Dynamic analysis of V-folded cavity for TEM_(00) operation of end-pumped solid-state laser

Based on graphic analysis design method of optical resonator, a simple design expression of V-folded cavity of end-pumped solid-state lasers with TEMoo operation is described, which satisfies two criterias of the resonator design. We give numerical simulation of spot size as a function of thermal focal length using this design approach whose advantages are validated experimentally.     

Experimental determination of the thermal lens parameters in a broad area semiconductor laser amplifier

Due to the build-up of temperature gradients along their width, semiconductor laser diodes tend to be affected by thermal lensing effects. We propose a simple and easy-to-implement experiment in order to determine the thermal lens coefficient in a broad area semiconductor laser amplifier during operation. The results obtained are compared to simulations of the temperature distribution in the laser structure. In order to further validate our method, we compare the measured M ² value of a free running broad area laser diode with the calculated M ² of such a laser under the influence of a thermal lens as predicted by diffraction theory of first-order optical resonators. The experimental results are seen to be in good agreement with the calculations.     

Theoretical studies on beam parameters of a self－start ring cavity Ti：sapphire laser

Ｔｈｅｏｒｅｔｉｃａｌ ｓｔｕｄｉｅｓ ｏｎ ｂｅａｍ ｐａｒａｍｅｔｅｒｓ ｏｆ ａ ｓｅｌｆ－ｓｔａｒｔ ｒｉｎｇ ｃａｖｉｔｙ Ｔｉ：ｓａｐｐｈｉｒｅ ｌａｓｅｒ￥ＺＨＡＮＧＧｕｉｚｈｏｎｇ；ＺＨＥＮＧＸｕｅｍｅｉ；ＷＡＮＧＱｉｎｇｙｕｅ（Ｄｅ...     

Passive mode locking of a Nd：YAG laser with co－doped Nd, Cr：YAG as saturable absorber

We demonstrate the characteristics of relatively low saturation intensity using co-doped Nd, Cr:YAG as saturable absorber for passively mode locking the Nd:YAG laser. The difference of the saturation intensity between Q-switched and mode-locked operation in co-doped Nd, Cr:YAG was only one to two orders of magnitude, while Cr:YAG was generally reported at a difference of five orders of magnitude. More than 80% mode locking modulation depth was achieved at an incident pump power of 4.4W, corresponding to an intracavity intensity of 6×10^4W/cm^2, using a 68cm long plano-concave cavity.     

Energy reduction:a technique for seed-injection locking of single-axial-mode Q-switched Nd:YAG laser

A new technique for seed-injection locking of single-axial-mode (SAM) Q-switched Nd:YAG laser is re- ported.The technique called energy reduction (ER) is utilized when SAM operation is locked to design its feedback scheme.This method ensures long-term 100% seed-injection locking performance and the pulsed SAM output energy can reach as high as 200 mJ.Both temporal and spatial interferometric experiments have been executed to confirm the SAM oscillation.     

New simplified coupling scheme for the delivery of 20 MW Nd:YAG laser pulses by large core optical fibers

The feasibility of transmitting 20 MW, 5 ns laser pulses from a frequency doubled Nd:YAG laser through a standard 1500 μm multi mode optical fiber is demonstrated. A new coupling scheme employing an optical homogenizer prevents breakdown in air without the use of a vacuum chamber. At the same time a very homogeneous flat top beam profile on the fiber surface is achieved. The new scheme therefore clearly simplifies fiber coupling of high power laser pulses. Experiments on the delivery of more than 20000 pulses with 110 mJ mean energy without fiber damage have been performed. Received: 2 August 2000 / Revised version: 18 August 2000 / Published online: 22 November 2000     

Fabrication of a quartz optical fiber tip for dental treatment with Nd:YAG laser—Proposal of a new process with TiO2 powder

In dental treatment with Nd:YAG laser beam, a quartz optical fiber is generally used to transmit the laser beam, which is irradiated to the hard and soft tissues for a caries treatment and a periodontal tissue excision. Since a normal optical fiber, which the laser beam comes out from the tip of the fiber, has difficulty irradiating to a narrow space and an inner root canal uniformly, it is effective to use a processed optical fiber tip from which is obtained a diffused and circumferential laser beam. In this paper, a new process to obtain these laser beams with TiO₂ powder is proposed, and the characteristics and the performances of the processed optical fiber were investigated. An experimental instrument was developed to measure the energy partition radiated from the processed fiber tip, and the ratio of a straight beam, a sideways beam and heat generated by the absorption of the laser beam was measured in each condition. As a result, the ratio of an energy partition was controllable by changing the incidence parameter to process the fiber tip, and the processed fiber tip corresponding to the clinical purpose could be obtained. The parameters which affected the processability of the fiber tip were processing time and incidence laser energy. The prepared cavity with processed fiber on the enamel was influenced by a straight beam, and the removal of enamel to the depth direction was controllable by using the processed fiber.     

一种CCD辅助测量基模(TEM_(00))激光光斑尺寸的方法

激光光束是一种振幅和等相位面都在变化的高斯球面光波 ,其最小光斑的位置和大小不易确定 ,本文在实践的基础上提出一种测量基模 ( TEM0 0 )激光光斑尺寸的方法 ,解决了这一问题     

小功率可调式TEM_00模CO_2激光器

本文给出获得TEM00模输出的小功率CO2 激光器制作工艺     

基模动态稳定望远镜谐振腔

本文使用等价腔和传播矩阵方法,在一般情况下推导出了望远镜腔的基模热稳条件,该表示式简单而又严格,还易于推广到含热透镜多元件腔的一般情况,并与用近似方法所得结果作了比较和讨论。     

交叉棱镜腔Nd:YAG板条激光器

对稳定和非稳共焦型Nd:YAG板条激光器的特性作了理论分析和实验研究.证实了使用交叉棱镜腔的流动空气-水混合冷却板条激光器有高的光束质量和对棱镜失调的不灵敏性,可望获得某些实际应用.关键词:交叉棱镜腔,板条激光器.     

Experimental studies of an unstable confocal resonator alexandrite laser

The effects of excited converging wave in an unstable confocal resonator onthe properties of an alexandrite laser are investigated experimentally.The results show thatexciting the converging wave inside the resonator is an effective method to reduce the diver-gence of the laser beam for low gain laser medium.     

输出功率5.2 W的全固态连续单横模671 nm红光激光器

设计了全固态连续单横模671 nm红光激光器.利用880 nm LD双端端面泵浦Nd:YVO4复合晶体,实现了均匀泵浦并改善了激光晶体热效应;考虑到影响倍频转化效率的各种因素,优化设计了Z字形四镜激光谐振腔,采用I类临界相位匹配晶体LBO作为腔内倍频晶体;当泵浦功率为42.5W时,获得了5.2W的连续单横模671 nm红光输出,光-光转化效率达到12.2％,激光器长期功率稳定性优于±2.5％(1 h).     

Study on transient mode formation of copper vapor laser with a modified off－axis unstable resonator

Ｓｔｕｄｙ ｏｎ ｔｒａｎｓｉｅｎｔ ｍｏｄｅ ｆｏｒｍａｔｉｏｎ ｏｆ ｃｏｐｐｅｒ ｖａｐｏｒ ｌａｓｅｒ ｗｉｔｈ ａ ｍｏｄｉｆｉｅｄ ｏｆ ｆ－ａｘｉｓ ｕｎｓｔａｂｌｅ ｒｅｓｏｎａｔｏｒ￥ＨＵＡＲｅｎｚｈｏｎｇ；ＬＩＡＮＧＰｅｉｈｕｉ；...     

二极管泵浦的高效连续波基横模Nd：YAG激光器

报道了用激光二极管端面泵浦的高效连续波ＴＥＭ００模Ｎｄ：ＹＡＧ激光器，最大输出为０．６５Ｗ，斜效率５１％，光－光效率最高达４０．６％，并给出了耦合光学系统和二极管泵浦Ｎｄ：ＹＡＧ激光器的器件结构．     

一种适用于脉冲Nd^3＋：YAG激光器的新型横模控制谐振腔

本文报道了一种新型横模控制谐振腔——圆形空心波导谐振腔。实验表明这种新型横模控制诣振腔与腔内加小孔光阑的横模控制谐振腔相比,有基模TEM_∞输出效率明显增高和远场发散角大大减小等优点,文中对其限横模机理进行了分析和讨论。     

圆形高斯镜平凹腔腔内外激光场研究

运用边界元素法把圆形高斯镜平凹腔的自再现模的衍射积分方程转化为有限阶矩阵方程。计算了圆形高斯镜取不同反射率膜斑半径和中心振幅反射率情况下基模的场强分布、相位分布和本征值。研究表明:腔内光场分布半径随反射率膜斑半径的减小而增大,中心振幅反射率不影响光场分布半径;反射率膜斑半径影响远场分布,当其数值较小时,在光束的远场分布主峰周围产生弱衍射环;当高斯镜中心全反射时,远场分布随反射率膜斑半径的变化无明显变化;模式本征值随反射率膜斑半径的增大而增大。