Fabrication and Properties of an Ultrafast NbN Hot-Electron Single-Photon Detector
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چکیده
34 LLE Review, Volume 85 Introduction Currently, visible photon counting is commonplace for advanced optical imaging and spectroscopy. Several types of devices, including photomultiplier tubes,1 quantum semiconductor avalanche photodiodes,2 and superconducting tunnel junctions,3 have been successfully implemented. In general, such detectors work by a cascade mechanism: an incident single photon is absorbed, releasing an electron, which then instigates a multiplication process, leading to a measurable electron current pulse. Unfortunately, vacuum photomultipliers are slow and bulky and have an extremely low quantum efficiency for longer-wavelength photons. The major drawback of the most popular and most successful silicon photodiodes is that the wavelength sensitivity is limited to below 1 μm, restricted by the Si bandgap. In addition, the singlephoton avalanche photodiodes exhibit low detection rates due to complicated Geiger-mode readout schemes.
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