Pulsed HF Laser Research Articles

Laser properties of active media based on ZnSe doped with Fe and In from spray pyrolysis deposited films

A technique was presented for obtaining laser media based on polycrystalline zinc selenide doped with iron from spray pyrolysis deposited films in the solid-phase diffusion process. The effect of the ligature film composition and the high-temperature treatment conditions on the lasing characteristics of Fe:(In):ZnSe active elements was investigated. Lasing with an energy of 100 mJ at a differential absorbed energy efficiency of 42% was obtained on 20 mm disk Fe:ZnSe element pumped by a pulsed electric-discharge HF laser.

Performance improvement of a Fe2+:ZnSe laser pumped by non-chain pulsed HF laser

The causes and suppression methods of parasitic lasing in transverse direction of Fe2+:ZnSe laser are analyzed theoretically and experimentally. For a crystal with given diameter, there exists a maximum pump spot diameter dmax, below which the parasitic lasing doesn’t occur. The effective maximum pump spot diameter dmax can be increased by coating graphite on the side of the laser crystal, and the average increase of dmax is about 1.7 times after coating. The thermoelastic stresses and deformations on the Fe2+:ZnSe crystal under pulsed pumping mode are modeled, with results showing that it is possible by choosing doping profile shape to significantly reduce optical distortions and increase pulse power.

Transversal parasitic oscillation suppression in high gain pulsed Fe2+:ZnSe laser at room temperature

The performance of a room temperature high gain solid-state Fe2+:ZnSe laser was investigated. Causes and affecting factors of Transversal Parasitic Oscillation (TPO) were analyzed theoretically. The results indicate that TPO could be suppressed by reducing pump spot size or coating graphite around the active element. Corresponding experiments were made on Fe2+:ZnSe laser pumped by a non-chain pulsed HF laser, and the results demonstrate that the combination of reducing spot size and coating graphite can successfully overcome gain depletion problem due to TPO in high gain Fe2+:ZnSe lasers. At room temperature, the output energy of Fe2+:ZnSe laser reached 502 mJ, and the slope efficiency, measured with respect to the input pump energy, was 32.6%. An average power of 21.7 W was obtained at a pulse repetition rate of 50 Hz.

Pulse energy sustainability of a burst mode closed-cycle pulsed HF chemical laser

Pulse energy sustainability of a burst mode closed-cycle pulsed HF laser is investigated with a simple theoretical model considering gas replenishment and chemical scrubbing. The effects of reactant gas consumption and de-excitation of excited HF by ground state HF are studied quantitatively. Also, experiments are carried out for comparison and validation. Simulation and experiments show that, in the burst mode operation, the energy loss caused by gas consumption is about 0.06–0.12 mJ per pulse while that induced by the de-excitation process is about 0.22–0.29 mJ per pulse, demonstrating that chemical scrubbing should play a more important role in the energy preservation of non-chain pulsed HF lasers.

An Installation for Fast and Safe Preparation of Working Mixtures in Reactors of Pulsed Chemical HF(DF) Lasers

A system for preparing working mixtures in reactors of pulsed chemical lasers based on the F2 + H2(D2) reactions is described. The design of a compact capillary mixer has been developed; its throughput of up to 2 (L atm)/s has been experimentally attained. A method for supplying gases using flow-control washers with holes operating in the critical mode is proposed. It provides a constant flow rate of mixed gases during the whole run-in. The described technology for preparing the working mixture of a pulsed chemical HF(DF) laser is theoretically analyzed and experimentally tested.

重复频率HF激光脉冲能量稳定性的理论分析

重复频率HF激光脉冲能量稳定性的理论分析

基态HF分子和介质消耗对重复频率脉冲HF激光输出的影响

基态HF分子和介质消耗对重复频率脉冲HF激光输出的影响

放电引发非链式脉冲HF激光器输出光谱特性研究

放电引发非链式脉冲HF激光器输出光谱特性研究

基于非稳腔的非链式脉冲HF激光光束质量优化

基于非稳腔的非链式脉冲HF激光光束质量优化

脉冲HF激光器预电离设计及效果评估

脉冲HF激光器预电离设计及效果评估

Room-temperature laser on a ZnS:Fe2+ polycrystal with a pulse radiation energy of 0.6 J

A laser on polycrystalline ZnS:Fe2+ samples pumped at room temperature by a pulsed electrodischarge HF laser was investigated. Samples of zinc sulphide grown by the method of chemical vapour deposition (CVD) were doped with iron ions from two sides by the diffusion method. The doping of the crystals was performed using the process of hot isostatic pressing (HIP treatment) at an argon pressure of 100 MPa and a temperature of 1265 °С. A longer duration of HIP treatment resulted in a greater depth of sample doping and higher slope efficiency of the laser. For a crystal subjected to HIP treatment for 151 h, a generation energy 660 mJ was obtained. The values of the slope and total efficiency of the energy absorbed in an active element were, respectively, ηslope = 36% and ηabs ≈ 26%. Based on the results obtained, and data from earlier published works, a conclusion has been made that to enhance the generation characteristics of a ZnS:Fe2+ laser it is necessary to increase the temperature of the HIP treatment of CVD ZnS.

流场均匀性对重频HF激光能量稳定输出的影响

流场均匀性对重频HF激光能量稳定输出的影响

非链式脉冲HF激光器激光介质净化技术

非链式脉冲HF激光器激光介质净化技术

流场均匀性对重频HF激光能量稳定输出的影响

流场均匀性对重频HF激光能量稳定输出的影响

Laser on single-crystal ZnSe:Fe2+ with high pulse radiation energy at room temperature

A laser on single-crystal ZnSe:Fe2+ was investigated at room temperature. Pumping of the laser was performed by a pulsed electrodischarge HF laser. In experiments, the spot diameter of HF laser radiation incident to the surface of the crystal varied from 5.6 to 17 mm. Generation energy of ~1.2 J was obtained and the efficiency with respect to the energy arriving at the crystal was ηin ≈ 25%. The slope efficiency with respect to the energy absorbed in the crystal at large spot dimensions was ηslope = 45%.

High-power pulse repetitive HF(DF) laser with a solid-state pump generator

Operation of a repetitively pulsed electric-discharge HF(DF) laser with an all-solid-state pump generator based on FID switches is demonstrated. The energy stored in the pump generator capacitors was at an open-circuit voltage of and a discharge pulse repetition rate of . The specific energy extractions were 3.8 and for the HF and DF lasers, respectively. The possibilities of improving the output laser characteristics are discussed.

Investigation of Fe : ZnSe laser in pulsed and repetitively pulsed regimes

The characteristics of a Fe : ZnSe laser pumped by a single-pulse free-running Er : YAG laser and a repetitively pulsed HF laser are presented. An output energy of is achieved in the case of liquid-nitrogen cooling of the : ZnSe active laser element longitudinally pumped by an Er:YAG laser with a pulse duration of and an energy up to . The laser efficiency with respect to the absorbed energy is 47%. The output pulse energy at room temperature is . The decrease in the output energy is explained by a strong temperature dependence of the upper laser level lifetime and by pulsed heating of the active element. The temperature dependence of the upper laser level lifetime is used to determine the pump parameters needed to achieve high pulse energies at room temperature. Stable repetitively-pulsed operation of the : ZnSe laser at room temperature with an average power of and a maximum pulse energy of is achieved upon pumping by a train of HF laser pulses with a repetition rate of .

Spectral and temporal characteristics of a ZnSe:Fe2+ laser pumped by a non-chain HF(DF) laser at room temperature

Spectral and temporal characteristics of a ZnSe:Fe2+ laser with a nonselective resonator pumped at room temperature by the radiation of a pulse-periodical electrodischarge HF(DF) laser are studied. It was established that the spectral distributions of the energy and peak power of ZnSe:Fe2+ laser generation depend on a spectral composition of the pumping radiation. The spectra exhibit a line structure with spectral intervals between neighboring lines δλ ≈ 6.8 ÷ 8.6 nm. The shape of the ZnSe:Fe2+ laser generation pulse is wavelength dependent. In a short-wavelength range, the pulse has the form of a peak with a duration of ~5 ns at half-maximum. At a longer wavelength, the peak is accompanied by a ‘tail’. The duration and amplitude of the tail increase with wavelength, in a long-wavelength spectrum range, the peak actually becomes unnoticeable on a background of the ‘tail’. The spectral dependence of the ZnSe:Fe2+ laser generation pulse’s shape affects the positions of the energy and peak power maxima on the wavelength axis. The dynamics of ZnSe:Fe2+ laser generation under the pumping by the pulsed HF(DF) laser is discussed.

High-power repetitively pulsed electric-discharge HF laser

A high-power non-chain electric-discharge repetitively pulsed HF laser based on SF6—hydrocarbon mixtures is developed and investigated. A pulse energy Wg = 67 J is obtained at a pulse repetition rate of 20 Hz.

电激励脉冲HF激光SF6/C2H6工作气体的放电特性

电激励脉冲HF激光SF₆/C₂H₆工作气体的放电特性