Fast rate dual-comb spectrometer in the water-transparent 7.5-11.5 µm region

Area of Science:

• Spectroscopy
• Laser Physics
• Environmental Science

Background:

• Dual-comb spectroscopy offers high resolution and broad bandwidth.
• Erbium fiber lasers are suitable for generating specific spectral ranges.
• Mid-infrared (MIR) spectroscopy is crucial for gas analysis.

Purpose of the Study:

• To introduce a novel dual-comb spectrometer system.
• To achieve high temporal resolution for transient gas phase processes.
• To enable sensitive multi-species atmospheric gas detection.

Main Methods:

• Utilized erbium fiber oscillators operating at 250 MHz.
• Implemented a dual-comb setup for spectral acquisition in the 7.5-11.5 µm range.
• Achieved optical bandwidths up to 9 THz with multi-kHz acquisition rates.

Main Results:

• Demonstrated a signal-to-noise ratio of 168 Hz^0.5 per spectral point at 26 kHz acquisition rate over 0.8 THz bandwidth.
• Operated the spectrometer in the 7.5-11.5 µm spectral range.
• Showcased the system's capability for high temporal resolution gas phase analysis.

Conclusions:

• The developed dual-comb spectrometer provides high performance for transient gas analysis.
• The system's water transparency window and detector cooling make it suitable for open-path atmospheric monitoring.
• Out-of-loop phase correction enhances interferogram quality for robust measurements.