Nonlinear optics in photonic crystal nanocavities: from light sources to quantum photonic interfaces

We demonstrate photonic interfaces between infrared and visible wavelength ranges by employing enhanced nonlinear frequency conversion in photonic crystal cavities in GaP or GaAs. We first show resonantly enhanced second harmonic and sum frequency generation in GaP photonic crystal cavities. We then integrate these nonlinear frequency conversion elements with a single InAs quantum dot to produce a fast single photon source that is optically triggered at telecommunications wavelength. These frequency conversion techniques are critical for applications including light sources at wavelengths that are difficult to access with existing lasers, IR upconversion-based detectors, and photonic quantum interfaces between the fiber-optic networks and quantum emitters.