Atomic vapor-based turnstile device for single photons

This project aims at developing a source of Fourier-transform-limited single-photons which does not require ultra-high-vacuum (UHV) or cryogenic environment. Thanks to these characteristics, such a source is ideally suited for practical applications.

It relies on a novel approach based on a collectively enhanced resonant light-atom interaction within an ensemble of weakly coupled emitters.

The key mechanism is a photon-number dependent quantum interference that can modify the photon-statistics of a weak coherent state, i.e. bunching or antibunching, when travelling through the ensemble.

Interestingly, when interacting with a critical number of emitters, the coherent state can be transformed into a stream of antibunched single photons. In such a case the ensemble acts as a single-photon turnstile.

The transmitted single photons are indistinguishable – an important feature for most quantum information applications.

While this interference mechanism was recently experimentally demonstrated with cold atoms in our team, in this proposal we explore a whole new regime with thermal atomic vapor of Rubidium.

Different strategies will be implemented to mitigate the effect of the much broader velocity class of the atoms in the thermal vapor. In particular, a velocity-selective excitation scheme will allow to circumvent the Doppler broadening.

In addition to the remarkable feature of not requiring complex optical setups and cooling, this new source would generate single photons at telecom wavelength of 1529 nm, well-suited for long distance communication. On the other hand, it also enables integration with the mature technological platform of silicon photonics.

Finally, in order to increase its practicability, the current proposal envisions to explore two different fiber-integrated designs for such a