RESUMEN
We use the finite-difference time domain method to calculate the vertical optical confinement, which corresponds to the quality factor in the vertical direction, of two-dimensional photonic-crystal (PC) lasers as a function of the asymmetry of the shape of the air holes that form the PC. The vertical optical confinement for triangular air holes, which give the highest output power measured thus far, is decreased by two thirds when V-shaped air holes are used. In contrast, the vertical optical confinement becomes infinite for rhomboid air holes. The vertical optical confinement decreases when the air holes are deformed such that areas of opposing electric fields exist in regions of the PC with different dielectric constants. In this way, the vertical optical confinement can be controlled by changing the shape of the air holes.
RESUMEN
We present a useful framework based on the coupled-wave theory, through which we can survey the resonant modes of TM polarization in 2D photonic-crystal lasers and understand their properties in detail. Through numerical calculations, we clarify their threshold gains, deviations from the Bragg frequency and field distributions. We find that the lasing mode can be selected by manipulating the hole-filling factor or the boundary reflection.
RESUMEN
Compact lasers that can produce a range of beam patterns are important for progress in several areas, including the improvement of optical tweezers, ultra-high-density optical memory and microfluidics. Here we engineer photonic crystals to generate semiconductor lasers that produce a range of beam patterns while maintaining stable single-mode oscillation. Our results could contribute to the realization of compact lasers that are capable of producing diverse beam patterns on demand.