Guided mode lasing in a double-layered square microcavity

We investigated the lasing characteristics of guided modes in a double-layered square microcavity made of a fused-silica hollow square capillary, in which the modes were formed by the total internal reflections off the inner and outer boundaries. Periodically peaked spectra of guided modes were observed when a dye-doped dielectric was coated on the outer boundary for a laser gain. By reducing the distance between the outer and the inner boundaries, we could achieve even a lasing of single closed guided modes with multiple reflections at each side of the inner boundary. Our double-layered square cavity can be adapted for various applications, particularly in the photonic integrated circuits. (C) 2003 American Institute of Physics.