Theoretical Characterization And Experimental Of Lithium Niobate Photonic Crystal

Photonic crystals are attractive artificial crystals for controlling the flow of light, with the structure basically in periodic changes of the dielectric constant on a length scale comparable to optical wavelengths. Photonic crystals in high refractive index contrast semiconductor materials, such as Si and GaAs, have got great attention, utilized in all-optical switching, channel-dropping filters, photoluminescence and so on. Lithium niobate is electro-optical, acousto-optic, thermoelectric, ferroelectric, non-linear. However, little is known about the properties of photonic crystals using this material, with low refractive index contrast. Based on lithium niobate photonic crystals have great potential , this paper will carry on the research and preparation of it.On theory , we analysis the structure of photonic crystals of air column, dielectric column, triangular lattice and affirmative lattice, combined with the concept of photonic crystal lattice vector, Brillouin zone, band , model complete band gap. We simulated transmission as a fuction of wavelength for 6, 12, 18 rows of holes. We design the structure 12×12 points, and period constant a=0.682μm, and the motif radius is chosen to be r=0.4a. The refractive index at 1.55μm wavelength is supposed to be 2.143, which is the crystal extraordinary index of refraction of lithium niobate. We get the widest TM mode. As lithium niobate have the characteristic of electro-optical, the index of refraction of it changes 0.1, the wavelength of peak transmission in this port shift by nearly 50 nm.In the production process, we use Ti:LiNbO3 waveguide in depth direction to limit the transmission of light. We produce photonic band gap structure on LiNbO3 substrates , which we designed, using focused ion beam bombardment(FIB).We get the aperture size and regular arrangement requirements, observed by scanning electron microscopy(SEM).