4-pixel heterodyne receiver at 1.9 THz using a CMOS spectrometer

This paper reports on engineering results from a high-sensitivity 4x1-pixel 1.9 THz heterodyne array for the astrophysically important [CII] spectral line. A 4-pixel multiplier chain at 1.9 THz, with a compact spacing of 5 mm, is used as an LO. Superconducting Hot Electron Bolometers (HEB) are used as mixers. Receiver performance is verified by y-factor measurements with measured sensitivities of 900 K uncorrected. Spectral measurements were obtained by mixing a coherent source near the target frequency of 1.9 THz and down converting the IF to baseband. Spectra were recorded with both an IBOB and a newly available CMOS-based spectrometer for comparison. This paper is the first to report on spectra obtained by CMOS spectrometer technology and this spectrometer provides several advantages over more traditional FFT spectrometers because of its compact size and low power consumption. This 4x1 receiver prototype is easily scalable to other frequencies and larger focal plane arrays. Furthermore, because of its compact configuration, it can be easily packaged for orbital or sub-orbital missions.