摘要
设计了一种使用两个不同波长的蓝光激光二极管合束抽运的261nm单纵模紫外激光器。激光器腔型结构为V型。单纵模的选取使用法布里-珀罗(F-P)标准具。将波长分别为444nm和469nm、最大抽运功率分别为1.4 W和1.5 W的蓝光激光二极管各一支作为抽运源。将尺寸为3mm×3mm×5mm、掺杂浓度(质量分数)为0.5%的掺镨氟化钇锂晶体作为增益介质。将I类相位匹配的偏硼酸钡(BBO)晶体用作倍频晶体。优化谐振腔参数并调整两个法布里-珀罗标准具的参数,当注入功率为2500mW时,获得了最大连续功率为110mW的单纵模261nm紫外激光输出。
Objective The single longitudinal mode laser has the advantages of narrow linewidth and stable frequency.It is widely used in the scientific research fields such as high-resolution laser spectroscopy,coherent communications,gravitational detection,quantum optics,and coherent detection.The ultraviolet(UV)laser can be used in UV lithography,Raman spectroscopy,semiconductor wafer micro-processing,and other fields,which has received extensive attention from researchers at home and abroad.All-solid-state lasers pumped by laser diodes have the advantages of high efficiency and stable output.At present,as far as we know,the 261 nm single longitudinal mode UV laser has not been reported at home and abroad.The 261 nm single longitudinal mode UV laser can provide a new light source for the above research fields.Methods The laser experimental apparatus uses two blue laser diodes as the pump source.A 444 nm blue laser diode has the maximum pump power of 1.4 W.And a 469 nm blue laser diode has the maximum power of 1.6 W.An aspherical lens with a focal length of 4 mm is used to collimate the blue laser diode.A 45°combiner is used to combine the pump light of the two blue laser diodes.The transmittance at 444 nm is more than 99.5%and the reflectivity at 469 nm is more than 99%.Finally,a spherical focusing lens with a focal length of 12 mm is used to inject the pump light into the Pr:YLF crystal.The Pr:YLF crystal with the size of 3 mm×3 mm×5 mm and doping concentration(mass fraction)of 0.5%is used as the gain medium.The end face of the Pr:YLF crystal near one end of the pump source is plated with 444 nm and 469 nm antireflective dielectric films.The other end face of the Pr:YLF crystal is plated with 261,444,469,and 522 nm antireflective dielectric films.The two blue laser diodes are fixed in the jc polarization direction.The purpose is to improve the absorption efficiency of the Pr:YLF crystal.A type-I phase-matched BBO crystal with the size of 3 mm×3 mm×3 mm is used as the frequency-doubling crystal.The surface of the BBO crystal is not coated to avoid UV laser damages to the crystal.The laser experimental apparatus is V-shaped.The purpose is to improve the conversion efficiency of the frequency doubling crystal.Two Fabry-Perot etalons are used to select the single longitudinal mode.The thermoelectric cooler is used to control the temperatures of the Pr:YLF crystal and the frequency doubling crystal to improve efficiency.The lead zirconate titanate piezoelectric ceramics is used to control the position of the Fabry-Perot etalon in the laser resonator.By carefully adjusting the length of the cavity,the position of the Fabry-Perot etalon,and the temperature of the thermoelectric cooler(TEC),a good 261 nm single longitudinal mode UV laser is realized.Results and Discussions The laser experimental apparatus(corresponding to the scheme mentioned above)achieves good experimental results with single longitudinal mode(Fig.7).The laser experimental apparatus uses two Fabry-Perot etalons.The purpose is to select a stable single longitudinal mode.The lead zirconate titanate piezoelectric ceramics is used to control the position of the Fabry-Perot etalon in the laser resonator(Fig.6).The maximum output power of the 261 nm single longitudinal mode laser is 110 mW when the incident pump power is 2500 mW(Fig.9).A CCD laser beam analyzer is used to measure the beam quality of the 261 nm single longitudinal UV laser with an output power of 110 mW.A laser beam quality analyzer is used to measure the beam quality factor of the 261 nm single longitudinal mode UV laser with an output power of 110 mW(Fig.8).A laser power detector is used to measure the power stability of the 261 nm single longitudinal mode UV laser for 2 h(Fig.10).Conclusions A 444 nm blue laser diode and a 469 nm blue laser diode,whose maximum pump powers are 1.4 W and 1.5 W,respectively,are used as the pumping source.The two blue laser diodes are fixed in the it polarization direction.A 45°combiner is used to combine the pump light of the two blue laser diodes.An aspherical lens with a focal length of 4 mm is used as a collimator to collimate the pump light emitted by the blue laser diode.A spherical lens with a focal length of 12 mm is used as a focusing lens to focus the pump light emitted by the blue laser diode.The cavity structure of the laser is V-shaped.The Fabry-Perot etalon is used to select a single-longitudinal mode.The Pr:YLF crystal with a size of 3 mm×3 mm×5 mm and doping concentration(mass fraction)of 0.5%is used as the gain medium.The type-I phase-matched BBO crystal with a size of 3 mm×3 mm×3 mm is used as the frequency-doubling crystal.By optimizing the resonator parameters and the parameters of two Fabry-Perot etalons,the maximum output power of 261 nm single-longitudinal ultraviolet laser is 110 mW when the incident pump power is 2500 mW.
作者
李昕奇
浦双双
牛娜
窦微
赵越
刘影
郑权
Li Xinqi;Pu Shuangshuang;Niu Na;Dou Wei;Zhao Yue;Liu Ying;Zheng Quan(Changchun New Industries Optoelectronics Technology Co.,Ltd.,Changchun 130103,Jilin,China;Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,Jilin,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2022年第9期11-17,共7页
Chinese Journal of Lasers
基金
吉林省科技攻关计划(20170203013GX)。
