High-speed Fourier-transform infrared spectroscopy with phase-controlled delay line

Abstract

Fourier-transform infrared spectroscopy (FTIR) is the golden standard of mid-infrared (MIR) molecular spectroscopic analysis through optically-encoded vibrational signatures. Michelson-type FTIR and MIR dual-comb spectrometers allow us to simultaneously investigate multiple molecular species via the broadband and high-resolution spectroscopic capabilities. However, these are not applicable to high-speed measurements due to the low temporal resolution which is fundamentally limited by the signal-to-noise ratio (SNR). In this study, we develop a high-speed FTIR spectroscopy technique called phase-controlled Fourier-transform infrared spectroscopy (PC-FTIR) that has the capability to measure MIR absorption spectra at a rate of above 10 kHz. PC-FTIR demonstrates the high scan rate with a high SNR for various spectral bandwidths by arbitrarily adjusting the instrumental spectral resolution. As a proof of principle demonstration, we measure high-speed mixing dynamics of two liquids at a rate of 24 kHz. We also measure MIR spectra of gas-phase molecules with higher spectral resolution at a rate of 12 kHz. This high-speed MIR spectrometer could be especially useful for measuring non-repetitive fast phenomena and acquiring a large amount spectral data within a short time.

References in corpus (3)

• Silicon-Chip Mid-Infrared Frequency Comb Generation
• Mid-Infrared Frequency Comb Fourier Transform Spectrometer
• Ultrafast-laser-absorption spectroscopy for single-shot, mid-infrared measurements of temperature, CO, and CH${}_4$ in flames

Cited by in corpus (6)

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• 1 GHz dual-comb spectrometer for fast and broadband measurements
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• Broadband complementary vibrational spectroscopy with cascaded intra-pulse difference frequency generation