1 空军工程大学信息与导航学院, 陕西 西安 710077
2 空军通信士官学校, 辽宁 大连 116600
3 中国空间技术研究院西安分院, 陕西 西安 710077
提出一种基于偏振复用-双平行马赫-曾德尔调制器(PDM-DPMZM)的微波光子变频移相信号生成方案。通过改变调制器的直流偏置电压可以实现二倍频移相信号生成或者上/下变频移相信号生成,生成信号的相位仅通过控制检偏器偏振方向与调制器一个主轴之间的角度α就能实现-180°~180°的连续调谐。在光频梳的支持下,本方案可扩展为多通道独立相位调谐的系统。仿真结果表明,频率为5 GHz的射频信号在三种功能下可以分别转换为二倍频信号10 GHz、下变频信号1 GHz和上变频信号13 GHz,它们的相位可实现-180°~180°的全范围连续调谐,且不同相位下生成信号的功率响应相对平坦。
光电子学 微波光子 多频段变频 全范围移相 二倍频信号
Author Affiliations
Abstract
Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621999, China
Fifth harmonic generation (5th HG) of a Nd:glass laser is an effective way to acquire high-energy coherent deep-ultraviolet radiation near 200 nm. In this work, cascade generation of the fifth harmonic of a Nd:glass laser in a 5 mm ammonium dihydrogen phosphate (ADP) crystal was investigated, and maximum conversion efficiency of 14% and large angular acceptance of 45 mrad were demonstrated at a noncritical phase-matching temperature of 75.1°C. However, as the results reveal, the temperature sensitivity and nonlinear absorption would hinder its high-energy application. As for that, based on the complementary relationship of the angle and temperature in the phase-matching condition, an upgraded focusing 5th HG design coupled with the cylindrical temperature distribution scheme was proposed. By this upgraded focusing design, more than the improvement of the conversion efficiency, the output 5 near-field intensity distribution turns out to be insensitive to the temperature gradient. Potentially, this idea can be applied for many other frequency conversion schemes such as high-repetition frequency lasers, which have similar temperature gradient problems.
140.3610 Lasers, ultraviolet 140.3515 Lasers, frequency doubled 190.2620 Harmonic generation and mixing Chinese Optics Letters
2019, 17(12): 121403
Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication System and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
2 Key Laboratory of Precision Opto-Mechatronics Technology, Ministry of Education, School of Instrumentation Science & Optoelectronics Engineering, Beihang University, Beijing 100191, China
We present an Er-doped fiber (Er:fiber)-based femtosecond laser at 780 nm with 256 MHz repetition rate, 191 fs pulse duration, and over 1 W average power. Apart from the careful third-order dispersion management, we introduce moderate self-phase modulation to broaden the output spectrum of the Er:fiber amplifier and achieve 193 fs pulse duration and 2.43 W average power. Over 40% frequency doubling efficiency is obtained by a periodically poled lithium niobate crystal. Delivering through a hollow-core photonic bandgap fiber, this robust laser becomes an ideal and convenient light source for two-photon autofluorescence imaging.
140.7090 Ultrafast lasers 140.3500 Lasers, erbium 140.3515 Lasers, frequency doubled Chinese Optics Letters
2019, 17(7): 071405
Author Affiliations
Abstract
Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ of 473 nm blue laser pulse energy was achieved by cascade frequency doubling. The second harmonic conversion efficiency was 64.5%, and overall optical-optical efficiency was 4.2%, respectively. The blue laser pulse width was less than 10 ns, and beam quality factor was less than 2.4.
140.3540 Lasers, Q-switched 140.3515 Lasers, frequency doubled 140.3530 Lasers, neodymium 140.3480 Lasers, diode-pumped Chinese Optics Letters
2019, 17(5): 051405
Author Affiliations
Abstract
1 State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China
2 Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
A scheme for measuring the intra-cavity round-trip loss of an all-solid-state single-frequency laser by inserting a type-I noncritical phase-matching nonlinear crystal introducing nonlinear loss into the resonator is presented. The intra-cavity round-trip loss is theoretically deduced by analyzing the dependence of the fundamental-wave (FW) and second-harmonic-wave (SHW) powers on the pump factor and the nonlinear conversion factor of the single-frequency laser and experimentally measuring them by recording different FW and SHW powers, which are decided by the temperature of the nonlinear crystal. The measured intra-cavity round-trip loss and pump factor are 4.84% and 6.91% W 1, respectively. The standard deviations of the measured intra-cavity round-trip loss and the pump factor are 0.26% and 0.07%, respectively. This scheme is very suitable for measuring the intra-cavity round-trip loss of a high-gain solid-state single-frequency laser.
140.3410 Laser resonators 140.3515 Lasers, frequency doubled 140.3570 Lasers, single-mode 140.3580 Lasers, solid-state 160.4330 Nonlinear optical materials Chinese Optics Letters
2017, 15(2): 021402
Author Affiliations
Abstract
1 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, and Shanghai Key Laboratory of Solid State Laser and Application, Shanghai 201800, China
2 e-mail: zhangl@siom.ac.cn
3 Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
A high power continuous-wave single-frequency green fiber laser by second-harmonic generation of a Yb-doped fiber amplifier (YDFA) is developed. A linearly polarized single-mode fiber amplifier produces a 60 W infrared laser at 1064 nm with a 103 W incident diode pump laser at 976 nm, corresponding to an optical conversion efficiency of 58%. An external bow-tie enhancement cavity incorporating a noncritically phase-matched lithium triborate crystal is employed for second-harmonic generation. A 33.2 W laser at 532 nm is obtained with a 45 W incident 1064 nm fundamental laser, corresponding to a conversion efficiency of 74%.
140.3510 Lasers, fiber 140.3515 Lasers, frequency doubled 140.3615 Lasers, ytterbium Chinese Optics Letters
2017, 15(4): 041402
1 山西大学光电研究所 量子光学与光量子器件国家重点实验室，山西 太原 030006
2 山西大学 极端光学协同创新中心，山西 太原 030006
本文采用包含有非线性晶体的四镜8字环形谐振腔结构，通过选取输出耦合镜的透射率和分析铽镓石榴石(TGG)晶体热透镜效应的影响，实现了输出功率达双10瓦级具有相位关联特性的单频连续波1 064/532 nm双波长激光器。实验中通过采用透射率为4%的输出耦合镜和长度为20 mm的三硼酸锂(LBO)晶体，实现了输出功率分别为11.30 W和11.23 W的1 064/532 nm双波长激光输出，线宽分别为165 kHz和330 kHz，对应的长期功率稳定性在3小时内分别优于±0.68%和±0.56%，光束质量因子M2均小于1.1。该种具有相位关联特性的双波长激光器可以用来制备稳定的双色光阱和泵浦多个光学参量(OPO)实现多组份纠缠态光场的产生。
端面泵浦 腔内倍频 环形谐振腔 单频 全固态激光器 diode pumped frequency doubled ring single-mode solid-state
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading District, Shanghai 201800, China
2 University of Chinese Academy of Sciences, No. 19, Yuquan Road, Shijingshan District, Beijing 100039, China
3 Shanghai Institute of Laser Plasma, Chinese Academy of Engineering Physics, No. 390, Qinghe Road, Jiading District, Shanghai 201800, China
The noncritically phase-matched (NCPM) fourth-harmonic generation (FHG) with partially deuterated dihydrogen phosphate (KD*P) crystal at an Nd:glass laser radiation wavelength of 1053.1 nm has been confirmed. NCPM FHG has been achieved in 70% and 65% deuterated KD*P crystal at the temperature of 17.7°C and 29.3°C, respectively. The angular acceptance of 70% and 65% deuterated KD*P crystals fixed at their NCPM temperature were measured, which were 53 and 55 mrad, respectively. The application of the NCPM FHG in a high-power laser facility for inertial confinement fusion is also discussed. Based on the theoretical analysis, the NCPM KD*P can be placed after the focus lens; thus, the laser-induced damage of a fused-silica lens at ultraviolet can be avoided.
Lasers frequency doubled Nonlinear optical materials Harmonic generation and mixing Collection Of theses on high power laser and plasma physics
2016, 14(1): 4132
Author Affiliations
Abstract
1 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
A compensation method for phase mismatch caused by temperature variation during the frequency conversion process is proposed and the theoretical model is established. The method is based on the principle that phase mismatch can be compensated via the electro-optic effect based on a compensation scheme consisting of two nonlinear crystals and an electro-optic crystal; further, a new dimension adjustment can be achieved by changing the voltage. In a proof-of-principle study, frequency conversion from 1053 nm to 526.5 nm and 351 nm by cascade KH2PO4 (KDP) and KD2PO4 (DKDP) crystals, respectively, is presented as an example. Three-dimensional numerical simulations are conducted to show that the conversion efficiency of frequency doubling and tripling varies with temperature. The results show that the temperature acceptance bandwidth of doubling and tripling can be 2.4 and 3.4 times larger, respectively, than that of the traditional method using a single crystal. We also analyze the stability of the conversion efficiency for 192 beams by our proposed method when the temperature is randomly varied within the range of 24°C–26°C. The standard deviation of the conversion efficiency of frequency doubling and tripling decreases from 1.25% and 6.61% to 0.18% and 0.56%, respectively. In addition, the influence of the reflection loss on the output efficiencies is also analyzed and the results show that it is very small. This indicates that this method may be effective in reducing the temperature sensitivity of conversion efficiency.
Lasers frequency doubled Harmonic generation and mixing Nonlinear wave mixing. Collection Of theses on high power laser and plasma physics
2016, 14(1): 525
1 南京信息工程大学江苏省气象探测与信息处理重点实验室, 江苏 南京 210044
2 南京信息工程大学江苏省大气环境与装备技术协同创新中心, 江苏 南京 210044
3 南京信息工程大学滨江学院电子工程系, 江苏 南京 210044
基于周期极化铌酸锂(PPLN)晶体提出并设计了一种高效紧凑腔内倍频绿光激光器。该激光系统采用808 nm激光二极管(LD)端面直接抽运Nd∶YVO4晶体，进而利用极化周期为7 μm 的PPLN 晶体倍频产生532 nm 绿光。通过在Nd∶YVO4和PPLN 晶体端面镀膜构成激光腔镜，无需采用任何光学透镜、反射镜等分立光学元件，大大降低了系统体积和成本。实验结果显示，当激光器谐振腔腔长为12 mm，抽运功率为4.1 W 时，绿光输出功率可达1.343 W，相应的光-光转换效率达32.8%。当LD 抽运功率稳定在3.33 W 时，2 h内的绿光输出功率波动小于5%。
激光器 非线性光学 绿光激光器 倍频 铌酸锂晶体 中国激光
2015, 42(11): 1102002
