The use of laser diffraction effect for small dimension measurement

Abstract

The diffraction and interference of light are easily observed phenomena that give direct, tangible evidence of the wave nature of light. Diffraction is the root of many technology, scientific techniques and common visual phenomena. In this study, an experimental setup for CD and DVD optical data storage, and human hair measurement were describes based on the diffraction effect. Investigations were performed using monochromatic laser light which will be diffracted on CD and DVD, and human hair. The diffraction patterns were observed on a target screen. From this diffraction pattern the thickness of human hair and track spacing on CD and DVD were measured. The thickness of human hair was obtained in the range between of 66.5 μm to 112.0 μm. While, track spacing on CD was obtained in the ranges between 9.42 nm to 10.23 nm and for DVD was between 3.03 nm to 3.91 nm.