Abstract
Recent calculations of the eigenmodes in waveguides grown on semipolar GaN suggest that the optical polarization of the emitted light as well as the optical gain depends on the orientation of the resonator. Our measurements on separate confinement heterostructures on semipolar (11 (2) over bar 2) and (10 (1) over bar2) GaN show that for laser resonators along the semipolar [1123] and [0 (1) over ...
Abstract
Recent calculations of the eigenmodes in waveguides grown on semipolar GaN suggest that the optical polarization of the emitted light as well as the optical gain depends on the orientation of the resonator. Our measurements on separate confinement heterostructures on semipolar (11 (2) over bar 2) and (10 (1) over bar2) GaN show that for laser resonators along the semipolar [1123] and [0 (1) over bar 11] directions (i.e. the projection of the c-axis onto the I plane of growth) the threshold,for amplified spontaneous emission is lower than for the nonpolar direction and that the stimulated emission is linearly polarized as TE mode. For the waveguide structures along the nonpolar [1 (1) over bar 00] or [11 (2) over bar0] direction on the other hand, birefringence and anisotropy of the optical gain in the plane of growth leads not only to a higher threshold but also to a rotation of the optical polarization which is not any more TE- or TM-polarized but influenced by the ordinary and extraordinary refractive index of the material. We observe stimulated emission into a mode which is linearly polarized in extraordinary direction nearly parallel to the c-axis. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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