Application Of Photonic And Phononic Crystals On The Detection Of Liquid Mass Fraction

Photonic crystal and the phononic crystals are novel optical structures that formed by periodic arrangement of two or more different dielectric constants and elastic coefficient materials.The band gaps of photonic and phononic crystals have become the research hotspots in the field of crystal structure design and optimization.Photonic crystal and phononic crystal are widely used in biochemical substances,various clinical and testing solutions for daily life,toxicants and optical switches,environmental pollutants and other fields.In addition,it can also be used in the design and optimization of crystal materials,various photonic and phononic crystal gas sensors,liquid sensors,biosensors and other fields.The mass fraction of the different liquids caused changes of bandgap width,so the mass fraction of the liquid can be detect by calculating of the band gap width.In this paper,photonic and phononic crystals are used as carriers to the design a liquid sensor that is sensitive to the band gap of photonic or phononic crystals.The liquid is injected into the cavity based on the photonic or phononic crystal sample.The mass fraction is detected by calculating the bandgap when electromagnetic waves or elastic waves are prohibited during the propagation of the liquid.The main contents are:Combining the domestic and foreign research and development status of photonic or phononic crystals,the research progress of mass fraction detection technology based on photonic crystal band gap theory is analyzed.The propagation characteristics of electromagnetic waves in photonic crystals and elastic waves in phononic crystals are introduced.Using bloch theorem and plane wave expansion method analyzed the dispersion relation of electromagnetic waves propagating in square crystal lattices,triangular lattices and special structure photonic crystals and elastic waves in phononic crystals and explained in detail the sensing principle of the mass fraction detection system.Similarly,filling with different mass fractions of the test liquid in the phononic crystal cavity,the relationship between the band gap of the phononic crystal and the mass fraction of the liquid is studied,finally obtained a linear fitting equation and a linear fitting ratio.Simulation results show that the change of the structural parameters and the mass fraction of the liquid has a significant influence on the band structure and bandgap width.The relative refractive index(or permittivity)of the material has a relatively greater influence on the band structure and bandgap width of photonic and phononic crystals.