Abstract
An apparatus is described for measuring the linear birefringence and linear dichroism induced in liquids or dispersions by an applied magnetic field. The apparatus uses a vibrating beam phase modulator and conventional optical and electro-optical components. It is capable of measuring Delta n' (the real part of the complex birefringence Delta n) down to about 10-12 and Delta n" (the imaginary part of Delta n) down to about 10-10. Results are given for liquids of very small Cotton-Mouton constant, hitherto unmeasurable, and very dilute colloidal dispersions. Dust removal from sample liquids is shown to be of major importance for weakly birefringent or dichroic samples.