Nonlinear photonic quantum gates

Two-photon quantum logic gate

Phase retarder

Pulsed laser system

For improving the scalability of entirely linear-optical quantum computing schemes we are doing research on strong nonlinear media that enable effective photon-photon interactions. One approach is based on the preparation of narrow-bandwidth single photons that are resonant to transitions of cold atoms that introduce strong nonlinear interactions. Alternatively we are also investigating graphene as strong nonlinear medium. Recently it has been shown that nanostructured graphene has a remarkably strong nonlinear response, which can be made substantial even at the single-photon level. Our group is testing graphene’s nonlinear properties and its use for deterministic two-photon logic gates that can operate at room temperature and without vacuum conditions.



Electrically tunable nonlinear plasmonics in graphene nanoislands
J.D. Cox, F.J.G. de Abajo
Nature Communications 5, 5725 (2014).

Single-Photon Nonlinear Optics with Graphene Plasmons
M. Gullans, D.E. Chang, F.H.L. Koppens, F.J.G. de Abajo, M.D. Lukin
Physical Review Letters 111, 247401 (2013).

Coherent Nonlinear Optical Response of Graphene
E. Hendry, P.J. Hale, J. Moger, A.K. Savchenko, S.A. Mikhailov
Physical  Review Letters 105, 097401 (2010).