[kolokvij-ijs] predavanje

[Tamara Matevc]

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Vabilo na predavanje:

Ultrafast Superconducting
Single-Photon Optical Detectors and Their Applications

Prof. Dr. Roman Sobolewski

Department of Electrical and Computer Engineering
and Laboratory for Laser Energetics
University of Rochester, Rochester, NY, USA


Abstract:
We present novel quantum devices for GHz-rate counting of both visible and
infrared single photons. Our superconducting single-photon detectors (SSPDs)
form 4-nm-thick and ~100-nm-wide NbN meanders and cover the 10x10
micrometer2 area. The detection mechanism is based on photon-induced
resistive hotspot formation and, subsequent, appearance of a transient
voltage pulse across a nanostructured superconducting stripe. Our devices
significantly outperform their semiconductor counterparts, with quantum
efficiency ~10% for 1.3-micrometer photons, 2-GHz photon counting rate,
timing jitter of 18 ps, and dark counts <0.1 per second. The best-measured
value of the noise-equivalent power (NEP) was 3 10-22 W/Hz1/2
at 1.3 micrometer. The SSPDs have been already adopted for
testers for debugging of VLSI CMOS circuits and are currently being
implemented for free-space communications and quantum key distribution
(cryptography) systems. Details of those applications will be discussed.


Predavanje bo v cetrtek, dne 26. augusta 2004, ob 13:15 v predavalnici
Podiplomske sole Jozefa Stefana (N 205).

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