Geometrical Representation of Sum Frequency Generation and Adiabatic Frequency Conversion

TL;DR

This paper introduces a geometrical model for sum frequency generation, drawing analogies with optical Bloch equations, and demonstrates a novel adiabatic frequency conversion technique with high efficiency and broad bandwidth, validated experimentally.

Contribution

It presents a new geometrical representation and a practical adiabatic inversion scheme for efficient, broadband sum frequency conversion, inspired by NMR and light-matter interaction techniques.

Findings

Achieved high efficiency signal to idler conversion.

Demonstrated 140nm bandwidth in experiments.

Validated the adiabatic frequency conversion scheme.

Abstract

We present a geometrical representation of sum frequency generation process in the undepleted pump approximation. The analogy of such dynamics with the known optical Bloch equations is discussed. We use this analogy to present a novel technique for the achievement of both high efficiency and large bandwidth in a sum frequency conversion processes using adiabatic inversion scheme, adapted from NMR and light-matter interaction. The adiabatic constraints are derived in this context. Last, this adiabatic frequency conversion scheme is realized experimentally by a proper design of adiabatic aperiodically poled KTP device, using quasi phased matched method. In the experiments we achieved high efficiency signal to idler conversion over a bandwidth of 140nm.