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Four decades ago, V. Veselago
derived the electromagnetic properties of a hypothetical
material having simultaneously-negative values of electric
permittivity and magnetic permeability [1]. Such a “left-handed”
material was predicted to exhibit a number of exotic properties
including a negative index of refraction and a negative response
to radiation pressure (pull). Since left-handed materials are
not available in nature, considerable efforts are currently
under way to implement them under the form of artificial
“metamaterials” – composite media with tailored bulk optical
characteristics resulting from constituent structures which are
smaller than the effective wavelength in the medium.
Here we show how surface-plasmon
modes propagating in a stacked array of metal-insulator-metal (MIM)
waveguides can be harnessed to yield a volumetric left-handed
metamaterial characterized by an in-plane-isotropic index of
refraction which is negative over a broad portion of the
visible-frequency range. By sculpting this metamaterial with a
focused-ion beam, we realize micro-cantilevers which we use to
demonstrate, for the first time, a negative radiation pressure.
We also predict and experimentally verify a negative
“super-pressure” of magnitude significantly greater than the
largest photon pressure achievable under normal circumstances –
that experienced by a perfect mirror.
[1] V. Veselago, “The
electrodynamics of substances with simultaneously negative
values of
e and
m,”
Sov. Phys. Usp. 10, 509-514 (1968). |