Analysis of EMCCD and sCMOS readout noise models for Shack-Hartmann wavefront sensor accuracy

TL;DR

This paper compares EMCCD and sCMOS detector noise models for Shack-Hartmann wavefront sensors, concluding EMCCD is generally advantageous and emphasizing the need for accurate noise modeling for sCMOS detectors.

Contribution

It provides a detailed comparison of readout noise models for EMCCD and sCMOS detectors, highlighting the appropriateness of simplified models for EMCCD and the need for more accurate modeling for sCMOS.

Findings

EMCCD technology is generally advantageous for wavefront sensing.

Simplified noise models are appropriate for EMCCD detectors.

Proper modeling of sCMOS noise distribution is necessary for accurate performance assessment.

Abstract

In recent years, detectors with sub-electron readout noise have been used very effectively in astronomical adaptive optics systems. Here, we compare readout noise models for the two key faint flux level detector technologies that are commonly used: EMCCD and scientific CMOS (sCMOS) detectors. We find that in almost all situations, EMCCD technology is advantageous, and that the commonly used simplified model for EMCCD readout is appropriate. We also find that the commonly used simple models for sCMOS readout noise are optimistic, and recommend that a proper treatment of the sCMOS rms readout noise probability distribution should be considered during instrument performance modelling and development.