| 摘要 |
PURPOSE:To reduce the influence of a back shadow light, and to improve S/N by executing a phase modulation by an angular frequency omega with respect to a sample reflected light or a sample incident light, and separating a DC component, an omega component, and a 2omega component of a detecting light intensity signal. CONSTITUTION:With respect to the reflected light of a sample 1, a phase modulation by an angular frequency omega is executed by a phase modulating element 13, and the DC component, the omega component, and the 2omega component of the detecting light intensity signal are separated by a signal component separating circuit 16. Subsequently, the azimuth of a linear polarizing element 12 or an analyzer 14 is brought to a rotation control so that the 2omega component goes to zero. From the rotational angle of that time, and the DC component and the omega component of that time, the refractive index and thickness of the sample 1 are derived. A fact that the modulation is executed in such a way the signal components are separated means an AC-like detection, and the influence by a back shadow light is reduced. |
