A novel method for switching the direction of surface plasmon polarition (SPP) launching is proposed. The principle behind the switching mechanism is based on the relative phase difference between the reference beam and the control beam. Selective guidance of the direction of SPP can be explained by the composition of the charge parity that is induced near the slit edge, which is caused by interference created by two incident beams. The switching of SPP launching direction could be implemented by simple phase modulation of the control beam when the slit parameters satisfy the specific conditions at the designed specific wavelength. An experimental demonstration, in good agreement with numerical results, shows that our configuration of SPP switching can be operated by a quite simple interaction.
The modulation of near-field signals has recently attracted considerable interest because of demands for the development of nano-scale optical devices that are capable of overcoming the diffraction limit of light. In this paper, we propose a new type of tuneable plasmonic lens that permits the foci of surface plasmon polariton (SPP) signals to be continuously steered by adjusting the input polarization state. The proposed structure consists of multi-lined nanoslit arrays, in which each array is tilted at a different angle to provide polarization sensitivity and the nanoslit size is adjusted to balance the relative amplitudes of the excited SPPs from each line. The nanoslits of each line are designed to focus SPPs at different positions; hence, the SPP focal length can be tuned by modifying the incident polarization state. Unlike in previously reported studies, our method enables plasmonic foci to be continuously varied with a smooth change in the incident linear polarization state. The proposed structures provide a novel degree of freedom in the multiplexing of near fields. Such characteristics are expected to enable the realization of active SPP modulation that can be applied in near-field imaging, optical tweezing systems, and integrated nano-devices.
As the demand for large-scale video analysis increases, video retrieval research is also becoming more active. In 2014, ISO/IEC MPEG began standardizing compact descriptors for video analysis, known as CDVA, and it is now adopted as a standard. However, the standardized CDVA is not easily compared to other methods because the MPEG-CDVA dataset used for performance verification is not disclosed, despite the fact that follow-up studies are underway with multiple versions of the CDVA experimental model. In addition, analyses of modules constituting the CDVA framework are insufficient in previous studies. Therefore, we conduct self-evaluations of CDVA to analyze the impact of each module on the retrieval task. Furthermore, to overcome the obstacles identified through these self-evaluations, we suggest temporal nested invariance pooling, abbreviated as TNIP, which implies temporal robustness realized by improving nested invariance pooling, abbreviated as NIP, one of the features in CDVA. Finally, benchmarks of the existing CDVA and the proposed approach are provided on several public datasets. Through this, we show that the CDVA framework is capable of boosting the retrieval performance if utilizing the proposed approach.INDEX TERMS Content based retrieval, information representation, MPEG standards.
A compact transmissive plasmonic waveguide mode converter which aims for the elimination of reflection and transmission of unconverted mode is proposed. The proposed scheme exploits a cavity formed by mode selective mirrors, which only allows two output modes: the transmission of the target mode and the reflection of the input mode. By appropriately tuning cavity lengths, the reflection of the input mode can also be suppressed to near zero by destructive interference, thereby all the residual outgoing modes are suppressed. The proposed device might be useful in the design of integrated photonic system since it relaxes the problem of unwanted reflection.
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