Research Of Terahertz Modulator Based On Hybrid Perovskites Films And Metamaterials

With the booming of terahertz communication technology,terahertz wave has become the main band of 6G communication in the future.As the key technology of terahertz communication,the research of terahertz modulation technology is urgent.Metamaterials,as synthetic periodic materials,have unique properties that natural materials do not have,and can easily realize many physical phenomena.Plasma-induced transparency has the characteristics of low loss,high Q value and slow light effect,which can be used in terahertz modulation.The organic-inorganic hybrid perovskite has the advantages of convenient processing,adjustable energy band and excellent photoelectric response performance.It has become a new type of photoelectric semiconductor with wide application prospect and provides a new choice for terahertz modulation technology.This paper mainly studies the modulation effect of terahertz modulator based on perovskite and metamaterials under the excitation of external light field.The main research results are as follows:(1)A terahertz modulator based on perovskite/silicon structure is studied.Under the action of 532 nm continuous laser pump,the maximum modulation depth of the modulator can reach 66%.This is due to the formation of heterojunction between perovskite and silicon substrate,and the internal electric field generated by the heterojunction makes the photogenerated carriers separate,leading to a significant increase in the concentration of photogenerated carriers in the structure,which further increases the electrical conductivity of the structure,and finally realizes the modulation of terahertz wave.(2)A terahertz modulator based on perovskite/metamaterial/silicon-based structure is studied.Under the action of 532 nm continuous laser pump,the plasma-induced transparency caused by the canceling interference between the two resonators gradually disappears,and the maximum modulation depth of the modulator can reach 82%.The photoconductivity of perovskite thin films was studied.It was found that under the excitation of external light field,the perovskite thin films generated a large number of photogenerated carriers,which resulted in a large increase in the conductivity of the structure,short-circuited the gap of the metamaterial structure,and inhibited the generation of plasma-induced transparency.(3)The ultra-fast terahertz modulator based on perovskite/metamaterial/sapphire structure is studied.The maximum modulation depth of the terahertz modulator can reach 38% under the action of pulse laser pumped at 800 nm.The carrier composite dynamics was used to fit the OPTP measurement results.It was found that the lifetime of the photogenerated carriers in the perovskite/metamaterial/sapphire structure was about 12.4 ? 14.7 ns,and the response time of the whole modulator was within the ns range.