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Vabilo na predavanje:<br><br>
<br>
<b>Ultrafast Superconducting <br>
Single-Photon Optical Detectors and Their Applications<br>
Prof. Dr. Roman Sobolewski<br>
</b>Department of Electrical and Computer Engineering <br>
and Laboratory for Laser Energetics <br>
University of Rochester, Rochester, NY, USA<br><br>
Abstract: <br>
We present novel quantum devices for GHz-rate counting of both visible
and <br>
infrared single photons. Our superconducting single-photon detectors
(SSPDs) <br>
form 4-nm-thick and ~100-nm-wide NbN meanders and cover the 10x10 <br>
micrometer2 area. The detection mechanism is based on photon-induced
<br>
resistive hotspot formation and, subsequent, appearance of a transient
<br>
voltage pulse across a nanostructured superconducting stripe. Our devices
<br>
significantly outperform their semiconductor counterparts, with quantum
<br>
efficiency ~10% for 1.3-micrometer photons, 2-GHz photon counting rate,
<br>
timing jitter of 18 ps, and dark counts <0.1 per second. The
best-measured <br>
value of the noise-equivalent power (NEP) was 3 10-22 W/Hz1/2 <br>
at 1.3 micrometer. The SSPDs have been already adopted for <br>
testers for debugging of VLSI CMOS circuits and are currently being
<br>
implemented for free-space communications and quantum key distribution
<br>
(cryptography) systems. Details of those applications will be
discussed.<br><br>
<b>Predavanje bo danes, v cetrtek, dne 26. avgusta 2004, ob 13:15 v
predavalnici <br>
Podiplomske sole Jozefa Stefana (N 205).<br>
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