500-nm Optical Gain Anisotropy of Semipolar (1122) InGaN Quantum Wells

We studied the effect of carrier population on light emission polarization of green InGaN quantum wells (QWs) on the semipolar (1122) plane. The 3 nm thick QWs emitting light at about 540 nm at low pumping power have electrical field (E) component E∥[1123] stronger than that E∥[1100]. However, we found that increasing the pumping power changed the sign of the polarization ratio. Using the varied stripe length (VSL) method, we measured the optical gain for light propagating ∥[1123] direction to be ~2 times that of light propagating ∥[1100] direction. We explain this behavior by inhomogeneous QW state filling.