Abstract
A new measurement technique of liquid film thickness, such as oil film thickness, proposed one of the authors, was developed in this study. In this technique, a fluorescent dye was dissolved in the liquid film and excited by a laser light. With appropriate concentration of fluorescent dye and intensity of incident Laser light, a beam of light with wavelengths corresponding to a liquid film thickness was emitted perpendicular to the liquid film by stimulated emission of radiation. To extend the applicability of this method to measure a thinner liquid film, selection of fluorescent dye was discussed in detail and the suitability of the combination of Rhodamine6G and the short pass filter was confirmed.
