SuperSpec: design concept and circuit simulations

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 −1 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.

Horn-coupled, commercially-fabricated aluminum lumped-element kinetic inductance detectors for millimeter wavelengths

“…Experiments that have deployed or plan to use MKID-based cameras include ARCONS, 12 MAKO, 13 MicroSpec, 14 MUSIC, 15 NIKA, 16 BLAST-TNG, 17 , and SuperSpec. 18 Laboratory studies show that state-of-the-art LEKID designs can achieve photon noise limited performance, 13,19 and photon noise lim- 1. (a) A schematic of a single LEKID.…”

On-chip filter bank spectroscopy at 600–700 GHz using NbTiN superconducting resonators

“…On-chip filter bank spectrometers using superconducting resonators as narrow band-separation filters have been theoretically studied [1][2][3] as one of the promising technologies for enabling multi-object broadband spectrometers on next-generation millimeter/submillimeter wave telescopes 4 for astronomy. The advantage of an integrated filter bank spectrometer, such as the proposed instrument DESHIMA (Delft-SRON High z Mapper) 1,2 , over conventional optical spectrometers 5 is the combination of; 1) photon-noise limited point-source sensitivity, ultimately equal to a grating spectrometer, 2) compact size of each filter, which is of the order of the wavelength on chip and independent of frequency resolution, and 3) flexibility for increasing the sampling in either frequency space, or in real space, by arranging multiple filter bank units on a focal plane.…”

Review: far-infrared instrumentation and technological development for the next decade

“…This means that very low backgrounds can be achieved, requiring detector NEPs below 10 −20 W Hz −1/2 . Filter banks do however have drawbacks (263) . For example, while filter banks are used in instruments operating from millimeter to radio wavelengths, they are currently difficult to manufacture for use at wavelengths shortward of about 500 µm.…”