Probe Emission-Probe Detection Type Terahertz Near-Field Imaging System

研制了一种采用全光纤耦合光路设计的探针发射–探针探测型太赫兹近场成像系统，其特点在于：系统中的太赫兹辐射源和探测器均采用了探针式光电导天线，这在国内尚属首次报道。测试结果表明：系统的光谱范围覆盖0.1~1.0 THz，动态范围达到45 dB；利用光电导探测探针对光电导发射探针产生的太赫兹波空间场分布进行了微米级高分辨率成像，表明光电导发射探针产生的太赫兹波以近似球面波形式向自由空间传播；将微带线样品靠近光电导发射探针的针尖时，微带线会显著影响太赫兹波在发射探针和探测探针之间的传输模式。本系统为太赫兹频段的超表面器件等相关领域的科学研究提供了一种高效便捷的测量手段。A probe emission-probe detection type terahertz near-field imaging system with an all-fiber-coupled optical design was developed. The system is characterized by the use of probe-type photoconductive antennas for both the terahertz radiation source and detector, which was reported for the first time domestically. Test results show that the system covers a spectral range of 0.1~1.0 THz with a dynamic range of 45 dB. Used the photoconductive detection probe, high-resolution imaging at the micrometer level was performed on the spatial field distribution of the terahertz waves generated by the photoconductive emission probe, revealing that the terahertz waves propagate in free space in an approximately spherical wave form. When a microstrip line sample was brought close to the tip of the photoconductive emission probe, the microstrip line significantly affected the transmission mode of terahertz waves between the emission probe and the detection probe. This system provides an efficient and convenient measurement tool for scientific research in related fields such as terahertz-frequency metasurface devices.