High repetition rate spiker-sustainer XeCl laser

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.     

Gas density perturbations in high repetition rate static fill tea lasers

The expression of the thermal perturbation on the optical beam of a high repetition rate, static fill TEA laser is given in terms of the ray-matrix in the approximation of a paraxial analysis. The dependence of the value of the matrix elements on the pulse repetition rate, pump energy, gas pressure and discharge geometry has been calculated in the ideal case of a perfectly homogeneous energy deposition in the laser medium.     

高重复频率XeCl准分子激光器

本文报道一台高重复频率XeC准分子激光器的结构及其特性。采用接地栅金属陶瓷闸流管开关和气体横向流动系统及自动紫外火花预电离的放电结构。该激光器最高单脉冲能量为200mJ,最高重复脉冲频率为107Hz,最大平均功率18W。     

高重复率XeCl准分子激光器的放电特性

本文报道紫外预电离放电泵浦的高重复率XeCl准分子激光器的放电特性,分析了放电参数的改变对放电过程的影响.最佳转换效率达2.2%.     

Limiting pulse repetition rate in copper vapor lasers

Two groups of processes which limit the rate-power characteristics of copper vapor lasers are examined. The first of these is related to the inadequate relaxation rate of the metastable states and accordingly their high prepulse concentration, which degrades the lasing pulse parameters. The second group of processes is initiated by the high prepulse electron concentration. It is shown that if the effect of the prepulse electrons is neutralized in pulse-periodic copper vapor lasers, then lasing starts up again in the next pulse within 1 μs after the preceding pulse stops. It is concluded that the rate of deexcitation of the metastable states is so high that it has no effect whatever on the lasing parameters in real gas-discharge lasers based on copper vapor or copper bromide vapor, and the prospects are opened up for attaining a lasing power of ∼10 kW/m with electron-beam pumping. Zh. Tekh. Fiz. 67, 54–60 (May 1997)     

Wide-aperture electric-discharge XeCl lasers

Experimental investigations have been performed for aXeCl laser with the active region aperture equal to 6.5×7 and 15×15 cm. To pump the laser, two types of generator were used: a generator connected in a double-loop circuit with a peaking capacitor and a multichannel spark gap switch and a magnetic thyratron generator. The working mixtureNe−Xe−HCl was preionized with soft x rays and a low-current electron beam, providing an initial electron density ranging from 10⁶ to 5·10¹³ cm⁻³. Conditions in which a homogeneous space discharge is initiated have been studied. It has been investigated how the degree of ionization of the gas and the aperture of the active region affect the discharge and lasing characteristics of the laser. The laser efficiency reaches 4% with an energy of ≈ 6 J extracted from one liter of the active region. Institute of High-Current Electronics, Siberian Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 54–59, April, 2000.     

High repetition rate mid-infrared laser source

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).     

Ultra-high repetition rate InAs/InP quantum dot mode-locked lasers

We have designed, grown and fabricated InAs/InP quantum dot (QD) waveguides as the gain materials of mode-locked lasers (MLLs). Passive InAs/InP QD MLLs based on single-section Fabry-Perot (F-P) cavities with repetition rates from 10 GHz to 100 GHz have been demonstrated in the C- and L-band. Femtosecond (fs) pulses with pulse duration of 295 fs have been achieved. The average output power is up to 50 mW at the room temperature of 18 °C. By using the external fiber mixed cavities fs pulse train with a repetition rate of 437 GHz has been generated. We have also discussed the working principles of the developed QD MLLs.     

The pumping discharge for XeCl lasers

This paper presents the results of experimental studies on the homogeneity of a discharge in aNe−Xe−HCl gas mixture at a pressure of 2 atm in relation to the discharge current density, the cathode material (Al, Cu, Ti), and the mode of preconditioning of the cathode. With freshCu electrodes, a discharge of current density j∼50 A/cm² with no cathode spot has been generated. Upon prolonged preconditioning ofAl andCu electrodes, a homogeneous discharge with j>100 A/cm² and a high density of cathode spots has been realized. The results of numerical calculations based on a plasma model which allows for more than 300 plasma chemical reactions agree well with experiment. The plasma particle densities and the rates of death and birth of charged species are presented as functions of time. The physical processes occurring in the discharge plasma are analyzed. Institute of High-Current Electronics, Siberian Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 76–86, April, 2000.     

高重复频率飞秒掺镱光纤放大器

 数值分析了掺镱单模光纤放大器的最佳增益光纤长度,并在实验上对掺镱单模光纤放大器和光栅对压缩器进行了研究。以最大平均输出功率为7 mW、重复频率为25.4 MHz、脉宽为56 ps的被动锁模环形腔掺镱光纤激光器作为种子脉冲,用250 mW的976 nm单模半导体激光器分别泵浦3种不同长度的掺镱单模光纤,对种子光进行放大,并用光栅对压缩器对放大后的脉冲在不同光栅距离上进行了压缩实验研究。当掺镱单模光纤长度为1.2 m时得到了较好的放大效果,种子脉冲被放大到140 mW,相应的增益为13 dB,放大后的单脉冲能量为5.5 nJ。在光栅距离为14.1 cm时获得了最短440 fs的脉冲,压缩后的功率为43 mW,相应的峰值功率为3.8 kW。     

高重复频率飞秒掺镱光纤放大器

数值分析了掺镱单模光纤放大器的最佳增益光纤长度,并在实验上对掺镱单模光纤放大器和光栅对压缩器进行了研究。以最大平均输出功率为7 mW、重复频率为25.4 MHz、脉宽为56 ps的被动锁模环形腔掺镱光纤激光器作为种子脉冲,用250 mW的976 nm单模半导体激光器分别泵浦3种不同长度的掺镱单模光纤,对种子光进行放大,并用光栅对压缩器对放大后的脉冲在不同光栅距离上进行了压缩实验研究。当掺镱单模光纤长度为1.2 m时得到了较好的放大效果,种子脉冲被放大到140 mW,相应的增益为13 dB,放大后的单脉冲能量为5.5 nJ。在光栅距离为14.1 cm时获得了最短440 fs的脉冲,压缩后的功率为43 mW,相应的峰值功率为3.8 kW。     

放电脉冲重频准分子激光器在不同应用领域的发展现状(英文)

研究了脉冲宽度为25～40 ns的放电脉冲XeCl准分子激光器的工作参数。结果显示,激光器产生的脉冲能量为0.2～0.7 J,重复频率为100 Hz,表明在泵浦功率为2.8～3.3 MW/cm3时,激光器实现了2.6%的激光效率和3.8%的本征效率。     

放电脉冲重频准分子激光器在不同应用领域的发展现状(英文)

研究了脉冲宽度为25～40 ns的放电脉冲XeCl准分子激光器的工作参数。结果显示,激光器产生的脉冲能量为0.2～0.7 J,重复频率为100 Hz,表明在泵浦功率为2.8～3.3 MW/cm3时,激光器实现了2.6%的激光效率和3.8%的本征效率。     

Electron beamexcitation of wide-aperture XeCl lasers

This paper presents the results of studies aimed at seeking efficient modes of electron beam excitation ofXeCl lasers with an active volume of some tens of liters. It has been shown that a lasing efficiency of about 4% is realized at an excitation pulse duration of 300 ns with a power of 200–400 kW/cm³. Institute of High-Current Electronics, Siberian Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 29–33, April, 2000.     

High repetition rate electro-optical-Q-switched intracavity optical parametric oscillator

A high repetition rate electro-optical-Q-switched intracavity optical parametric oscillator (IOPO) is realized by using two RbTiOPO₄ (RTP) crystals as electro-optic (EO) modulator. Three repetitions of the EO modulator ( f _p = 15, 20, and 30 kHz) were applied in the experiment. The pulse width can be minimized to 7ns when the input energy is 24.4 J at three modulating repetitions. The peak power of the signal light increases with reducing the pulse repetition rate. By considering the gradual loss from the delayed switched time of the EO switch, the coupled rate equations of IOPO under the assumption of the uniform distributions of the intracavity photon densities are given and the numerical solution of the equations fits the experimental data well.     

High repetition rate, compact micro-pulse all-solid-state laser

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.     

Investigation of practical high repetition rate copper vapour lasers with external heating

The characteristics of high repetition rate CVL devices incorporating passive external heating have been investigated. Pre-heating of the CVL plasma tube using external heating has been shown to significantly reduce CVL warm-up time, while supplementary heating of the CVL plasma tube using external heating allows efficient CVL operation with reduced discharge power input without any degradation in output power.     

Towards wafer-scale integration of high repetition rate passively mode-locked surface-emitting semiconductor lasers

One of the most application-relevant milestones that remain to be achieved in the field of passively mode-locked surface-emitting semiconductor lasers is the integration of the semiconductor absorber into the gain structure, enabling the realization of ultra-compact high-repetition-rate laser devices suitable for wafer-scale integration. We have recently succeeded in fabricating the key element in this concept, a quantum-dot-based saturable absorber with a very low saturation fluence, which for the first time allows stable mode locking of surface-emitting semiconductor lasers with the same mode areas on gain and absorber. Experimental results at high repetition rates of up to 30 GHz are shown. PACS 42.55.Px; 42.60.Fc; 42.82.Gw     

Scattering and chlorine absorption in discharge-pumped XeCl excimer lasers

Scattering microparticles were found to determine the characteristic behavior of the laser energy of discharge pumped XeCl excimer lasers with aluminium electrodes. All experimental results indicate that sputtered aluminium reacts with chlorine, a constituent of the laser gas, and forms aluminium chloride particles. Chlorine was observed to be formed by a reaction of oxygen, contained as an impurity, with the halogen donor hydrogen chloride under discharge conditions.     

High repetition rate CH4 laser

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.