Development of Microwave Kinetic Inductance Detectors for a THz On-Chip Spectrometer

Far-infrared (FIR) wavelength light provides a wealth of information about astrophysical processes. Large field-of-view FIR spectrometers face a variety of challenges that can be bypassed by utilizing on-chip filter bank technology. To this end, we have been developing microwave kinetic inductance detectors (MKIDs) to couple to on-chip spectrometric technologies. We utilize a unique two-silicon wafer design to create a waveguide for an on-chip spectrometer between 1.4 and 2 THz. The spectrometer’s principle of operation is electromagnetic radiation traveling down a center waveguide before being picked off by a resonance cavity and absorbed by a detector. The MKIDs are designed to couple directly to the waveguide using an annular antenna shape for the inductor. Alignment of the two-wafer design is achieved with two dowel pins and a hole and slot pattern in our custom designed box. We present the design and early test data from a 18-channel prototype device. The prototype yielded the full 18 resonances with quality factors \(Q_c\) $Q_c$ of about \(5\,\times \,10^4\) $5\times {10}^4$ and \(Q_i\) $Q_i$ of about \(1\,\times \,10^4\) $1\times {10}^4$ . We plan to use the technology we developed to create an \(n \times n\) $n\times n$ pixel device targeting \(R=100\) $R=100$ .