Average-power scaling of self-heated Sr+ afterglowrecombination lasers

The performance of a large-bore (25-mm) self-heated Sr⁺ (430.5-nm) recombination laser with longitudinal excitation is discussed in relation to the prospects for scaling average output power to the 5-10-W regime. Average-power scaling is found to be limited in large-bore laser tubes by slow interpulse thermal relaxation in the laser gas mixture with strong radial gradients in species' densities and temperatures at only modest pulse repetition frequencies, leading to premature termination of the population inversion on the tube axis. Proposals for circumventing these limitations in order to permit generation of multiwatt average laser output power at 430.5 nm from Sr ⁺ are discussed     

Repetitively pulsed transversely excited Sr+recombination laser

Operation of a transversely excited strontium-ion recombination laser at repetition rates up to 500 Hz is reported. Maximum average output power of 90 mW on the 430.5 nm transition has been obtained from a sealed-off device of active volume ∼ 40 cm³at a pulse repetition frequency of 200 Hz. This performace was achieved in the absence of any discharge preionization or forced recirculation of the gas mixture.     

放电激励的锶离子复合激光器

分析测量了放电激励的锶离子复合激光的电光特性．报道了一台平均功率２００ｍＷ的实验装置．     

Electrical characteristics of an E-beam controlled KrF*discharge

Plasma electrical characteristics have been measured as a function ofe-beam current density (JB) and fluorine concentration for Ar, Kr, and F2gas mixtures in order to identify the stable operating regime of KrF* laser interest. The data were obtained from a 120 cm³active volumee-beam controlled discharge laser. The optimum F2concentration was found to be 0.17 percent at JB= 17.9 A/cm². This mixture also gave the best laser extraction efficiency and consequently produced the highest laser output energy. The dissociative electron attachment rate constant in the laser mixture was determined from the discharge voltage and current measurements.     

Large-volume pulsed-RF excited waveguide CO2 lasers

Scalable pulsed-RF excitation of a sealed-off non-flowing CO₂ laser in a configuration compatible with high transverse and high longitudinal mode purity and compatible with very compact laser designs is described. The variation of maximum pulse-repetition frequency (PRF) with discharge transverse dimensions and the effects of electric field uniformity are described. Kinetics code calculations and laser design studies indicate that the results are scalable to the 10-J, 50-Hz level     

Area scaling in N2 waveguide lasers

The area scaling in a nitrogen (N₂: 337.1 nm) laser excited by the similar longitudinal discharges in single- and multichannel laser structures has been experimentally studied. The results demonstrate the capability of the area scaling method for increasing the average power and pulse-repetition frequency (PRF) of the laser. The variation of the laser output with the channel area and the effects of similar discharges are analyzed     

Single- and double-pulse experiments on the Sr+cyclic ion laser

Single- and double-pulse experiments have been conducted on a moderately large bore (19 mm) Sr+ cyclic ion laser oscillating at 1033 and 1092 nm. The dependence of the output energy on the bore temperature, buffer gas (HE) pressure, discharge capacitance, discharge voltage, and timing between successive pulses was determined. Saturation in the output energy as both the capacitance and voltage are increased is observed. An empirical exponential dependence of the energy on the discharge voltage was demonstrated. Results from the double-pulse experiments indicate that the Sr+ laser terminal levels depopulate much faster than do the Sr+ ions in the ground state, so that the efficiency of the laser increases as the interpulse delay time is decreased to 50 μs, and so that this laser system would be capable of more efficient operation at PRF in the region of 20 kHz, even in a large bore tube.     

Pulse broadening in multimode fibres excited by GaAs lasers

Pulse dispersion in multimode fibres depends strongly on mode excitation at the input and mode coupling in the fibre. Measurements on fibres of up to 160 m in length are given: pulse dispersion seems to follow a square-root law with the lengths of the fibres.     

Pulse characteristics of Q-switched fiber lasers

A theoretical investigation of the anticipated properties of optically end-pumpedQ-switched fiber lasers is reported. This analysis stresses the effect of the transverse structure of the interacting pump and signal (guided) waves, in particular of the fiberVnumber, on the device performance. In Nd : YAG single crystal fibers thresholds as low as a fraction of a milliwatt may be achieved; pulses with peak powers of hundreds of watts and subnanosecond widths may be generated under laser diode pumping conditions.     

Organic lasers excited by a pulsed N2laser

Laser action was obtained from rhodamine 6G and sodium fluorescein solutions by transverse pumping with a pulsed nitrogen laser. Relatively high efficiencies were observed and the threshold powers required were low. A repetition rate of ∼70 Hz was achieved with modest pump powers.     

Discharge-induced frequency modulation of RF excited CO2waveguide lasers

The mechanisms causing a shift in the oscillation frequency of an RF-excited CO₂ waveguide laser through changes in the discharge excitation power are investigated. Frequency shifts in the range of ±0.5 to 1 MHz per watt of RF input power were measured. These are shown to be consistent with the effects of thermal expansion of the laser gas caused by an increase of the gas temperature due to RF power absorption. It is also shown that the effects of gas dissociation are small but significant, whereas, contrary to earlier suggestions, the effects of electron density fluctuations are negligible. The discharge-induced frequency shift may be used as a simple frequency modulator with a frequency deviation of ±30 MHz, although the usefulness of this effect is limited to a bandwidth of about 500 Hz, due to the acoustic resonance of the waveguide channel     

Neutral-atom recombination lasers in CO2laser-vaporized target material

Neutral-atom recombination lasers in the vaporized plasmas of 28 different elements are reported. The results, which are consistent with the predictions of a simple model of a plasma-recombination laser, demonstrate the wide applicability of CO2laser-produced plasmas as sources for laser excitation.     

Comparison of threshold energy of selectively excited YAlO3:Er and YAG:Er lasers

Laser performance was studied for YAlO₃:Er and YAG:Er lasers that were excited with selective filtering of the pump light. In particular, the influence of the cross-relaxation process W was studied. The threshold energy for YAlO₃:Er is lower than for YAG:Er. This disparity is attributed to the differences in the lifetimes of the laser levels of the two crystals     

Ti~(3+):Al_2O_3激光特性的研究

本文详细报道了Ti~(3+):Al_2O_3激光器的实验结果.用一台Q开关脉冲Nd~(3+):YAG激光器的倍频光作泵浦源,获得了677～987nm调谐范围内O.5MW的峰值输出功率和13.9%的能量转换效率的TEM_(00)模输出.对实验结果进行了分析.l     

非对称Blumlein电路在锶离子复合激光器中的应用

脉冲放电Sr+离子复合激光器使用非对称Blumlein电路,得到的放电电流脉冲后沿陡峭,且没有起伏.极大激光平均功率高达524 mW.     

用扫描干涉仪观察Ar~+激光器主动锁模的某些特性

设计并制成了一台适用于Ar~+激光器的扫描干涉仪,用它观察了主动锁模Ar~+激光器频域的某些特性,拍摄到激光器在锁模状态下清晰的纵模频谱.实测干涉仪的分辨本领为30兆赫,精细常数为150.     

Influences of interfacial recombination on oscillation characteristics of InGaAsP/InP DH lasers

This paper presents the influences of interfacial recombination on the oscillation characteristics of InGaAsP/InP DH lasers. The effects of interfacial recombination at the two InP-InGaAsP interfaces, and a theoretical study of the oscillation characteristics such as threshold current density and differential quantum efficiency are discussed and compared with experimental results. The effects of interfacial recombination on the temperature dependence of threshold current are also examined.     

紫外铜离子激光器的理论研究

系统研究了连续工作的紫外铜离子激光器理论,即空心阴极放电的阴极位降理论,阴极溅射,放电等离子体中粒子的扩散和粒子数密度的速率方程。计算结果由实验得到验证。     

CW radio-frequency excited white-light He-Cd+ laser

We report on the design and performance of a continuous-wave transverse capacitively coupled radio-frequency excited He-Cd⁺ laser, which is capable of simultaneously delivering stable, tens-milliwatt power output at the three primary spectral lines blue: (λ=441.6 nm), green (λ=533.7 nm and λ=537.8 nm), and red (λ=635.5 nm and λ=636.0 nm). Mixing these lines can result in the laser beam featured by a wide band of colors, including white color. The radio-frequency discharge, that excited the He-Cd mixture inside an alumina ceramic tube (400 mm length and 4 mm inner diameter) inserted into the fused silica tubing, operated between 400 mm long and 4 mm wide outer electrodes. Transformation of the radio-frequency discharge impedance to the 50-Ω output resistance of the radiofrequency generator and symmetrization of the radio-frequency voltage were performed by a special matching circuit. Under single-line operation the He-Cd⁺ laser output powers of 60 mW, 38 mW and 14 mW were obtained for the blue, green and red lines, respectively, at an input radio-frequency power of 400 W. Owing to the power interaction between the laser oscillations at red and green higher laser output powers in red and green are possible under multi-line operation. At optimum conditions the white-light laser output power of about 60 mW is obtainable from the laser tube of 40 cm active length. The rms noise-to-signal ratio (lower than 0.4%) of the laser output power of the radio-frequency excited He-Cd⁺ laser was comparable to that of hollow cathode He-Cd⁺ lasers and much lower than that of conventional positive column He-Cd⁺ lasers. The presented laser has exhibited stable operation for more than 400 hours, showing ability to become a long life laser     

射频激励CO2激光器的十年发展

本文评述了射频激励CO2激光器十年的发展,介绍了几种典型器件的发展概况,以及国内射频激励CO2激光器的进展。