Interaction of electromagnetic, acoustic, and even gravitational waves with accelerating bodies forms a class of nonstationary time-variant processes. Scattered waves contain intrinsic signatures of motion, which manifest in a broad range of phenomena, including Sagnac interference, and both Doppler and micro-Doppler frequency shifts. Although general relativity is often required to account for motion, instantaneous rest frame approaches are frequently used to describe interactions with slowly accelerating objects. We investigate theoretically and experimentally an interaction regime that is neither relativistic nor adiabatic. The test model considers an accelerating scatterer with a long-lasting relaxation memory. The slow decay rates violate the instantaneous reaction assumption of quasistationarity, introducing non-Markovian contributions to the scattering process. Memory signatures in scattering from a rotating dipole are studied theoretically, showing symmetry breaking of micro-Doppler combs. A quasistationary numeric analysis of scattering in the short-memory limit is proposed and validated experimentally with an example of electromagnetic pulses interacting with a rotating wire.
Tailoring the parameters of a silver nanorod array for subwavelength imaging of arbitrary coherent sources is of recent interest. We evaluated the operational bandwidth of this type of superlens, and also the impact of source-offset in order to understand the level of tolerance offered by the superlens with regard to source location. The performance of the device was analyzed numerically both through analysis of transmission and reflection coefficients and by full-wave simulation for a particular sample source arrangement. We observed that such a device exhibited better imaging performances with the sources spread wider, offering a bandwidth of around 13.5%.
KEYWORDS: Imaging arrays, Coherence imaging, Silver, Near field scanning optical microscopy, Interfaces, Computer simulations, Metals, Near field optics, Near field, Nanorods
The arrays of silver nanorods are known as prospective structures for near-field transmission. However, the
available geometries are operating with incoherent sources and do not properly image the coherent ones. In this
paper it is demonstrated how the geometry proposed in [Phys. Rev. Lett. 95, 267407 (2005)] can be modified
to enable subwavelength imaging of arbitrary coherent sources. The greatly improved performance of the device
is demonstrated numerically both through analysis of transmission and reflection coefficients and by full-wave
simulation of a particular source imaging.
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