POLARIZATION MODULATED TRANSMISSION SPECTROELLIPSOMETRY

A polarization modulated transmission spectro-ellipsometer (PMTSE) fea tures high sensitivity for retardation and high-speed data acquisition . Although optical servo control of a photoelastic modulator (PEM) has improved the accuracy of the system, the residual birefringence mainl y of the PEM hinders detection of minute retardation. We have installe d a compensator in order to cancel out the residual birefringence and realized base line shift that is within 0.2% of full scale. Optical an isotropies are formulated in the Mueller matrices. Accuracy for a larg e signal was verified from measurements of a sheet polarizer and a qua rtz rotator. Detectability was ascertained from the retardation spectr um, <1 nm, of a amorphous poly-olefin film and aqueous solution of a c hiral metal complex, Delta-[Co(en)(3)](3+), whose peak signal magnitud e is <1% of full scale. A time resolution of 1 ms was utilized in the dynamic response measurement of a liquid crystal, 5CB, that had a resp onse time of 3-4 ms. (C) 1996 American Institute of Physics.