Harnessing nonlinearities strong enough to allow single photons to interact with one another is not only a fascinating challenge but also central to numerous advanced applications in quantum information science. Here we report the nonlinear interaction between two single photons. Each photon is generated in independent parametric down-conversion sources. They are subsequently combined in a nonlinear waveguide where they are converted into a single photon of higher energy by the process of sum-frequency generation. Our approach results in the direct generation of photon triplets. More generally, it highlights the potential for quantum nonlinear optics with integrated devices and, as the photons are at telecom wavelengths, it opens the way towards novel applications in quantum communication such as device-independent quantum key distribution.Harnessing nonlinearities strong enough to allow single photons to interact with one another is not only a fascinating challenge but also central to numerous advanced applications in quantum information science. Here we report the nonlinear interaction between two single photons. Each photon is generated in independent parametric down-conversion sources. They are subsequently combined in a nonlinear waveguide where they are converted into a single photon of higher energy by the process of sum-frequency generation. Our approach results in the direct generation of photon triplets. More generally, it highlights the potential for quantum nonlinear optics with integrated devices and, as the photons are at telecom wavelengths, it opens the way towards novel applications in quantum communication such as device-independent quantum key distribution.

arXiv:1403.2084Physical Review LettersOct 22, 201489 citations

On-demand single-photon state generation via nonlinear absorption

Tao Hong, Michael W. Jack, Makoto Yamashita

We propose a method for producing on-demand single-photon states based on collision-induced exchanges of photons and unbalanced linear absorption between two single-mode light fields. These two effects result in an effective nonlinear absorption of photons in one of the modes, which can lead to single-photon states. A quantum nonlinear attenuator based on such a mechanism can absorb photons in a normal input light pulse and terminate the absorption at a single-photon state. Because the output light pulses containing single photons preserve the properties of the input pulses, we expect this method to be a means for building a highly controllable single-photon source.We propose a method for producing on-demand single-photon states based on collision-induced exchanges of photons and unbalanced linear absorption between two single-mode light fields. These two effects result in an effective nonlinear absorption of photons in one of the modes, which can lead to single-photon states. A quantum nonlinear attenuator based on such a mechanism can absorb photons in a normal input light pulse and terminate the absorption at a single-photon state. Because the output light pulses containing single photons preserve the properties of the input pulses, we expect this method to be a means for building a highly controllable single-photon source.

arXiv:quant-ph/0405131Physical Review AJul 28, 20044 citations

The nonlinearity of single photons

Ping Koy Lam, B. C. Buchler

Nature PhotonicsSep 30, 20111 citation

Strongly Interacting Photons in a Nonlinear Cavity

Ataç İmamoğlu, Holger Schmidt, Gary L. Woods +1 more

We consider the dynamics of single photons in a nonlinear optical cavity. When the Kerr nonlinearities of atomic dark resonances are utilized, the cavity mode is well described by a spin- $1/2$ Hamiltonian. We show that it is possible to achieve coherent control of the cavity-mode wave function using $\ensuremath{\pi}$ pulses for single photons that switch the state of the cavity with very high accuracy. The underlying physics is best understood as the nonlinearity induced anticorrelation between single-photon injection/emission events, which we refer to as photon blockade. We also propose a method which uses these strong dispersive interactions to realize a single-photon turnstile device.We consider the dynamics of single photons in a nonlinear optical cavity. When the Kerr nonlinearities of atomic dark resonances are utilized, the cavity mode is well described by a spin- $1/2$ Hamiltonian. We show that it is possible to achieve coherent control of the cavity-mode wave function using $\ensuremath{\pi}$ pulses for single photons that switch the state of the cavity with very high accuracy. The underlying physics is best understood as the nonlinearity induced anticorrelation between single-photon injection/emission events, which we refer to as photon blockade. We also propose a method which uses these strong dispersive interactions to realize a single-photon turnstile device.

Physical Review LettersAug 25, 19971,090 citations

Single-Photon Interference

P. Hariharan

Elsevier eBooksJan 1, 20030 citations

We consider the dynamics of single photons in a nonlinear optical cavity. When the Kerr nonlinearities of atomic dark resonances are utilized, the cavity mode is well described by a spin-

1/2

Hamiltonian. We show that it is possible to achieve coherent control of the cavity-mode wave function using $\ensuremath{\pi}$ pulses for single photons that switch the state of the cavity with very high accuracy. The underlying physics is best understood as the nonlinearity induced anticorrelation between single-photon injection/emission events, which we refer to as photon blockade. We also propose a method which uses these strong dispersive interactions to realize a single-photon turnstile device.