Performance Simulations for Kola: Achieving High-Resolution, Visible-Light AO Correction Over a 1 Arcminute Field

TL;DR

This paper presents detailed performance simulations of KOLA, a proposed high-resolution visible-light adaptive optics system for the Keck I telescope, demonstrating its potential to achieve near diffraction-limited imaging over a 1 arcminute field.

Contribution

The paper introduces a novel multi-conjugate adaptive optics architecture for the Keck telescope, validated through simulations, to enable wide-field, high-resolution optical imaging.

Findings

Achieves 15 mas resolution with 34% Strehl ratio at 652 nm

Validates AO performance using the MAOS simulator against real on-sky data

Provides insights into design trade-offs for laser guide star configurations

Abstract

We present performance simulations for a proposed visible-light, multi-conjugate adaptive optics system for the 10-meter W. M. Keck I telescope that aims to deliver near diffraction-limited angular resolution at optical wavelengths. Our proposed architecture, the Keck Optical Laser Guide Star Adaptive Optics System (KOLA), combines multiple laser guide stars (LGS) and deformable mirrors to enable wide-field correction across a 60 arcsecond field of view. Simulations were conducted using the open-source Multi-Threaded Adaptive Optics Simulator (MAOS), which we validated against on-sky data for the current Keck I adaptive optics system. We evaluated KOLA performance across a range of design parameters and report key point spread function metrics, including Strehl ratio, full width at half maximum, and encircled energy radius. Example science-driven requirements include resolving black hole spheres of influence, probing crowded stellar fields, and imaging protoplanetary disks. Trade studies on actuator count and laser guide star configuration help inform future design decisions. We present a nominal KOLA design (10 LGS, 3 tip-tilt natural guide stars (TTNGS), and 3600 actuators on the adaptive secondary mirror). Performance simulations show a 15 mas angular resolution with a Strehl ratio of 34% at 652 nm on-axis. More work is needed to explore alternative LGS/TTNGS asterisms, optimize conjugation heights for high-altitude deformable mirrors, and test performance under poorer seeing conditions.