Optical pulse shaper with integrated slab waveguide for arbitrary waveform generation using optical gradient force

Integrated optical pulse shaper opens up possibilities for realizing the ultra high-speed and ultra wide-band linear signal processing with compact size and low power consumption. We propose a silicon monolithic integrated optical pulse shaper using optical gradient force, which is based on the eight-path finite impulse response. A cantilever structure is fabricated in one arm of the Mach–Zehnder interferometer（MZI） to act as an amplitude modulator. The phase shift feature of waveguide is analyzed with the optical pump power, and five typical waveforms are demonstrated with the manipulation of optical force. Unlike other pulse shaper schemes based on thermo–optic effect or electro–optic effect, our scheme is based on a new degree of freedom manipulation, i.e., optical force, so no microelectrodes are required on the silicon chip,which can reduce the complexity of fabrication. Besides, the chip structure is suitable for commercial silicon on an insulator（SOI） wafer, which has a top silicon layer of about 220 nm in thickness.     

Charge generation and electrostatic equilibrium for single granules during sliding

Electrostatic phenomena are commonly observed in the processing of solids. However, the working mechanism of electrostatic charge generation for single granules and particularly, their electrostatic equilibria have not been properly understood. In this work, repeated-sliding charging experiments with single granules were investigated for their electrostatic generation particularly from the perspective of triboelectrification equilibrium. Factors including granule length-ratio, sliding face shape, sliding times, sliding area, sliding velocity, front-facing edge, and sliding-plate inclined-angle were found to have an obvious effect on granule charge generation. Length-ratio and sliding area have significant effects as the granules evolved toward an equilibrium state. Equilibrium charge is suggested as a variable expressing the charging propensity of the material. In addition, under the same working conditions, a semi-cylindrical granule generates greater charge than a rectangular granule.     

Conduction mechanism of metal-TiO2–Si structures

The conduction model has been proposed for the metal-TiO₂–Si (MIS) structures. Rutile films have been prepared on Si substrates by magnetron sputtering of TiO₂ target and annealing in the air at temperatures T?=?800 and 1050 K. The current-voltage (CVC) and capacitance-voltage characteristics of the structures have been measured over the range of T?=?283–363 K. At positive potentials on the gate, the conductivity of the MIS structures is determined by the space charge-limited current in the dielectric layer.     

不均匀场中氢分子离子高次谐波产生的理论研究

在非Born-Oppenheimer近似下，通过求解含时薛定谔方程的方法，对氢分子离子在不均匀场中高次谐波的产生进行了理论研究.计算结果显示，同均匀场相比，电离的电子在不均匀场中加速会获得更多的能量，从而更有利于得到宽频谱.此外,通过优化不均匀场中的空间不均匀度，长量子路径被明显的抑制，最终通过叠加110阶到150阶谐波，获得一个60as的孤立阿秒脉冲.同时，通过库仑势和激光场的相互作用势以及时频分布图解释了其中的物理机制.     

Recent Advances in Spatial Self-Phase Modulation with 2D Materials and its Applications

In recent years, spatial self-phase modulation (SSPM) with two-dimensional (2D) materials has attracted the attention of many researchers as an emerging and ubiquitous nonlinear optical effect. In this review, the state of the art of 2D material-based SSPM is summarized. SSPM measures or tunes the nonlinearity of 2D materials, and it is also an effective approach to study the band structure of 2D materials. Several modified forms of SSPM, such as high-order, white-light-excited, vector field excited, and optically nonlinearly enhanced SSPM are also presented. Subsequently, the physical origin of the SSPM formation mechanism is compared and analyzed. Furthermore, the applications of SSPM with 2D materials, including passive photonic devices, generation of Bessel beams, and identifying the mode of the orbital angular momentum, are listed. Finally, several urgent problems of the SSPM with 2D materials, potential applications, and prospects for future development are presented.     

Generative Art with Swarm Landscapes

We present a generative swarm art project that creates 3D animations by running a Particle Swarm Optimization algorithm over synthetic landscapes produced by an objective function. Different kinds of functions are explored, including mathematical expressions, Perlin noise-based terrain, and several image-based procedures. A method for displaying the particle swarm exploring the search space in aesthetically pleasing ways is described. Several experiments are detailed and analyzed and a number of interesting visual artifacts are highlighted.     

On Current Developments in Partial Differential Equations

The first part of this article is an overview on some recent major developments in the field of analysis and partial different equations.It is a brief presentation given by the author at a round table discussion.The second part is a supplement of various details provided by several outstanding researchers on subjects.