摘要
阵列激光在传输过程中受大气湍流影响后会降低其在远场的光束质量.首先,以非相干合成形式的阵列激光为模型,通过生成随机大气湍流相位屏模拟激光在大气中的传输,同时依据阵列分布分割大气湍流畸变波前并求解子波前的倾斜像差系数;然后,将系数代入子激光束相位部分进行消除即实现模拟倾斜像差的校正过程;最后,对比计算了倾斜像差校正前后远场激光光束质量的变化情况.仿真和实验研究结果表明:在同一大气湍流条件下,远场激光的桶中功率(power-in-bucket, PIB)和斯特列尔比(strehl ratio, SR)在倾斜像差校正后得到提升;虽然校正子波前倾斜像前后的PIB和SR均随着大气湍流强度增强而下降,但是当湍流强度增大,校正倾斜像差对PIB和SR的提升效果更好.本文所做工作可为提升高能激光系统的使用性能提供数据支撑.
The beam quality of array lasers which propagate in atmosphere will degrade in far-field. Therefore, the ultimate efficiency of combined lasers will be affected if no compensation measure is taken in some typical systems such as high energy system. Based on the model of array lasers with incoherent combination, laser propagation in atmosphere is simulated by generating a random atmospheric turbulence phase screen to modulate the phase of the laser beam. The distorted wavefront of atmospheric turbulence is divided according to the array distribution. The phase generated by tilt aberration coefficient which is solved by the method of fitting sub-wavefront data is eliminated in the phase of sub-beam, which simulates the process of correcting tilt aberration. The simulation results show that comparing with the case of tilt aberration, the power in the bucket(PIB) and the Strehl rate(SR) of combined lasers focusing in far-field are improved when the tilt aberration influenced by the same atmospheric turbulence phase screen is corrected. At the same time, coherence length ranging from 4 cm to 45 cm is used to characterize atmospheric turbulence of different intensities. At each coherent length, the PIB and SR are calculated when the distances of propagation of lasers are 2 km and 3 km,separately. The simulation results show that although PIB and SR before and after tilt aberration are corrected,they become worse with the decrease of coherence length, and PIB and SR are improved more obviously when tilt aberration is corrected in stronger turbulence. An experiment in the case of 2 km is carried out by using a prototype of incoherent combination, and the data are obtained by measuring the focused spot at the target.The measurement results confirm that the correcting of tilt aberration can improve the beam quality of array lasers with incoherent combination in far-field. In summary, the research conducted in this work can obtain tilt aberration accurately and the corresponding method of correction is easy to implement, wh
作者
邓万涛
赵刚
夏惠军
张茂
杨艺帆
Deng Wan-Tao;Zhao Gang;Xia Hui-Jun;Zhang Mao;Yang Yi-Fan(School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;Southwest Institute of Technical Physics,Chengdu 610041,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第23期130-138,共9页
Acta Physica Sinica
基金
国防预研究基金(批准号:301040310)资助的课题~~
关键词
非相干合成
激光传输
大气湍流
倾斜像差校正
incoherent combination
laser propagation
atmospheric turbulence
tilt aberration correction
