A compact dual-crystal modulated birefringence-measurement system for microgravity applications

A compact modulated birefringence-measurement system has been developed for use in microgravity fluid physics applications with non-Newtonian fluids s uch as polymer solutions. This instrument uses a dual-crystal transverse el ectro-optical modulator capable of modulation frequencies in excess of 100 MHz. The two crystals are modulated 180 degrees out of phase from each othe r. The theoretical framework governing the development of this instrument u sing the Mueller-Stokes polarization matrices is discussed. Several ground- based experiments are performed to compare this system with the theoretical results. Results from this transverse electro-optical modulator-based bire fringence-measurement system agree well with the theory. The instrument is also very stable and robust, making it suitable for the extreme acceleratio n environment to be encountered in a NASA Black Brandt sounding rocket.