Optically rough TiO2 thin film surface study by laser speckle photography

Abstract

In this work, TiO2 thin film is exposed to the red laser and the scattered light progresses the self-interference granular appearance of images called speckle patterns. The statistical database of the scattered fingerprints of the object is computed. The speckle images are captured by a Charge Coupled Device(CCD) and are then explored by digital speckle processing to acquire the surface roughness. This technique is appropriate to determine the average optical roughness(Ra) of the specimen and the sub-micron range of Root Mean Square(RMS) values of the sample agreed well by way of the stylus conventional profilometer method.