Borri Simone, Siciliani de Cumis Mario, Insero Giacomo, Bartalini Saverio, Cancio Pastor Pablo, Mazzotti Davide, Galli Iacopo, Giusfredi Giovanni, Santambrogio Gabriele, Savchenkov Anatoliy, Eliyahu Danny, Ilchenko Vladimir, Akikusa Naota, Matsko Andrey, Maleki Lute, De Natale Paolo
CNR-INO - Istituto Nazionale di Ottica, Largo E. Fermi 6, 50125 Firenze, FI, Italy.
LENS - European Laboratory for Non-Linear Spectroscopy, Via Carrara 1, 50019 Sesto Fiorentino, FI, Italy.
Sensors (Basel). 2016 Feb 17;16(2):238. doi: 10.3390/s16020238.
The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF₂ microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line.
对用于中红外分子传感和计量的高性能且稳定的方法的需求推动了越来越紧凑且坚固的系统的发展。旨在满足对稳定中红外参考需求的创新解决方案中包括晶体微谐振器，其最近在紧凑装置中展现出了用于量子级联激光器频率稳定和线宽变窄的出色能力。在这项工作中，我们报告了首个基于锁定到CaF₂微谐振器的量子级联激光器的中红外高分辨率光谱系统。电子锁定将激光线宽缩小了一个数量级，并保证了长时间尺度上的良好稳定性，同时还提供了一种在分子吸收线上精细调谐激光频率的简便方法。通过对分子谱线的直接亚多普勒记录证明了光源在分辨率和频率稳定性方面的改进。
