Papers by Author: Qi Jun Liu

Abstract: Structural, electronic and optical properties of 2H-CuAlO₂ were computed, using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory (DFT). The equilibrium lattice parameters, band structure, densities of states (DOS) and charge densities of 2H-CuAlO₂ have been obtained. The equilibrium lattice parameters, band structure and DOS are found to be in good agreement with the available experimental and calculational values. The charge densities and the chemical bonding of 2H-CuAlO₂ are analyzed, which show that bonding between Cu and O is mainly covalent due to Cu 3d and O 2p hybridization and that bonding between Al and O is mainly ionic. The complex dielectric function, refractive index and absorption coefficient of 2H-CuAlO₂ have been predicted. The calculated static dielectric constant and static refractive index of 2H-CuAlO₂ is 7.1 and 2.66, respectively.

Abstract: The convex surface of the infrared dome is exposed to the harsh environment of the outside world, and therefore requires a coating which not only increases transmission but is able to withstand rain erosion so as to enhance system performance. This paper deals with the techniques that were developed to deposit a uniform thick SiO2 coating for sapphire dome by radio frequency magnetron sputtering. Results show that average transmission increment in wavelength range from 3 to 5um for the sapphire dome coated on convex surface was more than 4.0%. The transmission non-uniformity over the convex surface of the coated sapphire dome was less than 1.7%.