Electro-optical effect in InGaN–GaN resonant Bragg structure with double quantum wells in the unit cell

We report an experimental observation of a strong electro-optic effect in a resonant Bragg structure with 60 double (In,Ga)N/GaN quantum wells in the unit cell at room temperature. We achieved the absolute modulation of the reflection coefficient ΔR = 7.3% at a wavelength of 402.5 nm. The relative reflectivity modulation ΔR/R is 17% for the s-polarization and 36% for the p-polarization. The effect arises from enhanced coupling between quasi-2D excitons and light in the superradiant exciton–polariton mode upon applied reverse bias of 90 V.