Terahertz Sepctroscopic Research Of 3D Printing Photonic Crystals

Today,terahertz science and technology has attracted great attention because of its wide application prospects.Due to the development of ultra-short laser pulses and the emergence of terahertz time-domain spectroscopy,terahertz radiation sources and terahertz detection technologies have been developed rapidly as the basic link for converting terahertz technology into real productivity.However,there are relatively few studies on terahertz passive materials and devices.Therefore,if we want to promote the development of terahertz science and technology,we need to do more research on functional materials and devices in the terahertz band.As an effective materials to regulate the structure of photon energy bands and control the transmission of electromagnetic waves,photonic crystals have had a lot of research results in the microwave and visible wavelengths.At the same time,the increasingly mature 3D printing technology is forming a new preparation process for material and device,which can easily make microstructures with features ranging from millimeters to micrometers or even nanometers.According to the size invariance of Maxwell’s equations,we make three-dimensional photonic crystals in the terahertz band via the 3D printing process with micrometer accuracy,combining the simulation software and the terahertz time-domain spectroscopy system,the spectral properties of photonic crystal in the terahertz band was studied from simulation and experimental measurement.The thesis mainly includes three aspects of work:1)We use DLP 3D printer to prepare three-dimensional polymer photonic crystals,and obtain three-dimensional metal photonic crystals by chemical nickel plating post-processing;2)The numerical simulation software is used to analyze the transmission and reflection spectrum of the polymer photonic crystal,At the same time,the terahertz time-domain spectroscopy system is used to measure the spectrumof the photonic crystal,which reveals the Borrmann absorption modulation effect existing on both sides of the band gap due to Debye relaxation loss of the material;3)For nickel-plated metal photonic crystals,we use simulation software to calculate the bulk bands and projected band of it,based on the terahertz time-domain spectroscopy system,the angle-resolved transmission spectrum measurement was carried out to characterize a unique band with line degeneracies of nodal chains.In this paper,we take three-dimensional simple cubic structure of polymer photonic crystal and metal photonic crystal as examples,doing research on preparation,simulation and experimental characterization.Our results not only show that the advanced photocuring 3D printing process is particularly suitable for the synthesis of three-dimensional photonic crystals in the terahertz band,including the production of large-area,light-weight metal photonic crystals,but also have fundamental value in the development of functional materials such as terahertz wave absorbers and the research of three-dimensional photonic crystals with topological energy bands.Moreover,our research will have potential application value in the design of new communication materials and devices in the millimeter and terahertz band.