Ellipsometric memory which is optical memory based on the ellipsometric principle has been proposed in 1994 for the first time and was examined by preliminary experiments using multilayer thin film structures. Though this idea has a great potential for new high capacity optical memory, oblique angle incidence was inevitable and needed rather big sized cells because of the large incident angle. To overcome this difficulty we propose the transparent type ellipsometric memory with thin film multilayer structures. In the transparent ellipsometric memory, the ellipsometric parameters of transmitted light through thin film multilayer structures, instead of reflected light, are measured. This modification makes the normal incident light useful and the cell size small. We carried out model calculations and preliminary experiments using Mg-Mo two-layered thin film structures to confirm the feasibility of the transparent type ellipsometric memory. (C) 2003 Elsevier Science B.V. All rights reserved.