Design of photonic-crystal surface-emitting lasers with circularly-polarized beam.

We propose new structure of photonic-crystal surface-emitting lasers with oblique-triangular-prism-shaped air holes for direct emission of circularly polarized beam. We show appropriate height and tilt angle of oblique-triangular-prism-shaped air holes to achieve high degree of polarization. Secondly, we investigate the influence of cavity length. High degree of polarization can be obtained by appropriate air-hole shape and cavity length. We also show that right-handed or left-handed circular polarization can be chosen by changing tilt direction of air holes.