Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 37: Photonische Kristalle I

HL 37.7: Vortrag

Montag, 7. März 2005, 11:30–11:45, TU P270

Photonic crystals with negative refraction focus light beams below the diffraction limit — •Anton Husakou and Joachim Herrmann — Max Born Institute, Max Born Str. 2a, D-12489 Berlin, Germany

The resolution limit of all conventional optical devices is determined by the fact that all evanescent components of an electromagnetic wave are lost during propagation. It has been suggested that evanescent waves can be amplified by a slab with a negative refraction index leading to a sub-wavelength resolution of image. Up to now this superlensing effect was studied for imaging of sub-wavelength features. We show that a photonic crystal with negative refraction amplifying evanescent waves, combined with an aperture which creates seed evanescent waves, can focus light beams below the diffraction limit of half of the wavelength. We describe beam focusing both in the context of effective-medium theory as well as using the numerical solution for a realistic photonic crystal structure. We show that an input beam is focused to a spot with FWHM of 0.14λ in the case of effective-medium theory and 0.25λ for the realistic structure of a photonic crystal.