Lib, O., Hasson, G. & Bromberg, Y. Real-time shaping of entangled photons by classical control and feedback.
Science Advances 6, 37, (2020).
Publisher's VersionAbstractQuantum technologies hold great promise for revolutionizing photonic applications such as cryptography. Yet, their implementation in real-world scenarios is challenging, mostly because of sensitivity of quantum correlations to scattering. Recent developments in optimizing the shape of single photons introduce new ways to control entangled photons. Nevertheless, shaping single photons in real time remains a challenge due to the weak associated signals, which are too noisy for optimization processes. Here, we overcome this challenge and control scattering of entangled photons by shaping the classical laser beam that stimulates their creation. We discover that because the classical beam and the entangled photons follow the same path, the strong classical signal can be used for optimizing the weak quantum signal. We show that this approach can increase the length of free-space turbulent quantum links by up to two orders of magnitude, opening the door for using wavefront shaping for quantum communications.
Lib, O. & Bromberg, Y. Spatially entangled Airy photons.
Opt. Lett. 45, 6, 1399–1402 (2020).
Publisher's VersionAbstractOver the past decade, Airy beams have been the subject of extensive research, leading to new physical insights and various applications. In this Letter, we extend the concept of Airy beams to the quantum domain. We generate entangled photons in a superposition of two-photon Airy states via spontaneous parametric down conversion, pumped by a classical Airy beam. We show that the entangled Airy photons preserve the intriguing properties of classical Airy beams, such as free acceleration and reduced diffraction, while exhibiting non-classical anti-correlations. Finally, we discuss the advantages offered by entangled Airy photons for high-dimensional free-space quantum communications.
