Light-Matter Interaction

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I show here a fascinating effect discovered in 2002 - This might be the method of material analysis which we were searching for back then, to distinguish gems and natural/synthetic diamonds. 

Phonon-enhanced light–matter interaction at the nanometre scale

R. HILLENBRAND, T. TAUBNER & F. KEILMANN

Max-Planck-Institut für Biochemie, Abteilung Molekulare Strukturbiologie, 82152 Martinsried & Center for NanoScience, Ludwig-Maximilians-Universität, 80799 München, Germany
Correspondence and requests for materials should be addressed to F.K. (e-mail: keilmann@biochem.mpg.de).

Optical near fields exist close to any illuminated object. They account for interesting effects such as enhanced pinhole transmission or enhanced Raman scattering enabling single-molecule spectroscopy. Also, they enable high-resolution (below 10 nm) optical microscopy. The plasmon-enhanced near-field coupling between metallic nanostructures opens new ways of designing optical properties and of controlling light on the nanometre scale. Here we study the strong enhancement of optical near-field coupling in the infrared by lattice vibrations (phonons) of polar dielectrics. We combine infrared spectroscopy with a near-field microscope that provides a confined field to probe the local interaction with a SiC sample. The phonon resonance occurs at 920 cm-1. Within 20 cm-1 of the resonance, the near-field signal increases 200-fold; on resonance, the signal exceeds by 20 times the value obtained with a gold sample. We find that phonon-enhanced near-field coupling is extremely sensitive to chemical and structural composition of polar samples, permitting nanometre-scale analysis of semiconductors and minerals. The excellent physical and chemical stability of SiC in particular may allow the design of nanometre-scale optical circuits for high-temperature and high-power operation.

Macmillan MagazinesNature © Macmillan Publishers Ltd 2002 Registered No. 785998 England.  This was mirrored from the 11 July 2002 issue of Nature, 418, 159 - 162 (2002); doi:10.1038/nature00899

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