Mode analysis of two-dimensional photonic crystal terahertz lasers with gain/loss dispersion characteristics

Abstract

Gain/loss dispersion characteristics of photonic modes in a two-dimensional photonic crystal (PC) are demonstrated for the first time, to our knowledge. The dispersion analysis is based on an improved plane-wave expansion method that includes the gain/loss factor along the propagation direction of each plane wave and treats surface-emission properties. PC lasers operating at terahertz frequency are considered for the numerical calculation. Our analysis indicates that although PC lasers with different lattice periods possess almost the same photonic band structure, their gain/loss dispersion characteristics are significantly different. The systematic study on gain/loss dispersion characteristics reveals the optimum PC structure to obtain high-performance surface-emitting lasers.