Generating heralded single photons with a switchable orbital angular momentum mode

Abstract

The orbital angular momentum (OAM) carried by photons defines an infinitely dimensional discrete Hilbert space. With OAM modes, high-dimensional quantum states can be achieved for quantum communication and cryptography. Here we demonstrate a heralded single-photon source with a switchable OAM mode, which consists of a heralded single-photon source and an integrated OAM emitter as the mode converter. As the first step, the heralded single-photon source is based on the dispersion-shifted fiber. In this work, the OAM mode (quantized by topological charge l ) carried by the heralded single photon (at fixed wavelength of 1555.75 nm) can be switched within the range of l = 3 – 7 while the mode purity is more than 80%.