光学学报, 2016, 36(4): 0414001, 网络出版: 2016-04-01

PPKTP 晶体半整体谐振腔倍频的397.5 nm紫外激光输出

Generation of 397.5 nm Ultra-Violet Laser by Frequency Doubling in a PPKTP-Crystal Semi-Monolithic Resonant Cavity
作者单位

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

摘要
外腔谐振倍频是获得397.5 nm 紫外激光的重要方法。搭建了基于周期极化的磷酸氧钛钾(PPKTP)晶体的半整体谐振腔,对经半导体锥型放大器放大的795 nm 单频连续激光进行谐振倍频。在203 mW 的795 nm 基频光输入条件下,实现了60.4 mW 的397.5 nm 连续单频紫外激光输出,倍频转化效率为30%;在基频光功率约87.5 mW 时,得到最大的倍频效率约为34.6%。倍频紫外光光束质量因子M2优于1.21,光束质量良好,30 min内典型的倍频光功率均方根起伏小于1.9%。该倍频器结构紧凑,具有很好的机械稳定性,可实现紫外激光的稳定输出,可用于产生对应铷原子跃迁线的压缩、纠缠态光场,在量子光学和精密测量等领域发挥重要作用。
Abstract
Frequency doubling in an external cavity is a prevalent method to generate an ultra- violet laser at 397.5 nm . A semi-monolithic resonant frequency doubling cavity based on the PPKTP crystal is built and is used to realize the resonant frequency doubling of the 795 nm single frequency continuous-wave laser amplified via a semiconductor tapered amplifier. Under the condition of 203 mW input power of a 795 nm laser, the 397.5 nm single frequency continuous-wave ultra-violet laser with a power of 60.4 mW is obtained, and the frequency doubling conversion efficiency is 30%; and the maximum doubling efficiency is 34.6% with a fundamental power of about 87.5 mW. The beam quality factor M2 of the frequency doubling ultra-violet laser is superior to 1.21, indicating the better beam quality. The typical root-mean-square fluctuation of the output power within 30 min is less than 1.9%. This frequency doubler is compact, has good mechanical stability, and can be used to achieve steady output of ultraviolet laser. The ultra- violet laser can be used to generate the squeezed or entangled states of the rubidium transitionline, and plays an important role in the quantum optics, precise measurement and other fields.
参考文献

[1] Guan H, Guo B, Huang G L, et al.. Stabilization of the 397 nm and 866 nm external cavity diode lasers for cooling a single calcium ion [J]. Opt Commun, 2007, 274(1): 182-186.

[2] Wolfgramm F, Cerè A, Beduini F A, et al.. Squeezed-light optical magnetometry[J]. Phys Rev Lett, 2010, 105(5): 053601.

[3] Appel J, Figueroa E, Korystov D, et al.. Quantum memory for squeezed light[J]. Phys Rev Lett, 2008, 100(9): 093602.

[4] Jia X J, Yan Z H, Duan Z Y, et al.. Experimental realization of three-color entanglement at optical fiber communication and atomic storage wavelengths[J]. Phys Rev Lett, 2012, 109(25): 253604.

[5] Anderson U L, Neergaard-Nielson J S. Heralded generation of a micro-macro entangled state[J]. Phys Rev A, 2013, 88(2): 022337.

[6] 李志秀, 杨文海, 王雅君, 等. 用于795 nm 压缩光源的单频激光系统的优化设计[J]. 中国激光, 2015, 42(9): 0902002.

Li Zhixiu, Yang Wenhai, Wang Yajun, et al.. Optimal design of single-frequency laser system for 795 nm squeezed light source[J]. Chinese J Lasers, 2015, 42(9): 0902002.

[7] 郭善龙, 韩亚帅, 王杰, 等. 1560 nm 激光经PPLN 和PPKTP晶体准相位匹配倍频研究[J]. 光学学报, 2012, 32(3): 0319001.

Guo Shanlong, Han Yashuai, Wang Jie, et al.. Investigation of quasi-phase-matching frequency doubling of 1560 nm laser by use of PPLN and PPKTP crystals[J]. Acta Optica Sinica, 2012, 32(3): 0319001.

[8] 李嘉华, 郑海燕, 张玲, 等. 利用PPKTP晶体倍频产生397.5 nm 激光的实验研究[J]. 量子光学学报, 2011, 17(1): 30-33.

Li Jiahua, Zheng Haiyan, Zhang Ling, et al.. 397.5 nm laser produced by resonant frequency-doubling with PPKTP crystal[J]. Acta Sinica Quantum Optica, 2011, 17(1): 30-33.

[9] Pizzocaro M, Calonico D, Pastor P C, et al.. Efficient frequency doubling at 399 nm[J]. Appl Opt, 2014, 53(16): 3388-3392.

[10] Cruz L S, Cruz F C. External power-enhancement cavity versus intracavity frequency doubling of Ti:sapphire lasers using BIBO[J]. Opt Express, 2007, 15(19): 11913-11921.

[11] Han Y S, Wen X, Bai J D, et al.. Generation of 130 mW of 397.5 nm tunable laser via ring-cavity-enhanced frequency doubling[J]. J Opt Soc Am B, 2014, 31(8): 1942-1947.

[12] Wen X, Han Y S, Bai J D, et al.. Cavity-enhanced frequency doubling from 795 nm to 397.5 nm ultra-violet coherent radiation with PPKTP crystals in the low pump power regime[J]. Opt Express, 2014, 22(26): 32293-32300.

[13] Ast S, Nia R M, Sch nbeck A, et al.. High-efficiency frequency doubling of continuous-wave laser light[J]. Opt Lett, 2011, 36(17): 3467- 3469.

[14] Deng X, Zhang J. Zhang Y C, et al.. Generation of blue light at 426 nm by frequency doubling with a monolithic periodically poled KTiOPO4 [J]. Opt Express, 2013, 21(22): 25907-25911.

[15] Targat R L, Zondy J J, Lemonde P. 75%-efficiency blue generation from an intracavity PPKTP frequency doubler[J]. Opt Commun, 2005, 247(4): 471-481.

[16] Wiechmann W, Kubota S, Fukui T, et al.. Refractive-index temperature derivatives of potassium titanyl phosphate[J]. Opt Lett, 1993, 18(15): 1208-1210.

[17] Yang W H, Wang Y J, Zheng Y H, et al.. Comparative study of the frequency-doubling performance on ring and linear cavity at short wavelength region[J]. Opt Express, 2015, 23(15): 19624-19633.

[18] Torabi-Goudarzi F, Riis E. Efficient CW high-power frequency doubling in periodically poled KTP[J]. Opt Commun, 2003, 227(4): 389- 403.

[19] Liao Z M, Payne S A, Dawson J, et al.. Thermally induced dephasing in periodically poled KTP frequency-doubling crystals[J]. J Opt Soc Am B, 2004, 21(12): 2191-2196.

[20] Boulonger B, Rousseau I, Fève J P, et al.. Optical studies of laser-induced gray-tracking in KTP[J]. IEEE J Quantum Elect, 1999, 35 (3): 281-286.

00 11