Vibrational Stark Spectroscopy of Fluorobenzene Using Quantum Cascade Laser Dual Frequency Combs

Abstract

We demonstrate the performance of a dual frequency comb QCL spectrometer for the application of vibrational Stark spectroscopy. Measurements performed on fluorobenzene with the dual-comb spectrometer were compared to results obtained using a conventional Fourier transform infrared (FTIR) instrument in terms of spectral response, parameter estimation, and signal-to-noise ratio. The dual-comb spectrometer provided the same qualitative and quantitative data as the FTIR setup with an up to 9 or 52 times improved signal to noise ratio (SNR) in the current configuration when comparing against experimental or acquisition times, respectively. This improvement was made possible by the shorter experimental and acquisition times, and the brighter light-source. Additional characteristics of the dual-comb spectrometer applicable to vibrational Stark spectroscopy and their scaling properties for future applications are discussed.

QCL-Based Dual-Comb Spectrometer for Multi-Species Measurements at High Temperatures and High Pressures

“…The total laser power at the sample is attenuated to ~1 mW to remain in the linear regime of the detector [ 36 ]. The spectral noise is line-dependent and correlates with light intensity at each line [ 67 ]. A typical RMS noise value of a strong line is 4 mOD at a time resolution of 4 μs, which scales to 400 μOD at a 1 ms time resolution [ 36 ].…”

Coherently-Averaged Dual-Comb Spectrometer at 7.7 µm with Master and Follower Quantum Cascade Lasers

“…Mid-infrared (MIR) quantum cascade laser (QCL) frequency combs [2] are an appealing and thriving technology for DCS [3,4], as they cover strong spectroscopic absorption bands of many relevant molecules in the MIR region. Dual QCL comb spectrometers have become commercially available as a table-top instrument, which is leading to new discoveries in many fields of science including biology and chemistry [5][6][7][8][9][10][11][12]. One key advantage of QCL-based DCS is the ability to perform studies with up to sub-microsecond time-resolution [11].…”