Erwin Schrödinger Center for Quantum Science & Technology (ESQ)

Mid infrared quantum optics in graphene nanoribbons

In recent years, quantum computing has become a really hot topic due to the theoretically envisaged “quantum supremacy” compare to a classical computer. It has already been shown that universal quantum computing is possible using only single-photon sources and detectors, and simple (linear) optical circuits. However, for achieving a scalable quantum computer, the challenge is the realization of a deterministic two-photon logic gate, as photons do not interact with themselves. A possibility is to use a strong nonlinear medium, such as graphene. More in details, among the many interesting graphene’s properties, this unique 2D material possesses a strong third-order (χ(3))  nonlinear response. It has been reported that graphene’s strong χ(3) could allow single-photon level interactions. This makes graphene a very appealing material for nonlinear and quantum optical applications.

In the Walther group at the University of Vienna, the final goal is to generate single photons via a photon blockade process mediated by the strong χ(3)-based Kerr effect in graphene. The experiment exploits the electric field enhancement associated with the strong confinement of plasmons in nanoscale graphene-insulator-metal heterostructure. In this platform, resonant plasmonic excitation at about 6µm can be stimulated. It is expected that this route to photon generation will lead to on-demand single photon generation.

After his ESQ Fellowship Alessandro Trenti moved on to a permanent postion at AIT (Austrian Institute of Technology).