论文部分内容阅读
提出一种利用镀有金属薄膜的V形无孔光学探针构建的扫描近场光学显微镜,将圆偏振光注入镀有金属薄膜的V形槽内在针尖处形成近场照射光源,并利用探针收集样品表面近场光信号。理论分析表明:探针收集的近场和远场反射光之间存在一定的相位差,该相位差与探针机械结构、探针与样品的距离有关,可通过探针与样品之间的距离加以控制,因此利用偏振性器件可有效抑制远场光强。实验中,探针与样品之间的距离通过范德华力回馈控制,探针操作在接触模式,实验结果显示所测近场与远场光相位相差57°,近场光学图像横向分辨率优于12 nm。
A scanning near-field optical microscope using a V-shaped nonporous optical probe coated with a metal thin film is proposed. A circularly polarized light is injected into a V-shaped groove plated with a metal film to form a near-field illumination source at a needle tip. The needle collects the near-field optical signal on the surface of the sample. Theoretical analysis shows that there is a certain phase difference between the near-field and far-field reflected light collected by the probe. The phase difference is related to the mechanical structure of the probe, the distance between the probe and the sample, and the distance between the probe and the sample To control, so the use of polarization devices can effectively suppress the far-field light intensity. In the experiment, the distance between the probe and the sample is controlled by van der Waals forces, and the probe operates in the contact mode. The experimental results show that the measured near-field and far-field light have a phase difference of 57 ° and the lateral resolution of the near-field optical image is better than 12 nm.