Extra-cavity enhanced difference frequency generation at 163 μm

A 1632 nm laser has highly important applications in interfacing the wavelength of rubidium-based quantum memories (795 nm) and the telecom band (typically 1550 nm) by frequency conversion in a three-wave mixing processes. A 1632 nm laser source based on pump-enhanced difference-frequency generation is demonstrated. It has 300 mW of output power, in agreement with simulations, and a 55% quantum efficiency. An average power fluctuation of 0.51% over 1 h was observed, and 200 kHz linewidth was measured using a delayed self-heterodyne method.