Abstract
Unidirectional transmission is studied theoretically and experimentally for the gratings with one-side corrugations (non-symmetric gratings), which are based on two-dimensional photonic crystals composed of alumina rods. The unidirectional transmission appears at a fixed angle of incidence as a combined effect of the peculiar dispersion features of the photonic crystal and the properly designed corrugations. It is shown that the basic unidirectional transmission characteristics, which are observed at a plane-wave illumination, are preserved at Gaussian-beam and horn antenna illuminations. The main attention is paid to the single-beam unidirectional regime, which is associated with the strong directional selectivity arising due to the first negative diffraction order. An additional degree of freedom for controlling the transmission of the electromagnetic waves is obtained by making use of the asymmetric corrugations at the photonic crystal interface.
Highlights
Realization of various functions in the optical and microwave frequency ranges leads to the demand in the devices with strong directional selectivity
The transmission mechanism studied therein is based on exploiting the dispersion features of the photonic crystals (PCs), which facilitate that the zero order is not coupled to a Floquet-Bloch wave of the PC at a proper choice of the angle of incidence, while several higher diffraction orders may exist due to the effect of corrugations and may be coupled as long as the grating is illuminated from the side of corrugations
We have demonstrated unidirectional transmission in the PC gratings with oneside echelette-type corrugations at beam-type illumination
Summary
Realization of various functions in the optical and microwave frequency ranges leads to the demand in the devices with strong directional selectivity. The transmission mechanism studied therein is based on exploiting the dispersion features of the PCs, which facilitate that the zero (reciprocal) order is not coupled to a Floquet-Bloch wave of the PC at a proper choice of the angle of incidence, while several higher diffraction orders may exist due to the effect of corrugations and may be coupled as long as the grating is illuminated from the side of corrugations. The effect of the unidirectional transmission in non-symmetric gratings is rather general and can be obtained for various grating performances, provided that the corrugations, the dispersion, and the angle of incidence are properly chosen. The presented results include the transmission spectra of the examined structures for the plane-wave illumination, the frequency response of the transmittance for Gaussian-beam and horn antenna illuminations, and the angular distributions of the transmittance, at a proper value of the angle of incidence
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
