Two-dimensional beam steering is often required in medical laser scanning systems such as OCT or confocal
microscopy. Usually two linear galvo mirrors are used for their large apertures and large scan angles. The galvos are
placed at the vicinity of the scan lens entrance pupil and separated by a "displacement distance." This distance limits
the scan fields and/or reduces the effective aperture of the scan lens. Another option is to use a beam relay to relay one
galvo on to the other. However, beam (or pupil) relays are usually complicated, expensive and can add significant
This paper discusses a simple, all reflective, diffraction limited, color corrected, beam relay, capable of large scan angles
and large deflecting mirrors.
The design is based on a unique combination of an Offner configuration with a Schmidt aspheric corrector, which
allows a significantly larger scan field than scanners using galvos separated by the displacement distance.
Design example for 12 mm diameter pupil and 30 degrees optical field are shown. The design details and performance
are presented as well as different possible configurations for use in high performance microscopic systems and laser