Noda Naoki, Kamimura Shinji
Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan.
Rev Sci Instrum. 2008 Feb;79(2 Pt 1):023704. doi: 10.1063/1.2839914.
With conventional light microscopy, precision in the measurement of the displacement of a specimen depends on the signal-to-noise ratio when we measure the light intensity of magnified images. This implies that, for the improvement of precision, getting brighter images and reducing background light noise are both inevitably required. For this purpose, we developed a new optics for laser dark-field illumination. For the microscopy, we used a laser beam and a pair of axicons (conical lenses) to get an optimal condition for dark-field observations. The optics was applied to measuring two dimensional microbead displacements with subnanometer precision. The bandwidth of our detection system overall was 10 kHz. Over most of this bandwidth, the observed noise level was as small as 0.1 nm/radicalHz.
在传统光学显微镜中，当我们测量放大图像的光强时，标本位移测量的精度取决于信噪比。这意味着，为了提高精度，不可避免地需要获得更亮的图像并减少背景光噪声。为此，我们开发了一种用于激光暗场照明的新型光学器件。对于显微镜，我们使用激光束和一对轴锥镜（圆锥透镜）来获得暗场观察的最佳条件。该光学器件被应用于以亚纳米精度测量二维微珠位移。我们整个检测系统的带宽为10 kHz。在这个带宽的大部分范围内，观察到的噪声水平低至0.1 nm/√Hz。
