Quantum Nanoscope Detects Light Ripples

Electrons and light are moving in concert along the graphene sheet. (Source: F. Vialla, ICFO)

Researchers have studied how light can be used to detect the quantum nature of an elec­tronic material. They managed to do that by cap­turing light in a net of carbon atoms and slowing down light it down so that it moves almost as slow as the electrons in the graphene. Then electrons and light start to move in concert, unveiling their quantum nature at such large scale that it could observed with a special type of micro­scope.

The experi­ments were performed with ultra-high quality graphene. To excite and image the ultra-slow ripples of light in the graphene, plasmons, the researchers used a special antenna for light that scans over the surface at a distance of a few nano­meters. With this near field nano­scope they saw that the light ripples on the graphene moved more than 300 times slower than light, and drama­tically different from what is expected from clas­sical physics laws.

In reference to the accom­plished experiments, Frank Koppens comments: “Usually it is very difficult to probe the quantum world, and to do so it requires ultra-low tempe­ratures; here we could just see it with light and even at room tempera­ture”. This technique paves now the way for exploring many new types quantum materials, including super­conductors where elec­tricity can flow without energy con­sumption, or topo­logical materials that allow for quantum infor­mation proces­sing with topo­logical qubits.

The researchers state that “this could just be the begin­ning of a new era of near field nano­scopy”. This discovery may eventually lead to under­standing in a truly micro­scopic fashion complex quantum pheno­mena that occur when matter is subject to ultra-low tempera­tures and very high magnetic fields, like the frac­tional quantum Hall effect. (Source: ICFO)

Reference: M. B. Lundeberg et al.: Tuning quantum nonlocal effects in graphene plasmonics, Science, online 8 June 2017; DOI: 10.1126/science.aan2735

Link: Quantum Nano-Optoelectronics (F. Koppens), ICFO Institut de Cinècies Fotòniques, Barcelona Institute of Science and Technology, Castelldefels, Spain

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