Upconversion-based MIR Spectrometer with CMOS detectors by NLIR
Upconversion from mid-infrared (MIR) to near-visible wavelengths using sum-frequency generation enables sensitive and low-noise MIR light detection using near-visible-light detectors. MIR spectroscopy is important for a wide spectrum of compound characterization applications but challenged by the thermal noise inherent in conventional MIR detectors, giving low detectivity. In this Letter, we show an upconversion-based spectroscopy scheme with an unprecedented combination of large bandwidth and short sampling time. Using LiNbO3 crystals with a chirped poling structure placed inside a laser cavity, we demonstrate simultaneous upconversion from 2.15 μm to 5.3 μm with sampling times as low as 10.8 μs and an average signal-to-noise ratio of >6000 at 1 s. We conduct numerical studies to show the inverse relationship between efficiency and bandwidth of the upconversion process in the chirped crystal structure and find good agreement with our experimental results.
Would you like to learn more?
Are you interested in learning more about mid-infrared spectrometers based on Sum Frequency Generation (SFG) technology, delivering high-speed, room temperature measurements with a robust and portable equipment? Discover more about NLIR’s MIDWAVE Spectrometer.
