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1.
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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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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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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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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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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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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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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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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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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就水下探测设备要求激光器输出频率高、体积小、波段宽,提出通过侧面泵浦激光技术和电光调Q技术获得高重频1 064 nm波段激光。利用腔外波长变换技术,实现532 nm激光输出。在电源输入电流100 A,调Q驱动频率1 kHz的条件下, 获得36 mJ的1 064 nm激光输出和20 mJ的532 nm激光输出。试验结果表明:通过半导体泵浦技术和频率变换技术,可实现高重频窄脉宽双波段激光输出。  相似文献   

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研制了一种新型的预电离结构--管状预电离器,并将其应用于可调谐TEA CO2激光器.利用光栅选线方案,采用光栅谐振腔,实现了激光的调谐输出.在输出耦合率为50%、气压为40 kPa的条件下,10P(20),10R(20),9P(20),9R(20)四条谱线获得的最高电光转换效率,分别为9.5%,9.7%,9.8%,9....  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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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   

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