A waveguide spectrometer for high-resolution millimeter-wave imaging

We present the design and development of a novel, compact integrated on-chip spectrometer operating at millimeter (mm) and submillimeter (sub-mm) wavelengths. The Superconducting Waveguide Integrated Submillimeter Spectrometer (SWISS) promises significant improvements in spectral resolution, optical efficiency, and frequency coverage over current mm-wave spectrometers by using a free-space rectangular waveguide architecture. Light is coupled in through the antenna front end, which separates the two polarizations and passes them to the waveguide spectrometer through a contactless metamaterial transition. Each waveguide spectrometer consists of a feedline coupled to a series of filters based on single-pole cavity resonators with varying resonant frequencies. To maximize packing density, the filter banks are oriented out of the focal plane, and an E-plane bend in the output from the cavity filters enables a planar and scalable construction. The output of each filter is coupled to a kinetic inductance detector (KID) to enable high multiplexing factors. The spectrometer is fabricated using stacks of silicon wafers etched with a deep reactive-ion etch (DRIE) and metallized. In these proceedings, we discuss current development on a SWISS prototype including measurements on a prototype antenna front end contactless transition and fabrication a prototype waveguide spectrometer.