Broadband THz-TDS System Based On DSTMS And Terahertz Superconducting Metamaterials For Thermal Tunability

In the past 20 years, the research of THz technology had been developed widely and in-depth, but the generation, detection and control devices operating in THz spectrum range are still immature: in the field of THz time domain spectroscopy(THz-TDS) researches, pump sources with high prices, great bulk and difficult maintenance are still a bottleneck; Refers to active tunable devices, there is a lack of thermal tunable devices, even the tuning results are not ideal enough. In this thesis, we built up a set of THz-TDS system based on optical rectification with femtosecond fiber laser pump whose center wavelength is 1560 nm. The small size of the femtosecond fiber laser makes the whole system structure very compact. Also, we established the numerical analysis of two metamaterials(MM) fabricated by different types of superconducting(SC) film and made a comparison between the two MMs in terms of the critical temperature and electrical conductivity which determinately influences the responses of SC MMs. The main work content in this dissertation consists of 4 parts:1. We summarized the aspects of the generation and detection technology of THz as well as the particular characteristics of THz waves.2. Based on the principle of nonlinear optics and taking an electro-optical crystal in 43 m point group as the sample, we gave a brief theoretical analysis of the THz emission by optical rectification and the THz detection based on linear electro-optic effect, including the phase match issue in it.3. A 4-f THz-TDS based on two <110> ZnTe crystals pumped with infrared ultrashort laser pulses centered at 800 nm was established. We observed THz time domain signal with peak value arriving about 500 ?V and broadband spectrum reaching nearly 3 THz. Then we rebuilt this system into an ultra-broadband THz-TDS with organic crystal DSTMS pumped by femtosecond fiber laser centered at 1560 nm and finally we obtained the broadband THz signal in the new THz-TDS.4. Utilizing all-fiber quick-scan THz time domain magnetic spectroscopy system(THz-TDMS), we numerically studied the interaction between THz wave and the SC MMs and made a comparison of the SC MMs fabricated with different types of SC film in terms of the thermal tunability of the THz wave.