Zhang Jicheng

Fabrication of Diamond Microstructures by Using Dry and Wet Etching Methods

Diamond films have great potential for micro-electro-mechanical system (MEMS) application. For device realization, precise patterning of diamond films at micrometer scale is indispensable. In this paper, simple and facile methods will be demonstrated for smart patterning of diamond films, in which two etching techniques, i.e., plasma dry etching and chemical wet etching (including isotropic-etching and anisotropic-etching) have been developed for obtaining diamond microstructures with different morphology demands. Free-standing diamond micro-gears and micro-combs were achieved as examples by using the experimental procedures. It is confirmed that as-designed diamond structures with a straight side wall and a distinct boundary can be fabricated effectively and efficiently by using such methods.

Diffraction Properties for 1000 Line/mm Free-Standing Quantum-Dot-Array Diffraction Grating Fabricated by Focused Ion Beam

The traditional fabrication technique of quantum-dot-array diffraction grating (QDADG) is a hybrid lithography method that includes electron-beam lithography and x-ray lithography. In this work, 1000 line/mm free-standing QDADG has successfully been fabricated by focused ion beams (FIBs) for the first time. The diffraction patterns of the grating are measured in the 250–450 nm wavelength range from the xenon lamp source. In consequence, the QDADG in this experiment can be used to disperse light without high-order diffraction. The present inspiriting result demonstrates the prospect of FIB fabrication for high energy QDADG in the soft x-ray region.

Enhancement of the Number of Fast Electrons Generated in a Laser Inverse Cone Interaction

Enhancement of the energy-conversion efficiency from laser to target electrons is demonstrated by two-dimensional particle-in-cell simulations in a laser-inverse cone interaction. When an intense short-pulse laser illuminates the inverse cone target, the electrons at the cone end are accelerated by the ponderomotive force. Then these electrons are guided and confined to transport along the inverse cone walls by the induced electromagnetic fields. A device consisting of inverse hollow-cone and multihole array plasma is proposed in order to increase the energy-conversion efficiency from laser to electrons. Particle-in-cell simulations present that the multiholes transpiercing the cone end help to enhance the number of fast electrons and the maximum electron energy significantly.