Piston and tilt cophasing of segmented laser array using Shack-Hartmann sensor

Abstract

We describe a concept of detecting the piston and tilt errors with a Shack-Hartmann sensor and correcting them simultaneously via a segmented deformable mirror (DM) in a two-dimensional laser array. The concept in coherent beam combination (CBC) is demonstrated by both simulation and experiment. The simulative results show only two iterations are enough to correct the random initial phase errors in the steady condition. The experimental results confirm that this method works effectively in a dynamic condition. The study represents that the Shack-Hartmann sensor can extract any piston error in -π ~π, which means the concept is an arbitrary phasing technique for a laser array.