Imperial College London

ProfessorNeilAlford

Central FacultyOffice of the Provost

Associate Provost (Academic Planning)
 
 
 
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Contact

 

+44 (0)20 7594 6724n.alford

 
 
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Assistant

 

Miss Catherine Graham +44 (0)20 7594 3330

 
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Location

 

2..05 (in RSM) or 3.09 (in the Faculty Building)Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Breeze:2017:10.1038/s41534-017-0041-3,
author = {Breeze, JDB and Salvadori, E and Sathian, J and Alford, N and Kay, CWM},
doi = {10.1038/s41534-017-0041-3},
journal = {npj Quantum Information},
title = {Room-temperature cavity quantum electrodynamics with strongly-coupled Dicke states},
url = {http://dx.doi.org/10.1038/s41534-017-0041-3},
volume = {3},
year = {2017}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - The strong coupling regime is essential for efficient transfer of excitations between states in different quantum systems on timescales shorter than their lifetimes. The coupling of single spins to microwave photons is very weak but can be enhanced by increasing the local density of states by reducing the magnetic mode volume of the cavity. In practice, it is difficult to achieve both small cavity mode volume and low cavity decay rate, so superconducting metals are often employed at cryogenic temperatures. For an ensembles of N spins, the spin–photon coupling can be enhanced by N−−√N through collective spin excitations known as Dicke states. For sufficiently large N the collective spin–photon coupling can exceed both the spin decoherence and cavity decay rates, making the strong-coupling regime accessible. Here we demonstrate strong coupling and cavity quantum electrodynamics in a solid-state system at room-temperature. We generate an inverted spin-ensemble with N ~ 1015 by photo-exciting pentacene molecules into spin-triplet states with spin dephasing time T∗2~3T2~3 μs. When coupled to a 1.45 GHz TE01δ mode supported by a high Purcell factor strontium titanate dielectric cavity (Vm~0.25Vm~0.25 cm3, Q ~ 8,500), we observe Rabi oscillations in the microwave emission from collective Dicke states and a 1.8 MHz normal-mode splitting of the resultant collective spin–photon polariton. We also observe a cavity protection effect at the onset of the strong-coupling regime which decreases the polariton decay rate as the collective coupling increases.
AU - Breeze,JDB
AU - Salvadori,E
AU - Sathian,J
AU - Alford,N
AU - Kay,CWM
DO - 10.1038/s41534-017-0041-3
PY - 2017///
SN - 2056-6387
TI - Room-temperature cavity quantum electrodynamics with strongly-coupled Dicke states
T2 - npj Quantum Information
UR - http://dx.doi.org/10.1038/s41534-017-0041-3
UR - http://hdl.handle.net/10044/1/50401
VL - 3
ER -