Laser action from two-dimensional distributed feedback in photonic crystals

We report an analysis of the operation of a new type of laser resonator wit h two-dimensional distributed feedback from a photonic crystal. The gain me dium 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 dimin ish the group velocity of photons along some directions of crystallographic symmetry to zero, and the resulting feedback gives rise to laser oscillati ons. Dispersion relations for photons were calculated analytically and are used to interpret the laser emission spectra. (C) 1999 American Institute o f Physics. [S0003-6951(99)02001-X].