Experimental Trials With The Optical Differentiation Wavefront Sensor For Extended Objects

TL;DR

This paper introduces a new optical wavefront sensor, the Optical Differentiation Wavefront Sensor (ODWFS), designed for extended objects, demonstrating its potential advantages through initial experimental testing and comparison with simulations.

Contribution

The paper presents the development and initial testing of the ODWFS, a novel wavefront sensor that offers large dynamic range and suitability for extended objects, advancing adaptive optics technology.

Findings

ODWFS successfully assembled on a testbed with a deformable mirror.

Initial experiments show promising spatial frequency response.

Comparison with simulations indicates good agreement.

Abstract

Commonly used wavefront sensors, the Shack Hartmann wavefront sensor and the pyramid wavefront sensor, for example, have large dynamic range or high sensitivity, trading one regime for the other. A new type of wavefront sensor is being developed and is currently undergoing testing at the University of Arizona's Center for Astronomical Adaptive Optics. This sensor builds on linear optical differentiation theory by using linear, spatially varying halfwave plates in an intermediate focal plane. These filters, along with the polarizing beam splitters, divide the beam into four pupil images, similar to those produced by the pyramid wavefront sensor. The wavefront is then reconstructed from the local wavefront slope information contained in these images. The ODWFS is ideally suited for wavefront sensing on extended objects because of its large dynamic range and because it operates in a pupil plane which allows for on chip resampling even for arbitrarily shaped sources. We have assembled the ODWFS on a testbed using 32 by 32 square 1000 actuator deformable mirror to introduce aberration into a simulated telescope beam. We are currently testing the system's spatial frequency response and are comparing the resulting data to numerical simulations. This paper presents the results of these initial experiments.