Shack-Hartmann sensor

A Shack-Hartmann sensor is a device used to measure how a wave, like light, changes as it passes through a medium or system. It works by shining a beam of light onto a grid of tiny lenses, called a lenslet array. Each lenslet focuses a small part of the wave onto a detector. If the wavefront is perfectly uniform, the focused spots are aligned. If there's a distortion, the spots shift position. By analyzing these shifts, the sensor can determine the shape of the wavefront, helping in applications like correcting optical distortions or improving telescopic images.