New concepts for calibrating non-common path aberrations in adaptive optics and coronagraph systems

TL;DR

This paper introduces a novel pseudo-interferometer design utilizing two wavefront sensors for real-time calibration of non-common path aberrations in adaptive optics and coronagraph systems, enhancing high-contrast imaging capabilities.

Contribution

It proposes a new optical design for a pseudo-interferometer with dual wavefront sensors to improve NCPA calibration in AO and coronagraph systems, applicable to exoplanet imaging.

Findings

Design of a pseudo-interferometer for NCPA calibration

Real-time correction improves image quality

Applicable to imaging and spectroscopy with coronagraphs

Abstract

Non Common Path Aberrations (NCPA) are often considered as a critical issue in Adaptive Optics (AO) systems, since they introduce bias errors between real wavefronts propagating to the science detectors and those measured by the Wavefront Sensor (WFS). This is especially true when the AO system is coupled to a coronagraph instrument intended for the discovery and characterization of extra-solar planets, because useful planet signals could be mistaken with residual speckles generated by NCPA. Therefore, compensating for those errors is of prime importance and is already the scope of a few theoretical studies and experimental validations on-sky. This communication presents the conceptual optical design of a pseudo-interferometer arrangement suitable to accurate NCPA calibration, based on two WFS cooperating in real-time. The concept is applicable to both classical imaging and spectroscopy assisted by AO, and to high-contrast coronagraphs searching for habitable extra-solar planets. Practical aspects are discussed, such as the choice of WFS and coronagraph types, or specific requirements on additional hardware components, e.g. dichroic beamsplitters