1 山西能源学院 电气与控制工程系, 山西 榆次 030600
2 中国有研科技集团有限公司 有研国晶辉新材料有限公司, 北京 100088
提出了一种基于单柱面聚焦透镜的热透镜技术差分测量构型,并采用相移理论和高斯光束ABCD传输定律建立了热透镜信号理论模型,导出了最优构型条件及测量灵敏度理论极限,结果表明该测量构型能够获得与双柱面聚焦透镜测量构型相同的测量灵敏度。采用理论计算及有限元分析相结合的方法分析了构型参数对探测平面光强分布及热透镜信号幅值的影响,理论结果和有限元结果的一致性证明了单柱面聚焦透镜差分测量构型的可行性及理论模型的正确性。
光学测量 热透镜 差分测量 构型优化 有限元 optical measurement thermal lensing differential measurement configuration optimization finite-element method
山西能源学院电气与控制工程系, 山西 榆次 030600
构型优化条件要求柱面聚焦透镜与待测样品位置重合, 造成实验实现的困难, 因此通过数值计算分析了柱面聚焦透镜位置对其余构型参数优化值、聚焦误差信号幅值及其非线性误差的影响。提出了聚焦误差热透镜技术的单柱面聚焦透镜测量构型, 并建立了基于热透镜光学相移理论的热透镜聚焦误差信号理论模型, 获得了构型优化条件。计算结果表明:当柱面聚焦透镜与待测样品间距小于0.7倍的柱面聚焦透镜焦距时, 探测和激励光斑半径优化值与理论优化值基本一致, 探测器与聚焦透镜间距略有增大, 聚焦误差信号大于0.85倍的理论极值, 探测光最大光学相移小于0.2 rad时非线性误差小于1%。证明了聚焦误差热透镜技术的单柱面聚焦透镜测量构型的可行性。
热透镜效应 聚焦误差信号 单柱面透镜 构型优化 thermal lensing focus-error signal single cylindrical lens configuration optimization
Author Affiliations
Abstract
1 Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen518118, China
2 College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen518060, China
This study develops a Yb:KGW dual-crystal based regenerative amplifier. The thermal lensing and gain-narrowing effects are compensated by the dual-crystal configuration. Sub-nanojoule pulses are amplified to 1.5 mJ with 9 nm spectral bandwidth and 1 kHz repetition rate using chirped pulse amplification technology. Consequently, 1.2 mJ pulses with a pulse duration of 227 fs are obtained after compression. Thanks to the cavity design, the output laser was a near diffraction limited beam with M2 around 1.1. The amplifier has the potential to boost energy above 2 mJ after compression and act as a front end for a future kilohertz terawatt-class diode-pumped Yb:KGW laser system.
ultrafast laser regenerative amplifier thermal lensing effect compensation High Power Laser Science and Engineering
2020, 8(4): 04000e35
Author Affiliations
Abstract
1 State Key Laboratory Incubation Base of Photoelectric Technology and Functional Materials, National Photoelectric Technology and Functional Materials and Application of Science and Technology International Cooperation Center, Institute of Photonics & Photon-Technology, Northwest University, Xi’an 710069, China
2 School of Science, Engineering University of PAP, Xi’an 710086, China
3 e-mail: chenhaowei2005@126.com
We report on the enhancement of phase conjugation degenerate four-wave mixing (DFWM) in hot atomic Rb vapor by using a Bessel beam as the probe beam. The Bessel beam was generated using cross-phase modulation based on the thermal nonlinear optical effect. Our results demonstrated that the DFWM signal generated by the Bessel beam is about twice as large as that generated by the Gaussian beam, which can be attributed to the extended depth and tight focusing features of the Bessel beam. We also found that a DFWM signal with reasonable intensity can be detected even when the Bessel beam encounters an obstruction on its way, thanks to the self-healing property of the Bessel beam. This work not only indicates that DFWM using a Bessel beam would be of great potential in the fields of high-fidelity communication, adaptive optics, and so on, but also suggests that a Bessel beam would be of significance to enhance the nonlinear process, especially in thick and scattering media.
Nonlinear optics, four-wave mixing Thermal lensing Phase modulation Photonics Research
2018, 6(3): 03000162
西安电子科技大学物理与光电工程学院, 陕西 西安 710071
在固体激光器中, 热效应会同时影响抽运光和振荡光的空间分布。研究表明, 对于端面抽运固体激光器而言, 通常存在一个特定的抽运功率区间, 使抽运光与基模振荡光在热效应的作用下, 在增益介质内部高度重合, 激光器的抽运光效率和光束质量得到大幅度提升。利用这一特点, 设计了一种激光器, 在抽运功率为105~115 W时, 实现了抽运光与基模振荡光空间分布的高度重合, 激光器光束质量因子小于2.3。在此区间外, 激光器光束质量因子迅速增加到3以上。提出了一种计算上述抽运功率区间的优化算法, 在端面抽运固体激光器中, 可以快速寻找到理想的抽运功率区间, 并与上述实验进行对比, 结果表明使用该方法寻找到的抽运功率区间与实验所得到的区间高度吻合, 相对误差低于5%, 可靠性高。
激光器 固体激光器 热透镜 空间分布 光束质量
西安电子科技大学 物理与光电工程学院, 陕西 西安710071
在端面抽运固体激光器中, 就如何改善在高抽运功率时输出激光的光束质量, 提出一种激光器的设计方法。在激光器谐振腔中放入多根掺杂浓度不同的激光介质, 利用激光介质内部产生的热透镜控制抽运光和基模振荡光的空间分布, 并且最大限度地使抽运光的分布区和基模振荡光分布区重叠, 实现抽运光与基模振荡光在空间上高度匹配, 进而提高抽运光能量的利用效率和振荡光的光束质量。实验表明, 在不同抽运功率下, 抽运光和基模振荡光在晶体内部的光斑的空间分布可通过热透镜加以控制。在端面抽运功率200 W附近时, 实现了抽运光与基模振荡光较高程度匹配, 光束质量因子M2由14.7改善为4.1。
固体激光器 热透镜 空间分布 光束质量 solid-state laser thermal lensing special distribution M2
提出了一种新的制造微透镜的制作方法。该方法基于CO2激光与玻璃材料的热透镜效应, 在玻璃基片上制作微透镜阵列, 是一种低成本、高效率的制备玻璃微透镜阵列的方法。采用CO2激光照射在模板上, 模板上通光部分为圆孔阵列, 利用金属孔阵模板进行选择性投影扫描加工, 通过实验数据分析, 合理的控制离焦距离, 激光功率和辐照时间,可以制造微透镜阵列。最后用共聚焦显微镜及光纤探针扫描仪对微透镜的轮廓及聚焦光斑进行了检测, 样品的轮廓曲线较为平滑、对称, 且具有较好的聚光能力, 证实了该方法的可行性与可靠性。
玻璃 微透镜阵列 热透镜效应 共聚焦显微镜 光斑探针扫描仪 glass micro-lens array thermal lensing effect confocal microscopy spot probe scanning microscope
Author Affiliations
Abstract
The fluorescence spectrum and thermal properties of the mixed crystal Nd:Lu0.99La0.01VO4 are determined. The strongest emission peak located at 1065.6 nm had a full width at half maximum (FWHM) of 2.1 nm. Continuous-wave (CW) laser performance is demonstrated by a compact planar–planar cavity that is endpumped by a diode laser. The laser output characteristics are investigated by using output couplers with different transmissions. A maximum CW output power of 8.09 W was obtained at an incident pump power of 19.4 W, which corresponds to an optical-to-optical conversion efficiency of 41.7% and a slope efficiency of 54.6%. The dependence of optimum transmission on pump power is calculated theoretically and is found to be consistent with experimental results.
140.3380 Laser materials 350.6830 Thermal lensing 140.3480 Lasers, diode-pumped 140.3580 Lasers, solid-state Chinese Optics Letters
2013, 11(12): 121404
量子光学与光量子器件国家重点实验室, 山西大学光电研究所, 山西 太原 030006
设计了全固态连续单横模1.34 μm激光器。利用880 nm激光二极管双端纵向泵浦Nd:YVO4复合晶体,在泵浦功率为51 W时,获得12.4 W的连续单横模1.34 μm激光输出,光-光转换效率达到24.3％,激光器长期功率稳定性优于±1.2％(3 h)。
1.34 μm激光 880 nm双端纵向泵浦 热透镜效应 1.34 μm laser dual-end-pumped at 880 nm thermal lensing effect
Author Affiliations
Abstract
Quantitative phase microscopy by digital holography provides direct access to the phase profile of a transparent subject with high precision. This is useful for observing phenomena that modulate phase, but are otherwise difficult or impossible to detect. In this letter, a carefully constructed digital holographic apparatus is used to measure optically induced thermal lensing with an optical path difference precision of less than 1 nm. Furthermore, by taking advantage of the radial symmetry of a thermal lens, such data are processed to determine the absorption coefficient of transparent media with precisions as low as 1 \times 10^{-5} cm^{-1} using low power (30 mW) continuous wave (CW) excitation.
090.0090 Holography 090.1995 Digital holography 350.6830 Thermal lensing Chinese Optics Letters
2011, 9(12): 120001
