Spin-photon entanglement and downconversion

The results of my last set of projects at Stanford have recently been published in Nature.  With a large collaboration led by Kristiaan De Greve, we demonstrated entanglement between the spin state of a single electron trapped in a quantum dot and the polarization of the photon it emitted, via time-resolved downconversion to the 1550-nm telecom band.

Photo of PPLN waveguide used for downconversion of single photons from quantum dots.
(c) Jason Pelc.

The details of the downconversion technique and some additional results will be presented in another paper soon to be published in Optics Express and already posted on the arXiv.  Sophia Economou gave a nice News and Views piece on the Nature work (which was published simultaneously with work by an ETH Zurich team), and it also received some press coverage in the Stanford Report, and Physics World.

These experiments were definitely the most difficult ones I did during grad school, and I'm very happy to have worked with such a tremendously talented team, including Kristiaan, Leo Yu, Peter McMahon, and Chandra Natarajan, all of whom spent countless very long hours in the lab making these measurements happen.