Lin Kuan-Ting, Komiyama Susumu, Kim Sunmi, Kawamura Ken-Ichi, Kajihara Yusuke
Institute of Industrial Science, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo 153-8505, Japan.
Department of Basic Science, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan.
Rev Sci Instrum. 2017 Jan;88(1):013706. doi: 10.1063/1.4973985.
We have developed a passive long-wavelength infrared (LWIR) scattering-type scanning near-field optical microscope (s-SNOM) installed in a helium-free mechanically cooled cryostat, which facilitates cooling of an LWIR detector and optical elements to 4.5 K. To reduce mechanical vibration propagation from a compressor unit, we have introduced a metal bellows damper and a helium gas damper. These dampers ensure the performance of the s-SNOM to be free from mechanical vibration. Furthermore, we have introduced a solid immersion lens to improve the confocal microscope performance. To demonstrate the passive s-SNOM capability, we measured thermally excited surface evanescent waves on Au/SiO gratings. A near-field signal-to-noise ratio is 4.5 times the improvement with an acquisition time of 1 s/pixel. These improvements have made the passive s-SNOM a more convenient and higher-performance experimental tool with a higher signal-to-noise ratio for a shorter acquisition time of 0.1 s.
我们开发了一种安装在无氦机械冷却低温恒温器中的被动式长波红外（LWIR）散射型扫描近场光学显微镜（s-SNOM），它有助于将LWIR探测器和光学元件冷却至4.5K。为了减少来自压缩机组的机械振动传播，我们引入了金属波纹管阻尼器和氦气阻尼器。这些阻尼器确保s-SNOM的性能不受机械振动影响。此外，我们引入了固体浸没透镜以提高共聚焦显微镜性能。为了展示被动式s-SNOM的能力，我们测量了Au/SiO光栅上的热激发表面倏逝波。近场信噪比在采集时间为1s/像素时提高了4.5倍。这些改进使被动式s-SNOM成为一种更方便、性能更高的实验工具，在0.1s的更短采集时间内具有更高的信噪比。
