Cavity ring-down spectroscopy based on a comb-locked optical parametric oscillator source
Zhexin Zhang, Cunfeng Cheng, Yu Sun, A.-W. Liu, Shui-Ming Hu
Abstract
Spectroscopy of molecules in the mid-infrared (MIR) region has important applications in various fields, such as astronomical observation, environmental detection, and fundamental physics. However, compared to that in the near-infrared, precision spectroscopy in the MIR is often limited by the light source and has not shown full potential in sensitivity. Here we report a cavity ring-down spectroscopy system using a tunable narrow-linewidth optical parametric oscillator, which fulfills the requirement of high sensitivity and high precision in the MIR region. The Lamb-dip spectrum of the N 2 O molecule at 2.7 μ m was measured as a demonstration of spectroscopy in the MIR with kilohertz accuracy.