Entangled indistinguishable photon pairs at Rb transitions

Date

Dec 19, 2016

Time

10:00 AM - 11:00 AM

Speaker

Michael Zopf

Affiliation

IIN

Language

en

Main Topic

Materialien

Other Topics

Materialien, Physik

Host

Kristina Krummer-Meier

Description

Future quantum networks involve the transmission of information between different nodes using single photons and entangled photon pairs. To overcome transmission losses over large distances a so called quantum repeater is essential, which is the quantum mechanical equivalent to a classical signal amplifier. One key component of this technology is the entanglement swapping scheme [1]. It applies quantum interference between two entangled photon pairs and relies on a high degree of entanglement and indistinguishability of the emitted photons. Semiconductor quantum dots (QDs) are leading candidates for the deterministic emission of single photons and entangled photon pairs. However, matching the properties of two individual sources remains a challenge. Due to the random growth nature of QDs, post-growth tuning techniques become inevitable. A novel strain-tuning device, developed in our group [2], enables the Generation of wavelength-tunable entangled photons. It therefore renders entanglement swapping possible,since different entangled photon sources can be wavelength-matched. In this talk, I will carve out the requirements to the QDs and the optical setup for a successful implementation of the entanglement swapping scheme. In this context, the progress in the last year is presented and open tasks highlighted. On-demand emission of entangled photon pairs in aAs/AlGaAs QDs has been achieved by employing a resonant two-photon excitation scheme (Fig.1a) [3]. The obtained entanglement fidelities are among the highest ever reported for quantum dot systems [4]. The long-term coherence of the QD emission was quantified using Fourier-transform spectroscopy, and the photon indistinguishability on short timescales was measured (Fig. 1b). The progress on increasing the QD brightness by employing photonic microstructures will be discussed. Furthermore, first results of the locking the QD emission to Rb vapor will be presented.

Links

• Seminars at the IFW

Last modified: Dec 19, 2016, 8:51:34 AM