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The authors theoretically propose a design for electrically tuning a metasurface based on piezoelectric actuation. The design comprises 2D gap‐plasmon elements arranged periodically on a piezoelectric substrate which controls the period between them. The technique is numerically studied for a metasurface that anomalously reflects an incident p‐polarised wave by 30° at the optical communication wavelength, 1550 nm. The dynamic behaviour of the system is investigated for two main applications; (a) steering the reflection angle and (b) retrieving the reflection angle for an incident wave of a shifted wavelength. It is demonstrated that a reflected beam can cover an angle of ∼3° upon a strain of <3.3%. It is also shown that at the same strain value, the reflection angle is retrieved for a wavelength error of ±50 nm. These results suggest a potential to design large‐bandwidth, reconfigurable metasurfaces that are integrable with planar opto‐electromechanical devices. [ABSTRACT FROM AUTHOR]

Based on the definition of second order moment, fourth order moment and the approximate three-dimensional analytical formula for oblique laser beam passing through a cat's eye optical lens with centre shelter, the analytical expression of kurtosis parameter of the cat's eye effect reflected light under far field condition has been deduced. Evolution characteristics of kurtosis parameter affected by the incident angle, back backhaul transmission distance, local shift and centre shelter ratio are performed by numerical calculation, and analysed physically. The results show that the reflected beam at the return place changes from a leptokurtic beam into a mesokurtic beam along with the increase of the incident angle. Only when the focal shift and incident angle are all very small, the kurtosis parameter at the return place has a large value and the reflected beam has a leptokurtic profile. These evolution characteristics of kurtosis parameter can be used to classify the distorted reflected beam. [ABSTRACT FROM AUTHOR]

Abstract: Control of the longitudinal shifts, i.e., spatial and angular Goos–Hänchen (GH) shifts, is revisited to study the effect of width of incident Gaussian beam on the shifts and distortion in the reflected beam. The beam is incident on a cavity consisted of atomic medium where each four-level atom follows N-type atom-field configuration. The atom-field interaction leads to Raman gain process which has been used earlier to observe a significant enhancement of the negative group index, i.e., in the range −103 to −104 for 23 N a condensate [G.S. Agarwal, S. Dasgupta, Phys. Rev. A 70 (2004) 023802]. The negative and positive longitudinal shifts could be observed in the reflected light corresponding to the anomalous and normal dispersions of the intracavity medium, respectively. It is observed that the shifts are relatively large for small range of beam width and these became small for large width of the incident beam. It is also noticed that the magnitudes of spatial and angular GH shifts behave differently when the beam width increases. Further, distortion in the reflected beam decreases with an increase in beam width. [Copyright &y& Elsevier]

Presented is the use of a reflectarray‐based structure in order to enhance the radar cross‐section (RCS) of a flattened dihedral corner reflector. Phase‐shifting cells are printed on the panels of the reflector to steer the reflected beam so that a retrodirective radiation is obtained. An experimental validation is given at 9 GHz. [ABSTRACT FROM AUTHOR]

The reflective self-organized lightwave network (R-SOLNET) enables the formation of self-aligned waveguides in the photorefractive (PR) material between misaligned optical devices by introducing a write beam. The incident write beam from one device and the reflected write beam from the second device induce self-focusing in the PR material and construct a coupling waveguide. A wavelength filter on the waveguide edge is used to facilitate the reflected beam. The beam propagation method reveals that R-SOLNET exhibits higher coupling efficiencies and better tolerances than the one-beam-writing SOLNET and the free-space coupling. The apparent usefulness of R-SOLNET is remarkable for gaps wider than 100 μm in 8-μm-wide waveguide circuits. For 240-μm gap, coupling efficiency better than 50% can be achieved even when the lateral misalignment is as large as 4 μm. The results indicate that R-SOLNET may be useful for vertical waveguide constructions of optical z-connections in three-dimensional intrachip optical interconnects and switching systems, as well as for self-aligned optical couplings with devices that cannot emit write beams such as vertical-cavity surface-emitting lasers, photodetectors, and electrooptic switches. [ABSTRACT FROM PUBLISHER]