Resonant Reflection of Light from an Excitonic Optical Grating Formed by 100 InGaN Quantum Wells

The optical properties of a structure with a periodic system of 100 InGaN quantum wells separated by nontunneling GaN barriers are investigated at room temperature. The structure periodicity corresponds to the Bragg-diffraction condition at the quantum-well exciton frequency. The results of numerical simulation using transfer matrices are in reasonable quantitative agreement with the experimental data. The model includes the resonance response of A, B, and C excitons in the quantum wells and the optical absorption tail in the barrier and buffer layers. The radiative and nonradiative damping rates of excitons in the InGaN quantum wells are determined.