Fig. 2: Spectral Characteristics of Metasurface Filters and Gas Absorption.
From: Smart mid-infrared metasurface microspectrometer gas sensing system
a Filter transmission spectra of the fabricated metasurface filters measured using an FTIR spectrometer. The bandstop and bandpass filters have transmittance dips and peaks, respectively, spanning the 6–14 µm (1667–714 cm−1) wavelength (wavenumber) range. b Absorption cross section spectra of CO2, CH4, NH3 and MEK in the wavelength (wavenumber) range of 5–14.3 µm (2000–700 cm−1)
