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1.
A design of laser-diode array (LDA) end-pumped Nd:YVO4 laser that generates simultaneous laser action at wavelengths 1064 and 1342 nm is presented. Using type-I critical phase matching (CPM) BiB3O6, 593.5 nm continuous-wave (cw) Orange-yellow laser is obtained by 1064 nm and 1342 nm in an intra-cavity sum-frequency mixing. The maximum laser output power of 3.62 W is obtained when an incident pump laser of 27.5 W is used. The optical-to-optical conversion is up to 13.2%. To the best of our knowledge, this is the highest conversion efficiency at 593.5 nm in an intra-cavity sum-frequency Nd:YVO4 laser. 相似文献
2.
Selective laser isotope separation by TEA CO2 laser often needs short tail-free pulses. Using laser mixtures having very little nitrogen almost tail free laser pulses can be generated. The laser pulse characteristics and its gas lifetime is an important issue for long-term laser operation. Boltzmann transport equation is therefore solved numerically for TEA CO2 laser gas mixtures having very little nitrogen to predict electron energy distribution function (EEDF). The distribution function is used to calculate various excitation and dissociation rate of CO2 to predict laser pulse characteristics and laser gas lifetime, respectively.Laser rate equations have been solved with the calculated excitation rates for numerically evaluated discharge current and voltage profiles to calculate laser pulse shape. The calculated laser pulse shape and duration are in good agreement with the measured laser characteristics. The gas lifetime is estimated by integrating the equation governing the dissociation of CO2. An experimental study of gas lifetime was carried out using quadrapole mass analyzer for such mixtures to estimate the O2 being produced due to dissociation of CO2 in the pulse discharge. The theoretically calculated O2 concentration in the laser gas mixture matches with experimentally observed value. In the present TEA CO2 laser system, for stable discharge the O2 concentration should be below 0.2%. 相似文献
3.
A mathematical model is developed for analysis the dynamics of an intra-cavity laser spectroscopy and mode competition using the CO2 laser as the coherent source. The governing equations of system are derived and effect of the absorbing material on the laser modes, as a time-dependent term is considered. Thus, the application of the CO2 laser for intra-cavity laser spectroscopy with considering an inhomogeneous medium and effect of the absorbing material is investigated. 相似文献
4.
P.V. Kazakevich 《Applied Surface Science》2006,252(13):4373-4380
The review of results on nanoparticles formation is presented under laser ablation of Ag, Au, and Cu-containing solid targets in liquid environments (H2O, C2H5OH, C2H4Cl2, etc.). X-ray diffractometry (XRD), UV-vis optical transmission spectrometry, and high resolution transmission electron microscopy (HRTEM) characterize the nanoparticles. The morphology of nanoparticles is studied as the function of both laser fluence and nature of the liquid. The possibility to control the shape of nanoparticles by ablation of an Au target by an interference pattern of two laser beams is demonstrated. Formation of alloyed Au-Ag and Ag-Cu nanoparticles is reported under laser exposure of a mixture of individual nanoparticles. The effect of internal segregation of brass nanoparticles is discussed due to their small lateral dimensions. The factors are discussed that determine the distribution function of particles size under laser ablation. The influence of laser parameters as well as the nature on the liquid on the properties of nanoparticles is elucidated. 相似文献
5.
详细讨论了封离型CO2激光器中CO2,N2和He三混合气 体含量被优化组合后的激光动力 学机理. 气体优化可以提高激光输出功率的主要机理是通过适当增加N2含量, 使N2激发 态与CO2激光上能级的碰撞频率增加,提高了激光能级粒子数密度和相对布居数 . 同时, 适当减少CO2含量,使总的电子动量输运碰撞频率减小、放电电流增大,导致增 加激光上转动能级的弛豫
关键词:
2激光')" href="#">CO2激光
气体动力学
强化机理 相似文献
6.
M. Ghysels L. Gomez J. Cousin N. Amarouche H. Jost G. Durry 《Applied physics. B, Lasers and optics》2011,104(4):989-1000
The 3.25 micron spectral region is very suitable for the in situ sensing of CH4 in the troposphere and the lower stratosphere with light-weight laser sensors. Several transitions of the strong fundamental
ν
3 band of CH4 are revisited in this spectral region using an ultra-compact Difference-Frequency Generation (DFG) laser. Accurate intensities
as well as self-broadening coefficients are reported for several manifolds that are particularly relevant to the monitoring
of CH4. The study is extended to over hundred transitions reachable over the tunability range of the laser. Moreover, this DFG laser
is the light source of a new, highly-compact CH4 laser spectrometer to be operated from weather balloon. The CH4 laser sensor is described and preliminary flight results are reported. 相似文献
7.
A.V. Simakin V.V. Voronov N.A. Kirichenko G.A. Shafeev 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1127-1132
A review of results on nanoparticles formation is presented under laser ablation of Ag, Au, and Ti solids targets in liquid environments (H2O, C2H5OH, C2H4Cl2, etc.). X-ray diffractometry (XRD), UV-Vis optical transmission spectrometry, and high-resolution transmission electron microscopy (HRTEM) characterise the nanoparticles. The morphology of nanoparticles is studied as a function of both laser fluence and nature of the liquid. The evidence of an intermediate phase of Au-Ag alloy is presented under exposure of a mixture of individual nanoparticles to laser radiation. Self-influence of the beam of a femtosecond laser is discussed under the ablation of the Ag target in liquids under Ti:sapphire laser. The factors are discussed that determine the distribution function of particle size under laser ablation. The influence of laser parameters as well as the nature on the liquid on the properties of nanoparticles is elucidated. PACS 42.62.-b; 61.46.+w; 78.66.-w 相似文献
8.
The operation of an electrically excited gasdynamic CO laser with closed-cycle gas flow is described. Details of the gasdynamics,
the recompression, and the cooling of the flowing gas are given. The electrical discharge produces contaminating gas compounds—in
particular CO2—which accumulate in the recirculating gas. The resulting transient behavior of the laser gas composition, the discharge characteristics,
and the laser performance are studied and compared with the results obtained with the same CO laser in an open-flow system.
It is found that the closed-cycle system may be operated for considerable time if the CO2 contamination is removed from the laser gas. 相似文献
9.
The influence of a superintense laser field on the transmission probability of a charged particle through a potential barrier is discussed. It is shown that the effect of the intense laser field is to weaken the potential barrier in such a way that its height decreases exponentially with the laser field. The implications to the ferro — to para - electric phase transition in BaTiO3 under an intense CO2 - laser field is also discussed. 相似文献
10.
High-temperature laser annealing for thin film polycrystalline silicon solar cell on glass substrate
A. Chowdhury J. Schneider J. Dore F. Mermet A. Slaoui 《Applied Physics A: Materials Science & Processing》2012,107(3):653-659
Thin film polycrystalline silicon films grown on glass substrate were irradiated with an infrared continuous wave laser for defects annealing and/or dopants activation. The samples were uniformly scanned using an attachment with the laser system. Substrate temperature, scan speed and laser power were varied to find suitable laser annealing conditions. The Raman spectroscopy and Suns-V oc analysis were carried out to qualify the films quality after laser annealing. A maximum enhancement of the open circuit voltage V oc of about 100?mV is obtained after laser annealing of as-grown polysilicon structures. A strong correlation was found between the full width half maximum of the Si crystalline peak and V oc. It is interpreted as due to defects annealing as well as to dopants activation in the absorbing silicon layer. The maximum V oc reached is 485?mV after laser treatment and plasma hydrogenation, thanks to defects passivation. 相似文献
11.
Efficient and high-power laser-diode single-end-pumped Nd:YVO4 continuous wave laser at 1342nm 下载免费PDF全文
A compact, efficient and high-power laser diode (LD) single-end-pumped Nd:YVO4 laser with continuous-wave emission at 1342 nm is reported. With a single crystal single-end-pumped by fibre-coupled LD array, an output power of 7.36W is obtained from the laser cavity of concave-convex shape, corresponding to an optical-to-optical efficiency of 32.8%. The laser is operated in TEM00 mode with small rms amplitude noise of 0.3%. The influences of the Nd concentration, transmissivity of the output mirror and the cavity length on the output power have been studied experimentally. 相似文献
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14.
A chemical H2–F2 laser (oscillator and amplifier) initiated by means of IR radiative excitation of vibrational levels of HF molecules is studied under the conditions of development of a thermal-branched chain reaction caused by thermal dissociation of gaseous additions to the laser mixture. It is shown that, using F2SO3 addition at a partial pressure of 40 Torr, an H2–F2 laser with a mixture pressure of 1~bar initiated by a pulsed hydrogen fluorine laser can provide an output exceeding 120–200 J/liter in 20–50 ns laser pulses. 相似文献
15.
K. Obata K. Sugioka T. Akane N. Aoki K. Toyoda K. Midorikawa 《Applied Physics A: Materials Science & Processing》2001,73(6):755-759
A collinear irradiation system of F2 and KrF excimer lasers for high-quality and high-efficiency ablation of hard materials by the F2 and KrF excimer lasers’ multi-wavelength excitation process has been developed. This system achieves well-defined micropatterning
of fused silica with little thermal influence and little debris deposition. In addition, the dependence of ablation rate on
various conditions such as laser fluence, irradiation timing of each laser beam, and pulse number is examined to investigate
the role of the F2 laser in this process. The multi-wavelength excitation effect is strongly affected by the irradiation timing, and an extremely
high ablation rate of over 30 nm/pulse is obtained between -10 ns and 10 ns of the delay time of F2 laser irradiation. The KrF excimer laser ablation threshold decreases and its effective absorption coefficient increases
with increasing F2 laser fluence. Moreover, the ablation rate shows a linear increase with the logarithm of KrF excimer laser fluence when the
F2 laser is simultaneously irradiated, while single KrF excimer laser ablation shows a nonlinear increase. The ablation mechanism
is discussed based on these results.
Received: 16 July 2001 / Accepted: 27 July 2001 / Published online: 2 October 2001 相似文献
16.
Jens Gottmann Dirk Wortmann Ion Vasilief Leonid Moiseev Dimitri Ganser 《Applied Surface Science》2007,254(4):1105-1110
Laser radiation is used both for the deposition of the laser active thin films and for the micro structuring to define wave guiding structures for the fabrication of waveguide lasers. Thin films of crystalline and amorphous neodymium doped Gd3Ga5O12 are grown on single crystal yttrium aluminium garnet by pulsed laser deposition using excimer laser radiation.Manufacturing of the laser active waveguides by micro structuring is done using femtosecond laser ablation of the deposited films. The structural and optical properties of the films and the morphology of the structured waveguides are determined in view of the design and the fabrication of compact and efficient diode pumped waveguide lasers. The resulting waveguides are polished, provided with resonator mirrors, pumped using diode lasers and the waveguide lasers are characterized. The spectroscopic properties of the amorphous waveguide are investigated and an infrared waveguide laser is demonstrated. To our knowledge, there have been no reports by other groups of the successful operation of a structured waveguide laser fabricated by this technique or of a waveguide laser made from amorphous neodymium doped Gd3Ga5O12. 相似文献
17.
《Infrared physics》1987,27(5):317-326
An optically-pumped 385-μm D2O laser has been constructed for Thomson scattering ion temperature measurements in tokamak plasma. Stable single mode and stable tunable (over ±1 GHz) operation of the pump 9R (22) TEA CO2 laser is performed by using an intracavity ZnSe etalon which is temperature-controlled within ±0.01°C. The saturation broadening with D2O absorption line is observed for the first time using the tunable 9R (22) CO2 laser. The pressure broadening coefficient of the N2O absorption line is measured to be 7.6 MHz/torr using the ±1 GHz tunable 385-μm D2O Raman laser. At 385 μm, an output quantum efficiency as high as 21% is obtained. 相似文献
18.
J. M. Jiang Z. Zhuo T. Li H. B. Qin C. X. Shan J. Li B. Zhao J. Z. Chen 《Laser Physics》2011,21(8):1358-1361
A diode pumped Nd:Y0.5Lu0.5VO4 pulse laser modulated with an acousto-optic (AO) Q-switcher and Cr4+:YAG saturable absorber is first demonstrated in this paper. The laser is shown to generate shorter pulse width than AO Q-switched
laser alone, and have a higher peak power and single pulse energy than passively Q-switched laser with only Cr4+:YAG. A laser pulse width of 6.16 ns and a peak power of about 43.83 kW are achieved at the incident pumping power of 14.09
W. 相似文献
19.
The nitridation of titanium (Ti) caused by a Q-switched Nd:YAG laser under nitrogen gas atmosphere was investigated in situ using X-ray photoelectron spectroscopy (XPS). A laser having a wavelength of 1064 nm and 532 nm (SHG mode) was irradiated on a titanium substrate in an atmosphere-controlled chamber, and the substrate was then transported to an XPS analysis chamber without exposing it to air. The characteristics of the surface layer strongly depend on the laser power. When the power is relatively low, a titanium dioxide layer containing a small amount of nitrogen is formed on the substrate. Laser irradiation beyond a certain laser power is required to obtain a stoichiometric titanium nitride (TiN) layer. A TiN layer and an oxynitride layer with a TiOxNy-like structure are formed as the topmost and the lower surface layer, respectively, when the laser power exceeds this threshold value. The threshold laser power strongly depends on the wavelength of the laser, and this threshold value for the 532-nm laser is quite lower than that for the 1064-nm laser. 相似文献
20.
An eye-safe KTA OPO pumped by a Nd:YLF laser is demonstrated and a comparison with that pumped by a Nd:YVO4 laser is performed. Although the slope efficiency of the continuous-wave free-running Nd:YLF laser is lower than that of the Nd:YVO4 laser, the performance of KTA OPOs pumped by the Q-switched Nd:YLF laser is better, especially at lower repetition rates. The slope efficiency of KTA OPO pumped by a Nd:YLF laser is 14.6% at 30 kHz and 11.04% at 10 kHz. The better energy storage ability of Nd:YLF makes it an excellent laser medium in IOPOs. 相似文献