Theoretical Research On Ta₂O₅-Based Three-Dimensional Photonic Crystal With Band Gap Performance

Photonic crystal, are artificially arranged periodic electromagnetic structures in optical wavelength scale. Since the pioneering work of Yablonovitch and John there has been an enormous amount of interest in the fabrication and theoretical research of the so-called PC, has obtained the rapid development. This kind of system can be used to control light propagation in a way analogous to what semiconductors band structure do with electrons, photonic band gaps inhibit the existence of light in certain frequency ranges. Photonic have the advantage of fast and no interaction over electron, we can control light by designing photonic band gaps structure, so PC hopeful to realize revolution in photonic field.PC of the near infrared and visible regions is the focus of research in recent years, but research progress was slow because of a limited number of optional dielectric materials and a narrow band gaps. Usually, PCs properties may be modified via increasing dielectric constant of the dielectric materials; Subsequent to growth, research shows that the heterostructure PCs which was formed with various materials can improve optical properties.In this paper, we studied the material selection and structural optimization for three-dimensional photonic crystal. We calculated the optical properties of nitrogen doped Ta₂O₅ by density functional theory and applied it to the study of three-dimensional photonic crystal. Finally, we studied the diamond structure with nitrogen doped Ta₂O₅ and Ta₂O₅/MgF₂ heterostructure three-dimensional photonic crystal by calculation of the transfer matrix method(TMM) and plane wave expansion method(PWEM).It is shown that the refractive index of Ta₂O₅ could be remarkably increased by nitrogen doping, when the doping content was 7.14%, molecular formula is Ta₂O_4.5N_0.5 had the best optical properties. The three-dimensional photonic crystal with diamond structure of Ta₂O_4.5N_0.5 has an omnidirectional band gap withΔω=0.05 (a/λ, a is the lattice constant), this Provide theoretical support for the preparation of three-dimensional photonic crystal which have high reflectivity and application of novel optoelectronic devices. The three-dimensional photonic crystal with the heterostructure of Ta₂O₅/MgF₂ had characteristics of band gaps stacking, and remarkably increased the breadth of band gaps, adjusted the lattice constant could get better band gaps which can almost cover the whole red spectral band. At the same time, the three-dimensional photonic crystal with the heterostructure of Ta₂O₅/MgF₂ had omnidirectional band gaps without influence of incident angles around 820¹020 nm of near infrared region with TM polarization. The structure should enable new applications for polarizing devices.