October 20, 2023
Complex chemical and biological reactions require fast (sub-second) spectroscopy with high spectral resolution. Researchers from Switzerland have developed a Fourier Transform (FT) spectrometer designed around a custom, continuous rotation scanning mirror, enabling millisecond acquisition times while maintaining high spectral resolution in the sub-GHz range. The demonstrated system incorporates the advantages of both FT spectroscopy as well as dual-comb spectroscopy. This design not only uses a single frequency comb for dual-comb spectroscopy, but can prove useful in a variety of spectroscopy applications where high speed, large optical bandwidth, and high spectral resolution are desired.
Combining FT spectroscopy with dual-comb spectroscopy for fast acquisition and high-spectral resolution requires high precision and stable control of the quantum cascade laser. Wavelength Electronics’ QCL1000 OEM driver enabled precise current control with minimal electronic noise. The driver also allows analog wavelength modulation of up to 2-3 MHz. This enabled laser tuning by changing the drive current to the QCL with a triangular current modulation ramp. As laser linewidth is a major concern for QCLs, the QCL1000 OEM minimizes noise to as low as 0.7 μA up to 100kHz as well as keeping the average current noise density to as low as 2 nA / √Hz.
Our QCL driver enables sub-second spectroscopy with high spectral resolution with low noise and stable laser output. This makes the developed rotational FT spectrometer system a reliable tool for dual-comb spectroscopy for applications in reaction and leakage monitoring and in-line process analytical technology.
The complete case study is available as CS-LD09.