A photonic crystal (PhC)-based structure is designed to achieve subdiffraction imaging over the entire visible wavelength range. The designed structure is a two-dimensional triangular lattice PhC formed by making circular holes in a 100-nm film of electro-optic lithium niobate (LiNbO3) grown on indium tin oxide. The analysis is done by using MEEP and MPB softwares. This shows that by applying a voltage within ±460 V, equal frequency contour can be obtained for specific values of frequencies, which corresponds to wavelength (λ) in visible range (389 to 757 nm). This indicates that the designed structure will have effective negative refraction and hence subdiffraction imaging over the entire visible wavelength (frequency) range. By placing this type of PhC structure in front of the objective, the resolution of the conventional imaging system can be increased.
Vertical 2D PhC having a T-type three port channel on top of InGaAs/GaAs broadband IR LED is considered. Top PhC
is created by 2D periodic repetation of InAs rods in air. T-Channel is created by replacing some solid rods by air. Light
from LED is focussed within the channel. Part of LED light having wavelength out side the PhC bandgap will pass
normally and wavelength within PhC will be guided by the channel. By introducing two different defects in the two arms
of ‘T’ channel tuning of two demultiplexed narrowband sources is obtained.
The results of our analytical study on the formation of optical bands of III-Nitride Photonic Crystals are presented in this paper. The analysis is based on the propagation of Bloch waves through microstructured periodic dielectric materials, taking a model of 2D holey crystal of square lattice of GaN as example. Band gaps are opened up for both TE and TM modes in the square lattice for different d/a ratios, 'd' and 'a' being the diameter and lattice constant. The transmission bandwidth is seen to be wider for decreasing air -hole diameter irrespective of the polarization mode of the propagating light. Complete photonic gap may be found for material system of relatively higher contrast ratio.