Performance of the Nonlinear Curvature Wavefront Sensor as a Function of Scintillation Strength

TL;DR

This paper compares the performance of the nonlinear curvature wavefront sensor (nlCWFS) and Shack-Hartmann WFS under varying scintillation conditions, demonstrating nlCWFS's robustness and improved reconstruction accuracy in challenging low-light and high-scintillation environments.

Contribution

The study provides experimental data quantifying how the nlCWFS outperforms the SHWFS across different scintillation levels, extending previous simulations and laboratory results.

Findings

nlCWFS maintains better reconstruction performance under high scintillation.

Performance gap between nlCWFS and SHWFS increases with scintillation strength.

Experimental results validate the robustness of nlCWFS in adverse conditions.

Abstract

Local amplitude aberrations caused by scintillation can impact the reconstruction process of a wavefront sensor (WFS) by inducing a spatially non-uniform intensity at the pupil plane. This effect is especially relevant for the commonly-used Shack-Hartmann WFS (SHWFS), which can lose slope information for portions of the beam where the signal is faint, leading to reduced reconstruction performance and eventually total failure as the level of scintillation increases. An alternative WFS is needed for such conditions. The nonlinear curvature wavefront sensor (nlCWFS) has been shown to achieve better sensitivity compared to the SHWFS under low light levels. Additionally, the nlCWFS has demonstrated the ability to maintain its sensitivity in the presence of scintillation, using amplitude aberrations to help inform the reconstruction process, rather than hinder. Experiments to date have thus far only shown reconstruction results for a single scintillation value. Building upon previous simulations and laboratory experiments, we have built a testbed to quantify the effects of varying scintillation strength on the wavefront reconstruction performance of the nlCWFS compared to an equivalent SHWFS. In this paper, we present results showing the difference in performance between the nlCWFS and SHWFS as a function of relative flux and scintillation strength.