Adiabatic nonlinear optical frequency conversion based on the electro-optic effect

Abstract

We propose a novel, to the best of our knowledge, adiabatic nonlinear optical frequency conversion method based on the electro-optic effect, which can be applied in a plethora of bulky nonlinear crystals. Within our method, an electric field gradient is applied on the crystal, which causes the phase mismatch to also gradually vary in space, thus achieving adiabatic frequency conversion. We demonstrate the validity and feasibility of this new approach by providing a theoretical framework and experimental evidence. In the experiment, the second harmonic generation of 532 nm is conducted in K D 2 P O 4 . Conversion efficiency approaching 47.2% is achieved, with a corresponding temperature acceptance bandwidth of 4.56°C, which is about 4.3 times the temperature without the external electric field. We argue that the approach based on the electro-optic effect is promising for extending the range of applications of adiabatic frequency conversion and, consequently, for achieving efficient and robust frequency conversion.