MKID development for SuperSpec: an on-chip, mm-wave, filter-bank spectrometer

TL;DR

SuperSpec is a compact, chip-scale spectrometer for millimeter astronomy that uses superconducting resonators and Kinetic Inductance Detectors to achieve high multiplexing and spectral resolution in a small form factor.

Contribution

This work introduces the design and initial testing of a superconducting on-chip spectrometer with integrated KIDs for millimeter-wave astronomy.

Findings

Successful design of superconducting resonator filters and KIDs

Initial laboratory testing results of prototype device

Development of a multi-channel demonstration instrument

Abstract

SuperSpec is an ultra-compact spectrometer-on-a-chip for millimeter and submillimeter wavelength astronomy. Its very small size, wide spectral bandwidth, and highly multiplexed readout will enable construction of powerful multibeam spectrometers for high-redshift observations. The spectrometer consists of a horn-coupled microstrip feedline, a bank of narrow-band superconducting resonator filters that provide spectral selectivity, and Kinetic Inductance Detectors (KIDs) that detect the power admitted by each filter resonator. The design is realized using thin-film lithographic structures on a silicon wafer. The mm-wave microstrip feedline and spectral filters of the first prototype are designed to operate in the band from 195-310 GHz and are fabricated from niobium with at Tc of 9.2K. The KIDs are designed to operate at hundreds of MHz and are fabricated from titanium nitride with a Tc of 2K. Radiation incident on the horn travels along the mm-wave microstrip, passes through the frequency-selective filter, and is finally absorbed by the corresponding KID where it causes a measurable shift in the resonant frequency. In this proceedings, we present the design of the KIDs employed in SuperSpec and the results of initial laboratory testing of a prototype device. We will also briefly describe the ongoing development of a demonstration instrument that will consist of two 500-channel, R=700 spectrometers, one operating in the 1-mm atmospheric window and the other covering the 650 and 850 micron bands.