Study on symmetry of output beam of corner-pumped solid-state fundamental-mode laser

Aimed at solving the problem of the asymmetry of the output beam of corner-pumped solid-state fundamental-mode lasers, a simple resonant cavity design is presented. Using this method, no optical element needs to be inserted into the cavity. The symmetry of the output beam can be improved effectively by changing cavity parameters. The validity of this method is demonstrated by a corner-pumped Nd:YAG/YAG composite slab Q-switched fundamental-mode laser. The asymmetry of the output beam can be corrected effectively by adjusting the short arm length of the linear cavity and a symmetric output beam is obtained. The resonant cavity design method is simple and practical, which also applies to other lasers with the asymmetric output beam resulting from asymmetric cooling or asymmetric pumping.     

Laser Doppler velocimeter using a single longitudinal mode solid-state laser source

An experimental demonstration of using a single longitudinal mode solid-state laser source in laser Doppler velocimeter (LDV) is presented. The technology of frequency spectrum correction is used in processing Doppler signal. The results of the experiments show that: the magnitude and signal-to-noise ratio (SNR) of Doppler signal are both enhanced by the solid-state laser; the measurement accuracy of LDV is improved by the technology of frequency spectrum correction, and the variance of the measured Doppler frequency is larger than the Cramer-Rao low bound (CRLB) of Doppler frequency about one order of magnitude.     

Random-wavelength solid-state laser

The spectral properties of a diode-pumped Yb:Y2O3 ceramic laser are reported. We show experimentally that the instantaneous emission wavelengths of the laser change randomly with time, whereas its emission has fixed well-defined transverse modes. The central wavelength of the laser emission also shifts prominently with the increase of intracavity light intensity. It is found that the spectral properties of the laser can be explained well based on the strong reabsorption of light in the gain medium.     

Continuous-wave solid-state dye laser

We report the first realization of a cw solid-state dye laser. The laser medium consists of a laser dye (Rhodamine 6G) dissolved in a photopolymer. The UV-cured solution is sandwiched between two DVD substrates. The resonator design was derived from a conventional liquid solvent dye laser geometry. The laser radiation can be tuned from 565 to 615 nm by using a birefringent filter. A pump power of 2 W leads to a cw output power of more than 20 mW.     

High pulse energy output from tunable solid-state dye laser based on MPMMA doped with PM567

Tunable solid-state dye laser sample based on modified polymethyl methacrylate (MPMMA) with methanol co-doped with pyrromethene 567 (PM567) and Coumarin 440 (C440) was prepared. Tunable dye laser output wavelength from 546 to 594 nm was obtained in an oscillator-amplifier configuration. With the input seed laser energy being about 1.5 mJ, the highest dye laser output energy reached 113.9 mJ, and the corresponding conversion slope efficiency was 51.39%. To the best of our knowledge, the tuning range and narrow linewidth dye output energy is the best under the same condition so far. The linewidth for the seed laser and amplified laser were measured with the result of less than 0.2 nm. With the amplified medium being pumped at a repetition rate of 10 Hz with a pulse energy as high as 120 mJ (the fluence was 0.42 J/cm²), the laser output energy dropped to half of its initial value after approximate 43000 pulses.     

中红外固体激光器研究进展

本文介绍了中红外固体激光器中新型的Fe²⁺: ZnSe激光器和基于MgO: PPLN、ZnGeP₂晶体的光参量振荡器的发展现状,讨论了它们在发展过程中遇到的技术难题,探讨了中红外固体激光器的未来发展方向。波长为3~5 μm的中红外固体激光器具有效率高、体积小和重量轻等优点,在工业、医疗、军事等方面具有重要应用价值,研制大尺寸、高质量中红外激光晶体和输出波长更长的红外高功率激光泵浦源已成为中红外固体激光器未来发展方向之一。     

阵列口径Nd：YAG片状激光器重复频率输出特性研究

介绍了一种新型阵列口径的固体片状激光器的设计及初步实验,研究了其激光输出特性。激光器采用2×1阵列的以布儒斯特角放置的片状Nd:YAG激光头模块,并采用氙灯泵浦方式,由平均功率为60 kW电池组电源供电;电源采用大电流恒流放电,对输出放电进行可编程控制。实验得到32 J的单脉冲输出,小信号增益系数为0.047 5 cm-1;泵浦单脉冲运行,脉宽为1~5 ms时,输出能量呈线性增长;当重复频率为20 Hz时,5 ms脉宽比1 ms脉宽输出功率下降30%,其原因是布儒斯特角结构存在时,由热应力引起的热致双折射损耗造成输出下降。     

阵列口径Nd：YAG片状激光器重复频率输出特性研究

 介绍了一种新型阵列口径的固体片状激光器的设计及初步实验，研究了其激光输出特性。激光器采用2×1阵列的以布儒斯特角放置的片状Nd:YAG激光头模块，并采用氙灯泵浦方式，由平均功率为60 kW电池组电源供电；电源采用大电流恒流放电，对输出放电进行可编程控制。实验得到32 J的单脉冲输出，小信号增益系数为0.047 5 cm^-1；泵浦单脉冲运行，脉宽为1~5 ms时，输出能量呈线性增长；当重复频率为20 Hz时，5 ms脉宽比1 ms脉宽输出功率下降30%，其原因是布儒斯特角结构存在时，由热应力引起的热致双折射损耗造成输出下降。     

Medium performance effect on the high output energy from a xenon lamp-pumped pyrromethene-567 solid-state dye laser

In order to obtain a high output energy from a xenon lamp-pumped solid-state dye laser, homogeneities of laser mediums and flatnesses of medium faces with different processing treatments are discussed in the paper. The medi- ums without aging treatment, which are prepared by using a prepolymer process and have diamond-machined end faces to produce the required optical finish, give a highest laser output of 281.9 mJ with 0.215% slope efficiency at 2.0×10 4 mol/L. The best medium lifetime is 21 shots to 50% of original output equating 74.6 kJ/liter.     

Wavelength-tunable organic solid-state distributed-feedback laser

We report on a wavelength-tunable organic solid-state laser based on a second-order distributed-feedback (DFB) resonator design with the guest–host system Alq₃:DCM2 as the gain medium. The laser wavelength can be shifted from 608.9 to 646.5 nm by varying the grating period of the Bragg reflector. This allows the characterization of laser parameters for a large wavelength region on a single sample. The laser threshold and output characteristics are measured for different laser wavelengths. A minimum threshold for laser activity occurs at a lasing wavelength of 633 nm, giving the spectral position of the gain maximum. PACS 42.70.Jk; 78.45.+h; 78.66.Qn     

High-power monolithic unstable-resonator solid-state laser

We report the operation of a diode-pumped monolithic Q-switched unstable-resonator solid-state laser that generates 2.15-mJ, 2-ns pulses in a single transverse mode and a single longitudinal mode. We show that the unstable resonator is effective in suppressing the spatial and the temporal instability of the laser beam in a disk-shaped laser whose transverse dimension is comparable with or larger than its longitudinal dimension.     

Dispersive solid-state dye laser oscillators

Narrow-linewidth multiple-prism grating solid-state dye laser oscillators are analysed using ray transfer matrices. Attention is given to beam divergence measurements and the effect on them of thermal lensing, at the solid-state gain medium. It is found that although thermal lensing leads to an increment of beam divergence, it induces oscillation in the unstable resonator regime, thus contributing to the attainment of TEM00 beam profiles. In addition, narrow-linewidth emission in dispersive oscillators, incorporating rhodamine 6 G doped HEMA:MMA gain media, is reported for the first time. Laser efficiency is 4–5% at a laser linewidth ≤1.8 GHz for double-longitudinal-mode emission. Beam divergence is measured in the 2–2.3 mrad range, in good agreement with theory. This revised version was published online in November 2006 with corrections to the Cover Date.     

激光二极管泵浦双频固体激光器

研制了0~1.5GHz频差的LD泵浦双频固体激光器。利用端面泵浦和F-P标准具的选模作用得到单频连续输出,在单频基础上将λ/4波片加入谐振腔中,造成本征光频率分裂,实现频差连续可调的双频激光输出。采用琼斯矩阵分析光在腔内的本征值及本征向量,实现了定量分析模在腔内的相位延迟和偏振状态,定量计算双频频差大小。     

YAG固体激光器的时间延迟特性

在电光调Q激光装置上,设计了KD*P晶体电光效应验证实验,总结了简单易行的光路调整方法,测试和讨论了调Q延迟时间对激光器输出能量和脉宽的影响.结果表明,最佳延迟时间的设定可以提高激光器输出能量.     

Laser ceramics: Mechanisms of solid-state reactions

The role of twinning in synthesizing Y₃Al₅O₁₂ from Al₂O₃ and Y₂O₃ powders during milling and compacting is shown by the example of obtaining laser ceramics based on yttrium-aluminum garnet. Simulation of twins in aluminum and yttrium oxides revealed the possibility of forming fragments of the garnet structure near the twin boundary. It is concluded that process of solid-state reactions is mainly associated with twinning, which leads to local variation in the symmetry and/or phase transitions.     

Cavity-taper output nitrogen laser

The experimental realization of a wide-aperture laser with a direct optical fiber taper output has been demonstrated. The cavity and output field distributions have been studied experimentally. The various loss mechanisms associated with the tapered optical fiber output are discussed.     

激光二极管泵浦的重复频率大能量低温Yb:YAG激光器设计

为实现重复频率大能量激光输出,基于Yb:YAG激光介质低温下良好的热特性和激光特性,设计了12 kW高功率激光二极管(LD)阵列泵浦的V型腔低温Yb:YAG激光器（液氮温度）。对于泵浦耦合系统和散热结构两个关键点,分别使用光线追迹方法和有限元方法进行了分析,提出了楔形真空窗口和低温热管等解决方案。模拟结果表明,该设计的激光器热效应较低,可实现重复频率大能量输出。     

激光二极管泵浦的重复频率大能量低温Yb:YAG激光器设计

为实现重复频率大能量激光输出,基于Yb:YAG激光介质低温下良好的热特性和激光特性,设计了12kW高功率激光二极管(LD)阵列泵浦的V型腔低温Yb:YAG激光器(液氮温度)。对于泵浦耦合系统和散热结构两个关键点,分别使用光线追迹方法和有限元方法进行了分析,提出了楔形真空窗口和低温热管等解决方案。模拟结果表明,该设计的激光器热效应较低,可实现重复频率大能量输出。     

Broadly tunable femtosecond solid-state laser sources

The techniques of coupled-cavity modelocking and self-modelocking in which intensity-induced nonlinear effects are exploited have been reviewed for broad-band gain media. Particular emphases have been placed upon the archetypical colour-centre and titanium-sapphire laser configurations in which these techniques were first demonstrated and subsequent refinements are set in context. A femtosecond optical parametric oscillator pumped by a self-mode-locked titanium-sapphire laser has also been described as an exemplar of a practical means of extending the source tunability into the mid-infrared spectral region.     

Towards a solid-state ring laser gyroscope

In this paper, we report our recent progress towards a solid-state ring laser gyroscope (RLG), where mode competition is circumvented by active control of differential losses, and nonlinear effects are mitigated by longitudinal vibration of the gain medium. The resulting dynamics is significantly different from that of a classical helium–neon RLG, owing in particular to parametric resonances that occur when the Sagnac frequency is an integer multiple of the crystal vibration frequency. We describe the main experimental and theoretical results obtained so far, and the prospects of practical applications in the near future.