A self-heated iron bromide (λ=452.9 nm) laser with Ne-HBr buffer gas

A self-heated multikilohertz laser is reported which operates on the 452.9 nm cyclic transition of atomic iron. The iron atoms are provided by dissociation of iron bromide donor molecules, formedin situ by passing Ne-HBr buffer gas over iron pieces in the laser-discharge active region. The output characteristics of the laser are described. Laser oscillation predicted by Walteret al. (IEEE J. Quantum Electron. QE-2 (1966) 474) for the 583.4 nm transition of rhenium was searched for using the same laser device, but was not realized.     

A practical CuBr laser with flowing buffer gas

Experiments on the lifetime of a CuBr laser with flowing neon as a buffer gas are reported. The CuBr laser with a discharge tube of inner diameter 18 mm, electrode separation 465 mm at an average output power of 3 W, an efficiency of 0.4% for a lifetime of 734 h is obtained. In consideration of the flow of the buffer gas and combined structure of the discharge tube we have achieved prolongation of the laser lifetime.     

Characteristics of a wire preionized nitrogen laser with helium as buffer gas

The operation of a small N₂ laser using wire preionization and He as a buffer gas is discussed. The preionization is found to increase the output power and energy by 50% while the addition of helium can increase fourfold the output power.     

Enhanced performance of a wide-aperture copper vapour laser with hydrogen additive in neon buffer gas

A wide-aperture copper vapour laser was demonstrated at ∼10 kHz rep-rate with hydrogen additive in its buffer gas. Maximum power in excess of ∼50 W (at 10 kHz) was achieved by adding 1.96% hydrogen to the neon buffer gas at 20 mbar total gas pressure. This increase in output power was about 70% as compared to ∼30 W achieved with pure neon at 5.5 kHz rep-rate. The 70% enhancement achieved was significantly higher than the maximum reported value of 50% so far in the literature. The enhancement was much higher (about 150%) as compared to its 20 W power at 10 kHz rep-rate using pure neon as the standard CVL operation.     

Frequency dependence of amplifying parameters of a copper vapor laser using air as a buffer gas

We use a pair of copper vapor lasers in an oscillator–amplifier configuration to investigate amplifying parameters such as the small signal gain and the saturation intensity versus the pulse repetition frequency when two different types of buffer gases are employed. We show that the values of these parameters are not the same if different gas mixtures are used in the gain medium. We show that the values of the parameters are estimated to be higher if a He–Ne buffer gas is used than in the case of air. The laser output power is relatively high and has fairly good stability at some special pulse repetition frequencies when air is used as a buffer gas.     

Effects of H2 buffer gas additive on repetition rate scaling of a copper vapour laser

The variations in the output power of a copper vapour laser resulting from H₂ additive to neon buffer gas are investigated for a wide range of pulse repetition frequencies (3.2 to 19.7 kHz). Small improvements in laser output power (9%) were observed for 2% H₂-Ne admixture at low repetition frequency, these improvements becoming progressively larger (up to 250%) as the repetition rate increased. These observations are consistent with added H₂ modifying the interpulse kinetics, thereby altering the spatiotemporal evolution of the output pulse. In particular, the observed average output power increases at elevated repetition rates owing to both increased laser pulse energy and increased optimum pulse repetition frequency.     

Excimer laser photolysis of molybdenum hexacarbonyl with buffer gas

We have studied the photolysis of molybdenum hexacarbonyl by focused excimer laser radiation. It was found that electronically excited Mo atoms detected in the focus region of a KrF laser are due to a direct two photon absorption transition. The upper limit of the energy for complete dissociation of Mo(CO)₆ has been derived from these results. Two photon dissociation in the gas phase should be the dominant process at metal film deposition on substrates positioned perpendicularly and near to the focus. Adding buffer gases to the organometallic vapor particle formation was observed in the whole irradiated gas volume. The analysis of scattered He-Ne laser light yields information about the density and size of these particles. Some conclusions are drawn with respect to structured metal film deposition with high spatial selectivity.Dedicated to Prof. Dr. Herbert Welling on the occasion of his 60th birthday     

溴化亚铜激光泵浦的可调谐微微秒染料激光

本文首次报道了利用脉宽为25ns重复率为10kHz的溴化亚铜激光泵浦混有饱和吸收体DODCI的超短腔染料激光,产生出30ps光脉冲.在理论上对混入DODCI的超短腔染料激光脉冲压缩效应作了分析计算,计算结果与实验基本一致.在实验上又通过一个放大-色散系统实现对此染料激光脉冲的同步放大和调谐,并达到傅里叶变换极限.     

Characteristics of a flowing He-SrCl2 vapor laser

An experimental investigation on the characteristics of a flowing He-SrCl₂ vapor laser is carried out. The output power as a function of the SrCl₂ vapor pressure is presented by calculating the radial temperature distribution of the discharge tube. The temporal dependences of the discharge current pulse on the laser pulses at 1 μm, ∼ 3 μm and 6.45 μm lines in strontium atom and ion, as well as the spot modes of the laser beam are measured and analyzed under different laser output power.     

溴化亚铜激光脉宽压缩研究

本文首次报道了利用注入放大方法将溴化亚铜激光578nm谱线压缩至接近傅里叶变换极限脉宽,并研究了其输出特性.     

Development of copper bromide laser master oscillator power amplifier system

Development of master oscillator power amplifier (MOPA) system of copper bromide laser (CBL) operating at 110 W average power is reported. The spectral distribution of power at green (510.6 nm) and yellow (578.2 nm) components in the output of a copper bromide laser is studied as a function of operating parameters. The electrical input power was varied from 2.6 to 4.3 kW, the pulse repetition frequency (PRF) was changed from 16 to 19 kHz, and the pressure of the buffer gas (neon) was kept fixed at 20 mbar. When the electrical input power was increased to 4.3 kW from 2.6 kW, the tube-wall temperature also increased to 488°C from 426°C but the ratio of the green to yellow power decreased to 1.53 from 3.73. The ratio of green to yellow power decreased to 1.53 from 1.63 when the PRF of the laser was increased to 19 kHz from 16 kHz. These observations are explained in terms of electron temperature, energy levels of transitions, and voltage and current waveforms across the laser head.     

A gold-vapor laser using Ne-H2 as buffer gas

A small amount of hydrogen was added to neon buffer gas in a discharge-heated gold vapor laser. It was found that the output power and efficiency of the gold-vapor laser dramatically increased. The average output power and efficiency increased as much as 60%, when 0.5–1.0 Torr of hydrogen was added to neon. Maximum average power of 8 W was obtained using a plasma tube with 30 mm^00D8×100 cm active volume.     

Performance comparison of supersonic ejectors with different motive gas injection schemes applicable for flowing medium gas laser

A class of flowing medium gas lasers with low generator pressures employ supersonic flows with low cavity pressure and are primarily categorized as high throughput systems capable of being scaled up to MW class. These include; Chemical Oxygen Iodine Laser (COIL) and Hydrogen (Deuterium) Fluoride (HF/DF). The practicability of such laser systems for various applications is enhanced by exhausting the effluents directly to ambient atmosphere. Consequently, ejector based pressure recovery forms a potent configuration for open cycle operation. Conventionally these gas laser systems require at least two ejector stages with low pressure stage being more critical, since it directly entrains the laser media, and the ensuing perturbation of cavity flow, if any, may affect laser operation. Hence, the choice of plausible motive gas injection schemes viz., peripheral or central is a fluid dynamic issue of interest, and a parametric experimental performance comparison would be beneficial. Thus, the focus is to experimentally characterize the effect of variation in motive gas supply pressure, entrainment ratio, back pressure conditions, nozzle injection position operated together with a COIL device and discern the reasons for the behavior.     

Resonance transition 795-nm rubidium laser using He buffer gas

We report a demonstration of a 795-nm rubidium optical resonance transition laser using a buffer gas consisting of pure ³He. This follows our recent demonstration of a hydrocarbon-free 795-nm rubidium resonance laser which used naturally-occurring He as the buffer gas. Using He gas that is isotopically enriched with ³He yields enhanced mixing of the Rb fine-structure levels. This enables efficient lasing at reduced He buffer gas pressure, improved thermal management in high average power Rb lasers and enhanced power scaling potential of such systems.     

Reduction of copper bromide molecules in the plasma of a CuBr laser during the interpulse period

The operation of a CuBr laser in an excitation pulse train mode has been investigated. The experimental data obtained allow one to determine the characteristic time for which copper atoms are lost by the active medium of the laser. The analysis performed based on a numerical simulation of the laser operation has shown that the copper atoms are lost in the processes of reduction of CuBr molecules due to reactions of interaction of copper atoms with bromine ions. The predicted time for which copper atoms are lost by the laser active medium (150 μs) is in good agreement with the experimental one.     

Modeling of flowing gas diode pumped alkali lasers: dependence of the operation on the gas velocity and on the nature of the buffer gas

A simple, semi-analytical model of flowing gas diode pumped alkali lasers (DPALs) is presented. The model takes into account the rise of temperature in the lasing medium with increasing pump power, resulting in decreasing pump absorption and slope efficiency. The model predicts the dependence of power on the flow velocity in flowing gas DPALs and checks the effect of using a buffer gas with high molar heat capacity and large relaxation rate constant between the P_3/22 and P_1/22 fine-structure levels of the alkali atom. It is found that the power strongly increases with flow velocity and that by replacing, e.g., ethane by propane as a buffer gas the power may be further increased by up to 30%. Eight kilowatt is achievable for 20?kW pump at flow velocity of 20 m/s.     

Neutron electric dipole moment measurement with a buffer gas comagnetometer

A neutron EDM measurement with a comagnetometer is discussed. For magnetometry, polarized xenon atoms are injected into a cylindrical cell where a cylindrically symmetric magnetic field and an electric field are applied for the EDM measurement. The geometric phase effect (GPE), which originates from particle motion in a magnetic field gradient, is analyzed in terms of the Dyson series. The motion of the xenon atom is largely suppressed because of a small mean free path. The field gradient is controlled by means of NMR measurements, where the false effect of Earth?s rotation is removed. As a result, the GPE is reduced below 10⁻²⁸e cm${10}^{-28}e\text{cm}$.