Near-diffraction-limited flattop laser beam adaptively generated by stochastic parallel gradient descent algorithm.
We demonstrate the adaptive generation of a near-diffraction-limited flattop laser beam in the near field based on the stochastic parallel gradient descent algorithm and dual-phase-only liquid crystal spatial light modulators (LC-SLMs). One LC-SLM redistributes the intensity, and the other compensates the wavefront of the output beam. The experimental results show that approximately 69% of the power is enclosed in a region with less than 6% rms intensity variation. The 5mm diameter near-diffraction-limited output beam retains a flattop intensity distribution without significant diffraction peaks for a working distance of more than 30 cm.
Ma
Haotong
H
College of Photon-electron Science and Engineering, National University of Defense Technology, Changsha, Hunan, 410073, China.
Liu
Zejin
Z
Xu
Xiaojun
X
Wang
Sanhong
S
Liu
Changhai
C