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Science Groups Forum Index » Physics - Research » Metamaterial to refract electons
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| cyber |
 Posted: Thu Jul 23, 2009 4:57 pm |
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Guest
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Metamaterials with negative index of refraction have been demonstrated
for microwaves and IR and for sound.
In theory, could a metamaterial, with patterns smaller than 1/2 the
De Broglie wavelength of an electron, be used for negative refraction
of electrons? |
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| Guest |
| Posted: Sat Jul 25, 2009 1:50 am |
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cyber <jg@searchexpress.com> wrote:
Quote: Metamaterials with negative index of refraction have been demonstrated
for microwaves and IR and for sound.
In theory, could a metamaterial, with patterns smaller than 1/2 the
De Broglie wavelength of an electron, be used for negative refraction
of electrons?
First up, you need to define what you will mean by negative refraction,
and what by negative index of refraction (NRI). The term "negative refraction"
is often used in place of NRI, but should really be restricted to
the case of (reversed) refraction at an _interface_.
In EM, "negative index of refraction" usually translates to "negative
phase velocity", i.e. a phase velocity opposed to the ExH Poynting
vector (which I denote NPVP); although some authors prefer a phase
velocity opposed to the group velocity (NPVG), or a phase velocity
opposed to the energy velocity (NPVE).
At this point you could probably wander over to the solid state literature,
and look at electron bandstructure calculations. Some of these, in some
materials, will give negative (effective) electron masses, which
would easily match some kind of idea of "NPV for electrons".
--
---------------------------------+---------------------------------
Dr. Paul Kinsler
Blackett Laboratory (Photonics) (ph) +44-20-759-47734 (fax) 47714
Imperial College London, Dr.Paul.Kinsler@physics.org
SW7 2AZ, United Kingdom. http://www.qols.ph.ic.ac.uk/~kinsle/ |
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