Surface profiling using a double-fiber optical design

Abstract

In this study surface profiling is performed by using a scanning system and an opto-pair fiber design. In this method one fiber transmits the laser light to the target and the second one transmits back the light reflected off the target to a photodetector. The monitoring of the reflected light signal from a surface is accomplished by converting the photon light into an electric signal and measuring by a digital multimeter. By scanning an object mounted on a XYZ-translational stage the reflection signal profiles are obtained for plane and curved surfaces. Output reflection signal variations in the X-, Y-, and Z-directions are measured for different plane and cylindrical surfaces and compared. Reflecting signals can provide information about the structure of the surface and in particular, can provide information about the shape of surface under study. It is noted that the fiber arrangement and the position of the object surface in respect to fibers are important in reflecting signal measurements. The convex surface of the same quality reflecting material has a reflection lower than that of the plane/concave surface. For a brass half-cylindrical shell when the fiber arrangement is vertical but the half-cylinder is horizontal the reflected signal power is lower than for the case that both fibers and cylinder are either horizontal or vertical. The reported opto-mechanical system can also be used to investigate surfaces made from different materials and different final finishes. As a result, the proposed system provides a simple and accurate means for the object shape study and determination of different surface structures through the reflection analysis.