Fig. 2: Experimental setup.
From: Temporal fusion of entangled resource states from a quantum emitter
a Schematic diagram of the experiment. The photons generated at time a and b, 300 ns apart, are entangled with the same quantum dot spin embedded in a photonic crystal waveguide. An electro-optic modulator switches the first photon into path a and the second to path b. In path a, a fiber coupler (FC) collects the photon into a 300 ns fiber delay. The two photons overlap in time at a 50/50 beamsplitter. The joint detection of two photons in path c or d heralds an entangled state of the spin. b Energy level diagram of the quantum dot spin with an electron spin ground state of \(\left\vert \uparrow \right\rangle\) or \(\left\vert \downarrow \right\rangle\). Controlled Rabi oscillations of the spin state can be achieved through a Raman laser Ωr. c Pulse sequence applied to the quantum dot spin. Before initialization of the spin, nuclear spin narrowing is performed to increase the spin-coherence time. The spin-photon entanglement consists of a π/2 and a π rotation together with the emission of a photon in different time bins. The spin state can be measured in different bases by rotating the spin before readout.
