Radiation outcoupling from microdisk lasers via dielectric resonant nanoantennas

Abstract

Microdisk lasers that support whispering gallery modes are very prospective devices in modern nanophotonics due to high Q-factors and low lasing generation thresholds. One of the main fundamental problems of these lasers is the low efficiency of the radiation outcoupling. Moreover, the radiation of the disks propagates mainly in the plane of the disk, whereas in some applications, a vertical radiation outcoupling is required. In this work, we use resonant dielectric nanospheres for the microdisks radiation outcoupling. We have determined the radii at which the radiation outcoupling is most efficient. After transferring a particle to the surface of the disks, we found that the particle shifted the spectral position of the disk’s resonances relative to their original position on the value less than 1 nm and reduced the thresholds of lasing on ≈ 20 %, without broadening the line. Finally, we measured directivities from such disks and observed that nanoantennas results in appearance if the directed emission