
Set Homepage  Favorite Coherent frequency bridge between visible and telecommunications band for vortex lightIn quantum communications, vortex photons can encode higherdimensional quantum states and build highdimensional communication networks(HDCNs). The interfaces that connect different wavelengths are significant in HDCNs. We construct a coherent orbital angular momentum (OAM) frequency bridge via difference frequency conversion in a nonlinear bulk crystal for HDCNs. Using a single resonant cavity, maximum quantum conversion efficiencies from visible to infrared are 36%, 15%, and 7.8% for topological charges of 0,1, and 2, respectively. The average fidelity obtained using quantum state tomography for the downconverted infrared OAMstate of topological charge 1 is 96.51%. We also prove that the OAM is conserved in this process by measuring visible and infrared interference patterns. This coherent OAM frequencydown conversion bridge represents a basis for an interface between two highdimensional quantum systems operating with different spectra. Fig. 1: The experimental setups. Fig. 2:The main results of OAMfrequency bridge. Article: Opt. Express 25 (20) (2017) 24290–24298. 