Photon pair generation from lithium niobate metasurface with tunable spatial entanglement[Invited]  

作　　者：张吉化 马进勇 Dragomir N.Neshev Andrey A.Sukhorukov Jihua Zhang;Jinyong Ma;Dragomir N.Neshev;Andrey A.Sukhorukov(Centre of Excellence for Transformative Meta-Optical Systems(TMOS),Department of Electronic Materials Engineering(EME),Research School of Physics,The Australian National University,Canberra,ACT 2601,Australia)

机构地区：[1]Centre of Excellence for Transformative Meta-Optical Systems(TMOS),Department of Electronic Materials Engineering(EME),Research School of Physics,The Australian National University,Canberra,ACT 2601,Australia

出　　处：《Chinese Optics Letters》2023年第1期25-31,共7页中国光学快报（英文版）

基　　金：supported by the Australian Research Council(DP190101559,CE200100010).

摘　　要：The two-photon state with spatial entanglement is an essential resource for testing fundamental laws of quantum mechanics and various quantum applications.Its creation typically relies on spontaneous parametric downconversion in bulky nonlinear crystals where the tunability of spatial entanglement is limited.Here,we predict that ultrathin nonlinear lithium niobate metasurfaces can generate and diversely tune spatially entangled photon pairs.The spatial properties of photons including the emission pattern,rate,and degree of spatial entanglement are analyzed theoretically with the coupled mode theory and Schmidt decomposition method.We show that by leveraging the strong angular dispersion of the metasurface,the degree of spatial entanglement quantified by the Schmidt number can be decreased or increased by changing the pump laser wavelength and a Gaussian beam size.This flexibility can facilitate diverse quantum applications of entangled photon states generated from nonlinear metasurfaces.

关 键 词：spontaneous parametric downconversion metasurface spatial entanglement 

分 类 号：O43[机械工程—光学工程]