DYE FILMS FOR OPTICAL DEMONSTRATIONS IN THE UNDERGRADUATE LABORATORY

Homogenous films are needed in optical applications of dye doped polym ers; for example in holography, in holographical memories or in phase conjugation. Typically organic and bio-organic films are made in the l aboratories by pouring the dye-polymer solution onto the substrate, wh ich leads often to inhomogenities in the thickness and thus in the opt ical density, especially by inexperienced students. We have made good quality dye films with optical densities varying by +/-10% by using co mmercial gelatin plates and soaking them in the dye solution. We prese nt the influence of the processing parameters to the optical density o f the methylene blue and erythrosin gelatin films. The phase conjugati on intensity in degenerate four wave mixing experiment is shown as an example of the optical experiments realized in the undergraduate labor atory. (C) 1998 Published by Elsevier Science B.V. All rights reserved .