Premium
Room‐Temperature, High‐SNR Upconversion Spectrometer in the 6–12 µm Region
Author(s) -
Rodrigo Peter John,
Høgstedt Lasse,
Friis Søren Michael Mørk,
Lindvold Lars René,
TidemandLichtenberg Peter,
Pedersen Christian
Publication year - 2021
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.202000443
Subject(s) - spectrometer , fourier transform infrared spectroscopy , photon upconversion , infrared , materials science , detector , spectral resolution , optics , fourier transform spectroscopy , fourier transform , near infrared spectroscopy , spectroscopy , resolution (logic) , optoelectronics , analytical chemistry (journal) , physics , computer science , chemistry , spectral line , luminescence , chromatography , quantum mechanics , astronomy , artificial intelligence
Mid‐infrared (MIR) spectroscopy, which has important applications in medicine, environmental monitoring, materials, and food science, is widely performed using Fourier transform infrared (FTIR) spectrometers as gold standard. Despite decades of development, FTIR systems are vulnerable to vibration and have limited temporal resolution due to reliance on mechanically scanned mirrors and MIR direct detectors that have a slower response than their near‐infrared counterparts. Using cryogenically cooled detectors, state‐of‐the‐art FTIR systems have reached a signal‐to‐noise ratio (SNR) of ≈6000 at 1 s integration time (at 4 cm −1 spectral resolution). Here, a novel MIR upconversion spectrometer (MIRUS) is presented with a record‐high SNR > 10 000 at 1 s (6 cm −1 resolution), outperforming FTIR systems by circumventing the need for sophisticated cooling and any moving part, thus enabling operation in harsh environments. It has a spectral coverage of 6–12 µm—the broadest for an upconversion spectrometer to date. The MIRUS uses broadband intracavity upconversion to convert the signal spanning the MIR fingerprint region to the near‐infrared where sensitive Si‐detector based spectrometers operate with rates easily reaching kilo spectra per second. Applications of MIRUS for gas sensing, plastic identification, and rapid photopolymerization monitoring are demonstrated.