Superconducting Bolometers
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We are developing antenna-coupled superconducting bolometers as fast and sensitive direct
detectors for terahertz spectroscopy. The bolometer consists of a niobium microbridge
electrically biased on its superconducting transition, where its resistance changes in
proportion to absorbed terahertz power. This detector can record changes in terahertz
transmission, reflection, or emission from a sample on nanosecond to millisecond timescales.
Applications include studies of transient photoconductivity in molecules and semiconductor
nanocrystals, as well as the rotational and vibrational modes of excited molecular species.
This work is in collaboration with the group of Prof. C. Schmuttenmaer (Yale Chemistry) and
is supported by NSF-CHE.
Left: 2" silicon wafer after microfabrication of more than a hundered
antenna-coupled bolometer devices. Top right: Optical micrograph of niobium bolometer
with log spiral antenna. Bottom right: Measured frequency response of device with log spiral antenna.
We are also developing terahertz single-photon bolometric detectors based on a
superconducting titanium nanobridge. These devices have a lower superconducting critical
temperature and a smaller volume than the niobium detectors, resulting in significantly
greater sensitivity but with a slower response time and much lower saturation power.
We have characterized these devices using a pulsed microwave technique, where the absorbed
energy of a fast microwave pulse simulates the energy of a single terahertz photon.
This work is in collaboration with Dr. B. Karasik at the Jet Propulsion Lab and Prof.
B. Reulet at the University of Paris, Orsay.
Recent Publications:
- "Energy resolution of
terahertz single-photon-sensitive bolometric detectors," D.F. Santavicca, B. Reulet,
B.S. Karasik, S.V. Pereverzev, D. Olaya, M.E. Gershenson, L. Frunzio and D.E. Prober,
submitted (2009). [arXiv:0906.1205]
- "A Far-Infrared Fourier Transform Spectrometer with an Antenna-Coupled Niobium Bolometer," D.F. Santavicca, A.J. Annunziata, M.O. Reese, L. Frunzio and D.E. Prober, Supercond. Sci. Technol. 20, S398-S402 (2007).
- "Antenna-Coupled Niobium Bolometers for Terahertz Spectroscopy," D.F. Santavicca, M.O. Reese, A.B. True, C.A. Schmuttenmaer and D.E. Prober, IEEE Trans. Appl. Supercond. 17(2), 412 (2007).
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Previous work in our lab focused on the development of superconducting
bolometers as heterodyne mixers for applications in far-infrared astronomy. We developed
niobium bolometers utilizing out-diffusion of hot electrons to achieve response times
as fast as 20 ps, corresponding to output bandwidths approaching 10 GHz. We also
investigated the use of lower critical temperature superconducting materials,
including aluminium and niobium-gold bilayers, to improve device sensitivity.
More information on this work can be found in the following publications:
- "Nb-Au bilayer hot-electron bolometers for low-noise THz heterodyne detection," I. Siddiqi and D.E. Prober, Appl. Phys. Lett. 84, 1404 (2004).
- "Heterodyne Mixing in Diffusion-Cooled Superconducting Aluminum Hot-Electron Bolometers," I. Siddiqi, A. Verevkin, D.E. Prober, A. Skalare, W.R. McGrath, P.M. Echternach and H.G. LeDuc, J. Appl. Phys. 91, 4646 (2002).
- "Length scaling of bandwidth and noise in hot-electron superconducting
mixers," P.J. Burke, R.J. Schoelkopf, D.E. Prober, A. Skalare, W.R. McGrath,
B.Bumble and H.G. LeDuc, Appl. Phys. Lett. 68, 3344 (1996).
- "Superconducting Terahertz Mixer using a Transition-Edge Microbolometer," D.E. Prober, Appl. Phys. Lett. 62, 2119 (1993).
- more
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