# Efficient low-power terahertz generation via on-chip triply-resonant nonlinear frequency mixing

## TL;DR

This paper proposes a novel on-chip triply-resonant nonlinear frequency mixing approach that significantly enhances terahertz generation efficiency at low power levels, potentially enabling practical, compact THz sources.

## Contribution

It introduces a triply-resonant photonic resonator design that dramatically improves THz generation efficiency and reduces power requirements compared to existing methods.

## Key findings

- Predicted up to three orders of magnitude reduction in pump power needed.
- Designed a realistic, experimentally accessible device.
- Achieved near quantum-limited conversion efficiency.

## Abstract

Achieving efficient terahertz (THz) generation using compact turn-key sources operating at room temperature and modest power levels represents one of the critical challeges that must be overcome to realize truly practical applications based on THz. Up to now, the most efficient approaches to THz generation at room temperature -- relying mainly on optical rectification schemes -- require intricate phase-matching set-ups and powerful lasers. Here we show how the unique light-confining properties of triply-resonant photonic resonators can be tailored to enable dramatic enhancements of the conversion efficiency of THz generation via nonlinear frequency down-conversion processes. We predict that this approach can be used to reduce up to three orders of magnitude the pump powers required to reach quantum-limited conversion efficiency of THz generation in nonlinear optical material systems. Furthermore, we propose a realistic design readily accesible experimentally, both for fabrication and demonstration of optimal THz conversion efficiency at sub-W power levels.