Optica-template-preprint.pdf (3.48 MB)
Background-free mid-infrared absorption spectroscopy using sub-cycle pulses
preprint
posted on 2024-03-22, 08:46 authored by Takao Fuji, Neil Cabello, Shinta Ozawa, Shota Kusama, Wei-Hong Huang, Chih Wei Luo, Yue ZhaoWe have demonstrated highly sensitive single-shot based background-free mid-infrared (MIR) absorption spectroscopy using sub-cycle MIR pulses generated through filamentation. The MIR pulse transmitted through a sample was upconverted with a fast rising and long tailing gate pulse through four-wave difference frequency generation in a silicon membrane. By recording the upconverted spectrum of the free induction decay alone, we successfully measured the absorption spectrum as a positive signal in the wavenumber range from 500 to 4500 cm-1, which covers both the fingerprint and functional group regions. We obtained an absorption spectrum of ∼50 mM of aqueous glucose, which is not detectable with a standard Fourier transform infrared spectrometer.