High performance integrated photonic circuit based on inverse design method

The basic indexes of all-optical integrated photonic circuits include high-density integration, ultrafast response and ultra-low energy consumption. Traditional methods mainly adopt conventional micro/nano-structures. The overall size of the circuit is large, usually reaches hundreds of microns. Besides, it is difficult to balance the ultrafast response and ultra-low energy consumption problem, and the crosstalk between two traditional devices is difficult to overcome. Here, we propose and experimentally demonstrate an approach based on inverse design method to realize a high-density, ultrafast and ultra-low energy consumption integrated photonic circuit with two all-optical switches controlling the input states of an all-optical XOR logic gate. The feature size of the whole circuit is only 2.5 μm × 7 μm, and that of a single device is 2 μm × 2 μm. The distance between two adjacent devices is as small as 1.5 μm, within wavelength magnitude scale. Theoretical response time of the circuit is 150 fs, and the threshold energy is within 10 fJ/bit. We have also considered the crosstalk problem. The circuit also realizes a function of identifying two-digit logic signal results. Our work provides a new idea for the design of ultrafast, ultra-low energy consumption all-optical devices and the implementation of high-density photonic integrated circuits

Chlorination behaviors for green and efficient vanadium recovery from tailing of refining crude titanium tetrachloride

The refined tailing, generated from refining of titanium tetrachloride (TiCl4) for vanadium (V) removal, is a hazardous material to environment due to the high content of V. Aiming at effective and selective extraction of V from the refined tailing, a fluidized chlorination process was proposed in present work. The chlorination behaviors of the refined tailing which determine the efficiency and selectivity of V extraction were emphatically investigated. A resultant 96.36% of V and 4.23% of Ti can be synchronously extracted from the tailing at the optimum conditions of 800 degrees C for 60 min, with the pressure fraction of chlorine [P(Cl-2)/P(Cl-2 +N-2)1 = 0.5 and the mass fraction of petroleum coke in raw materials for chlorination at 10 wt%. High purity vanadium oxytrichloride (VOCl3, higher than 99.99 wt%) can be finally obtained via further simple purification of the collected chloride product. Moreover, the chlorination residue containing concentrated TiO2 has the potential to be further utilized for Ti extraction. Thus the process provides a new prospect for effective, clean and comprehensive utilization of the refined tailing, which can solve the hazardous waste recycle and environmental concerns simultaneously

Edge states in plasmonic meta-arrays

Photonic edge states provide a novel platform to control and enhance light-matter interactions. Recently, it becomes increasing popular to generate such localized states using the bulk-edge correspondence of topological photonic crystals. While the topological approach is elegant, the design and fabrication of these complex photonic topological crystals is tedious. Here, we report a simple and effective strategy to construct and steer photonic edge state in a plasmonic meta-array, which just requires a small number of plasmonic nanoparticles to form a simple lattice. To demonstrate the idea, different lattice configurations, including square, triangular, and honeycomb lattices of meta-arrays, are fabricated and measured by using an ultrahigh spatial resolution photoemission electron microscopy. The properties of edge states depend on the geometric details such as the row and column number of the lattice, as well as the gap distance between the particles. Moreover, numerical simulations show that the excited edge states can be used for the generation of the quantum entanglement. This work not only provides a new platform for the study of nanoscale photonic devices, but also open a new way for the fundamental study of nanophotonics based on edge states