Fast and efficient demultiplexing of single photons from a quantum dot with resonantly enhanced electro-optic modulators

Abstract

We report on a multi-photon source based on active demultiplexing of single photons emitted from a resonantly excited GaAs quantum dot. Active temporal-to-spatial mode demultipexing is implemented via resonantly enhanced free-space electro-optic modulators, making it possible to route individual photons at high switching rates of 38 MHz. We demonstrate routing into four spatial modes with a high end-to-end efficiency of ≈ 79 % and measure a four-photon coincidence rate of 0.17 Hz mostly limited by the single-photon source brightness and not by the efficiency of the demultiplexer itself. We use the demultiplexer to characterize the pairwise indistinguishability of consecutively emitted photons from the quantum dot with variable delay time.

Demultiplexed single-photon source with a quantum dot coupled to microresonator

“…The emission of two indistinguishable photons by two different quantum dots (QDs) has already been shown [9], but scaling this approach to more photons is a challenge. A more realistic way to create a multiphoton state is based on the demultiplexing of radiation from a single-photon source (SPS) generating a stream of single photons that are indistinguishable from each other [10,11]. The temporal-tospatial mode demultipexing is the most common scheme; in particular, it was used in [8] to prepare a 20-photon state for the boson sampling.…”