• Acta Physica Sinica
  • Vol. 68, Issue 23, 234205-1 (2019)
Wan-Tao Deng1、2, Gang Zhao2、*, Hui-Jun Xia2, Mao Zhang2, and Yi-Fan Yang2
Author Affiliations
  • 1School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
  • 2Southwest Institute of Technical Physics, Chengdu 610041, China
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    DOI: 10.7498/aps.68.20190961 Cite this Article
    Wan-Tao Deng, Gang Zhao, Hui-Jun Xia, Mao Zhang, Yi-Fan Yang. Method of correcting tilt aberration for array laser of incoherent combination[J]. Acta Physica Sinica, 2019, 68(23): 234205-1 Copy Citation Text show less

    Abstract

    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, which can provide supporting data for improving the performances high energy laser systems.
    Wan-Tao Deng, Gang Zhao, Hui-Jun Xia, Mao Zhang, Yi-Fan Yang. Method of correcting tilt aberration for array laser of incoherent combination[J]. Acta Physica Sinica, 2019, 68(23): 234205-1
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