Fast infrared spectrometer for flowing gases by the use of a hollow fiber and a PtSi sensor array

Fast-response infrared spectrometer was fabricated for spectral analysis of flowing gases. An infrared-transmitting AgI/Ag hollow fiber of 1 mm diameter was used as a flow cell to reduce both a sample volume and a sampling time. An infrared beam that passed the flow cell was diffracted by a grating, and was detected by a 256-channel PtSi sensor array. Transmission spectra of CH4 and CO2 gases were measured in the 3-5 μm wavelength range at 1/60 s intervals.