Progress on SuperSpec Filterbank Improvements for Future Far-IR Spectroscopic Astronomical Measurements

25 Jul 2019, 17:45
1h 15m
Piazza Città di Lombardia (Milano)

Piazza Città di Lombardia

Milano

Piazza Città di Lombardia, 1, 20124 Milano MI
Poster Low Temperature Detector fabrication techniques and materials Poster session

Speaker

Ryan McGeehan (The University of Chicago)

Description

SuperSpec is an ultra-sensitive on-chip spectrometer for mm and sub-mm wave observations of high-redshift dusty galaxies. The device employs a filterbank architecture in which kinetic inductance detectors (KIDs) are coupled to mm-wave resonant filters along a single microwave feedline. We present the progress on several advances to the SuperSpec filter bank technology that will be crucial for future far-IR missions. In particular, we present the characterization of a prototype filterbank utilizing thin film aluminum (Al) KIDs for higher sensitivity compared to previous titanium nitride (TiN) devices. In addition, in order to target higher resolving power ($R \sim 3000$), we must reduce filterbank dielectric losses ($Q_{loss} \sim 2 \times 10^{4}$). We will pursue two technologies using a silicon (Si) inner layer dielectric over the current silicon nitride (SiN). First, amorphous silicon (a-Si) offers simple fabrication and low loss at low power. Second, crystalline silicon (c-Si) presents a more challenging fabrication process, including a “flipped-SOI" process using silicon-on-oxide wafers, but has been shown to have $\tan \delta $ as low as $5 \times 10^{-6}$. Finally, in order to push the SuperSpec filterbank technology frequencies up to 1.3 THz, we require a higher $T_{c}$ film replacement for our niobium (Nb) microstrip. For this purpose, we offer preliminary data on niobium titanium nitride (NbTiN) and niobium nitride (NbN) films.

Student (Ph.D., M.Sc. or B.Sc.) Y
Less than 5 years of experience since completion of Ph.D Y

Primary author

Ryan McGeehan (The University of Chicago)

Co-authors

Dr Charles Bradford (Jet Propulsion Laboratory) Erik Shirokoff (University of Chicago) Henry G. Leduc (Jet Propulsion Laboratory) Dr Peter Barry (High Energy Physics Division - Argonne National Laboratory) Steven Hailey-Dunsheath (California Institute of Technology)

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