Niobium HotElectron Bolometers

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Niobium Hot-Electron Bolometers
Matthew Reese Daniel Santavicca Dr. Luigi
Frunzio Prof. Daniel Prober
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Hot-Electron Bolometers
Direct detection P ? dT ? dR Mixing P
V2/R V(t) Acos(wLOt) Bcos(wRFt) wLO-wRF
IF
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Diffusion Cooling vs. Phonon Cooling
tthermal-1 te-ph-1 tdiffusion-1 f-3dB
1/(2ptthermal)
Long Microbridge ? Phonon Cooling Short
Microbridge ? Diffusion Cooling
te-ph ? 1ns for Nb at 5K ? f-3dB ? 160 MHz
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Fabrication of Niobium HEBs
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Coupling THz Radiation to a Detector
Quasi-optical
Waveguide
Phonon-cooled Nb HEB with double-dipole antenna
Diffusion-cooled Nb HEB (left) and sketch showing
cross section of feedhorn, waveguide, and mixer
mount (right)
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Microwave Measurement Setup
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Niobium HEB 10 x 170 x 360nm
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Comparison of Direct Detectors - 4.2K
Frequency Detector Readout Range NEP
(W/Hz1/2) Bandwidth Multi-mode devices Si
bolometer all 10-13 100 Hz InSb HEB lt0.6
THz 10-12 0.5 MHz stressed GaGe gt1.5 THz 2 x
10-11 1 MHz photoconductor Single-mode
devices Nb HEB set by 4 x 10-14 150
MHz antenna
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Work In Progress

• HEB Mixers
• Fabrication and microwave characterization of
  diffusion-cooled Nb HEBs at Yale
• THz characterization in waveguide system at
  University of Arizona
• Fabrication and characterization of 8x8 HEB array
  for deployment on the Heinrich Hertz
  Submillimeter Telescope on Mt. Graham, Arizona

• HEB Direct Detectors
• Fabrication and initial characterization of
  phonon-cooled Nb HEBs at Yale
• Device and antenna characterization at THz
  frequencies at Caltech/JPL
• Refine antenna design