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-------- Original Message --------
| Subject: | Re: University PhD Dissertation Defense of Jason Scott Pelc |
|---|---|
| Date: | Thu, 10 May 2012 11:44:17 -0700 |
| From: | Claire Nicholas <claireni@stanford.edu> |
| To: | apgradstudents@lists.stanford.edu, apfaculty@lists.stanford.edu |
Department of Applied Physics
University PhD Dissertation Defense
Frequency Conversion of Single Photons: Physics, Devices, and Applications
Research Advisor: Professor Martin Fejer
Monday, May 14, 2012 @ 2:00 PM
ABSTRACT
The ability to manipulate the carrier frequency of quantum states of light, through a process that has been termed quantum frequency conversion (QFC), has numerous applications for both technology and basic science. For example, one can upconvert a single-photon-level signal in the 1550-nm telecommunications band (where single-photon detection has been challenging) to a visible wavelength to take advantage of well-developed single-photon detectors based on silicon avalanche photodiodes. On the more fundamental side, the manipulation of a single photon’s frequency may enable the construction of networks of dissimilar quantum systems, whereby one can imagine generating many-body entangled quantum states over vast distances.
Quantum frequency conversion will only be useful if it can be done both efficiently and with little added noise. The use of periodically poled lithium niobate waveguides has enabled conversion efficiencies exceeding 99.99%, with as little as 100 mW of pump power. Noise has been a far thornier issue: the generation of noise photons, due to inelastic scattering of light from the strong pump laser used to drive the frequency conversion, has limited the utility of QFC devices in many applications. I have analyzed the two primary noise processes in QFC devices (spontaneous Raman scattering and spontaneous parametric fluorescence), and offer solutions on how they may be either mitigated or avoided completely. I will also discuss applications of QFC to low-noise and high-speed telecom-band single-photon detection via upconversion, and the demonstration of a temporally shaped telecom-band single-photon source based on downconversion of light from a single InAs/GaAs quantum dot.
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