Electrically switchable third-harmonic generation in photonic crystals

We demonstrate electrically switchable third-harmonic generation in low refractive index contrast one-dimensional photonic crystals pumped by a near-infrared laser beam. A dramatic enhancement of the third-harmonic signal is observed on the short wavelength side of the photonic crystal stop band. The enhancement of the third-harmonic generation disappears when an electric field is applied, revealing the electrical switchability of the third-harmonic generation. The observed phenomenon of enhancement is explained theoretically with a coupled-mode model. We also show that up to a modulation frequency of 10 kHz the switching properties are supported in the photonic crystal.