Adaptive optics systems are highly complicated networks of devices that makes an analytical study of such systems difficult. Hence numerical simulations are crucial in providing a quantitative evaluation of capabilities of adaptive optics systems. The integrated simulations of atmospheric turbulence, wind profiles, Fresnel light propagation, model of Shack- Hartmann wavefront sensor, and wavefront reconstruction are done, and the aim is to simulate adaptive optics correction process and investigate the atmospheric turbulence and Shack-Hartmann sensor parameters on optimal results. The results of simulation of light propagation through turbulent atmosphere are presented.
The coherent addition of multiple beams is one of the great challenges in terms of large-scale lasers. Implementing the capability to generate ultra-high-focus power intensity on the focal plane places stringent requirements on the control of each beam’s pointing and intra-beam phasing. The random beam-to-beam phase jumps, mainly induced by the catoptric elements’ rapid vibration, should be eliminated to realize phase locking. A two-way laser beam’s coherent combination test bed is designed to test the capabilities of phase-locking system. The results show that the closed-loop feedback system achieved a high contrast of the in-phase intensity pattern at the receiving plane after correcting for piston and tip/tilt errors between two adjacent laser beams by the stochastic parallel gradient descent algorithm.
The stability of phased-array optics is a crucial issue for far-field focal-spot quality. The tiled approach of phasing optical elements is a widely used technique. Here it is adopted to maintain the long-time stability of a tiled system by a proportional-integral-differential (PID) algorithm. Experimental data is taken with 2×1 tiled-flat square mirrors driven by 3-axis piezoelectric actuators. The feedback frequency is over 80 Hz and the displacement error is below 4 nm. The optical measurement results show that the state-locked operation is continuously maintained for hour-long periods in PID control mode.