Robust, frequency-stable and accurate mid-IR laser spectrometer based on frequency comb metrology of quantum cascade lasers up-converted in orientation-patterned GaAs

TL;DR

This paper presents a robust method for stabilizing and precisely measuring mid-infrared quantum cascade lasers using frequency comb metrology and upconversion in orientation-patterned GaAs, achieving high accuracy and stability.

Contribution

It introduces a novel approach combining upconversion and frequency combs for accurate, stable, and tunable mid-IR laser measurement and stabilization, specifically for quantum cascade lasers.

Findings

Achieved frequency measurement at 100 kHz level.

Demonstrated stabilization to sub-10 kHz.

Enabled controlled tuning and long-term stability.

Abstract

We demonstrate a robust and simple method for measurement, stabilization and tuning of the frequency of cw mid-infrared (MIR) lasers, in particular of quantum cascade lasers. The proof of principle is performed with a quantum cascade laser at 5.4 \mu m, which is upconverted to 1.2 \mu m by sum-frequency generation in orientation-patterned GaAs with the output of a standard high-power cw 1.5 \mu m fiber laser. Both the 1.2 \mu m and the 1.5 \mu m waves are measured by a standard Er:fiber frequency comb. Frequency measurement at the 100 kHz-level, stabilization to sub-10 kHz level, controlled frequency tuning and long-term stability are demonstrated.