and astigmatism may be corrected by laser milling of the cornea. An apparatus combining automatic refraction/keratometry and an excimer type laser for precision reshaping of corneal surfaces has been developed for testing. When electronically linked to a refractometer or keratometer or holographic imaging device, the laser is capable of rapidly milling or ablating corneal surfaces to preselected dioptric power shapes without the surgical errors characteristic of radial keratotomy, cryokeratomileusis or epikeratophakia. The excimer laser simultaneously generates a synthetic Bowman's like layer or corneal condensate which appears to support re-epithelialization of the corneal surface. An electronic feedback arrangement between the measuring instrument and the laser enables real time control of the ablative milling process for precise refractive changes in the low to very high dioptric ranges. One of numerous options is the use of a rotating aperture wheel with reflective portions providing rapid alternate ablation/measurement interfaced to both laser and measurement instrumentation. The need for the eye to be fixated is eliminated or minimized. In addition to reshaping corneal surfaces, the laser milling apparatus may also be used in the process of milling both synthetic and natural corneal inlays for lamellar transplants.

  1. Chemical lasers

    NASA Astrophysics Data System (ADS)

    Khariton, Y.

    1984-08-01

    The application and the advances of quantum electronics, specifically, of optical quantum generators lasers is reviewed. Materials are cut, their surfaces are machined, chemical transformations of substances are carried out, surgical operations are performed, data are transmitted, three dimensional images are produced and the content of microimpurities, in the atmosphere, are analyzed by use of a beam. Laser technology is used in conducting investigations in the most diverse fields of the natural and technical sciences from controlled thermonuclear fusion to genetics. Many demands are placed on lasers as sources of light energy. The importance of low weight, compactness of the optical generator and the efficiency of energy conversion processes is emphasized.

  2. Laser propulsion

    NASA Technical Reports Server (NTRS)

    Rom, F. E.; Putre, H. A.

    1972-01-01

    The use of an earth-based high-power laser beam to provide energy for earth-launched rocket vehicle is investigated. The laser beam energy is absorbed in an opaque propellant gas and is converted to high-specific-impulse thrust by expanding the heated propellant to space by means of a nozzle. This laser propulsion scheme can produce specific impulses of several thousand seconds. Payload to gross-weight fractions about an order of magnitude higher than those for conventional chemical earth-launched vehicles appear possible. There is a potential for a significant reduction in cost per payload mass in earth orbit.

  3. Laser goniometer

    DOEpatents

    Fairer, George M.; Boernge, James M.; Harris, David W.; Campbell, DeWayne A.; Tuttle, Gene E.; McKeown, Mark H.; Beason, Steven C.

    1993-01-01

    The laser goniometer is an apparatus which permits an operator to sight along a geologic feature and orient a collimated lamer beam to match the attitude of the feature directly. The horizontal orientation (strike) and the angle from horizontal (dip), are detected by rotary incremental encoders attached to the laser goniometer which provide a digital readout of the azimuth and tilt of the collimated laser beam. A microprocessor then translates the square wave signal encoder outputs into an ASCII signal for use by data recording equipment.

  4. Explosive laser

    DOEpatents

    Robinson, C.P.; Jensen, R.J.; Davis, W.C.; Sullivan, J.A.

    1975-09-01

    This patent relates to a laser system wherein reaction products from the detonation of a condensed explosive expand to form a gaseous medium with low translational temperature but high vibration population. Thermal pumping of the upper laser level and de-excitation of the lower laser level occur during the expansion, resulting in a population inversion. The expansion may be free or through a nozzle as in a gas-dynamic configuration. In one preferred embodiment, the explosive is such that its reaction products are CO$sub 2$ and other species that are beneficial or at least benign to CO$sub 2$ lasing. (auth)

  5. Laser arthroscopy.

    PubMed

    Sherk, H H; Lane, G J; Black, J D

    1992-09-01

    Lasers have become widely used in several medical and surgical disciplines. In ophthalmology and plastic surgery, their use has permitted the development of therapeutic modalities that would have been otherwise impossible. In such specialties as gynecology and general surgery, lasers provide advantages that make certain procedures more convenient and easier to perform. In contrast, orthopaedic surgeons have, to date, been slow to accept these devices into the therapeutic armamentarium. The purpose of this paper is to describe the status of laser use in the orthopaedic subspecialty of arthroscopy. PMID:1437258

  6. Compact Fiber Laser for 589nm Laser Guide Star Generation

    NASA Astrophysics Data System (ADS)

    Pennington, D.; Drobshoff, D.; Mitchell, S.; Brown, A.

    Laser guide stars are crucial to the broad use of astronomical adaptive optics, because they facilitate access to a large fraction of possible locations on the sky. Lasers tuned to the 589 nm atomic sodium resonance can create an artificial beacon at altitudes of 95-105 km, thus coming close to reproducing the light path of starlight. The deployment of multiconjugate adaptive optics on large aperture telescopes world-wide will require the use of three to nine sodium laser guide stars in order to achieve uniform correction over the aperture with a high Strehl value. Current estimates place the minimum required laser power at > 10 W per laser for a continuous wave source, though a pulsed format, nominally 6?s in length at ~ 16.7 kHz, is currently preferred as it would enable tracking the laser through the Na layer to mitigate spot elongation. The lasers also need to be compact, efficient, robust and turnkey. We are developing an all-fiber laser system for generating a 589 nm source for laser-guided adaptive optics. Fiber lasers are more compact and insensitive to alignment than their bulk laser counterparts, and the heat-dissipation characteristics of fibers, coupled with the high efficiencies demonstrated and excellent spatial mode characteristics, make them a preferred candidate for many high power applications. Our design is based on sum-frequency mixing an Er/Yb:doped fiber laser operating at 1583 nm with a 938 nm Nd:silica fiber laser in a periodically poled crystal to generate 589 nm. We have demonstrated 14 W at 1583 nm with an Er/Yb:doped fiber laser, based on a Koheras single frequency fiber oscillator amplified in an IPG Photonics fiber amplifier. The Nd:silica fiber laser is a somewhat more novel device, since the Nd3+ ions must operate on the resonance transition (i.e. 4F3/2-4I9/2), while suppressing ASE losses at the more conventional 1088 nm transition. Optimization of the ratio of the fiber core and cladding permits operation of the laser at room

  7. Laser fusion

    SciTech Connect

    Smit, W.A.; Boskma, P.

    1980-12-01

    Unrestricted laser fusion offers nations an opportunity to circumvent arms control agreements and develop thermonuclear weapons. Early laser weapons research sought a clean radiation-free bomb to replace the fission bomb, but this was deceptive because a fission bomb was needed to trigger the fusion reaction and additional radioactivity was induced by generating fast neutrons. As laser-implosion experiments focused on weapons physics, simulating weapons effects, and applications for new weapons, the military interest shifted from developing a laser-ignited hydrogen bomb to more sophisticated weapons and civilian applications for power generation. Civilian and military research now overlap, making it possible for several countries to continue weapons activities and permitting proliferation of nuclear weapons. These countries are reluctant to include inertial confinement fusion research in the Non-Proliferation Treaty. 16 references. (DCK)

  8. Laser barometer

    SciTech Connect

    Abercrombie, K.R.; Shiels, D.; Rash, T.

    1998-04-01

    This paper describes an invention of a pressure measuring instrument which uses laser radiation to sense the pressure in an enclosed environment by means of measuring the change in refractive index of a gas - which is pressure dependent.

  9. Laser Research

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Eastman Kodak Company, Rochester, New York is a broad-based firm which produces photographic apparatus and supplies, fibers, chemicals and vitamin concentrates. Much of the company's research and development effort is devoted to photographic science and imaging technology, including laser technology. Eastman Kodak is using a COSMIC computer program called LACOMA in the analysis of laser optical systems and camera design studies. The company reports that use of the program has provided development time savings and reduced computer service fees.

  10. Laser Technology

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Amoco Laser Company, a subsidiary of Amoco Corporation, has developed microlasers for the commercial market based on a JPL concept for optical communications over interplanetary distances. Lasers emit narrow, intense beams of light or other radiation. The beams transmit communication signals, drill, cut or melt materials or remove diseased body tissue. The microlasers cover a broad portion of the spectrum, and performance is improved significantly. Current applications include medical instrumentation, color separation equipment, telecommunications, etc.

  11. Laser optomechanics.

    PubMed

    Yang, Weijian; Gerke, Stephen Adair; Ng, Kar Wei; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J

    2015-01-01

    Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors. PMID:26333804

  12. Laser optomechanics

    PubMed Central

    Yang, Weijian; Adair Gerke, Stephen; Wei Ng, Kar; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J.

    2015-01-01

    Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors. PMID:26333804

  13. Laser optomechanics

    NASA Astrophysics Data System (ADS)

    Yang, Weijian; Adair Gerke, Stephen; Wei Ng, Kar; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J.

    2015-09-01

    Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors.

  14. Laser Angioplasty

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The principal method of dealing with coronary artery blockage is bypass surgery. A non-surgical alternative available to some patients is balloon angioplasty. For several years, medical researchers have been exploring another alternative that would help a wider circle of patients than the balloon treatment and entail less risk than bypass surgery. A research group is on the verge of an exciting development: laser angioplasty with a 'cool' type of laser, called an excimer laser, that does not damage blood vessel walls and offers non-surgical cleansing of clogged arteries with extraordinary precision. The system is the Dymer 200+ Excimer Laser Angioplasty System, developed by Advanced Intraventional Systems. Used in human clinical tests since 1987, the system is the first fully integrated 'cool' laser capable of generating the requisite laser energy and delivering the energy to target arteries. Thirteen research hospitals in the U.S. have purchased Dymer 200+ systems and used them in clinical trials in 121 peripheral and 555 coronary artery cases. The success rate in opening blocked coronary arteries is 85 percent, with fewer complications than in balloon angioplasty. Food and Drug Administration approval for the system is hoped for in the latter part of 1990. * Advanced Intraventional Systems became Spectranetics in 1994 and discontinued the product.

  15. Laser therapy for cancer

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000905.htm Laser therapy for cancer To use the sharing features ... Lasers are also used on the skin. How Laser Therapy is Used Laser therapy can be used ...

  16. Tunable solid state lasers

    SciTech Connect

    Hammerling, R.; Budgor, A.B.; Pinto, A.

    1985-01-01

    This book presents the papers given at a conference on solid state lasers. Topics considered at the conference included transition-metal-doped lasers, line-narrowed alexandrite lasers, NASA specification, meteorological lidars, laser materials spectroscopy, laser pumped single pass gain, vibronic laser materials growth, crystal growth methods, vibronic laser theory, cross-fertilization through interdisciplinary fields, and laser action of color centers in diamonds.

  17. Collisional Transfer of Population and Orientation in NaK

    NASA Astrophysics Data System (ADS)

    Wolfe, C. M.; Ashman, S.; Huennekens, J.; Beser, B.; Bai, J.; Lyyra, A. M.

    2010-03-01

    We report current work to study transfer of population and orientation in collisions of NaK molecules with argon and potassium atoms using polarization labeling (PL) and laser- induced fluorescence (LIF) spectroscopy. In the PL experiment, a circularly polarized pump laser excites a specific NaK A^1&+circ;(v'=16, J') <- X^1&+circ;(v''=0, J'±1) transition, creating an orientation (non-uniform MJ' level distribution) in both levels. The linearly polarized probe laser is scanned over various 3^1π(v, J'±1) <- A^1&+circ;(v'=16, J') transitions. The probe laser passes through a crossed linear polarizer before detection, and signal is recorded if the probe laser polarization has been modified by the vapor (which occurs when it comes into resonance with an oriented level). Using both spectroscopic methods, analysis of weak collisional satellite lines adjacent to these directly populated lines, as a function of argon buffer gas pressure and cell temperature, allows us to discern separately the effects collisions with argon atoms and potassium atoms have on the population and orientation of the molecule. In addition, code has been written which provides a theoretical analysis of the process, through a solution of the density matrix equations of motion for the system.

  18. Active beam shaping in multiple laser guide stars

    NASA Astrophysics Data System (ADS)

    Jones, Katharine J.

    2012-10-01

    Adaptive beam shaping is a critical part of multiple Laser Guide Stars (LGS) for Multiple Conjugate Adaptive Optics (MCAO) for ground-based astronomical telescopes. There are two kinds of Laser Guide Stars: Na Laser Guide Stars (at 589 nm and 92 km altitude) and Rayleigh Laser Guide Stars (at 532 nm and 20 km altitude). Multiple Conjugate Adaptive Optics (MCAO) corrects for each "layer" of atmosphere independently. Multiple Laser Guide Stars are being developed to achieve a measure of tilt and increase the isoplanatic patch. Multiple Laser Guide Stars are being combined with Multiple Conjugate Optics in the Large Binocular Telescope (LBT): more than one Laser Guide Star (4-5) and two different wavelengths: 589 nm and 532 nm. Other observatories have multiple Laser Guide Stars but only one wavelength: 589 nm or 532 nm. Because Laser Guide Stars are launched into the atmosphere, adaptive beam shaping will be carried out before the laser is launched and will be different depending on which laser is being used, presumably to effect the tightest beam which can be achieved at the power level which is required to provide the requisite return to gound-based wavefront sensors. A complete range of devices are used. Beam attenuation and divergnece will take place. Multiple Laser Guide Stars of major observatories (SOR, LBT, MMT, ESO VLT and Gemini South) will be evaluated for effective adaptive beam shaping and impact on performance

  19. Excimer lasers

    NASA Technical Reports Server (NTRS)

    Palmer, A. J.; Hess, L. D.; Stephens, R. R.

    1976-01-01

    A theoretical and experimental investigation into the possibility of achieving CW discharge pumped excimer laser oscillation is reported. Detailed theoretical modeling of capillary discharge pumping of the XeF and KXe and K2 excimer systems was carried out which predicted the required discharge parameters for reaching laser threshold on these systems. Capillary discharge pumping of the XeF excimer system was investigated experimentally. The experiments revealed a lower excimer level population density than predicted theoretically by about an order of magnitude. The experiments also revealed a fluorine consumption problem in the discharge in agreement with theory.

  20. Laser Resonator

    NASA Technical Reports Server (NTRS)

    Harper, L. L. (Inventor)

    1983-01-01

    An optical resonator cavity configuration has a unitary mirror with oppositely directed convex and concave reflective surfaces disposed into one fold and concertedly reversing both ends of a beam propagating from a laser rod disposed between two total internal reflection prisms. The optical components are rigidly positioned with perpendicularly crossed virtual rooflines by a compact optical bed. The rooflines of the internal reflection prisms, are arranged perpendicularly to the axis of the laser beam and to the optical axes of the optical resonator components.

  1. Airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-06-01

    The US Air Force Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the risk reduction approach being utilized to ensure program success.

  2. Laser barometer

    DOEpatents

    Abercrombie, Kevin R.; Shiels, David; Rash, Tim

    2001-02-06

    A pressure measuring instrument that utilizes the change of the refractive index of a gas as a function of pressure and the coherent nature of a laser light to determine the barometric pressure within an environment. As the gas pressure in a closed environment varies, the index of refraction of the gas changes. The amount of change is a function of the gas pressure. By illuminating the gas with a laser light source, causing the wavelength of the light to change, pressure can be quantified by measuring the shift in fringes (alternating light and dark bands produced when coherent light is mixed) in an interferometer.

  3. Lidar observations of Na density, Ca ion density, temperature, and wind in the mesopause region

    NASA Astrophysics Data System (ADS)

    Nagasawa, Chikao; Abo, Makoto; Shibata, Yasukuni

    2001-02-01

    We have developed the resonance scattering lidar system for measurements of mesospheric metallic species such as Na, K, Fe atoms and Ca ions and mesospheric temperature and wind. The flashlamp pumped Ti:sapphire laser injected by the seeder that consists of an external cavity laser diode is applied for measurements of the K and Fe atoms and the Ca ions. The sophisticated lidar system which consists of a pulsed dye oscillator and an amplifier system injection-seeded by a stabilized cw ring dye laser is also applied for Na atoms, temperature and wind measurements. Its injection-seeder consists of the single mode ring dye laser locked to the Na fluorescence line using the wavemeter and the Na vapor cell. The most characteristic of this laser system is to generate the comparatively high pulse energy ( more than 100mJ/pulse ) keeping up the narrow bandwidth ( about 0.1pm ). In this paper, the details of the laser design and the results observed by these lidar system are shown.

  4. Specific oxidation pattern of soluble starch with TEMPO-NaBr-NaClO system.

    PubMed

    Hao, Jie; Lu, Jiaojiao; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing

    2016-08-01

    Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25°C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions. PMID:27112871

  5. Blue satellites of absorption spectrum study of sodium based excimer-pumped alkali vapor laser

    NASA Astrophysics Data System (ADS)

    Hu, Shu; Gai, Baodong; Guo, Jingwei; Tan, Yannan; Liu, Jinbo; Li, Hui; Cai, Xianglong; Shi, Zhe; Liu, Wanfa; Jin, Yuqi; Sang, Fengting

    2015-02-01

    Sodium based excimer-pump alkali laser (Na-XPAL) is expected to be an efficient method to generate sodium beacon light, but the information about the spectroscopic characters of Na-XPAL remains sparse so far. In this work, we utilized the relative fluorescence intensity to study the absorption spectrum of blue satellites of complexes of sodium with different collision partners. The yellow fluorescence of Na D1 and D2 line was clearly visible. After processing the fluorescence intensity and the input pumping laser relative intensity, we obtained the Na-CH4 system's blue satellites was from 553nm to 556nm. Meanwhile, we experimentally demonstrated the Na-Ar and Na-Xe system's wavelength range of blue satellites. Also, it was observed that the Na-Xe system's absorption was stronger than the other two systems.

  6. Laser Cladding

    NASA Astrophysics Data System (ADS)

    Lepski, Dietrich; Brückner, Frank

    Laser cladding is a modern technology whose uses include, for example, the creation of protective coatings to reduce wear and corrosion on engine parts and tools. The aircraft and automotive industries are examples of industries in which it is much used. This account considers the theory of a number of aspects of the process in detail. The first to be studied is the interaction of the laser beam directly with the powder that is being deposited; the effects of gravity, beam shadowing, and particle heating are investigated. This is followed by a discussion of the mechanisms by which the particles adhere to the surface of the work piece and are absorbed into it. In order to understand the process, a study of the melt pool and the associated temperature distribution is necessary; it is then possible to infer the final bead geometry. An inevitable consequence of a thermal process such as laser cladding is the induced thermal stress and resulting distortion of the work piece. The fundamentals are discussed, a numerical model presented and in addition a simple heuristic model is given. The use of induction-assisted laser cladding as a means of preventing the formation of cracks is discussed.

  7. Excimer lasers

    NASA Technical Reports Server (NTRS)

    Palmer, A. J.; Hess, L. D.; Stephens, R. R.; Pepper, D. M.

    1977-01-01

    The results of a two-year investigation into the possibility of developing continuous wave excimer lasers are reported. The program included the evaluation and selection of candidate molecular systems and discharge pumping techniques. The K Ar/K2 excimer dimer molecules and the xenon fluoride excimer molecule were selected for study; each used a transverse and capillary discharges pumping technique. Experimental and theoretical studies of each of the two discharge techniques applied to each of the two molecular systems are reported. Discharge stability and fluorine consumption were found to be the principle impediments to extending the XeF excimer laser into the continuous wave regime. Potassium vapor handling problems were the principal difficulty in achieving laser action on the K Ar/K2 system. Of the four molecular systems and pumping techniques explored, the capillary discharge pumped K Ar/K2 system appears to be the most likely candidate for demonstrating continuous wave excimer laser action primarily because of its predicted lower pumping threshold and a demonstrated discharge stability advantage.

  8. Laser iridotomy.

    PubMed

    Perkins, E S

    1970-06-01

    A ruby laser has been used to produce a permeable lesion in the iris to establish a communication between the anterior and posterior chambers. In a preliminary study in nine patients the technique gave satisfactory results in the prophylactic treatment of four cases of incipient closed-angle glaucoma and of two cases of iris bombé following uveitis. PMID:5526615

  9. Laser capture.

    PubMed

    Potter, S Steven; Brunskill, Eric W

    2012-01-01

    This chapter describes detailed methods used for laser capture microdissection (LCM) of discrete subpopulations of cells. Topics covered include preparing tissue blocks, cryostat sectioning, processing slides, performing the LCM, and purification of RNA from LCM samples. Notes describe the fine points of each operation, which can often mean the difference between success and failure. PMID:22639264

  10. Laser altimeter

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development of a laser altimeter for use in the Apollo Lunar Orbital Experiments mission is discussed. The altimeter provides precise measurement of an Apollo vehicle above the lunar surface from an orbit of 40 to 80 nautical miles. The technical characteristics of the altimeter are described. Management of the altimeter development program is analyzed.

  11. Nanowire Lasers

    NASA Astrophysics Data System (ADS)

    Couteau, C.; Larrue, A.; Wilhelm, C.; Soci, C.

    2015-05-01

    We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs), solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D) nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

  12. Perovskite-to-postperovskite transitions in NaNiF3 and NaCoF3 and disproportionation of NaCoF3 postperovskite under high pressure and high temperature.

    PubMed

    Yusa, Hitoshi; Shirako, Yuichi; Akaogi, Masaki; Kojitani, Hiroshi; Hirao, Naohisa; Ohishi, Yasuo; Kikegawa, Takumi

    2012-06-18

    High-pressure structural phase transitions in NaNiF(3) and NaCoF(3) were investigated by conducting in situ synchrotron powder X-ray diffraction experiments using a diamond anvil cell. The perovskite phases (GdFeO(3) type) started to transform into postperovskite phases (CaIrO(3) type) at about 11-14 GPa, even at room temperature. The transition pressure is much lower than those of oxide perovskites. The anisotropic compression behavior led to heavily tilted octahedra that triggered the transition. Unlike oxide postperovskites, fluoropostperovskites remained after decompression to 1 atm. The postperovskite phase in NaCoF(3) broke down into a mixture of unknown phases after laser heating above 26 GPa, and the phases changed into amorphous ones when the pressure was released. High-pressure and high-temperature experiments using a multianvil apparatus were also conducted to elucidate the phase relations in NaCoF(3). Elemental analysis of the recovered amorphous samples indicated that the NaCoF(3) postperovskite disproportionated into two phases. This kind of disproportionation was not evident in NaNiF(3) even after laser heating at 54 GPa. In contrast to the single postpostperovskite phase reported in NaMgF(3), such a postpostperovskite phase was not found in the present compounds. PMID:22656193

  13. Laser weapons. II - Strategic laser weapons

    NASA Astrophysics Data System (ADS)

    Hecht, J.

    1982-07-01

    Potential strategic missions for laser weapons, particularly those involving space-based lasers, are discussed. The functions of space-based lasers and the history of their conceptual development are summarized, and the problems of implementing such systems, including the building of a suitable laser and power source, and resolving the problem of optics, are discussed. Ongoing development programs are described, and the contrasting views of the necessity and usefulness of strategic laser systems are set forth.

  14. Spectroscopic Analysis of High Intensity Laser Beam Jets Interaction Experiments on the Leopard Laser at UNR

    NASA Astrophysics Data System (ADS)

    Petkov, E. E.; Weller, M. E.; Kantsyrev, V. L.; Safronova, A. S.; Moschella, J. J.; Shrestha, I.; Shlyapsteva, V. V.; Stafford, A.; Keim, S. F.; University of Nevada Reno Team

    2013-10-01

    Results of Ar gas-puff experiments performed on the high power Leopard laser at UNR are presented. Flux density of laser radiation in focal spot was up to 2 × 1016 W/cm2 (pulse duration was 0.8 ns and laser wavelength was 1.057 μm). Specifically, spectroscopic analysis of K-shell Ar spectra are investigated and compared as functions of the orientation of the laser beam to linear gas jet. The laser beam axis was positioned either along the jet plane or orthogonal to it at a distance of 1 mm from the nozzle output. The diagnostics used included a time-integrated x-ray spectrometer along with a set of filtered Si diodes with various cutoff energies. In order to identify lines, a non-local thermodynamic equilibrium (non-LTE) kinetic model was utilized and was also used to determine plasma parameters such as electron temperature and density. The importance of the spectroscopic study of high intensity laser beam-jets interaction experiments is discussed. This work was supported by the Defense Threat Reduction Agency, Basic Research Award # HDTRA1-13-1-0033, to University of Nevada, Reno, and in part by the DOE/NNSA Cooperative agreements DE-NA0001984 and DE-FC52-06NA27616.

  15. Preparation of platinum nanoparticles in liquids by laser ablation method

    NASA Astrophysics Data System (ADS)

    Binh Nguyen, The; Dinh Nguyen, Thanh; Nguyen, Quang Dong; Trinh Nguyen, Thi

    2014-09-01

    Platinum (Pt) nanoparticles were prepared in solutions of ethanol and TSC (trisodium citrate—Na3C6H5O7.nH2O) in water by laser ablation method using Nd:YAG laser. The role of laser fluence, laser wavelength and concentration of surfactant liquids in laser ablation process were investigated. The morphology, size distribution and optical properties of the Pt nanoparticles (NPs) were observed by transmission electron microscopy (TEM), UV-vis spectrometer and x-ray diffraction measurements. The average diameter of Pt NPs prepared in ethanol and TSC solutions ranges around 7-9 nm and 10-12 nm, respectively. The results showed advantages of the laser ablation method.

  16. Laser radiometer

    SciTech Connect

    Stein, A.; Kaldor, A.; Rabinowitz, P.

    1983-11-29

    The present invention teaches a unique laser radiometer capable of accurately measuring the radiation temperature of a radiant surface and independently measuring the surface's emissivity. A narrow-band radiometer is combined with a laser reflectometer to measure concurrently radiance and emissivity of a remote, hot surface. Together, radiance and emissivity yield the true surface temperature of the remote target. A narrow receiver bandwidth is attained by one of two methods; (a) heterodyne detection or (b) optical filtering. A direct measurement of emissivity is used to adjust the value obtained for the thermal radiation signal to substantially enhance the accuracy of the temperature measurement for a given subject surface. The technique provides substantially high detection sensitivity over a very narrow spectral bandwidth.

  17. Infrared Lasers in Chemistry.

    ERIC Educational Resources Information Center

    John, Phillip

    1982-01-01

    Selected infrared laser chemistry topics are discussed including carbon dioxide lasers, infrared quanta and molecules, laser-induced chemistry, structural isomerization (laser purification, sensitized reactions, and dielectric breakdown), and fundamental principles of laser isotope separation, focusing on uranium isotope separation. (JN)

  18. Heterodyne laser diagnostic system

    DOEpatents

    Globig, Michael A.; Johnson, Michael A.; Wyeth, Richard W.

    1990-01-01

    The heterodyne laser diagnostic system includes, in one embodiment, an average power pulsed laser optical spectrum analyzer for determining the average power of the pulsed laser. In another embodiment, the system includes a pulsed laser instantaneous optical frequency measurement for determining the instantaneous optical frequency of the pulsed laser.

  19. Making a Laser Level

    ERIC Educational Resources Information Center

    Hawkins, Harry

    2004-01-01

    This article describes how to construct a laser level. This laser level can be made using a typical 4' (or shorter) bubble level and a small laser point. The laser unit is detachable, so the bubble level can also be used in the conventional way. However, the laser level works better than a simple bubble level. Making this inexpensive device is an…

  20. Sequential growth of sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell-shell nanoparticles for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Peng, Huang-Yong; Ding, Bin-Bin; Ma, Yin-Chu; Sun, Shi-Qi; Tao, Wei; Guo, Yan-Chuan; Guo, Hui-Chen; Yang, Xian-Zhu; Qian, Hai-Sheng

    2015-12-01

    Upconversion (UC) nanostructures have attracted much interest for their extensive biological applications. In this work, we describe a sequential synthetic route to prepare sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell upconversion nanoparticles. The as-prepared products were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM, JEM 2100F), respectively. The as-prepared core-shell nanoparticles of NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb are composed of elliptical nanoparticles with a length of 80 nm and width of 42 nm, which show efficient upconversion fluorescence excited at 808 nm indicating the formation of core-shell-shell sandwiched nanostructures. In addition, the as-prepared sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell upconversion nanoparticles also show strong upconversion fluorescence excited at 980 nm. Amphiphilic mPEG2k-b-PEBEP6K copolymers (denoted as PPE) were chosen to transfer these hydrophobic UCNPs into the aqueous phase for biological application. In vitro photodynamic therapy of cancer cells show that the viability of cells incubated with the nanoparticles loaded with MC 540 was significantly lower as compared to the nanoparticles without photosensitizers exposed to NIR laser.

  1. Project LASER

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA formally launched Project LASER (Learning About Science, Engineering and Research) in March 1990, a program designed to help teachers improve science and mathematics education and to provide 'hands on' experiences. It featured the first LASER Mobile Teacher Resource Center (MTRC), is designed to reach educators all over the nation. NASA hopes to operate several MTRCs with funds provided by private industry. The mobile unit is a 22-ton tractor-trailer stocked with NASA educational publications and outfitted with six work stations. Each work station, which can accommodate two teachers at a time, has a computer providing access to NASA Spacelink. Each also has video recorders and photocopy/photographic equipment for the teacher's use. MTRC is only one of the five major elements within LASER. The others are: a Space Technology Course, to promote integration of space science studies with traditional courses; the Volunteer Databank, in which NASA employees are encouraged to volunteer as tutors, instructors, etc; Mobile Discovery Laboratories that will carry simple laboratory equipment and computers to provide hands-on activities for students and demonstrations of classroom activities for teachers; and the Public Library Science Program which will present library based science and math programs.

  2. Laser nitriding and laser carburizing of surfaces

    NASA Astrophysics Data System (ADS)

    Schaaf, Peter

    2003-11-01

    Laser irradiation of surfaces with short pulses in reactive atmospheres (nitrogen, methane) can lead to very effective nitrification and carburization via complicated laser-surface-gas-plasma-interactions. This laser nitriding and laser carburizing and their basic underlying phenomena will be presented and partly explained by results of example materials (iron, titanium, aluminum, silicon) where nitride and carbide coatings can be formed by fast and easily by Excimer Laser, Nd:YAG laser, Free Electron Laser and also by femtosecond Ti:sapphire laser. This implies laser pulse durations from the nanosecond to the femtosecond regime and wavelengths from ultra-violet to infrared. The resulting surfaces, thin films, coatings and their properties are investigated by combining Mossbauer Spectroscopy, x-ray diffraction, x-ray absorption spectroscopy, Nanoindentation, Resonant Nuclear Reaction Analysis, and Rutherford Backscattering Spectroscopy.

  3. Theoretical studies of solar-pumped lasers

    NASA Technical Reports Server (NTRS)

    Harries, W. L.

    1983-01-01

    Metallic vapor lasers of Na2 and Li2 are examined as solar energy converters. The absorbed photons cause transitions to vibrational-rotational levels in an upper electronic state. With broad band absorption the resultant levels can have quantum numbers considerably higher than the upper lasing level. The excited molecule then relaxes to the upper lasing level which is one of the lower vibrational levels in the upper electronic state. The relaxation occurs from collisions, provided the molecule is not quenched into the ground level electronic state. Lasing occurs with a transition to a vibrational level in the lower electronic state. Rough estimates of solar power efficiencies are 1 percent for Na2 and probably a similar figure for Li2. The nondissociative lasers from a family distinct from materials which dissociate to yield an excited atom.

  4. Mars Observer Laser Altimeter: laser transmitter.

    PubMed

    Afzal, R S

    1994-05-20

    The Mars Observer Laser Altimeter utilizes a space-qualified diode-laser-pumped Q-switched Nd:YAG laser transmitter. A simple numerical model of the laser energetics is presented, which predicts the pulse energy and pulse width. Comparisons with the measured data available are made. The temperature dependence of the laser transmitter is also predicted. This dependence prediction is particularly important in determining the operational temperature range of the transmitter. Knowing the operational temperature range is especially important for a passive, thermally controlled laser operating in space. PMID:20885685

  5. Holmium laser pumped with a neodymium laser

    SciTech Connect

    Bowman, S.R.; Rabinovich, W.S.

    1991-07-30

    This patent describes a solid-state laser device. It comprises a holmium laser having a first host material doped with an amount of holmium ions sufficient to produce an output laser emission at about 3 {mu}m when the holmium ions in the holmium laser are pumped by a pump beam at a wavelength of about 1.1 {mu}m; and neodymium laser pump source means for supplying a pump beam to pump the holmium ions in the holmium laser at a wavelength of about 1.1 {mu}m.

  6. Hypersonic gasdynamic laser system

    SciTech Connect

    Foreman, K.M.; Maciulaitis, A.

    1990-05-22

    This patent describes a visible, or near to mid infra-red, hypersonic gas dynamic laser system. It comprises: a hypersonic vehicle for carrying the hypersonic gas dynamic laser system, and also providing high energy ram air for thermodynamic excitation and supply of the laser gas; a laser cavity defined within the hypersonic vehicle and having a laser cavity inlet for the laser cavity formed by an opening in the hypersonic vehicle, such that ram air directed through the laser cavity opening supports gas dynamic lasing operations at wavelengths less than 10.6{mu} meters in the laser cavity; and an optical train for collecting the laser radiation from the laser cavity and directing it as a substantially collimated laser beam to an output aperture defined by an opening in the hypersonic vehicle to allow the laser beam to be directed against a target.

  7. Laser therapy (image)

    MedlinePlus

    A laser is used for many medical purposes. Because the laser beam is so small and precise, it enables ... without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  8. Laser-Driven Fusion.

    ERIC Educational Resources Information Center

    Gibson, A. F.

    1980-01-01

    Discusses the present status and future prospects of laser-driven fusion. Current research (which is classified under three main headings: laser-matter interaction processes, compression, and laser development) is also presented. (HM)

  9. Lasers in Medicine.

    ERIC Educational Resources Information Center

    Hill, P. D.

    1989-01-01

    Described are the characteristics of the laser and its effects on the body. Discussed are examples of laser treatments, including angioplasty, ophthalmology, and dermatology. A discussion of lasers of clinical interest and their applications is presented. (YP)

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

  11. Laser accidents: Being Prepared

    SciTech Connect

    Barat, K

    2003-01-24

    The goal of the Laser Safety Officer and any laser safety program is to prevent a laser accident from occurring, in particular an injury to a person's eyes. Most laser safety courses talk about laser accidents, causes, and types of injury. The purpose of this presentation is to present a plan for safety offices and users to follow in case of accident or injury from laser radiation.

  12. Dissolution in a supercritical liquid as a mechanism of laser ablation of sapphire

    SciTech Connect

    Dolgaev, Sergei I; Karasev, M E; Kulevskii, L A; Simakin, Aleksandr V; Shafeev, Georgii A

    2001-07-31

    The laser ablation of sapphire is studied by irradiating its interface with water and aqueous solutions of KOH, KCl and Na{sub 2}CO{sub 3} by 2.92-{mu}m 130-ns holmium laser pulses. The ablation rate depends on the concentration and type of the dissolved substance. The highest ablation rate is 2.5{mu}m per pulse for a laser fluence of 120 J cm{sup -2}. The ablation of sapphire is attributed to its dissolution in water or in aqueous solutions in the supercritical state. (interaction of laser radiation with matter. laser plasma)

  13. Laser satellite power systems

    SciTech Connect

    Walbridge, E.W.

    1980-01-01

    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  14. New laser protective eyewear

    NASA Astrophysics Data System (ADS)

    McLear, Mark

    1996-04-01

    Laser technology has significantly impacted our everyday life. Lasers are now used to correct your vision, clear your arteries, and are used in the manufacturing of such diverse products as automobiles, cigarettes, and computers. Lasers are no longer a research tool looking for an application. They are now an integral part of manufacturing. In the case of Class IV lasers, this explosion in laser applications has exposed thousands of individuals to potential safety hazards including eye damage. Specific protective eyewear designed to attenuate the energy of the laser beam below the maximum permissible exposure is required for Class 3B and Class IV lasers according to laser safety standards.

  15. PHYSICAL AND OPTICAL PROPERTIES OF STEAM-EXPLODED LASER-PRINTED PAPER

    EPA Science Inventory

    Laser-printed paper was pulped by the steam-explosion process. A full-factorial experimental design was applied to determine the effects of key operating variables on the properties of steam-exploded pulp. The variables were addition level for pulping chemicals (NaOH and/or Na2SO...

  16. Time-Resolved Spectroscopy With A Narrow-Band Pulsed Dye Laser At High Irradiances

    NASA Astrophysics Data System (ADS)

    van Bergen, A. R.; Hollander, Tj.; Alkemade, C. T.

    1985-03-01

    We measured the fluorescence spectrum of the Na-D lines in a sodium vapour cell filled with Ar gas, excited by an intense, nearly monochromatic laser near resonance. In this case the theory (dressed-atom model) predicts a line splitting dependent on the laser intensity.

  17. Laser-induced fluorescence detection strategies for sodium atoms and compounds in high-pressure combustors

    NASA Technical Reports Server (NTRS)

    Weiland, Karen J. R.; Wise, Michael L.; Smith, Gregory P.

    1993-01-01

    A variety of laser-induced fluorescence schemes were examined experimentally in atmospheric pressure flames to determine their use for sodium atom and salt detection in high-pressure, optically thick environments. Collisional energy transfer plays a large role in fluorescence detection. Optimum sensitivity, at the parts in 10 exp 9 level for a single laser pulse, was obtained with the excitation of the 4p-3s transition at 330 nm and the detection of the 3d-3p fluorescence at 818 nm. Fluorescence loss processes, such as ionization and amplified spontaneous emission, were examined. A new laser-induced atomization/laser-induced fluorescence detection technique was demonstrated for NaOH and NaCl. A 248-nm excimer laser photodissociates the salt molecules present in the seeded flames prior to atom detection by laser-induced fluorescence.

  18. Laser Stabilization

    SciTech Connect

    Hall, John L.; Taubman, Matthew S.; Ye, Jun

    2010-01-01

    This book chapter covers the basics of the field of stabilizing lasers to optical frequency references such as optical cavities and molecular transitions via the application of servo control systems. These discussions are given with reference to the real-life frequency metrology experienced in Hall-Labs (now Ye-Labs), JILA, University of Colorado. The subjects covered include: the basics of control system stability, a discussion of both the theoretical and experimental limitations, an outline of optical cavity susceptibility to environmental noise, and a brief introduction to the use and limitations of molecular transitions as frequency references.

  19. Laser biophotonics

    NASA Astrophysics Data System (ADS)

    Bashkatov, A. N.; Genina, E. A.; Priezzhev, A. V.; Tuchin, V. V.

    2016-06-01

    This issue of Quantum Electronics presents the papers that reflect the state-of-the-art of laser technologies used in biomedical studies and medical practice. Among the new technologies, one can note the methods of correlation and Doppler spectroscopy, as well as THz spectroscopy, in which biologically significant molecules are characterised by specific resonances. The latter topic is considered in the paper by Nazarov et al., where the dielectric function of aqueous solutions of glucose and albumin is studied using pulsed THz spectroscopy.

  20. Laser Propulsion - Quo Vadis

    SciTech Connect

    Bohn, Willy L.

    2008-04-28

    First, an introductory overview of the different types of laser propulsion techniques will be given and illustrated by some historical examples. Second, laser devices available for basic experiments will be reviewed ranging from low power lasers sources to inertial confinement laser facilities. Subsequently, a status of work will show the impasse in which the laser propulsion community is currently engaged. Revisiting the basic relations leads to new avenues in ablative and direct laser propulsion for ground based and space based applications. Hereby, special attention will be devoted to the impact of emerging ultra-short pulse lasers on the coupling coefficient and specific impulse. In particular, laser sources and laser propulsion techniques will be tested in microgravity environment. A novel approach to debris removal will be discussed with respect to the Satellite Laser Ranging (SRL) facilities. Finally, some non technical issues will be raised aimed at the future prospects of laser propulsion in the international community.

  1. Polarization/Spatial Combining of Laser-Diode Pump Beams

    NASA Technical Reports Server (NTRS)

    Gelsinger, Paul; Liu, Duncan

    2008-01-01

    A breadboard version of an optical beam combiner is depicted which make it possible to use the outputs of any or all of four multimode laser diodes to pump a non-planar ring oscillator (NPRO) laser. The output of each laser diode has a single-mode profile in the meridional plane containing an axis denoted the 'fast' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis. One of the purposes served by the beam-combining optics is to reduce the fast-axis numerical aperture (NA) of the laser-diode output to match the NA of the optical fiber. Along the slow axis, the unmodified laser-diode NA is already well matched to the fiber optic NA, so no further slow-axis beam shaping is needed. In this beam combiner, the laser-diode outputs are collimated by aspherical lenses, then half-wave plates and polarizing beam splitters are used to combine the four collimated beams into two beams. Spatial combination of the two beams and coupling into the optical fiber is effected by use of anamorphic prisms, mirrors, and a focusing lens. The anamorphic prisms are critical elements in the NA-matching scheme, in that they reduce the fast-axis beam width to 1/6 of its original values. Inasmuch as no slow-axis beam shaping is needed, the collimating and focusing lenses are matched for 1:1 iumaging. Because these lenses are well corrected for infinite conjugates the combiner offers diffraction-limited performance along both the fast and slow axes.

  2. Studies on lasers and laser devices

    NASA Technical Reports Server (NTRS)

    Harris, S. E.; Siegman, A. E.; Young, J. F.

    1983-01-01

    The goal of this grant was to study lasers, laser devices, and uses of lasers for investigating physical phenomena are studied. The active projects included the development of a tunable, narrowband XUV light source and its application to the spectroscopy of core excited atomic states, and the development of a technique for picosecond time resolution spectroscopy of fast photophysical processes.

  3. The Geoscience Laser Altimeter System Laser Transmitter

    NASA Technical Reports Server (NTRS)

    Afzal, R. S.; Dallas, J. L.; Yu, A. W.; Mamakos, W. A.; Lukemire, A.; Schroeder, B.; Malak, A.

    2000-01-01

    The Geoscience Laser Altimeter System (GLAS), scheduled to launch in 2001, is a laser altimeter and lidar for tile Earth Observing System's (EOS) ICESat mission. The laser transmitter requirements, design and qualification test results for this space- based remote sensing instrument are presented.

  4. Single-frequency glass waveguide lasers

    NASA Astrophysics Data System (ADS)

    Taccheo, S.; Della Valle, G.; Milanese, D.

    2008-10-01

    We report results on a single-end pumped waveguide laser for sensing applications Output power in excess of 20 mW with 17% slope efficiency in robust single-frequency operation at 1533.5 nm is demonstrated. The overall laser cavity laser was 60-mm long but the active medium, an Er:Yb-doped phosphate glass, was only 9-mm long. The waveguide was fabricated by two-step Ag-Na ion-exchange technique. The overall cavity length including butt-coupled fiber- Bragg-grating mirrors was <60 mm. We also reports on recent work to reach 100-mW single-frequency output power. To extend the operation wavelength to 2-micron wavelength region we also developed new tellurite glasses. Preliminary results on glass investigation are also reported.

  5. Experimental femtosecond laser photodisruption of rabbit sclera for minimally invasive laser sclerostomy: An in vitro study

    NASA Astrophysics Data System (ADS)

    Yang, Xiaobo; Dai, Nengli; Long, Hua; Lu, Peixiang; Li, Wan; Jiang, Fagang

    2010-07-01

    Femtosecond laser technology, used as a minimally invasive tool in intrastromal refractive surgery, may also have potential as a useful instrument for glaucoma filtration surgery. The purpose of the present study was to evaluate the feasibility of minimally invasive laser sclerostomy by femtosecond laser photodisruption and seek the appropriate patterns of laser ablation and relevant laser parameters. A femtosecond laser (800 nm/50 fs/1 kHz), focused by a 0.1 numerical aperture (NA) objective lens, with different pulse energies and exposure times was applied to ablate hydrated rabbit sclera in vitro. The irradiated samples were examined by scanning electron microscopy (SEM). By moving a three-dimensional, computer-controlled translation stage to which the sample was attached, the femtosecond laser could produce three types of ablation patterns, including linear ablation, cylindrical aperture and rectangular cavity. With pulse energies ranging from 37.5 to 150 μJ, the linear lesions were consistently observed at the inner surface of sclera, whereas it failed to make any photodisruption if pulse energy was below the threshold value of 31.25 μJ, with the corresponding threshold intensity of 4.06×10 14 W/cm 2. The depths of the linear lesions increased linearly with both pulse energy (37.5-150 μJ) and exposure time (0.1-0.4 s). Histological examination showed the incisions produced by femtosecond laser photodisruption had precise geometry and the edges were sharp and smooth, with no evidence of collateral damage to the surrounding tissue. Our results predict the potential application of femtosecond laser pulses in minimally invasive laser sclerostomy for glaucoma treatment.

  6. Above threshold dissociation of LiNa +: monitoring an avoided crossing with femtosecond spectroscopy

    NASA Astrophysics Data System (ADS)

    Magnier, S.; Toniolo, A.

    2001-04-01

    Computer simulations of one- and two-color experiments in above threshold dissociation (ATD) are reported for the first heteronuclear alkali ion LiNa +. We focus on the 1 2Σ +→1 2Π→4,5 2Σ + process, with dissociation to Li ++Na(3p) or Li(3s)+Na +. The product yields are determined by the presence of an avoided crossing between the 4 and 5 2Σ + potential curves, according to the frequency and delay of the second laser pulse.

  7. Phosphate glass useful in high energy lasers

    DOEpatents

    Hayden, Y.T.; Payne, S.A.; Hayden, J.S.; Campbell, J.H.; Aston, M.K.; Elder, M.L.

    1996-06-11

    In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

  8. Phosphate glass useful in high energy lasers

    DOEpatents

    Hayden, Yuiko T.; Payne, Stephen A.; Hayden, Joseph S.; Campbell, John H.; Aston, Mary Kay; Elder, Melanie L.

    1996-01-01

    In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

  9. Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Katori, H.; Yoneda, H.; Nakagawa, K.; Shimizu, F.

    2010-02-01

    .] -- Ultracold Ytterbium atoms in optical lattices / S. Sugawa ... [et al.] -- Ultracold polar molecules in the rovibrational ground state / J. Deiglmayr ... [et al.] -- Polar molecules near quantum degeneracy / J. Ye and D. S. Jin -- Production of a quantum gas of rovibronic ground-state molecules in an optical lattice / J. G. Danzl ... [et al.] -- Recent progress in x-ray nonlinear optics / K. Tamasaku, K. Sawada, and T. Ishikawa -- Gas in scattering media absorption spectroscopy - laser spectroscopy in unconventional environments / S. Svanberg -- Laser spectroscopy on relativistic ion beams / S. Reinhardt ... [et al.] -- Single frequency microcavity lasers and applications / L. Xu ... [et al.].

  10. The combined use of Er,Cr:YSGG laser and fluoride to prevent root dentin demineralization

    PubMed Central

    GERALDO-MARTINS, Vinícius Rangel; LEPRI, Cesar Penazzo; FARAONI-ROMANO, Juliana Jendiroba; PALMA-DIBB, Regina Guenka

    2014-01-01

    The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria. Objective To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz) irradiation associated with 2% neutral sodium fluoride (NaF) to prevent root dentin demineralization. Material and Methods One hundred human root dentin samples were divided into 10 groups (G) and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm2) with water cooling (WC=5.4 mL/min); G4: laser (4.64 J/cm2) without WC; G5: laser (8.92 J/cm2) with WC; G6: laser (8.92 J/cm2) without WC; G7: laser (4.64 J/cm2) with WC and NaF; G8: laser (4.64 J/cm2) without WC and NaF; G9: laser (8.92 J/cm2) with WC and NaF; G10: laser (8.92 J/cm2) without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN) test was done at different depths (30, 60, 90 and 120 μm) from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher's test (α=5%). Results The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p<0.05). Conclusions The use of Er,Cr:YSGG laser irradiation at 4.64 J/ cm2 and 8.92 J/cm2 without water cooling and associated with 2% NaF can increase the acid resistance of human root dentin. PMID:25466479

  11. Laser Wire Stripper

    NASA Technical Reports Server (NTRS)

    1983-01-01

    NASA-developed space shuttle technology is used in a laser wire stripper designed by Raytheon Company. Laser beams cut through insulation on a wire without damaging conductive metal, because laser radiation that melts plastic insulation is reflected by the metal. The laser process is fast, clean, precise and repeatable. It eliminates quality control problems and the expense of rejected wiring.

  12. Reverse laser drilling

    NASA Technical Reports Server (NTRS)

    Anthony, Thomas R. (Inventor)

    1984-01-01

    This invention provides a method for laser drilling small diameter, closely-spaced, and accurately located holes in a body of material which is transparent or substantially transparent to the laser radiation employed whereby the holes are drilled through the thickness of the body from the surface opposite to that on which the laser beam impinges to the surface of laser beam impingement.

  13. Longitudinal discharge laser baffles

    DOEpatents

    Warner, B.E.; Ault, E.R.

    1994-06-07

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam. 1 fig.

  14. Longitudinal discharge laser baffles

    DOEpatents

    Warner, Bruce E.; Ault, Earl R.

    1994-01-01

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam.

  15. Obstacles to Laser Safety

    SciTech Connect

    Barat, K

    2005-04-25

    The growth of laser development & technology has been remarkable. Unfortunately, a number of traps or obstacles to laser safety have also developed with that growth. The goal of this article is to highlight those traps, in the hope that an aware laser user will avoid them. These traps have been the cause or contributing factor of many a preventable laser accident.

  16. Laser surgery - skin

    MedlinePlus

    A laser is a light beam that can be focused on a very small area. The laser heats cells in the area being ... burst." There are several types of lasers. Each laser has specific uses. The color of the light beam used is directly related to the type of ...

  17. Narrow gap laser welding

    DOEpatents

    Milewski, J.O.; Sklar, E.

    1998-06-02

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables. 34 figs.

  18. Narrow gap laser welding

    DOEpatents

    Milewski, John O.; Sklar, Edward

    1998-01-01

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables.

  19. Short wavelength laser

    DOEpatents

    Hagelstein, P.L.

    1984-06-25

    A short wavelength laser is provided that is driven by conventional-laser pulses. A multiplicity of panels, mounted on substrates, are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path. When the panels are illuminated by the conventional-laser pulses, single pass EUV or soft x-ray laser pulses are produced.

  20. Laser accelerometer

    SciTech Connect

    Vescial, F.; Aronowitz, F.; Niguel, L.

    1990-04-24

    This patent describes a laser accelerometer. It comprises: an optical cavity characterizing a frame having an input axis (x), a cross axis (y) orthogonal to and co-planar with the input axis and a (z) axis passing through the intersection of the (x) and (y) axes, the (z) axis being orthogonal to the plane of the (x) and (y) axes; and (x) axis proof mass having a predetermined blanking surface; a flexible beam having a first end coupled to the (x) axis proof mass and a second end coupled to the frame, deflection of the flexible beams permitting a predetermined range of movement of the (x) proof mass on the input axis in a direction opposite to sensed acceleration of the frame; a laser light source having a mirror means within the cavity for providing a light ray coaxially aligned with the (z) axis; detector means having at least a first detector on a sensitive plane, the plane being normal to the (z) axis; bias and amplifier means coupled to the detector means for providing a bias current to the first detector and for amplifying the intensity signal; the (x) axis proof mass blanking surface being centrally positioned within and normal to the light ray null intensity region to provide increased blanking of the light ray in response to transverse movement of the mass on the input axis; control means responsive to the intensity signal for applying an (x) axis restoring force to restore the (x) axis proof mass to the central position and for providing an (x) axis output signal proportional to the restoring force.

  1. What is a Laser?

    NASA Astrophysics Data System (ADS)

    Julien, Lucile; Schwob, Catherine

    2015-10-01

    The first laser was built more than 50 years ago, inMay 1960: it was a pulsed ruby laser. It was a simple laboratory curiosity and nobody knew what its usefulness could be. Other devices were rapidly demonstrated, and the variety and number of lasers in the world increased at a huge rate. Currently, the annual laser world market is worth about 6 billion dollars. Thanks to the remarkable properties of laser light, laser applications increase steadily in the domains of industry, building, medicine, telecommunications, etc. One can find many lasers in research laboratories, and they are used more and more in our everyday life and almost everybody has already seen a laser beam. The goal of the first chapter of this book is to explain simply what a laser is, how it is built and how it operates. Firstly, let us point out the outstanding properties of the laser light.

  2. Tunable lasers- an overview

    SciTech Connect

    Guenther, B.D.; Buser, R.G.

    1982-08-01

    This overview of tunable lasers describes their applicability to spectroscopy in the ultraviolet and middle infrared ranges; to rapid on-line diagnostics by ultrashort cavity lasers; to exploration, by the free electron laser, for its wide tuning in the far infrared to submillimeter region; to remote detection, in areas such as portable pollution monitors, on-line chemical analyzers, auto exhaust analyzers, and production line controls; to photochemistry; and to other potential areas in diagnostics, communications, and medical and biological sciences. The following lasers are characterized by their tunability: solid state lasers, primarily alexandrite, with a tuning range of ca 1000 Angstroms; color center lasers; semiconductor lasers; dye lasers; gas lasers, where high-pressure CO/sub 2/ discharges are the best known example for a wide tunability range, and research is continuing in systems such as the alkali dimers; and, at wavelengths beyond 10 micrometers, the possibilities beyond Cerenkov and free electron lasers.

  3. Assignment of the /Li-7/2 optically pumped laser transitions pumped by Ar/+/ and Kr/+/ laser lines

    NASA Technical Reports Server (NTRS)

    Verma, K. K.; Stwalley, W. C.; Zemke, W. T.

    1981-01-01

    Welling and Wellegehausen (1977) have reported a list of Na2 and Li2 lines (belonging to B-X and A-X systems) which lase when vapors of these dimers are pumped with an Ar(+) or Kr(+) laser. A description is presented of a fluorescence study of the A-X system of the (Li-7)2 molecule excited by a Kr(+) laser (6471 A). The optically pumped laser lines are identified as P and R doublets in two different fluorescence series. The conditions which favor lasing action of these lines are pointed out. All but one of the known optically pumped laser lines of (Li-7)2 along with their assignments are presented in a table. For each pumping line, several additional wavelengths are listed which satisfy the condition for laser oscillations and which might well lase well under slightly improved conditions.

  4. Effect of ADP on Na+-Na+ Exchange Reaction Kinetics of Na,K-ATPase

    PubMed Central

    Peluffo, R. Daniel

    2004-01-01

    The whole-cell voltage-clamp technique was used in rat cardiac myocytes to investigate the kinetics of ADP binding to phosphorylated states of Na,K-ATPase and its effects on presteady-state Na+-dependent charge movements by this enzyme. Ouabain-sensitive transient currents generated by Na,K-ATPase functioning in electroneutral Na+-Na+ exchange mode were measured at 23°C with pipette ADP concentrations ([ADP]) of up to 4.3 mM and extracellular Na+ concentrations ([Na]o) between 36 and 145 mM at membrane potentials (VM) from −160 to +80 mV. Analysis of charge-VM curves showed that the midpoint potential of charge distribution was shifted toward more positive VM both by increasing [ADP] at constant Na+o and by increasing [Na]o at constant ADP. The total quantity of mobile charge, on the other hand, was found to be independent of changes in [ADP] or [Na]o. The presence of ADP increased the apparent rate constant for current relaxation at hyperpolarizing VM but decreased it at depolarizing VM as compared to control (no added ADP), an indication that ADP binding facilitates backward reaction steps during Na+-Na+ exchange while slowing forward reactions. Data analysis using a pseudo three-state model yielded an apparent Kd of ∼6 mM for ADP binding to and release from the Na,K-ATPase phosphoenzyme; a value of 130 s−1 for k2, a rate constant that groups Na+ deocclusion/release and the enzyme conformational transition E1∼P → E2-P; a value of 162 s−1M−1 for k−2, a lumped second-order VM-independent rate constant describing the reverse reactions; and a Hill coefficient of ∼1 for Na+o binding to E2-P. The results are consistent with electroneutral release of ADP before Na+ is deoccluded and released through an ion well. The same approach can be used to study additional charge-moving reactions and associated electrically silent steps of the Na,K-pump and other transporters. PMID:15298896

  5. FY 2005 Quantum Cascade Laser Alignment System Final Report

    SciTech Connect

    Myers, Tanya L.; Cannon, Bret D.; Wojcik, Michael D.; Broocks, Bryan T.; Stewart, Timothy L.; Hatchell, Brian K.

    2006-01-11

    The Alignment Lasers Task of Pacific Northwest National Laboratory's (PNNL's) Remote Spectroscopy Project (Project PL211I) is a co-funded project between DOE NA-22 and a Classified Client. This project, which began in the second half of FY03, involved building and delivering a Quantum Cascade (QC) Laser Alignment System to be used for testing the pupil alignment of an infrared sensor by measuring the response from four pairs of diametrically opposed QC lasers. PNNL delivered the system in FY04 and provided technical assistance in FY05 culminating into a successful demonstration of the system. This project evolved from the Laser Development Task of PL211I, which is involved in developing novel laser technology to support development of advanced chemical sensors for detecting the proliferation of nuclear weapons. The laser systems are based on quantum cascade (QC) lasers, a new semiconductor source in the infrared. QC lasers can be tailored to emit light throughout the infrared region (3.5 ? 17 ?m) and have high output power and stability. Thus, these lasers provide an infrared source with superb power and spectral stability enabling them to be used for applications such as alignment and calibration in addition to chemical sensing.

  6. The laser in urology

    NASA Astrophysics Data System (ADS)

    Hofstetter, Alfons G.

    2002-10-01

    Laser is an acronym for a physical principle and means: Light Amplification by stimulated Emission of Radiation. This principle offers a lot of tissue/light effects caused by the parameters: power density/time and the special qualities of the laser light. Nowadays for diagnosis and therapy following lasers are used in urology: Krypton- and Dye-lasers as well as the Neodymium-YAG- (nd:YAG-), Holmium-YAG (Ho:YAG-), Diode-, Argon- and the CO2-lasers.

  7. Intracavity Raman lasers

    SciTech Connect

    Band, Y.B.; Ackerhalt, J.R.; Krasinski, J.S.; Heller, D.F.

    1989-02-01

    Experimental and theoretical studies of intracavity Raman lasers are presented. Advantages of intracavity Raman lasers, particularly for low-emission cross section and broadly tunable vibronic gain media, are described. Experimental studies of a hydrogen gas Raman laser pumped inside the cavity of an alexandrite laser are presented. A theoretical model of the dynamics of a unidirectional intracavity Raman ring laser is developed and solved analytically. This model is adapted to simulate experiments.

  8. Surgical lasers in dermatology

    NASA Astrophysics Data System (ADS)

    Szymanczyk, Jacek; Nowakowski, Wlodzimierz; Golebiowska, Aleksandra; Michalska, I.; Mindak, Marek K.

    1997-10-01

    Almost every laser for medical applications was first tried in dermatology. The efficiency of YAG, CO2, and Argon lasers on this area and their potential advantages over conventional methods were mostly evaluated by cosmetic effect of laser therapy. The indications for different laser treatment in such dermatological cases as: angiomas, telangiectasias, pigmented lesions, nevus flammeus congenitus, deep cavernous angiomas, skin neoplasms and condylomata acuminata are discussed in this paper and the results of the laser therapy are also presented.

  9. Tunable Dual Semiconductor Laser

    NASA Technical Reports Server (NTRS)

    Mukai, Seiji; Kapon, Eli; Katz, Joseph; Margalit, Shlomo; Yariv, Amnon

    1987-01-01

    Parallel lasers interact in shared space to alter output wavelength. New device consists of two stripe lasers in aluminum gallium arsenide chip. Parallel stripes close enough so light from lower laser coupled into upper laser and vice versa. Lasers operated by low-duty-cycle current pulses. Lasing threshold of each about 100 mA. Currents controlled independently. Useful in optical communications systems employing wavelength-division multiplexing.

  10. Na Cauda do Cometa

    NASA Astrophysics Data System (ADS)

    Voelzke, M. R.

    2009-01-01

    Quando viam um cometa, os antigos gregos imaginavam uma estrela com uma vasta cabeleira. Não à toa, a palavra deriva do termo koma, que significa cabelo. Constituídos por fragmentos de gelo e gases, os cometas possuem um núcleo sólido, que pode ter vários quilômetros de diâmetro, e uma cauda que sempre aponta na direção contrária ao Sol, devido aos ventos solares. Graças à aparência de pontos luminosos em movimento (ao contrário de outros astros, que parecem estáticos), esses corpos celestes foram interpretados por diferentes povos com muito misticismo, inspirando mitos tanto de boas-novas como de maus presságios. Conheça algumas dessas histórias:

  11. Study of the nanobubble phase of aqueous NaCl solutions by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Bunkin, N. F.; Shkirin, A. V.; Burkhanov, I. S.; Chaikov, L. L.; Lomkova, A. K.

    2014-11-01

    Aqueous NaCl solutions with different concentrations have been investigated by dynamic scattering of laser radiation. It is experimentally shown that these solutions contain scattering particles with a wide size distribution in a range of ~10 - 100 nm. The experimental results indirectly confirm the existence of quasi-stable gas nanobubbles in the bulk of aqueous ionic solutions.

  12. Study of the nanobubble phase of aqueous NaCl solutions by dynamic light scattering

    SciTech Connect

    Bunkin, N F; Shkirin, A V; Burkhanov, I S; Chaikov, L L; Lomkova, A K

    2014-11-30

    Aqueous NaCl solutions with different concentrations have been investigated by dynamic scattering of laser radiation. It is experimentally shown that these solutions contain scattering particles with a wide size distribution in a range of ∼10 – 100 nm. The experimental results indirectly confirm the existence of quasi-stable gas nanobubbles in the bulk of aqueous ionic solutions. (light scattering)

  13. Blue upconversion thulium laser

    SciTech Connect

    Nguyen, D.C.; Faulkner, G.E.; Weber, M.E.; Dulick, M.

    1990-01-01

    Upconversion has been an active area of research for at least two decades, mainly because of its wide ranging applications from infrared quantum counters, visible-emitting phosphors, to upconversion lasers. The upconversion lasers have recently become attractive with the advent of semiconductor laser diodes as the pump source. In an upconversion laser, the laser active ion is excited by internal upconversion of near-ir or red light via multiphoton excitation or cooperative processes and emits anti-Stokes visible light. Since the laser diode output wavelength can be composition turned to match the upconversion laser ion absorption lines, a substantial fraction of the ions can be driven into higher energy levels, thus enhancing the upconversion process. These upconversion solid-state lasers offer a potentially simple and compact source of visible coherent light with semiconductor laser diode excitation. We recently reported a novel upconversion thulium laser that emits blue light at 77 K. In this paper additional data on this 77 K upconversion laser as well as preliminary results on the room temperature upconversion laser are presented. In these demonstrations, dye lasers were used instead of diode lasers because they were more readily available than high power semiconductor laser diodes and their wavelengths could be adjusted easily. 14 refs., 5 figs., 1 tab.

  14. Laser in dermatology.

    PubMed

    Boord, Mona

    2006-08-01

    The laser is a tool that will augment the surgical techniques available to the veterinarian. When using the laser compared with traditional surgery there are multiple procedures that can be performed with much greater ease, and some procedures that previously could not be performed. Specialty and academic practices have used lasers for photodynamic therapy, lithotripsy of urinary calculi, and percutaneous disk ablation. This article will focus on the lasers use in dermatology. It is essential that the surgeon learn the basics of laser physics, how the laser interacts with tissue and the safety issues one needs to consider during its use. On deciding to use the laser the surgical techniques chosen should always be based on considering the advantages and disadvantages the laser has to offer. The use of biomedical lasers is a "cutting edge" technique now available to our veterinary field. PMID:16933481

  15. Developments in laser trabeculoplasty.

    PubMed

    Tsang, Susanna; Cheng, Jason; Lee, Jacky W Y

    2016-01-01

    Laser trabeculoplasty has an increasing important role in the management of glaucoma as more emphasis is placed on minimally invasive therapies. In recent years, the following laser trabeculoplasty technologies have been introduced: micropulse laser trabeculoplasty, titanium-sapphire laser trabeculoplasty and pattern scanning trabeculoplasty. These lasers help to reduce the intraocular pressure (IOP) and the burden of glaucoma medical therapy. Literature findings regarding the safety and efficacy of these newer forms of laser trabeculoplasty in the treatment of open-angle glaucoma is summarised. These relatively newer procedures appear to have similar efficacy when compared with the former selective laser trabeculoplasty or argon laser trabeculoplasty. In addition, they potentially offer a more favourable safety profile with fewer complications, including postlaser inflammation and IOP spikes. Further large-scale studies are necessary to evaluate the long-term benefits of these newer forms of laser trabeculoplasty. Their initial promising results offer patients with glaucoma additional treatment alternatives. PMID:26377417

  16. Investigation of laser injuries

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas E.; Keeler, Natalie; Dennis, Jerome E.; Figueroa, Colin L.; Press, Howard A.; Rockwell, R. James, Jr.; Stuck, Bruce E.; Roach, William P.; Wartick, Ardith L.

    2003-06-01

    Recently a review of multiple laser injury and accident databases was initiated. Last year we reported on preliminary findings in this area. This past year the search for laser injury and accident reports was expanded, and a significant number of additional laser incidents were located. The database from the Food and Drug Administration"s Center for Devices and Radiological Health was supplemented with more up to date information and non-medical laser incidents were added. Rockwell Laser Industries database was verified to not contain duplicates from the new information, as was the Army"s Laser Accidents and Incidents Registry. Information from the Federal Aviation Administration regarding laser accidents and incidents were also included. Incidents not resulting in laser specific injuries has been tracked. This information was not included in our previous report. In this study, case reports are used to show gross trends in laser injury, accident and incident reporting. This study is still in progress, and evaluation is incomplete.

  17. Infrared laser system

    DOEpatents

    Cantrell, Cyrus D.; Carbone, Robert J.; Cooper, Ralph

    1982-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

  18. Infrared laser system

    DOEpatents

    Cantrell, Cyrus D.; Carbone, Robert J.; Cooper, Ralph S.

    1977-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

  19. Nanocrystal waveguide (NOW) laser

    DOEpatents

    Simpson, John T.; Simpson, Marcus L.; Withrow, Stephen P.; White, Clark W.; Jaiswal, Supriya L.

    2005-02-08

    A solid state laser includes an optical waveguide and a laser cavity including at least one subwavelength mirror disposed in or on the optical waveguide. A plurality of photoluminescent nanocrystals are disposed in the laser cavity. The reflective subwavelength mirror can be a pair of subwavelength resonant gratings (SWG), a pair of photonic crystal structures (PC), or a distributed feedback structure. In the case of a pair of mirrors, a PC which is substantially transmissive at an operating wavelength of the laser can be disposed in the laser cavity between the subwavelength mirrors to improve the mode structure, coherence and overall efficiency of the laser. A method for forming a solid state laser includes the steps of providing an optical waveguide, creating a laser cavity in the optical waveguide by disposing at least one subwavelength mirror on or in the waveguide, and positioning a plurality of photoluminescent nanocrystals in the laser cavity.

  20. Quantum well lasers

    SciTech Connect

    Zory, P.S. Jr.

    1993-01-01

    The semiconductor quantum well (QW) laser structure is rapidly becoming the preferred design in many applications because of its low threshold, design flexibility, and high reliability. The book begins with a brief, interesting foreword by C.H. Henry on the history of the QW laser concept and its early development. Following this introduction is a 79-page chapter by S.W. Corzine et al. on optical gain in III-V bulk and QW lasers. The next chapter on intraband relaxation and line broadening effects by M. Asada is an excellent expanded review of a topic introduced by Corzine. The remaining chapters describe multiple QW lasers, low-threshold QW laser, special aspects of AlGaAs and (short-wavelength) InGaAsP lasers, valence-band engineering, strained-layer QW lasers, AlGaInP QW lasers, and quantum wire lasers. These chapters are well written by recognized experts in the field.

  1. Laser Surveying

    NASA Technical Reports Server (NTRS)

    1978-01-01

    NASA technology has produced a laser-aided system for surveying land boundaries in difficult terrain. It does the job more accurately than conventional methods, takes only one-third the time normally required, and is considerably less expensive. In surveying to mark property boundaries, the objective is to establish an accurate heading between two "corner" points. This is conventionally accomplished by erecting a "range pole" at one point and sighting it from the other point through an instrument called a theodolite. But how do you take a heading between two points which are not visible to each other, for instance, when tall trees, hills or other obstacles obstruct the line of sight? That was the problem confronting the U.S. Department of Agriculture's Forest Service. The Forest Service manages 187 million acres of land in 44 states and Puerto Rico. Unfortunately, National Forest System lands are not contiguous but intermingled in complex patterns with privately-owned land. In recent years much of the private land has been undergoing development for purposes ranging from timber harvesting to vacation resorts. There is a need for precise boundary definition so that both private owners and the Forest Service can manage their properties with confidence that they are not trespassing on the other's land.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  3. Alexandrite laser pumped by semiconductor lasers

    SciTech Connect

    Scheps, R.; Gately, B.M.; Myers, J.F. ); Krasinski, J.S. ); Heller, D.F. )

    1990-06-04

    We report the first operation of a direct diode-pumped tunable chromium-doped solid-state laser. A small alexandrite (Cr:BeAl{sub 2}O{sub 4}) crystal was longitudinally pumped by two visible laser diodes. The threshold pump power was 12 mW using the {ital R}{sub 1} line at 680.4 nm for the pump transition, and the slope efficiency was 25%. The measured laser output bandwidth was 2.1 nm.

  4. Laser ablation of blepharopigmentation

    SciTech Connect

    Tanenbaum, M.; Karas, S.; McCord, C.D. Jr. )

    1988-01-01

    This article discusses laser ablation of blepharopigmentation in four stages: first, experimentally, where pigment vaporization is readily achieved with the argon blue-green laser; second, in the rabbit animal model, where eyelid blepharopigmentation markings are ablated with the laser; third, in human subjects, where the argon blue-green laser is effective in the ablation of implanted eyelid pigment; and fourth, in a case report, where, in a patient with improper pigment placement in the eyelid, the laser is used to safely and effectively ablate the undesired pigment markings. This article describes in detail the new technique of laser ablation of blepharopigmentation. Potential complications associated with the technique are discussed.

  5. Tunable chromium lasers

    SciTech Connect

    Chase, L.L.; Payne, S.A.

    1989-01-01

    During the decade that has passed since the discovery of the alexandrite laser, many other tunable vibronic sideband lasers based on Cr/sup 3 +/ have been developed. These lasers span the wavelength range from 700 nm to at least 1235 nm. Experimental and theoretical research has provided an understanding of the important factors that influence the performance of these Cr/sup 3 +/ lasers and other solid state vibronic lasers. The intrinsic performance levels of some of the most promising Cr/sup 3 +/ lasers are evaluated from extrapolated slope efficiency measurements. 7 refs., 4 figs., 2 tabs.

  6. Laser Safety Device

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A major focus of work done at Air Products and Chemicals' Laser Application Laboratory is on use of ultraviolet radiation using high energy excimer lasers. Because light within the wavelength of excimer lasers is invisible, it can cause serious damage to eyes and tissue. To contain the laser beam, Air Products Incorporated a Jet Propulsion Laboratory invention described in a technical support package into its beam stops. The technology interrupts the laser pathway and allows workers to remain in the target area without shutting off the laser.

  7. Lasers in aviation

    NASA Astrophysics Data System (ADS)

    Goncharov, I. N.; Dezhin, V. N.; Kutakhov, V. P.; Petukhov, A. V.; Sidorin, V. M.; Sukhar, I. M.

    The way in which lasers are being incorporated into the military aircraft of the United States and the countries of Western Europe is discussed. Descriptions are given of laser weapons-guiding systems (including ranger finders and systems for target illumination), laser systems for navigation and flight-safety assurance (gyroscopes, velocity gauges, altimeters, systems providing meteorological data, proximity warning systems), and laser systems for air reconnaissance, communications, and control. Attention is also given to the Glissada laser guide path system, developed in the USSR. The physics of the systems is emphasized in the description and the principles underlying the operation of a laser are discussed in the introduction.

  8. Laser Wakefield Acceleration Experiments Using HERCULES Laser

    SciTech Connect

    Matsuoka, T.; McGuffey, C.; Dollar, F.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Rousseau, P.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Horovitz, Y.

    2009-07-25

    Laser wakefield acceleration (LWFA) in a supersonic gas-jet using a self-guided laser pulse was studied by changing laser power and plasma electron density. The recently upgraded HERCULES laser facility equipped with wavefront correction enables a peak intensity of 6.1x10{sup 19} W/cm{sup 2} at laser power of 80 TW to be delivered to the gas-jet using F/10 focusing optics. We found that electron beam charge was increased significantly with an increase of laser power from 30 TW to 80 TW and showed density threshold behavior at a fixed laser power. We also studied the influence of laser focusing conditions by changing the f-number of the optics to F/15 and found an increase in density threshold for electron production compared to the F/10 configuration. The analysis of different phenomena such as betatron motion of electrons, side scattering of the laser pulse for different focusing conditions, the influence of plasma density down ramp on LWFA are shown.

  9. Laser peening of metals- enabling laser technology

    SciTech Connect

    Dane, C.B.; Hackel, L.A.; Daly, J.; Harrisson, J.

    1997-11-13

    Laser peening, a surface treatment for metals, employs laser induced shocks to create deep and intense residual stresses in critical components. In many applications this technology is proving to be superior to conventional treatments such as shot peening. The laser peening process has generated sufficiently impressive results to move it from a laboratory demonstration phase into a significant industrial process. However until now this evolution has been slowed because a laser system meeting the average power requirements for a high throughput process has been lacking.

  10. Geodynamic laser ranging system laser transmitter

    NASA Technical Reports Server (NTRS)

    Dallas, J. L.; Czechanski, J. P.; Coyle, D. B.; Zukowski, B. J.; Seery, B. D.

    1991-01-01

    A description is given of the requirements and design options in the development of a spaceborne laser transmitter for NASA's Geodynamic Laser Ranging System. Three different oscillators are considered. The first is an injection-seeded ring oscillator yielding 1 mJ of energy within a 120-ps pulse. The second is a frequency-modulated mode-locked oscillator emitting 0.30 nJ in a 20-ps pulse. The third is a self-starting, additive pulse mode-locked laser. Detailed design considerations and preliminary results of these lasers are reported as well as the design of a unique multipass amplifier.

  11. Laser amplifier and method

    DOEpatents

    Backus, S.; Kapteyn, H.C.; Murnane, M.M.

    1997-07-01

    Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethrough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate. 7 figs.

  12. Laser amplifier and method

    DOEpatents

    Backus, Sterling; Kapteyn, Henry C.; Murnane, Margaret M.

    1997-01-01

    Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate.

  13. Phased laser array for generating a powerful laser beam

    DOEpatents

    Holzrichter, John F.; Ruggiero, Anthony J.

    2004-02-17

    A first injection laser signal and a first part of a reference laser beam are injected into a first laser element. At least one additional injection laser signal and at least one additional part of a reference laser beam are injected into at least one additional laser element. The first part of a reference laser beam and the at least one additional part of a reference laser beam are amplified and phase conjugated producing a first amplified output laser beam emanating from the first laser element and an additional amplified output laser beam emanating from the at least one additional laser element. The first amplified output laser beam and the additional amplified output laser beam are combined into a powerful laser beam.

  14. Laser gas assisted treatment of AISI H12 tool steel and corrosion properties

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Toor, Ihsan-ul-Haq; Malik, Jahanzaib; Patel, F.

    2014-03-01

    Laser gas assisted treatment of AISI H12 tool steel surface is carried out and the electrochemical response of the laser treated surface is investigated. Morphological and metallurgical changes in the treated layer are examined using a scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction. Potentiodynamic polarization tests are carried out for untreated and laser treated specimen in 0.2 M NaCl solution at room temperature. It is found that the laser treated AISI H12 workpiece surfaces exhibit higher corrosion resistance as compared to untreated specimen as confirmed by lower corrosion rate, higher pitting potential, and lower passive current density.

  15. Laser therapy for cancer

    MedlinePlus

    Laser therapy uses a very narrow, focused beam of light to shrink or destroy cancer cells. It can ... to cut out tumors without damaging other tissue. Laser therapy is often given through a thin, lighted tube ...

  16. MESSENGER Laser Altimeter

    NASA Video Gallery

    MESSENGER's Mercury Laser Altimeter sends out laser pulses that hit the ground and return to the instrument. The amount of light that returns for each pulse gives the reflectance at that point on t...

  17. Direct nuclear pumped laser

    DOEpatents

    Miley, George H.; Wells, William E.; DeYoung, Russell J.

    1978-01-01

    There is provided a direct nuclear pumped gas laser in which the lasing mechanism is collisional radiated recombination of ions. The gas laser active medium is a mixture of the gases, with one example being neon and nitrogen.

  18. Laser Acne Treatment

    MedlinePlus

    ... rashes clinical tools newsletter | contact Share | Acne Treatment, Laser A A A BEFORE: This patient wanted laster ... A popular approach is to combine an infrared laser with skin cooling to target oil gland production, ...

  19. Laser Radar Animation

    NASA Video Gallery

    Laser and radar instruments aboard NASA aircraft provide measurements of the snow and ice surface and down to the bedrock under the ice. Lasers, with a shorter wavelength, measure the surface eleva...

  20. Laser device and method

    SciTech Connect

    Myers, J. D.

    1985-06-25

    A simplified, relatively inexpensive laser device, wherein the laser elements are fixed in a body exoskeleton of electrical insulating material having a low coefficient of thermal expansion. The preferred embodiment includes a shotgun type laser filter having parallel bores which receive the laser flashlamp and laser rod in fixed relation in a body chamber. The reflector surrounds the laser filter and retains the filter within the body chamber. In the preferred method of this invention, several controlled lasing pulses are generated with each illumination pulse of the flashlamp, substantially increasing the efficiency of the laser device. The number of pulses is generally controlled by increasing the voltage to the flashlamp. The rapid multiple lasing pulses generate an elongated plasma in a fluid medium, such as the vitreous fluid body of an eye which makes the laser device extemely efficient for treating glaucoma and other medical treatments.

  1. Laser programs highlights 1993

    SciTech Connect

    1995-06-01

    Over the last two decades, the scope of our laser research has grown immensely. The small, low-power laser systems of our early days have given way to laser systems of record-breaking size and power. Now we are focusing our activities within the target physics and laser science programs to support the ignition and gain goals of the proposed glass-laser National Ignition Facility. In our laser isotope separation work, we completed the most important set of experiments in the history of the AVLIS Program in 1993, which culminated in a spectacularly successful run that met or exceeded all our objectives. We are also developing lasers and laser-related technologies for a variety of energy, commercial, and defense uses. On the horizon are transfers of important technologies for waste treatment, x-ray lithography, communications and security, optical imaging, and remote sensing, among others.

  2. Transmyocardial Laser Revascularization

    MedlinePlus

    ... Vascular Access for Hemodialysis Ventricular Assist Devices Transmyocardial Laser Revascularization Like every other organ or tissue in ... bypass surgery, there is a procedure called transmyocardial laser revascularization, also called TMLR or TMR. TMLR cannot ...

  3. Slender tip laser scalpel

    DOEpatents

    Veligdan, James T.

    2004-01-06

    A laser scalpel includes a ribbon optical waveguide extending therethrough and terminating at a slender optical cutting tip. A laser beam is emitted along the height of the cutting tip for cutting tissue therealong.

  4. Laser surgery - skin

    MedlinePlus

    Surgery using a laser ... used is directly related to the type of surgery being performed and the color of the tissue ... Laser surgery can be used to: Close small blood vessels to reduce blood loss Remove warts , moles , sunspots, and ...

  5. Laser particle sorter

    DOEpatents

    Martin, John C.; Buican, Tudor N.

    1989-01-01

    Method and apparatus for sorting particles, such as biological particles. A first laser defines an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam interrogates the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam intersects the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis.

  6. Laser particle sorter

    DOEpatents

    Martin, J.C.; Buican, T.N.

    1987-11-30

    Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

  7. Laser therapy (image)

    MedlinePlus

    ... is used for many medical purposes. Because the laser beam is so small and precise, it enables physicians to safely treat specific tissue without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  8. LASIK - Laser Eye Surgery

    MedlinePlus

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics ...

  9. Laser hair removal.

    PubMed

    Wanner, Molly

    2005-01-01

    Since 1996, there have been numerous advances in hair laser removal that utilize melanin as a chromophore. All of the devices on the market may be used in patients with light skin (phototypes I-III) and yield hair reduction near 75%. The ruby (694 nm) laser, alexandrite (755 nm) laser, and diode (810 nm) laser, as well as intense pulsed light are commonly used devices for hair laser removal. The long-pulsed Nd:YAG (1064 nm) laser represents the safest device for hair removal in dark-skinned patients because of its long wavelength, although the diode laser, alexandrite laser, and intense pulse light may be used. For treatment of light hair, combination radiofrequency and optical devices as well as photodynamic therapy are under investigation. PMID:16229722

  10. Optics and lasers

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Report describes twenty-seven optical concepts developed for holographic viewing, spectral transmission, and film camera technology. Articles include developments in laser-Doppler systems, laser beam deflection controls, X-ray photography, and camera components.

  11. Comparison of laser spectroscopic PNC method with laser integral fluorescence in optical caries diagnostics

    NASA Astrophysics Data System (ADS)

    Masychev, Victor I.

    2001-05-01

    In this research we represent the results of approbation of two methods of optical caries diagnostics: PNC-spectral diagnostics and caries detection by laser integral fluorescence. The research was conducted in a dental clinic. PNC-method analyzes parameters of probing laser radiation and PNC-spectrums of stimulated secondary radiations: backscattering and endogenous fluorescence of caries- involved bacteria. Ia-Ne laser ((lambda) equals632.8 nm, 1-2 mW) was used as a source of probing (stimulated) radiation. For registration of signals, received from intact and pathological teeth PDA-detector was applied. PNC-spectrums were processed by special algorithms, and were displayed on PC monitor. The method of laser integral fluorescence was used for comparison. In this case integral power of fluorescence of human teeth was measured. As a source of probing (stimulated) radiation diode lasers ((lambda) equals655 nm, 0.1 mW and 630 nm, 1 mW) and Ia-Na laser were applied. For registration of signals Si-photodetector was used. Integral power was shown in a digital indicator. Advantages and disadvantages of these methods are described in this research. It is disclosed that the method of laser integral power of fluorescence has the following characteristics: simplicity of construction and schema-technical decisions. However the method of PNC-spectral diagnostics are characterized by considerably more sensitivity in diagnostics of initial caries and capability to differentiate pathologies of various stages (for example, calculus/initial caries). Estimation of spectral characteristics of PNC-signals allows eliminating a number of drawbacks, which are character for detection by method of laser integral fluorescence (for instance, detection of fluorescent fillings, plagues, calculus, discolorations generally, amalgam, gold fillings as if it were caries).

  12. CO2 laser modeling

    NASA Technical Reports Server (NTRS)

    Johnson, Barry

    1992-01-01

    The topics covered include the following: (1) CO2 laser kinetics modeling; (2) gas lifetimes in pulsed CO2 lasers; (3) frequency chirp and laser pulse spectral analysis; (4) LAWS A' Design Study; and (5) discharge circuit components for LAWS. The appendices include LAWS Memos, computer modeling of pulsed CO2 lasers for lidar applications, discharge circuit considerations for pulsed CO2 lidars, and presentation made at the Code RC Review.

  13. Tunable high pressure lasers

    NASA Technical Reports Server (NTRS)

    Hess, R. V.

    1976-01-01

    Atmospheric transmission of high energy CO2 lasers is considerably improved by high pressure operation which, due to pressure broadening, permits tuning the laser lines off atmospheric absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers and for vertical transmission through the entire atmosphere. Applications of tunable high pressure CO2 lasers to energy transmission and to remote sensing are discussed along with initial efforts in tuning high pressure CO2 lasers.

  14. Alkali-vapor lasers

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Komashko, A.; Krupke, W. F.

    2010-02-01

    We report on the results from several of our alkali laser systems. We show highly efficient performance from an alexandrite-pumped rubidium laser. Using a laser diode stack as a pump source, we demonstrate up to 145 W of average power from a CW system. We present a design for a transversely pumped demonstration system that will show all of the required laser physics for a high power system.

  15. Single mode cavity laser

    SciTech Connect

    Martin, D.W.; Levy, J.L.

    1984-01-17

    This external cavity laser utilizes an unstable resonator in conjuction with a high reflectivity stripe end mirror which is oriented substantially parallel to the plane of the maximum divergence of the laser diode output beam and whose axis is substantially parallel to the plane of the junction of the laser diode. This configuration operates with high efficiency to select only the fundamental mode of the laser diode with a minimal divergence in the output beam.

  16. Carbon dioxide slab laser

    SciTech Connect

    Tulip, J.

    1988-01-12

    A gas slab laser is described comprising: first and second elongated electrodes each including a planar light reflecting surface disposed so as to form a light guide only in a plane perpendicular to the planar surface and to define a gas discharge gap therebetween; a laser gas disposed in the gap; and means for applying a radio frequency current between the first and second electrodes to establish a laser-exciting discharge in the laser gas.

  17. Short wavelength laser

    DOEpatents

    Hagelstein, Peter L.

    1986-01-01

    A short wavelength laser (28) is provided that is driven by conventional-laser pulses (30, 31). A multiplicity of panels (32), mounted on substrates (34), are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path (42). When the panels (32) are illuminated by the conventional-laser pulses (30, 31), single pass EUV or soft x-ray laser pulses (44, 46) are produced.

  18. Laser cutting system

    SciTech Connect

    Dougherty, Thomas J

    2015-03-03

    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  19. Tunable semiconductor lasers

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    Tunable semiconductor lasers are disclosed requiring minimized coupling regions. Multiple laser embodiments employ ring resonators or ring resonator pairs using only a single coupling region with the gain medium are detailed. Tuning can be performed by changing the phase of the coupling coefficient between the gain medium and a ring resonator of the laser. Another embodiment provides a tunable laser including two Mach-Zehnder interferometers in series and a reflector coupled to a gain medium.

  20. Carbon dioxide laser guidelines.

    PubMed

    Krupa Shankar, Ds; Chakravarthi, M; Shilpakar, Rachana

    2009-07-01

    The carbon dioxide (CO(2)) laser is a versatile tool that has applications in ablative lasing and caters to the needs of routine dermatological practice as well as the aesthetic, cosmetic and rejuvenation segments. This article details the basics of the laser physics as applicable to the CO(2) laser and offers guidelines for use in many of the above indications. PMID:20808594

  1. Laser bottom hole assembly

    DOEpatents

    Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

    2014-01-14

    There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

  2. Optically biased laser gyro

    SciTech Connect

    Anderson, D.Z.; Chow, W.W.; Scully, M.O.; Sanders, V.E.

    1980-10-01

    We describe a four-mode ring laser that exhibits none of the mode-locking characteristics that plague laser gyros. This laser is characterized by a bias that changes sign with a change in the direction of rotation and prevents the counterpropagating modes from locking. A theoretical analysis explaining the experimental results is outlined.

  3. Excimer Lasers In Medicine

    NASA Astrophysics Data System (ADS)

    Tittel, Frank K.; Saidi, Iyad S.; Pettit, George H.; Wisoff, P. J.; Sauerbrey, Roland A.

    1989-06-01

    Excimer lasers emit light energy, short optical pulses at ultraviolet wavelengths, that results in a unique laser tissue interaction. This has led to an increasing number of studies into medical applications of these lasers in fields such as ophthalmology, urology, cardiology and neurology.

  4. Laser Programs Highlights 1998

    SciTech Connect

    Lowdermilk, H.; Cassady, C.

    1999-12-01

    This report covers the following topics: Commentary; Laser Programs; Inertial Confinement Fusion/National Ignition Facility (ICF/NIF); Atomic Vapor Laser Isotope Separation (AVLIS); Laser Science and Technology (LS&T); Information Science and Technology Program (IS&T); Strategic Materials Applications Program (SMAP); Medical Technology Program (MTP) and Awards.

  5. Carbon Dioxide Laser Guidelines

    PubMed Central

    Krupa Shankar, DS; Chakravarthi, M; Shilpakar, Rachana

    2009-01-01

    The carbon dioxide (CO2) laser is a versatile tool that has applications in ablative lasing and caters to the needs of routine dermatological practice as well as the aesthetic, cosmetic and rejuvenation segments. This article details the basics of the laser physics as applicable to the CO2 laser and offers guidelines for use in many of the above indications. PMID:20808594

  6. Laser Detection of Pollution.

    ERIC Educational Resources Information Center

    Patel, C. K. N.

    1978-01-01

    Discusses the use of laser spectroscopy in determining the presence of specific gaseous constituents. Three of currently used modes for laser detection of pollution are reviewed; (1) long-path measurements; (2) laser raman (differential absorption) measurements; and (3) optoacoustic detection. (HM)

  7. Solar pumped laser

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Hohl, F.; Weaver, W. R. (Inventor)

    1984-01-01

    A solar pumped laser is described in which the lasant is a gas that will photodissociate and lase when subjected to sunrays. Sunrays are collected and directed onto the gas lasant to cause it to lase. Applications to laser propulsion and laser power transmission are discussed.

  8. Polarization feedback laser stabilization

    DOEpatents

    Esherick, Peter; Owyoung, Adelbert

    1988-01-01

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other.

  9. LaserFest Celebration

    SciTech Connect

    Dr. Alan Chodos; Elizabeth A. Rogan

    2011-08-25

    LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

  10. Laser material processing system

    DOEpatents

    Dantus, Marcos

    2015-04-28

    A laser material processing system and method are provided. A further aspect of the present invention employs a laser for micromachining. In another aspect of the present invention, the system uses a hollow waveguide. In another aspect of the present invention, a laser beam pulse is given broad bandwidth for workpiece modification.