Laboratory Simulations of Tomographic AO

The MCAO/MOAO testbench in the Laboratory for Adaptive Optics (LAO) is an integrated wide-field AO system on a 10-meter telescope delivering 20-33% Strehl over 45 arcseconds at a science wavelength of R-band (see Strehl map at left).  

Our team has demonstrated multi-object adaptive optics (MOAO) operation and laser tomography AO (LTAO) with this system.  The wavefront sensor accuracy in open-loop is 30 nm with a realistic atmosphere.  

Visible-light results:        Ammons et al. 2010, (link to ADS)
MOAO results:                 Ammons et al. 2007, proc. SPIE   (link to ADS)  
Tomography:                  Gavel et al. 2007, OSA Tech. Digests      (link)
Results on 30-m:             Ammons et al. 2006, proc. SPIE   (link to ADS)

Calibrated Astrometry with Tomographic AO

MCAO systems on ELTs should deliver the best available relative astrometric precision from the ground, which may be sufficient to detect exo-earths orbiting nearby brown and red dwarfs (< 30 μas).   Yet despite the success of AO astrometry on large telescopes, we still do not understand the systematic errors that may dominate long-term astrometric stability with MCAO, such as dynamic optical distortion and differential atmospheric refraction (DAR). 

We have performed an on-sky test of the "diffractive pupil" concept, intended to calibrate changing optical distortion with diffracted light from the target star (Guyon et al. 2012), on a 1-meter Nickel telescope at Lick Observatory.  These data indicate PSF modeling systematics of one thousandth of the star FWHM (1 mas) for individual stars.  The diffractive pupil stabilizes the instrumental distortion to at least the precision of the experiment (~1 mas over 3’) and reduces the systematic component by 2x.

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The AO Demonstrator

I designed and built the AO Demonstrator, a $25k self-enclosed adaptive optics system exclusively for education.  With a 37-actuator AgilOptics DM and an 8x8 wavefront sensor, the system corrects turbulence at 30 Hz.

Two similar clones exist at UH Maui (Joe Curamen) and UH Hilo (James Ah Heong).