共查询到20条相似文献,搜索用时 15 毫秒
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Yijun Zheng Rongqing Tan Donglei Wang Guang Zheng Changjun Ke Kuohai Zhang Chongyi Wan Jin Wu 《中国光学快报(英文版)》2006,4(2)
Because pulse repetition rate affected directly the momentum coupling coefficient of transversely excited atmospheric (TEA) CO2 laser propulsion, a double pulse trigger, controlling high voltage switch of laser excitation circuit, was designed. The pulse interval ranged between 5 and 100 ms. The momentum coupling coefficient for air-breathing mode laser propulsion was studied experimentally. It was found that the momentum coupling coefficient decreased with the pulse repetition rate increasing. 相似文献
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Guilong Yang Dianjun Li Jijiang Xie Laiming Zhang Fei Chen Jin Guo Lihong Guo 《Laser Physics》2012,22(7):1173-1176
A high power repetitive spark-pin UV-preionized TEA CO2 laser system is presented. The discharge for generating laser pulses is controlled by a rotary spark switch and a high voltage pulsed trigger. Uniform glow discharge between two symmetrical Chang-electrodes is realized by using an auto-inversion circuit. A couple of high power axial-flow fans with the maximum wind speed of 80 m/s are used for gas exchange between the electrodes. At a repetitive operation, the maximum average output laser power of 10.4 kW 10.6 ??m laser is obtained at 300 Hz, with an electro-optical conversion efficiency of 15.6%. At single pulsed operation, more pumping energy and higher gases pressures can be injected, and the maximum output laser energy of 53 J is achieved. 相似文献
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N. Bernard Th. Hofmann B. L. Fontaine Ph. Delaporte M. Sentis B. M. Forestier 《Applied physics. B, Lasers and optics》1996,62(5):431-435
An X-ray preionized spiker-sustainer XeCl-excimer laser operating at high repetition frequency (1000 Hz) and 220 W of average laser power is demonstrated. The pulse energy and the pulse duration (160 ns) are virtually independent of the repetition frequency. Comparison with aC-L-C circuit shows superior properties of spiker-sustainer excitation for high-frequency operation. Furthermore, a variation of the overshoot mode is proposed. 相似文献
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Martin Schellhorn Marc Eichhorn Christelle Kieleck Antoine Hirth 《Comptes Rendus Physique》2007,8(10):1151-1161
An efficient, high-power mid-infrared laser source based on ZnGeP2 (ZGP) optical parametric oscillator (OPO) is presented. Using a Q-switched Ho:YAG laser as the pump source a total output power of 10.6 W was obtained in the 3–5 μm band at 10 kHz and 8.5 W at 20 kHz. The Ho:YAG laser was pumped by two diode-pumped polarization coupled Tm:YLF lasers. Optical-to-optical efficiency achieved is >8.8% (laser-diode 792 nm to mid-IR 3–5 μm). With a commercial PtSi infrared camera (256×256 pixel focal plane array, 24 μm pitch) the pointing stability of Ho pump, signal and idler beam was measured to be better than 30 μrad. Whilst propagating the OPO beams over 100 m, little absorption for the idler beam was observed, resulting in a significant higher peak-to-peak value of ±22%, whereas the peak-to-peak stability of the signal pulses remained unchanged (±13%). To cite this article: M. Schellhorn et al., C. R. Physique 8 (2007). 相似文献
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In this paper, a mechanical Q-switching is used in radio frequency (RF) excited waveguide CO2 laser to obtain high pulse repetition frequency (PRF) laser. The Q-switching system includes two confocal ZnSe lenses and a high speed mechanical chopper, which is inserted into the cavity. The peak power is up to 730 W and the pulse width 200 ns at the highest PRF 20 kHz. The laser also has the advantages of compact, small-volume, and low-cost. 相似文献
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N. R. Heckenberg B. J. Renton S. T. Shanahan W. Wright 《Applied physics. B, Lasers and optics》1982,29(2):67-72
The effect of injecting radiation from a cw waveguide CO2 laser into a TEA laser through a hole in one mirror of its unstable resonator has been studied experimentally. High-power single longitudinal mode operation of the TEA laser is achieved over a wide but finite range of injection frequencies, the frequency of the single-mode pulse being that of the TEA laser cavity mode lying closest to the injected frequency. Although a simple theoretical model shows good qualitative agreement with observations it underestimates the range of injection frequencies which result in single-mode pulses unless a fast chirping of the cavity mode frequency is postulated. 相似文献
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《Infrared Physics & Technology》2000,41(3):139-142
In this article, an experimental study of a miniature, sealed-off, high-repetition-rate transversely excited atmospheric-pressure (TEA) CO2 laser with a kind of surface-wire-corona preionization (SWCP) is described. We have utilized an SWCP consisting of SiO2 dielectric tube and a fine wire strained and attached to the dielectric surface. A BN ceramic material, which has an extremely low coefficient of thermal expansion of about 5 × 10−7/°C was employed as a supporter of the resonator. A measurement on emission spectra of SWCP has been reported. By applying SWCP to the TEA CO2 laser, efficient laser operation at an overall efficiency of 9.8% with an output energy of 150 mJ has been achieved from a small discharge volume of 25 cm3 with an active length of 230 mm. At the pulse repetition frequency of 60 Hz, the TEM00 mode of laser beam with pulse width of 60 ns was obtained. 相似文献
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Rongqing Tan Chongyi Wan Jilan Qi Shiming Liu Jinwen Zhou Wenjie Xie Jin Wu 《Optics & Laser Technology》1999,31(5):393
In this paper, a novel excitation method named as sequential discharge is realized in a two-module TEA CO2 laser by using a special rotating spark gap. It is demonstrated that the repetition rate and the output power of a laser can be multiplied through this method. For the two-module TEA CO2 laser in the experiment, the repetition rate is 300 Hz and the average power is 356 W when each module discharges; the repetition rate is 600 Hz and the average power is 713 W when the two modules discharge sequentially. 相似文献
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A high repetition rate, compact micro-pulse all-solid-state laser is designed. The diffusion bonded crystal of YAG, Nd:YAG, and Cr4+:YAG is taken as a monolithic cavity. The optimized initial transmission,output coupling, and pumping size of Cr4+:YAG are calculated. The experimental results show that the laser satisfies the requirement of a spaceborne laser range finder. 相似文献
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B. Tan A. Dalili K. Venkatakrishnan 《Applied Physics A: Materials Science & Processing》2009,95(2):537-545
Thin film laser micromachining has been utilized for repairing semiconductor masks, creating solar cells and fabricating MEMS
devices. A unique high repetition rate femtosecond fiber laser system capable of variable repetition rates from 200 KHz to
25 MHz along with helium gas assist was used to study the effect of pulse repetition rate and pulse energy on femtosecond
laser machining of gold-coated silicon wafer. It was seen that high repetition rates lead to smaller craters with uniform
line width. Craters created at 13 MHz pulse repetition rate with 2.042 J/cm2 beam energy fluence measured 110 nm in width and had a heat affected zone of 0.79 μm. It was found that pulse repetition
rate only played a significant role in the size of the heat affected zone in the lower pulse energy ranges. In the future,
a 1 W laser system will be acquired to find the optimal repetition rate that would create the minimal feature size with the
least heat affected zone. Using this kind of setup along with techniques such as radial polarization and a different gas assist
may enable us to create sub 100 nm feature size with good quality. 相似文献
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John M. Telle 《International Journal of Infrared and Millimeter Waves》1982,3(2):153-157
A 16-m CF4 laser oscillator has operated at 1 kHz in a cooled static cell. Pump energies required from the low pressure, Q-switched, cw discharge CO2 laser were as low as 60 J. The laser cavity employed a multiple-pass off-axis path resonator in a ring configuration. CF4 laser power at 615 cm–1 and a 1-kHz repetition rate exceeded 300 W. 相似文献
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具有同空间特性的双波长可调谐TEACO2激光器 总被引:7,自引:0,他引:7
研制成功一种新型双波长TEACO2激光器,激光器在一对横向放电电极之间设置两个空间部分重叠的光栅_平面腔,两光栅沿腔轴一前一后放置,且在空间上交叠,两个腔相互利用,能够输出含有两种波长成分的激光脉冲。输出的同一激光脉冲中两波长激光场在空间上部分重叠,重叠程度和两种波长激光场的能量比均可通过调整前面光栅的水平横向位置加以控制,通过调节两光栅的角度选择所需支线,波长调谐方便且调谐范围较宽。该激光器在分离硼同位素的实验中得到了初步成功的应用。 相似文献
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A. A. Serafetinides H. Gonis M. Makropoulou E. Agapitos N. Kavantzas C. Politopoulos D. Yova 《Il Nuovo Cimento D》1995,17(3):213-219
Summary One of the prerequisites for successful laser angioplasty is the ablation of the atherosclerotic lesions, without thermal
or shock-wave damage of the healthy tissue. In this study was evaluated the effectiveness of a TEA CO2 laser, emitting pulses of the lower TEM mode, 100 ns duration, at a repetition rate of 2.4 Hz, for the ablation of cardiovascular
tissue. Normal and atherosclerotic human arteries (post mortem) were irradiated for a range of fluences up to 10J pulse−1 cm−2. After irradiation, the samples were prepared for histologic examination. The results showed that controlled ablation of
normal and atherosclerotic coronary artery can be accomplished with the TEA CO2 laser, with minimal thermal damage. 相似文献