Research on the Zooming Characteristics of Micro-lens Arrays in Two-Dimensional Negative Refractive Index Photonic Crystals

Abstract

Regarding the slow response speed and wear-prone issue of the mechanical zoom function in the sub-wavelength imaging system.
This paper proposes a sub-wavelength imaging system that uses a liquid crystal (LC) lens as the zoom component. This system combines LC
lenses, silicon microlenses, and photonic crystals. Firstly, the FDTD algorithm was used to simulate and analyze the negative refractive index
of the photonic crystal, the focusing characteristics of the silicon microlens, and the zoom characteristics of the LC lens. Finally, a parallel
light incident combined optical system was used. When the effective refractive index of the LC lens varies within the range of 1.5 to 1.72,
sub-wavelength imaging can be achieved with an image distance ranging from 0.352? to 0.727? and a half-width ranging from 0.377? to 0.398?.
Additionally, a point light source with a wavelength of 1.55 micrometers was introduced to combine the optical system. It was found that the
image points at each object distance would change their position and half-width with the effective refractive index of the LC lens. By changing the effective refractive index of the LC lens, images ranging from 0.728 to 0.737 micrometers can be formed on the emission surface of
the photonic crystal for different object distances, thereby achieving the effect of fixed focal length and dynamic zooming.