Spatial mode structure in a half-disk cavity laser

Summary form only given. We experimentally and theoretically examined the mode structure of half-disk lasers fabricated by cleaving whispering gallery mode (WGM)-disk lasers. The WGM lasers with a radii R of 50-150 μm emitting near 2.2 μm were fabricated using the GaSb-based quantum well structure [1]. The cleavage usually passes not through the centre of the disk with the deviation δ/R up to 20 % (Fig. 1a). Recently we have demonstrated that in the half-disk lasers the output beam is formed by optical modes located at a distance of 5-20 μm from the disk periphery [2], whereas in the full disk the light propagates along the disk wall, much closer to its edges.