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Light transmission asymmetry and optical diode
We have suggested and realized a giant asymmetry of the transmission of light propagating through a linear nonmagnetic optical system that consists of a nanohole in metal film deposited on the surface of a one-dimensional photonic crystal. The asymmetry of the light transmission is caused by two factors: (i) practical impossibility to reverse the wavefront of light passing through a nanohole whose diameter is much smaller than the wavelength of light; and (ii) increase of photonic crystal transmission at photonic bandgap wavelengths due to strong modification of k-vector of incident light caused by diffraction on a nanohole (optical “clearance” of the photonic crystal). We show that in such optical element it is possible to realize optical diode whose reverse transmission can be suppressed by a factor of more than 30 000.