Fig. 1: Wavevector-multiplexed quantum memory as a Bell-state generator.
From: Massively-multiplexed generation of Bell-type entanglement using a quantum memory
a Photonic modes of write-out photons emitted from the atomic cloud (MOT) are divided by their emission angle into horizontally (H, red beam) and vertically (V, blue beam) polarized parts which are further superimposed creating polarization Bell states across many modes. Such an operation of the memory is facilitated with two Mach–Zehnder interferometers (MZI) placed in the write-out and read-out paths of the atomic emission. HWP half-wave plate set for H ↔ V conversion, PBS polarizing beamsplitter. b Double lambda configuration of Rb-87 energy levels constituting the light-matter interface of WV-MUX-QM. W write beam, R read beam, w write-out photons, r read-out photons. c Multimode Bell-state measurement (BSM) between the write-out and read-out photons generated in the WV-MUX-QM. I-sCMOS intensified scientific CMOS camera facilitating single-photon measurements, BD beam displacer, HWP half-wave plate, QWP quarter-wave plate.
