Electromagnetic eigenmodes of microdisc resonators

Summary form only given. Recently a new class of semiconductor micro-resonators has been shown to achieve low-threshold lasing. The main objective to use micro-resonators is that a decrease of the size of such structure decreases the number of modes in optically active spectral region. Thus if the volume of the resonator approaches the cubic wavelength, one can obtain ultra-low-threshold lasing into a single mode. Despite their importance, modes of microdisc resonators have been analyzed only within a scalar approximation or have been treated as microsphere analog to "whispering gallery modes" (WGM). In this contribution we study the microdisc analog to WGMs calculated from Maxwell equations.