Slow and fast single photons from a quantum dot interacting with the excited state hyperfine structure of the Cesium D1-line
Sprache des Titels:
Englisch
Original Kurzfassung:
Hybrid interfaces between distinct quantum systems play a major role in the implementation of
quantum networks. Quantum states have to be stored in memories to synchronize the photon
arrival times for entanglement swapping by projective measurements in quantum repeaters or for
entanglement purification. Here, we analyze the distortion of a single-photon wave packet propagating
through a dispersive and absorptive medium with high spectral resolution. Single photons are
generated from a single In(Ga)As quantum dot with its excitonic transition precisely set relative to
the Cesium D1 transition. The delay of spectral components of the single-photon wave packet with
almost Fourier-limited width is investigated in detail with a 200 MHz narrow-band monolithic Fabry-
Pérot resonator. Reflecting the excited state hyperfine structure of Cesium, ?slow light? and ?fast
light? behavior is observed. As a step towards room-temperature alkali vapor memories, quantum dot
photons are delayed for 5 ns by strong dispersion between the two 1.17 GHz hyperfine-split excited
state transitions. Based on optical pumping on the hyperfine-split ground states, we propose a simple,
all-optically controllable delay for synchronization of heralded narrow-band photons in a quantum
network.
Forschungs-