Research And Application Of Optical Sensors Based On Negative Refraction Phenomenon In 2D Photonic Crystal Structure

Photonic crystal is an optical structure with spatially periodic dielectric constants. One of its basic characteristics is the photonic band gap. As the photons in photonic crystals can be controlled by its photonic band structure, we change the band structure of the photonic crystal to achieve the optical control. In this way, photonic crystal have a wide range of applications in optical devices. Compared with traditional photoelectric sensors, sensors based on photonic crystals have many advantages, such as fast responsing, convenient operating, small size, avoiding electromagnetic interferences, durability and easy integrated with lasers. All these make it more consistent with the trend of device integration development. In view of this,this paper studied in the negative refraction of photonic crystal, and at last put forward optical sensor applications based on two-dimensional photonic crystal negative refraction effect.Various optical properties of the triangular lattice photonic crystal with silicon dielectric cylinder were theoretical studied by using the plane wave expansion method(PWE) and finite difference time domain method(FDTD). Characteristics analyses in two-dimensional photonic crystal were including: the influence of the dielectric cylinder radius constant b exert on the photonic band structure and negative refraction frequency rang; the influence of the substrate refractive index exert on the photonic band structure;the influence of the incident light frequency, which variating close to the photonic band gap, exert on the negative refractive deflection angle and output power.With the analyses on the negative refraction effect and photonic band structure of the triangular lattice photonic crystal with silicon dielectric cylinder, we proposed two optical sensor applications. After optimized fitting degree of the relation curve of photonic crystal substrate refractive index and negative refractive power output, a fluid refractive index sensor application based on two-dimensional photonic crystal negative refraction effect is obtained. Combining with the corresponding relation between the refractive index and the concentration of sugar solution, we have gotten the linear relationship between the concentration of sugar solution and negative refractive power. the other application is a sugar solution concentration detector based on two-dimensional photonic crystal negative refraction effect. The detecting range of the fluid refractive index sensor application based on two-dimensional photonic crystal negative refraction effect is 1.33- 1.49. The detecting range of the sugar solution concentration detector based on two-dimensional photonic crystal negative refraction effect is 0- 60%.