Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 1: Tutorial: Plasmonics

HL 1.1: Tutorium

Sonntag, 6. März 2016, 16:00–16:45, H15

Graphene and Metal Plasmonics for Mid-IR Biosensing — •Hatice Altug — Bionanophotonics Systems Laboratory, EPFL Lausanne, Switzerland

Mid-IR absorption spectroscopy is a powerful label-free biosensing technique enabling chemical identification of molecules through their vibrational fingerprints. However, the method is not effective in detecting nanometric biomolecules due to the large size-mismatch with several microns long Mid-IR light. By engineering on-chip plasmonic nano-antennas, we overcome this fundamental limitation and enhance intrinsic signals of molecules by many orders of magnitude. Using extreme field concentration we also monitor in real-time and in-situ biomolecular interactions from low quantities of molecules. Most recently we showed that graphene could revolutionize biosensing due to its exceptional opto-electronic properties. Graphene plasmons can be tuned by electrostatic gating, in contrast to conventional plasmonic materials such as noble metals. By exploiting this unique feature we demonstrated a dynamically tunable plasmonic Mid-IR biosensor that can extract complete optical properties of proteins over a broad spectrum.In addition, the extreme light confinement in graphene*up to two orders of magnitude higher than in metals*produces an unprecedentedly strong overlap with nanometric biomolecules, enabling superior sensitivity. The combination of tunable spectral selectivity and enhanced sensitivity of graphene opens exciting prospects for sensing, not only proteins but also a wide range of chemicals and thin films.