TIME millimeter wave grating spectrometer
The Tomographic Ionized-carbon Mapping Experiment (TIME) adopted a grating type spectrometer to achieve instantaneous wideband spectral coverage with background-limited sensitivity. A unique approach uses curved gratings in parallel-plate waveguides to focus and diffract broadband light from feedhorns to detector arrays. TIME will measure 3-D [CII] fluctuations from 5 < z < 9 galaxies by using 32 independent spectrometers. Each grating has 190 facets and provides a resolving power of 140 over 183–326 GHz range.