Linearly-Polarized Single-Lobed Beam in a Surface-Emitting Photonic-Crystal Laser

A linearly-polarized, single-lobed beam has been demonstrated in a surface-emitting photonic-crystal laser under single-mode operation by employing fine-tuned elliptical lattice points and π-phase shift. A crystal structure, including the elliptical lattice points with a short/long axis ratio of 0.95, has been successfully fabricated. The resulting beam was strongly polarized in one direction, although the shape of the lattice points was nearly circular. It was found that two-dimensional optical coupling was compatible with strong linear polarization.