Near-infrared photonic band structure in a semiconductor metamaterial photonic crystal

Abstract

In this study, we theoretically investigate the near-infrared (NIR) photonic band structure (PBS) in a one-dimensional semiconductor metamaterial (MM) photonic crystal (PC). The considered PC is (AB)^N, where N is the stack number, A is a dielectric, and B is a semiconductor MM composed of Al-doped ZnO and ZnO. It is found that the photonic band gaps (PBGs) can be tunable by the variations in filling factor, and thicknesses of A and B. It is of particular interest to see that the PBG will vanish when the thicknesses of A and B satisfy a certain condition. The results provide fundamental information on a NIR PBS that could be of technical use in photonic applications using such a semiconductor MM. The band gap vanishing makes it possible to design a wider band pass filter at NIR based on the use of such a PC.

Auto Focusing in Digital Holography to Study Marine Microorganism

“…The method based on SD of the gradient distribution presented in Literature [2], takes advantage of the speciality that the gradient can reflect the target edge sharpness (details), and get image clarity through solving discrete degree of edge sharpness. But the gradient operator is influenced by noise easily, so its robustness is lower, and its commonality is poor.…”

“…Optical holography and digital holography, with the development of computer technology and the CCD technology, play more and more important role in the research of real-time analysis and identification, spatial distribution for ocean zooplankton and other particles, and other underwater application [1]. Accurate auto-focusing is one of the key technologies to realize automatic reconstruction in digital holography [2]. The object can be clear only when it is reconstructed in its focusing distance (FD)/reconstruction distance.…”

“…There is a method in literature [4], called Tenegrad, which is used More widely a. In literature [2], gradient variance method (SOG) makes use of spatial gradient in frequency domain, which has very good effects, but consumes more time. Literature [5] presents a contrast method (Contrast) for speckle hologram, which defines the square root of the image variance to mean ratio as FCF.…”