Production of Entangled Photons via Spontaneous Parametric Down-Conversion

宋媛媛 Song Yuanyuan, 陈鼎 Chen Ding, 丛爽 Cong Shuang

Ting Gu

Phillip Heitert, Finn Buldt, Pascal Bassène +1 more

We present a novel yet simple approach to produce multiple entangled photon pairs through spontaneous parametric down conversion (SPDC). We have designed Gaussian masks to subdivide the pump beam before passing it through a nonlinear medium. In this way, we are able to observe simultaneous separate down converted emission cones with spatial overlap. The technique we employ can be used to greatly increase the dimensionality of entangled photonic systems generated from spontaneous parametric down conversion, affording greater scalability to optical quantum computing than previously explored.

Dong Ding, Ying-Qiu He, Fengli Yan +1 more

Maria V. Chekhova

Miniaturization of nonlinear optical elements is one of the major trends of modern photonics. In particular, in the ‘flatoptics’ geometry, the sample is ultrathin along the light propagation direction. For nonlinear optical effects in such samples, phase matching is satisfied automatically, which allows for the use of materials with giant nonlinear susceptibilities. The tiny thickness reduces the efficiency but it can be compensated for by using geometric and material resonances. Recently also spontaneous parametric down-conversion (SPDC), leading to the generation of entangled photons, has been implemented in ultrasmall sources: subwavelength layers, metasurfaces, even nanoantennas. The lifted constraint of phase matching gives to SPDC even more freedom than to classical frequency conversion effects. The reason is that SPDC, as a spontaneous effect, is stimulated by quantum vacuum fluctuations, which populate all modes uniformly. SPDC in ultrathin samples demonstrates very broad spectral and angular width, extremely high degrees of continuous-variable entanglement, tunable polarization entanglement, and orders of magnitude enhancement of photon pair production rate due to the geometric resonances of dielectric metasurfaces.

Finn Buldt, Phillip Heitert, Pascal Bassène +1 more

We have designed Gaussian masks to subdivide the pump beam before passing it through a BBO. In this way, present an approach to possibly produce multiple entangled photon pairs through spontaneous parametric down-conversion (SPDC).