Paper 13102-39
4×2 hot electron bolometer mixer arrays for detection at 1.4, 1.9, and 4.7 THz for a balloon borne terahertz observatory
Abstract
We have demonstrated three 4×2 hot electron bolometer (HEB) mixer arrays for operation at local oscillator (LO) frequencies of 1.4, 1.9 and 4.7 THz, respectively. These arrays consist of spiral antenna coupled NbN HEB mixers combined with elliptical lenses. These are to date the highest pixel count arrays using a quasi-optical coupling scheme at supra-THz frequencies. At 1.4 THz, we obtained an average double sideband mixer noise temperature of 330 K, a mixer conversion loss of 5.2 dB, and an optimum LO power of 210 nW. The array at 1.9 THz has an average mixer noise temperature of 425K, a mixer conversion loss of 6.4 dB, and an optimum LO power of 190 nW. For the array at 4.7 THz we obtained an average mixer noise temperature of 715 K, a mixer conversion loss of 8.9 dB, and an optimum LO power of 240 nW. We found the arrays to be uniform regarding the mixer noise temperature with a standard deviation of 3-4%, the conversion loss with a standard deviation of 8-11%, and optimum LO power with a standard deviation of 5-6%. The noise bandwidth was also measured, being 3.5 GHz for the three arrays. These performances are comparable to previously reported values in the literature for single pixels and also other detector arrays at similar frequencies. Our arrays met the requirements and were employed in the Galactic/Extra-Galactic ULDB Spectroscopic Terahertz Observatory (GUSTO), a NASA balloon borne observatory. GUSTO launched from Antarctica on the 31st December 2023 having a successful flight of 57 days, the longest ever recorded by NASA for such mission profile.
Presenter
SRON Netherlands Institute for Space Research (Netherlands), Kapteyn Astronomical Institute, Univ. of Groningen (Netherlands)
José Rui Gaspar da Silva was born in 1993 in Ansiao, Portugal. In 2016 he graduated from a master program in Micro and Nanotechnology Engineering at the New University of Lisbon as the university’s Best Engineering Student. In 2022 he obtained his PhD in Astronomy (Instrumentation), where he developed the three Hot Electron Bolometer mixer arrays for the NASA Balloon mission GUSTO. He was deployed in Antarctica from November 2023 until January 2024 in the GUSTO launch campaign, resulting in a record breaking balloon mission.