ABSTRACT
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.
ABSTRACT
We experimentally investigate the focusing properties of first- and second-order vector beams and vector vortex beams generated by photonic-crystal lasers. When the azimuthal indices of the vector beam (l) and the phase dependence (n) match, strong intensity appears at the center of focus. Our theoretical analyses agree well with the experimental results and predict that the central intensity has circular polarization.