High-efficiency frequency doubling of continuous-wave laser light

TL;DR

This paper demonstrates a highly efficient frequency doubling of 1550 nm laser light using a nonlinear cavity with PPKTP, achieving 95% conversion efficiency, suitable for quantum light applications.

Contribution

The study reports a record-high external conversion efficiency of 95% for frequency doubling in a continuous-wave laser system using PPKTP, with insights into limiting factors.

Findings

Achieved 95% external conversion efficiency.

Efficiency limited by mode-matching and pump power.

Results support PPKTP for quantum frequency conversion.

Abstract

We report on the observation of high efficiency frequency doubling of 1550 nm continuous-wave laser light in a nonlinear cavity containing a periodically poled potassium titanyl phosphate crystal (PPKTP). The fundamental field had a power of 1.10 W and was converted into 1.05 W at 775 nm, yielding a total external conversion efficiency of (95 \pm 1)%. The latter value is based on the measured depletion of the fundamental field being consistent with the absolute values derived from numerical simulations. According to our model, the conversion efficiency achieved was limited by the non-perfect mode-matching into the nonlinear cavity and the pump power available. Our result shows that cavity-assisted frequency conversion based on PPKTP is well suited for low-decoherence frequency conversion of quantum states of light.