Yeh W H, Carriere J, Mansuripur M
Optical Sciences Center, University of Arizona, Tucson, Arizona 85721, USA.
Appl Opt. 1999 Jun 10;38(17):3749-58. doi: 10.1364/ao.38.003749.
Polarization microscopes are widely used to image the magnetic domains of a magneto-optical disk and to characterize the birefringence of the disk substrate. For high-resolution imaging, unfortunately, the coupling of the polarization rotation from the Kerr signal, the effect of Fresnel's reflection coefficients, and the substrate birefringence severely deteriorate the image contrast obtained from conventional observations. Here we present the technique of differential polarization microscopy, which replaces the analyzer with a Wollaston prism, for providing better image contrast. Images of a magnetic pattern obtained with both conventional and differential methods are observed for objective lenses that have different numerical apertures and magneto-optical disks with and without a birefringent substrate. The computer simulations and experimental results show that the use of this differential method improves the image contrast and provides excellent tolerance for defects of the optical system.
偏振显微镜被广泛用于对磁光盘的磁畴进行成像，并表征光盘基板的双折射特性。然而，对于高分辨率成像而言，克尔信号引起的偏振旋转耦合、菲涅尔反射系数的影响以及基板双折射会严重降低传统观测所获得的图像对比度。在此，我们提出了差分偏振显微镜技术，该技术用沃拉斯顿棱镜取代检偏器，以提供更好的图像对比度。对于具有不同数值孔径的物镜以及有无双折射基板的磁光盘，我们分别用传统方法和差分方法观察了磁图案的图像。计算机模拟和实验结果表明，使用这种差分方法可提高图像对比度，并对光学系统的缺陷具有出色的耐受性。
