Improved signal-to-noise ratio in a passive THz near-field microscope equipped with a helium-free cryostat

作者：Kuan-Ting Lin, Susumu Komiyama, S. Kim, Kenji Kawamura, Yusuke Kajihara · 年份：2016 · DOI：10.1109/irmmw-thz.2016.7758551 · 被引用次数：1 · 研究领域：Near-Field Optical Microscopy、Thermal Radiation and Cooling Technologies、Superconducting and THz Device Technology

We have developed a passive THz s-SNOM (scattering-type scanning near-field optical microscope) equipped with a helium-free cryostat. The mechanical vibration from the compressor is reduced for accurately controlling the probe-sample distance. Besides, the confocal system with a solid immersion lens leads to gather higher signal-to-noise ratio. To demonstrate the capability of the s-SNOM, we measured the thermally excited surface evanescent wave on a Au/SiO2sample. Achieved SNR of the near-field signal on Au is 5.5 with a 0.1 s/pixel scan rate. These results show that the improved passive s-SNOM not only provides more convenient cooling process but also significantly speeds up the scan rate for the passive THz near-field image.