Nonlinear interaction between two heralded single photons

Abstract

Harnessing nonlinearities strong enough to allow two single photons to interact with one another is not only a fascinating challenge but is central to numerous advanced applications in quantum information science. Currently, all known approaches are extremely challenging although a few have led to experimental realisations with attenuated classical laser light. This has included cross-phase modulation with weak classical light in atomic ensembles and optical fibres, converting incident laser light into a non-classical stream of photon or Rydberg blockades as well as all-optical switches with attenuated classical light in various atomic systems. Here we report the observation of a nonlinear parametric interaction between two true single photons. Single photons are initially generated by heralding one photon from each of two independent spontaneous parametric downconversion sources. The two heralded single photons are subsequently combined in a nonlinear waveguide where they are converted into a single photon with a higher energy. Our approach highlights the potential for quantum nonlinear optics with integrated devices, and as the photons are at telecom wavelengths, it is well adapted to applications in quantum communication.

4 pages, 4 figures

References in corpus (7)

• All-optical switching in rubidium vapor
• Nonlinear interactions with an ultrahigh flux of broadband entangled photons
• Direct generation of photon triplets using cascaded photon-pair sources
• Observation of optical-fiber Kerr nonlinearity at the single-photon level
• Two-photon gateway in one-atom cavity quantum electrodynamics
• Tunable Up-Conversion Photon Detector
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Cited by in corpus (2)

• Power-efficient production of photon pairs in a tapered chalcogenide microwire
• Experimental generation of tripartite telecom photons via an atomic ensemble and a nonlinear waveguide