Terahertz Waves Encoding Based On Memory Effect Of Vanadium Dioxide

Terahertz(THz)waves are located between the microwave and infrared regions of the electromagnetic spectrum and are one of the most popular and cutting-edge research areas.It has wide application prospects in the fields of security scanning,biomedical imaging,material characterization,ultra-fast electronics and 5G communications(and the development of higher-performance communications).In order to realize these functional applications of terahertz waves,we often need to actively take control of terahertz waves.With the development of science and technology,many devices(modulators,sensors,transceivers,and metamaterial devices)have also been developed around the active control of terahertz waves.Hertz wave memory research is very rare.The study of terahertz wave memory devices will effectively solve the problem of pulse synchronization that is often encountered in the application of terahertz waves,and this kind of memory retention allows us to have more operations on the device during its storage,so for terahertz waves The study of memory devices will be of great significance.In the work of this thesis,we propose an all-optical drive terahertz wave encoding storage scheme.This paper mainly contains five parts.The first part of the work introduces the terahertz time-domain spectroscopy and the use of vanadium dioxide film(VO2 Film);the second part of the work,the phase change material(PCM)and the principle of vanadium dioxide phase change Composition,crystal structure characteristics and properties of the vanadium dioxide film phase transition process);The third part of the work includes the preparation and characterization of the vanadium dioxide film,and the wire grid electrode is designed based on the Fresnel diffraction integration method.By adjusting the electric field to make a phase change,and at the same time through the terahertz time domain spectroscopy to characterize and analyze the experiment to prepare for the memory experiment;the fourth part of the work,proposed an all-optical drive terahertz wave encoding storage system Introduced the working principle of the optical system used in the experiment in detail;based on THz-TDS and the existing experimental equipment,designed the experimental system of the all-optical drive terahertz memory storage experiment,and introduced its work flow and precautions.The fifth part of the work is based on the all-optical drive terahertz wave coding and storage system.The continuous-wave laser(CW laser)is used for the terahertz wave switching under the all-optical drive.Code storage),and characterize and analyze its storage time and stability.Finally,based on the all-optical drive terahertz wave code storage system,we used a femtosecond laser instead of a continuous laser for optical writing,using non-thermal excitation for the first time The vanadium dioxide thin film device realizes the memory storage of terahertz waves.Through the proposed all-optical drive terahertz wave encoding and storage scheme,the problem of laser pulse synchronization in the application of terahertz waves will be effectively solved,so that the application of terahertz waves will no longer be limited by pulse synchronization There are more choices for THz sources and more different system designs in the application.