Laser action from two-dimensional distributed feedback in photonic crystals

Abstract

We report an analysis of the operation of a new type of laser resonator with two-dimensional distributed feedback from a photonic crystal. The gain medium consists of a 2-(4-biphenylyl)-5(4-tert-butylphenyl)-1,3,4-oxadiazole host doped with Coumarin 490 and DCM and is deposited on lithographically patterned Si/SiO2 structures. Bragg reflections caused by the grating diminish the group velocity of photons along some directions of crystallographic symmetry to zero, and the resulting feedback gives rise to laser oscillations. Dispersion relations for photons were calculated analytically and are used to interpret the laser emission spectra.