Optical retardation properties of stretched Sylgard® 184

Abstract

This study investigates retardation of polarized light passing through Sylgard® 184 under tension. Using a photoelastic setup, the phase shift and retardation were determined from intensities of the emerging beam when polarizers were aligned and crossed and were found to be linearly proportional to strain. Sylgard® 184 with varying base to curing agent ratios exhibits this behavior. Strain-optic coefficient k allows us to evaluate changes in the refractive index of stretched sample. Its characterization and determination show that k varies with the amount of curing agent in the samples. This behavior is associated with the expected crosslink density of the samples.