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Fast-sweeping continuous wave quantum cascade laser operating in an external cavity with polygon mirror.
Optics Express
|October 13, 2022
Summary
This study presents a fast-tuning quantum cascade laser (QCL) for rapid spectral measurements. The room-temperature QCL achieves wide wavenumber sweeps in microseconds, enabling quick analysis of chemical samples.
Area of Science:
- Mid-infrared spectroscopy
- Quantum cascade lasers
- Optical engineering
Background:
- Quantum cascade lasers (QCLs) are crucial for mid-infrared applications.
- Fast wavelength tuning is essential for time-resolved spectroscopy.
- External cavity configurations offer wavelength tunability.
Purpose of the Study:
- To develop a room-temperature quantum cascade laser with rapid, wide-range wavelength sweeping.
- To demonstrate the laser's capability for fast spectral acquisition.
- To enable time-resolved measurements in the mid-infrared spectrum.
Main Methods:
- Utilized a continuous wave (CW) room-temperature quantum cascade laser.
- Employed an external cavity in the Littrow configuration.
- Incorporated a 10-facet polygon mirror rotating at 24,000 RPM for rapid tuning.
Main Results:
- Achieved a wavelength sweep from ~1520 to 1625 cm⁻¹ in ~45 µs.
- Observed a sweep repetition rate of 4 kHz.
- Measured maximum output power of ~90 mW and average power of ~50 mW.
- Demonstrated spectral acquisition of acetophenone and water vapor within 45 µs.
Conclusions:
- The developed QCL system enables ultra-fast mid-infrared spectral measurements.
- The rapid tuning capability is suitable for time-resolved chemical analysis.
- This technology advances spectroscopic techniques for dynamic systems.
