Supplementary active optics for illumination within an adaptive optics system

The use of additional adaptive optics to manipulate the beacon in an adaptive optics system for the human eye opens up many opportunities. Possibilities include better beacon creation, correction of gross aberrations that the beam acquires as it passes into the eye, symbiotic beams to guide or locate a probe or medical beam, and examination of the higher order aberrations experienced by the beam as it enters the eye. We describe the use of active optics for creation of the beacon in an adaptive optics system that incorporates a fundus imaging arm. In describing the possibilities for beacon shaping and steps that may be employed to use this to create a sharper or more versatile beacon, we determine the effects of such shaping on the performance of the system. Results are presented for both model and human eyes. The beacon shaping incorporates Bessel beam creation with tip-tilt and defocus correction from a mask on a spatial light modulator. Visual feedback from images of the beacon as it appears at the retina is used to refine it.