NASA's Langley Research Center has developed an adaptable and powerful interferometric test platform that uniquely enables multi-parameter evaluation of a wide variety of smart optical materials (SOM). The patent-pending SOM characterization system was created to measure the dynamic optical response of stimuli-responsive (“smart”) optical materials while external physical/electrical/thermal/chemical/pressure/magneto stimuli are applied to the material. Using novel interferometric fringe analysis software and a multi-stimuli-capable SOM test cell, the SOM characterization system enables a wide variety of materials — such as liquid crystals, nonlinear crystals, electro- and thermo-active polymer optics, and magneto- or piezo-driven optics — to be optically characterized for real-time changes in intensity, phase, and polarization. The versatility of the SOM test platform combined with the powerful, efficient, and user-friendly software interface makes it a valuable tool for the research or commercial development of smart materials.
Using a Michelson interferometer platform and a single, custom SOM test cell capable of providing multiple types of external stimuli, the characterization system software dynamically controls stimuli (e.g. physical, electrical, thermal, magneto, or chemical) to the SOM under test and then measures the resulting changes in intensity, phase angle, polarization state, and coherence of the transmitted or reflected light. The accompanying software records and analyzes the dynamic change of interference patterns on multiple pixels in a time sequence as the stimuli are applied, and presents a phase/intensity time ripple map for the SOM under test. The SOM characterization system provides variable (milliseconds to hours) acquisition rates for multipoint, full-aperture measurements.
The system supports evaluation of up to 10 key optical parameters from a single interferometric data set. These can include index of refraction, optical intensity, phase, and polarization. Dynamic SOM test cell control is combined with interferometric fringe analysis and data visualizations through a page-driven menu. The system provides a flexible yet material-specific test platform for evaluating smart optical materials. Using a common optical platform and multi-stimuli test cell, the system provides full-aperture (20-50 mm), full-transmitted, or reflected-wavefront measurements.
Applications include nonlinear and liquid crystal switching and waveguide device testing for telecommunications; liquid crystal materials, 2D pixel arrays, and device testing for 2D/3D displays; active and adaptive materials and component evaluation for precision and adaptive optics; and evaluation of the stimuli-responsive materials used in sensors and detectors.