Cottrell College Science Awards - 2014
Optimization of index contrast in holographic photopolymers able to create waveguides and fluid channels in optofluidic devices
Refractometers are useful devices in many areas, including medicine, the food industry and even the classification of gemstones.
They operate on the fundamental principle that when light enters a target material the light refracts, or bends, a specific amount depending on the composition of material. By measuring how much the light bends, one can learn important information about the chemical composition of the target material.
Martha-Elizabeth “Marty” Baylor, assistant professor of physics, Carleton College, is working to improve optofluidic refractometers.
They work by putting refracted light into a thin strand of fiber-optic cable – termed a “waveguide” because it guides the light waves along its length -- perpendicular to a small channel where a tiny amount of fluid is made to flow. By analyzing the light after it has interacted with the fluid, this device can determine certain qualities of the fluid.
“This is a particularly useful technique for measuring sugar concentrations of liquids such as wine and fruit juice,” Baylor notes.
Unfortunately, optical fiber is fragile and difficult to work with when creating small optofluidic refractometers.
Thus Baylor and her students are working with a special light-sensitive polymer – plastic – material that should make fabrication of these devices easier. Their new polymer uses ultraviolet light and masks to create perfectly aligned tiny channels for light and fluid to interact with simple techniques and minimal cost.
Baylor and her students will study the chemical and material properties of their polymer for possible application to other optofluidic device applications.