REVOLT-COPPER: a pyramid wavefront sensor testbed from RTCs to novel wavefront sensing

The 1.2m McKellar telescope in Victoria, Canada has been outfitted with an adaptive optics (AO) system, REVOLT, to test new hardware, mitigate risks, improve technology

readiness, and perform fundamental research and development. Having recently been upgraded and expanded, we now have complemented the original Shack-Hartmann WFS

(SHWFS) arm with a pyramid wavefront sensing (PWFS) arm named REVOLT-COPPER, which is used to test various PWFS-specific software and algorithms in addition to

building in-house expertise for on-sky operation of a PWFS. In this paper, we present the various capabilities of REVOLT-COPPER and the results of tests that have been done on

a variety of different related topics. Specifically, the real-time-controller (RTC; i.e., HEART) for the Gemini Planet Imager 2.0 (GPI2) has been tested on-sky on REVOLT-COPPER

along with its dithering-based optical gain optimization routine. The infinite impulse response (IIR) has been tested in this work. Furthermore, a gain scheduling camera has been

implemented as an alternative way to track optical gains. REVOLT also has the capabilities to gather telemetry from both the PWFS and the SHWFS as well as seamlessly swap

on-sky operation between the two sensors. This allows for us to directly compare the performance of the two wavefront sensors. Finally, we will discuss future planned experiments

with REVOLT-COPPER including the implementation a machine learning reconstructor on REVOLT using the python RTC (pyRTC) framework as well as time-resolved wavefront

sensing with a SPAD array.