SuperSpec: design concept and circuit simulations

TL;DR

SuperSpec is a compact, chip-scale spectrometer design for millimeter-wave astrophysics, demonstrated through circuit simulations, which could enable high-resolution, wide-bandwidth observations in a small footprint.

Contribution

This paper introduces a novel circuit simulation-based design concept for millimeter-band spectrometers, assessing performance and fabrication tolerances for future astrophysical instruments.

Findings

Circuit simulations validate the SuperSpec concept.

Design strategies mitigate losses and fabrication tolerances.

Potential for complete millimeter-band spectrometers in small footprints.

Abstract

SuperSpec is a pathfinder for future lithographic spectrometer cameras, which promise to energize extra-galactic astrophysics at (sub)millimeter wavelengths: delivering 200--500 km/s spectral velocity resolution over an octave bandwidth for every pixel in a telescope's field of view. We present circuit simulations that prove the concept, which enables complete millimeter-band spectrometer devices in just a few square-millimeter footprint. We evaluate both single-stage and two-stage channelizing filter designs, which separate channels into an array of broad-band detectors, such as bolometers or kinetic inductance detector (KID) devices. We discuss to what degree losses (by radiation or by absorption in the dielectric) and fabrication tolerances affect the resolution or performance of such devices, and what steps we can take to mitigate the degradation. Such design studies help us formulate critical requirements on the materials and fabrication process, and help understand what practical limits currently exist to the capabilities these devices can deliver today or over the next few years.