Abstract

The advent of lossless graded-reflectivity mirrors (GRMs) is now widely recognized as an important headway in the field of optical resonators.¹ When used as the feedback output mirror inside an unstable resonator cavity (Fig. 1), a GRM greatly improves the quality of the nearfield by yielding a wide beam with reduced ripples thanks to its tapered edges. In contrast, the more conventional unstable cavity yields an annular output beam with hard-edge truncation and disappointing beam quality for near-field applications.

© 1994 IEEE