Performance of a MEMS-based AO-OCT system

Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-resolution, 3-D images of the retina. The AO-OCT system at UC Davis has been under development for 2 years and has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging. The current system uses a bimorph deformable mirror (DM) made by AOptix Technologies, Inc. for low-order, high-stroke correction and a 140-actuator mirco-electrical-mechanical-system (MEMS) DM made by Boston Micromachines Corporation for high-order correction. We present our on-going characterization of AO system performance. The AO-OCT system typically has residual wavefront error of 100 nm rms. The correctable error in the system is dominated by low-order error that we believe is introduced by aliasing in the control loop. Careful characterization of the AO system will lead to improved performance and inform the design of future systems.