Low symmetric photonic crystals for biosensor applications

The surface mode of low symmetric photonic crystal which has triangular distribution of air holes on dielectric backgorund was used for biosensor design. The symmetry of photonic crystal is reduced by breaking rotational symmetry while preserving translational symmetry in terms of unit cell dimension and numerical analysis of the designed structure in both frequency domain and time domain have been performed. The effect of the angular displacement of the small air holes placed on the surface to get low symmetry at the surface of the structure on the band diagram is investigated and thus a strong light-matter interaction has been achieved. By creating distortion on the surface of the structure in order to obtain the surface mode, it is ensured that light is trapped in this area. High sensitivity values (approximately 2300 nm/RIU) are achieved due to the light wave that travels along the structure confining to the interface, strongly interacts with the material to be detected.