It is shown that the 'flower-like' emission patterns along the perimeter of broad-area circular vertical-cavity surface-emitting lasers can be interpreted in a first approximation as annular standing waves. Their modulation period follows the dispersion relation of tilted plane waves for a plano-planar cavity. For high enough divergence angle, they show a very peculiar polarization behavior of radial polarization in near field and azimuthal polarization in far field. The polarization selection is qualitatively explained by the breaking of the isotropy between s- and p-components for waves propagating off axis in the Bragg reflectors.
- annular standing waves
- surface-emitting lasers