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Atomic Physics Seminars

ics Atomic
Monday, April 20, 2009
4:00 PM
Physics Building, Room 313
Note special time.
Note special room.
Sae Woo Nam [Host: Olivier Pfister]
"Superconducting detectors for quantum information science and technology"
There is increasing interest in using superconducting optical photon detectors in a variety of applications in quantum information science and technology. These applications require detectors that have extremely low dark count rates, high count rates, and high quantum efficiency. I will describe our work on two types of superconducting detectors, the Single Photon Superconducting Detector (SSPD) and superconducting Transition-Edge Sensor (TES). An SSPD is an ultra-thin, ultra-narrow (nm scale) superconducting meander that is current biased just below its critical current density. When one or more photon is absorbed, a hot spot is formed that causes the superconductor to develop a resistance and consequently a voltage pulse. By exploiting the sharp superconducting-to-normal resistive transtion of tungsten at 100mK, TES detectors give an output signal that is proportional to the cumulative energy in an absorption event. This proportional pulse-height enables the determination of the energy absorbed by the TES and the direct conversion of sensor pulse-height into photon number. I will discuss our results of using both of these new types of detector in quantum information applications and our progress towards developing detectors with quantum efficiencies approaching 100%.

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