Enhanced Absorption Of Photonic Crystals Containing Transparent Conductive Thin Film

In recent years,photonic crystals are developed rapidly as nanophotonic techniques.Photonic crystals with excellent properties can be used to make super prism,efficient light-emitting diodes,no threshold laser,sensors and optical storage.Devices which absorb light totally have been applied widely.To realize enhanced optical absorption,there are some important physical mechanisms to enhance the interactions between the light and photonic crystals,such as surface plasmon resonance,optical Tamm state and F-P cavity resonance.Based on surface plasmon resonaces,the light can localize at the interface of metal and medium where the field intensities are increased obvious.Someone used metal nanoparticles to excite surface plasmon resonances and achieved enhanced absorption of the light,which can improve the conversion efficiency of the solar cell.The optical Tamm state also can be as a kind of the interface mode.Near the interface of the metal and the medium,the intensities of the electromagnetic field increased rapidly.Due to the strong localization of the electromagnetic field,it was potentially used in the polarization laser and etc.In addition,the hybrid modes of the F-P cavity resonances and optical Tamm states can also achieve the field enhancement.In this paper,we achieve enhanced absorption based on F-P cavity resonance,surface plasmon resonance and optical Tamm state using Several different photonic nanostructures.In the second part,we mainly theoretically investigated multi-channel enhanced absorptions in photonic sandwich structures containing the metal.The sandwich structure composed of a symmetrical photonic crystal inserted between metallic film and the photonic crystal heterostructure.The results showed that enhanced multiple-channel absorption can be realized.Meanwhile the characteristics of the absorbers wwere one-way.Adjusting the period numbers of absorbers,we could obtain multiple-channel absorptions from single channel to many channels.F-P cavity resonances and optical Tamm states result in the enhanced multiple-channel absorptions according to the electromagnetic field distributions.Besides,we also studied other characteristics of absorbers.Among them,the photonic crystal heterostructures were used as a good dielectric reflectors which had widened and adjustable photonic band gap.The thickness variation of the metallic thin film,polarization and incidence angles could alter the resonant absorption frequency and absorptance.In the third part,we mainly theoretically investigated the enhanced absorption containing transparent conductive thin films in the near-infrared spectra.Photonic crystals containing the metal can excite the optical Tamm states and surface plasmons resonances.Be different from the metal,we try to use ITO,GZO,AZO thin film to replace the metal film.First,we used the envelope method to calculate the thickness of single-layer ITO,GZO,AZO films.In the near-infrared spectra,we obtained the dielectric constant model of the ITO,GZO,AZO based on the Drude model.Then,we designed Kretschmann configuration:Prism-SiO2-ITO Prism-SiO2-GZO and Prism-SiO2-AZO.It is proved that the light can be absorbed fully for the TM polarization in the infrared range when the light waves are incident at a certain angle.Analyzing the distribution of the electromagnetic field,it is found that the localized magnetic field is the strongest at the interface.The results indicated that photonic crystals containing the transparent conductive thin film can inspire SPPs and enhanced absorption.Finally,we designed photonic heterostructures:ITO-photonic crystal heterostructure,GZO-photonic crystal heterostructure,AZO-heterostructure.It is proved that the light can be absorbed completely for both of the TE and TM polarizations in the infrared range when the light waves are at the condition of the normal incidence.It also have been demonstrated that the transparent conductive thin films owe similar characteristics with metals.Moreover,SPPs and optical Tamm state are obtained in such photonic nanostructures.