SCExAO as a precursor to an ELT exoplanet direct imaging instrument

TL;DR

SCExAO is a high-performance extreme adaptive optics system designed for high contrast exoplanet imaging, serving as a testbed for future ELT instruments and enabling advanced observational techniques.

Contribution

The paper reports recent developments in SCExAO, including new components and capabilities, positioning it as a precursor and testbed for ELT exoplanet imaging instruments.

Findings

Achieved >90% Strehl ratio in H-band with the new AO system

Added visible wavelength capabilities with a new bench and wavefront sensor

Integrated guest instruments like CHARIS and VAMPIRES for expanded observations

Abstract

The Subaru Coronagraphic Extreme AO (SCExAO) instrument consists of a high performance Phase Induced Amplitude Apodisation (PIAA) coronagraph combined with an extreme Adaptive Optics (AO) system operating in the near-infrared (H band). The extreme AO system driven by the 2000 element deformable mirror will allow for Strehl ratios >90% to be achieved in the H-band when it goes closed loop. This makes the SCExAO instrument a powerful platform for high contrast imaging down to angular separations of the order of 1lambda/D and an ideal testbed for exploring coronagraphic techniques for ELTs. In this paper we report on the recent progress in regards to the development of the instrument, which includes the addition of a visible bench that makes use of the light at shorter wavelengths not currently utilized by SCExAO and closing the loop on the tip/tilt wavefront sensor. We will also discuss several exciting guest instruments which will expand the capabilities of SCExAO over the next few years; namely CHARIS which is a integral field spectrograph as well as VAMPIRES, a visible aperture masking experiment based on polarimetric analysis of circumstellar disks. In addition we will elucidate the unique role extreme AO systems will play in enabling high precision radial velocity spectroscopy for the detection of small companions.