Miniature Birefringence-Measuring System

A miniature birefringence-measuring system has been developed for use in investigating extensional flows of non-Newtonian polymers in microgravity. The system could also be used on Earth to perform general optical-retardation and dichroism measurements, to measure stresses with high sensitivity, to characterize polymers, and to measure orientation angles of molecular chains. The system includes a dual-crystal transverse electro-optical phase modulator that makes it possible to measure small (of the order of 10 -9) changes in the birefringence of a material under test as the material is subjected to extensional deformation or shear stress.