Condensed Matter Physics Seminar
2 p.m., Thursday, April 10, 2003
Room 1201, Physics Building
Control of surface plasmons
emitted from arrays of subwavelength aperture
Girsh Blumberg
(Lucent)
Abstract: Surface
plasmons (SPs) are coherent fluctuations of electron charges on metallic
surfaces. These collective charge density waves are characterized by intense
mixed transverse and longitudinal electromagnetic fields, strongly localized at
the metallic surface. Unlike collective electron oscillations in bulk materials,
SPs can couple to propagating photons and therefore be used to trap and nano-focus
enormous amounts of electromagnetic energy into very small volumes [1].
Recently, works on extraordinary optical transmission [2, 3] and light beaming
[4] in sub-wavelength periodically structured metal films have reached
particular prominence, suggesting a direction for fabricating optical devices
that operate below the diffraction limit. Significant advances in this area may
be possible if SPs can be controllably converted to and from free-space photons,
and if their surface propagation can be intentionally directed. In this talk we
demonstrate the controlled emission of coherent jets of SPs in a metallic array
of subwavelength apertures. We manipulate the SP jet intensity and propagation
direction by varying the wavelength, incidence angle, and polarization of the
excitation photons. Also we demonstrate conversion of SPs back into light, and
observe directional beaming of light from this device.
References:
1. Pendry, J. Playing tricks with light. Science 285, 1687-1688 (1999).
2. Ebbesen, T. W., Lezec, H. J., Ghaemi, H. F., Thio, T. & Wolff, P. A.
Extraordinary optical transmission through sub-wavelength hole arrays. Nature
391, 667-669 (1998).
3. Altewischer, E., van Exter, M. P. & Woerdman, J. P. Plasmon-assisted
transmission of entangled photons. Nature 418, 304-306 (2002).
4. Lezec, H. J. et al. Beaming Light from a Subwavelength Aperture. Science 297,
820-822 (2002).
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Host: Greene
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