Yunhui Chen

Enhancement of terahertz radiation from GaP emitters by subwavelength antireflective micropyramid structures

Subwavelength antireflective micropyramid structures, designed by rigorous coupled-wave analysis and fabricated by precision micromachining, are used to enhance the terahertz (THz) radiation output of optical rectification in GaP crystal-based emitters. An average 16% increase in the THz radiation power emitted by a 3 mm GaP crystal is experimentally demonstrated using an antireflective micropyramid grating with a period of 60 μm and a base angle of 55.5°. Optimized pyramidal-frustum gratings are shown to operate as highly efficient antireflective structures within an ultrabroadband range of 0.5-5 THz.

Nanometric cutting of crystal surfaces modified by ion implantation

Single-crystal materials are widely used in optics and electronics field and are essential in condensed matter physics andmaterials science researches. However, the hard and brittle nature of the materials prevents it from manufacturing intricate features and optical quality surfaces. Nanometric cutting assisted with ion implantation surface modification method reduces the fracture and tool wear during machining by improving the surface mechanical properties. The mechanism, techniques, and applications of this method are specifically explained in the chapter.

Molecular dynamics simulation of the deformation of single crystal gallium arsenide

Three-dimensional molecular dynamics (3D MD) simulation was carried out to investigate the deformation of single crystal gallium arsenide (GaAs) during nanoindentation. Tersoff potential was used to simulate the atomistic interaction under an extremely low load of indentation. The coordination number and atomic displacement were studied and the cross-sectional profiles of the simulated indent were examined. The simulation results revealed that the lattice deformation of GaAs was influenced by polarity, showing distinct patterns on different crystalline planes. Slip band and dislocation were found to be the dominant deformation phenomena.