Research On The Density Of States And Band Gap Characteristics Of One-Dimensional Photonic Crystal

Photonic crystal is a regular optical structure consisting of a periodic array of different reflectivity. This kind of periodic optical structure possesses photonic band gap and thus it can block the specific frequency photon, thereby affecting the movement of the photon. Since the concept of photonic crystal has been proposed, it has aroused the great interest of scholars. The band gap characteristics of one dimensional photonic crystal are analyzed based on the density of states (DOS) in this paper.The characteristics of DOS and the change of band gap of one dimensional photonic crystal are summarized. The details are described as follows1. DOS formulas of one-dimensional photonic crystal are calculated used transfer matrix method which can be simplified when the film thickness satisfies the λ0/4 relation, and then the band gap characteristics of DOS can be obtained.2. The DOS characteristic curve is plotted. Then, the effect on DOS properties by refractive index ratio, cycle number and the thickness of the film are analyzed through the control variables method. A further research is made to reveal the corresponding relationship between the DOS at the band edge at the sudden enhancement phenomenon and Bloch phase β rate of change.3. One-dimensional photonic crystal made of positive and negative refractive index is constructed. First, these crystals were studied by the transfer matrix method, and then analyzed compared with the traditional one-dimensional photonic crystals. It is observed that the band gap becomes wide and smooth, the conduction band become sharp peaks. These two band gap characteristics are different and the corresponding physical interpretation is present. Then, the DOS band gap characteristics of one-dimensional photonic crystal with positive and negative refractive index are studied according to the mathematical description of the second chapter. Finally, the influence on band gap characteristics between the relative refractive rate difference, number of cycles and film thickness are analyzed through the control variable method.