Photon-noise-limited direct detector based on disorder-controlled electron heating
We present a concept for a hot-electron direct detector capable of counting single millimeter-wave photons. The detector is based on a microbridge (1 μm size) transition edge sensor made from a disordered superconducting film. The electron–phonon coupling strength at temperatures of 100–300 mK is pr...
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Veröffentlicht in: | Journal of applied physics 2000-05, Vol.87 (10), p.7586-7588 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We present a concept for a hot-electron direct detector capable of counting single millimeter-wave photons. The detector is based on a microbridge (1 μm size) transition edge sensor made from a disordered superconducting film. The electron–phonon coupling strength at temperatures of 100–300 mK is proportional to the elastic electron mean free path l and can be reduced by over an order of magnitude by decreasing l. The microbridge contacts are made from a different superconductor with higher critical temperature Nb, which blocks the thermal diffusion of hot carriers into the contacts. The low electron–phonon heat conductance and the high thermal resistance of the contacts determine the noise equivalent power of ∼10−20–10−21 W/√Hz at 100 mK, which is 102–103 times better than that of state-of-the-art bolometers. Due to the effect of disorder, the electron cooling time is ∼10−1–10−2 s at 0.1 K. By exploiting negative electrothermal feedback, the detector time constant can be made as short as 10−3–10−4 s without sacrificing sensitivity. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.373026 |