Removal of bromate (BrO₃⁻) has gained increasing attention in drinking water treatment process. Photocatalysis technology is an effective strategy for bromate removal. During the photocatalytic reduction of bromate process, the photo-generated electrons are reductive species toward bromate reduction and photo-generated holes responsible for water oxidation. In this study, the monoclinic bismuth vanadate (BiVO₄) single crystal was developed as a visible photocatalyst for the effective removal of bromate. The as-synthesized BiVO₄ photocatalyst with optimized {010} and {110} facets ratio could achieve almost 100% removal efficiency of BrO₃⁻ driven by visible light with a first-order kinetic constant of 0.0368 min⁻¹. As demonstrated by the electron scavenger experiment and density functional theory (DFT) calculations, the exposed facets of BiVO₄ should account for the high photocatalytic reduction efficiency. Under visible light illumination, the photo-generated electron and holes were spatially transferred to {010} facets and {110} facets, respectively. The BiVO₄ single crystal photocatalyst may serve as an attractive photocatalyst by virtue of its response to the visible light, spatially charge transfer and separation as well as high photocatalytic activity, which will make the removal of BrO₃⁻ in water much easier, more economical and more sustainable.

Optical antennas enable efficient coupling between propagating light and bonding electromagnetic waves like surface plasmon polaritons (SPPs). Under the illumination of inhomogeneous optical fields, propagating SPPs mediated by multimode antennas could be spatially asymmetric and the asymmetry strongly depends on the position of the antennas relative to the illumination field. Here we develop such asymmetric excitation of SPPs through illuminating a pair of slot antennas with the (1,0) mode Hermite-Gaussian beam. The physical scenario of the interaction between the illumination optical field and the paired slot antennas are elaborated by full-wave electromagnetic simulations. We also carry out experiments to monitor the asymmetric SPPs propagation with a back-focal plane imaging technique. By retrieving the asymmetric intensity ratio of the SPP pattern in the back-focal plane image, lateral displacement of the antennas down to angstrom level is demonstrated.

This paper focuses on a new non-ideal phenomenon induced by the power supply crosstalk (PSC) of the row drive circuit in 8 T global shutter (GS) CMOS image sensors (CISs). A method to eliminate the non-ideal phenomenon is presented. Based on the circuit simulation, the relationship between the parasitic resistance and PSC is analyzed. The PSC would cause a charge leakage on the sampling hold (S/H) capacitors in the 8 T pixel, which in turn attenuates the output signal of the image sensor. Through the mathematical model of the in-pixel S/H circuit, the effect of PSC and exposure on signal attenuation is analyzed. To eliminate signal attenuation, this paper utilizes a separate power layout method that isolates the row drivers in different columns by using multiple power supplies. In contrast to the method of sharing the power supply, the proposed method can reduce the maximum power supply crosstalk noise from 1.17 V to 2.58 μV in the 2000 × 2 row drive array. Based on the 0.13 μm CMOS process, the measurement results of the 1st chip design using the typical shared power structure and the 2nd chip design using the separate power supply structure are compared. The measurement results show that the output signal of the 1st chip design is limited to about 303 ADU due to the power supply crosstalk. The saturated output signal of the 2nd chip design is 2200 ADU, which is in accordance with the theoretical signal output value (2200 ADU) when the pixel is saturated. The proposed method can effectively eliminate signal attenuation induced by the PSC, thereby improving the image quality of 8 T GS CIS.