532nm激光对兔视网膜损伤阈值研究

目的:确定532nm激光对兔视网膜的损伤阈值.方法:以家兔14只28眼为实验对象,倍频Nd:YAG激光(532nm)通过裂隙灯照射兔视网膜后极部,光斑直径为2mm,照光时间100s,功率密度为900mW/cm2 -1500 mW/cm2,于照后24h观察视网膜损伤发生率,并用加权概率单位法计算损伤发生率为50%时所对应的激光剂量,即损伤阈值ED＜50.结果:532nm激光照射兔视网膜的ED＜50为119.7J/cm2,95%置信区间为:(112.6J/cm2,127.0J/cm2),斜率S为1.18.结论:当光斑直径为2mm,照光时间100s时,532nm激光敛兔视网膜损伤的阈值为119.7J/cm2.     

激光清洗阈值和损伤阈值的研究

讨论了采用波长为３０８ｎｍ，脉冲宽度为２８ｎｓ的准分子激光清洗基片的实验研究，分析了激光清洗过程中清洗阈值和损伤阈值存在的原因，并对它们进行了定量性推导。     

光学薄膜激光损伤阈值测试方法的介绍和讨论

目前国内外对光学薄膜激光损伤阈值的测试方法基本上可归纳为3类:国际标准ISO 11254、国军标G JB1487-1992和各单位的企业标准。在简要介绍这些方法的基础上,对各类测试方法的有关内容进行了讨论,并提出尽快与国际标准接轨以及研制并生产这种测试仪器的重要性和迫切性。     

调Q Nd：YAG激光对兔眼视网膜损伤及修复的观察

目的 用调Q Nd:YAG（1064nm)激光照射兔眼视网膜,观察随着能量及频率的增加视网膜损伤的变化,并长期随访眼底的修复情况。结果 1064nm激光照射兔眼视网膜可造成视网膜光凝斑、出血及玻璃体出血,视网膜损伤程度与能量及频率呈正相关,并在没有任何药物的治疗干预下,在三月内损伤可不同程度的修复。     

激光对光电探测器的损伤阈值研究

本文研究了1.06μm和0.53μm激光对硅pin光电二极管以及硅雪崩光电管的永久性损伤效应,测出了损伤阈值。实验发现,光电探测器的PN结受到激光热烧伤是造成其永久性损伤的重要因素,损伤阈值的大小与激光波长、脉冲宽度以及光电探测器结构有关。     

紫外激光对眼和皮肤的照射装置及损伤阈值研究

本文介绍266nm,355nm激光照射兔眼、人前臂屈侧皮肤及白色幼猪皮肤损伤阈值研究的照射装置、方法与结果。     

光学薄膜激光损伤阈值的智能检测研究

为了解决当前光学薄膜激光损伤阈值检测方法准确性差、可视化和灵活性不理想等难题,提出基于软件测试算法的光学薄膜激光损伤阈值检测方法。首先计算损伤阈值最终不确定度,并将不确定度计算结果代入损伤阈值检测中,然后利构成测量光路,激光在透镜上聚焦照射到待测样品上,根据测试软件程序对激光照射前后的图像进行预处理,判断是否存在损伤,若存在损伤,结合高斯光束理念获取有效光斑面积,最后损伤阈值,并进行了仿真实验,结果表明,该方法检测准确率和可视化程度高,且灵活性强。     

Singlemode passive Q-switched ruby laser

Results are reported on a passiveQ-switched ruby laser utilizing a special rooftop prism cavity. With a 40 cm long resonator, a single transverse and longitudinal mode has been obtained. With a 3 meter long resonator, a single transverse mode self-locked beam has been obtained.     

高功率Q开关双脉冲红宝石激光器

本文叙述了双脉冲激光器的基本原理及调试方法，这个方法原则上可适用于其他类型KDP—Q开关高功率双脉冲激光器的研制（如钕玻璃，Nd：YAG双脉冲激光器）。     

Energy losses in a passive Q-switched ruby laser

An experimental investigation has been performed in order to explain why the output energy from a ruby laser is always reduced when passing from normal laser operation toQ-switching operation. A saturable absorber was used as the switching element; however, the discussion about the energy losses is valid for everyQ-switching system. Experimental data allow one to evaluate the decrease of the output energy due to the reduced pumping efficiency, to the losses in the optical switch, and to the incomplete depletion of the inversion arising from the spatial inhomogeneity of the standing wave in the resonator and from the relaxation processes in the ruby line.     

9C1--Single transverse and longitudinal mode Q-switched ruby laser

Single transverse and longitudinal modes have been observed in the output of a passiveQ-switched ruby laser when two spherical mirrors are used for the resonator. This result has been consistently obtained with several rods, with two sets of mirrors of different radius of curvature, and with a few values of reflectivity of the mirrors which proves that it is typical of a spherical resonator. The saturable absorber is a solution of vanadium phtalocyanine in nitrobenzene. To have a single transverse mode, the mirror alignment and the position of the rod within the cavity is critical. When the laser oscillates in a single mode, the output pulse is very reproducible and the fluctuations of peak amplitude and width of the pulse are less than ∼3 percent. Furthermore, as expected, the output beam has a very good spatial coherence and its divergence approaches the limits set by diffraction. As far as peak output power and width of the pulse, the best results have been obtained with one concave and one convex mirror of ∼ 5-m radius of curvature, one mirror being 99 percent and the other 50 percent reflecting. A pulse of 1 MW peak power and 30 ns half-width has been obtained.     

Q-switched laser damage of infrared nonlinear materials

Q-switched laser-damage thresholds have been determined for six materials (proustite-Ag3AsS3, pyrargyrite-Ag3SbS3, cinnabar-HgS, silver thiogallate-AgGaS2, tellurium-Te, and gallium arsenide-GaAs) of interest for nonlinear optics in the medium infrared. Four TEM00mode lasers were employed with outputs at wavelengths of 694 nm, 1.06, 2.098, and 10.6 μm. Damage has been found to be confined to the surface of the crystals and occurs for radiation intensities between 3 and 75 MW/cm². Particular care is needed in the cutting and polishing of tellurium crystals if a high-damage threshold is to be achieved.     

A continuously pumped repetitively Q-switched ruby laser and applications to frequency-conversion experiments

A repetitivelyQ-switched ruby laser with 30-kW 30-ns pulses, suitable for many nonlinear optics experiments, is described. Using this laser SHG in KDP located outside the laser cavity yielded ≳ 4-kW pulses at 3472 Å with conversion efficiencies of ∼16 percent at the peak. A correction to existing SHG theories accounting for pump depletion (important at high conversions) has been calculated with the resulting improvement in agreement between theory and experiment. Experiments involving stimulated Raman scattering and vacuum UV generation from laser-produced plasmas are briefly described.     

Pulse stretching and shape control by compound feedback in a Q-switched ruby laser

Feedback control is employed to stabilize the output of aQ-switched ruby laser. A computational model of the rate equations plus feedback terms is used to examine pulse shapes with changing feedback parameters. It is shown that a lengthened flat-top pulse cannot be obtained with negative feedback alone, a compound feedback arrangement is suggested to facilitate this. A practical laser system is constructed with an associated feedback loop, good agreement is found between theory and experiment. Pulses flat to within ±5 percent are obtained with durations up to 600 ns and are amplified with no apparent saturation. Output powers of 15 MW are achieved for hundreds of nanoseconds with a divergence of 7 mrad and a spectrum consisting of transform-limited lines separated by the axial mode spacing.     

Single-transverse-mode mode-locked ruby laser

A mode-locked ruby laser has been built, utilizing a new kind of prism ring cavity that gives reliable single-transverse-mode operation. The cavity also operates in single-transverse mode whenQswitched and when operated in normal lasing action.     

红宝石激光周边虹膜切除术

本文介绍了用红宝石激光器系统治疗早期闭角性青光眼所作的周边虹膜切除术,64只眼中61只眼一次治疗击穿虹膜,3只眼两次治疗击穿.