Dec 7 2007
Stefan Strauf, Assistant Professor in the Department of Physics & Engineering Physics at Stevens Institute of Technology, along with colleagues from the University of California, Santa Barbara and Leiden University (Netherlands), has authored the article, “High-frequency single-photon source with polarization control,” the cover article of the December 2007 issue of Nature Photonics.
The article reports on important advances in high-performance single-photon sources that bring such possibilities closer to reality. In particular, single photons can be used to implement absolutely secure optical communication, also known as Quantum Cryptography. With this new source, recording a single-photon signature that took eight hours five years back can now be achieved on a millisecond time scale. This remarkable progress was achieved by developing a novel type of microcavity structure which strongly enhances the light extraction from the optically active material. Moreover, with the help of embedded electrical gates, the researchers demonstrated suppression of unwanted dead-times in the emission process itself resulting in a net single photon generation rate of 100 MHz into an optical fiber.
As described in the News & Views section of the issue, “More futuristic applications of single photon states include photonic networks designed to achieve scalable quantum computation, which one day will hopefully solve problems exponentially faster than classical computers.”
Strauf also was interviewed by the publication regarding his work on the project. “The traditional approach to generating single photons is to use weak laser pulses. In order to reach the single-photon level, you have to attenuate the light very strongly, limiting the efficiency of the device. Also, the photons emitted are governed by statistics. What we need is a high-efficiency source where we can generate photons one by one. Luckily, nature provides a solution in the form of the two-level system, just like the one we use: self-assembled quantum dots,” said Strauf.