Taghi Tavassoly Mohammad, Moaddel Haghighi Iman, Hassani Khosrow
Department of Physics, University of Tehran, Kargar Shomally Avenue, Tehran 14394-547, Iran.
Appl Opt. 2009 Oct 10;48(29):5497-501. doi: 10.1364/AO.48.005497.
When a thin film that is prepared in a step form on a substrate and coated uniformly with a reflective material is illuminated by a parallel coherent beam of monochromatic light, the Fresnel diffraction fringes are formed on a screen perpendicular to the reflected beam. The visibility of the fringes depends on film thickness, angle of incidence, and light wavelength. Measuring visibility versus incident angle provides the film thickness with an accuracy of a few nanometers. The technique is easily applicable and it covers a wide range of thicknesses with highly reliable results.
当在基板上以阶梯形式制备并均匀涂覆有反射材料的薄膜被平行相干单色光束照射时，菲涅耳衍射条纹会在垂直于反射光束的屏幕上形成。条纹的可见度取决于薄膜厚度、入射角和光波长。测量可见度与入射角的关系可提供精度达几纳米的薄膜厚度。该技术易于应用，并且能覆盖很宽的厚度范围，结果高度可靠。
