Design of hybrid optical waveguide with a 90° bend structure for high density photonics integrated circuits

A hybrid optical waveguide having a 90° sharp bend structure, composed of a dielectric straight waveguide, tapered dielectric strip waveguide, and microscale metal gap waveguide, is proposed and simulated to improve the efficiency of light coupling between dielectric and plasmonic waveguides. Our simulation result is a critical step for the hybrid integration of plasmonic components with conventional dielectric components.     

Nonadiabatic multi-step excitation for the blue–green light emission from dye grains induced by the near-infrared optical near-field

Blue–green light emission (wavelength range: 460–520 nm) from coumarin dye grains due to near-infrared excitation (CW, λ _ex=808 nm), based on the nonadiabatic excitation process induced by an optical near-field, was observed. A maximum frequency up-shift of 1.17 eV was confirmed. Based on the excitation intensity dependence, a light emission mechanism originating from a nonadiabatic three-step excitation was confirmed for the first time. The lifetime of the intermediate excited state was approximately 1.1–1.9 ps, and thus realization of frequency up-conversion with a rapid response can be expected.     

Terahertz optical asymmetric demultiplexer based tree-net architecture for all-optical conversion scheme from binary to its other 2~n radix based form

To exploit the parallelism of optics in data processing,a suitable number system and an efficient encod- ing/decoding scheme for handling the data are very essential.In the field of optical computing and parallel information processing,several number systems like binary,quaternary,octal,hexadecimal,etc.have been used for different arithmetic and algebraic operations.Here,we have proposed an all-optical conversion scheme from its binary to its other 2n radix based form with the help of terahertz optical asymmetric demultiplexer (TOAD) based tree-net architecture.