5.3 THz MgB 2 hot electron bolometer mixer operated at 20 K

• Heterodyne receivers combining a NbN HEB mixer with a local oscillator (LO) are the work horse for high resolution (≥106) spectroscopic observations at supra-Terahertz frequencies. We report an MgB2 HEB mixer working at 5.3 THz with 20 K operation temperature based on a previously published paper [Y. Gan et al, Appl. Phys. Lett., 119, 202601 (2021)]. The HEB consists of a 7 nm thick MgB2 submicron-bridge contacted with a spiral antenna. It has a Tc of 38.4 K. By using hot/cold blackbody loads and a Mylar beam splitter all in vacuum, and applying a 5.25 THz FIR gas laser as the LO, we measured a minimal DSB receiver noise temperature of 3960 K. The latter gives a DSB mixer noise temperature of 1470 K. This sensitivity is 28 times better than a room temperature Schottky mixer at 4.7 THz, but about 2.5 times less sensitive than an NbN HEB mixer. The latter must be operated around 4 K. The IF noise bandwidth is about 10 GHz, which is 2.5-3 times larger than an NbN HEB. With further optimization, such MgB2 HEBs are expected to reach a better sensitivity. That the low noise, wide IF bandwidth MgB2 HEB mixers can be operated in a compact, low dissipation 20 K Stirling cooler can significantly reduce the cost and complexity of heterodyne instruments and therefore facilitate new space missions.

Ämnesord

NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Signalbehandling (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Signal Processing (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

IF bandwidth

Mixer

MgB2

High Tc

Space instrumentation

THz

Superconductor

Hot electron bolometer

Publikations- och innehållstyp

kon (ämneskategori)

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