Apparatus & Method to Certify Properties of Infrared Optical Materials

AbstractThis proposal addresses the DoD’s solicitation for precise refractive index measurement of infrared (IR) optical materials by  employing coherent light sources, and utilizing advanced modeling techniques.Phase I will focus on conceptualizing and mathematically substantiating a novel methodology for achieving high-precision refractive index measurements. We will investigate the use of a coherent laser source to enhance measurement accuracy. A detailed study will be conducted to model the light-material interaction using 4 × 4 matrix formalism to account for bulk and surface effects. This will involve designing experiments to determine the impact of spot size reduction on measurement precision and validating the approach against established standards.  Construction of a prototype laboratory apparatus  will be initiated. We will construct and test the apparatus, focusing on optimizing acquisition and maintenance costs and operational efficiency. The prototype will be evaluated with various IR materials such as Ge, GaAs, ZnSe  to confirm the capability of achieving refractive index precision of 0.001. Performance metrics will include accuracy, repeatability, and operational practicality for in-line manufacturing applications. we will also address the need to measure the refractive index across a wide temperature range from -40°C to +71°C. The proposed methodology will incorporate a temperature-controlled environment to ensure precise measurement of temperature-dependent refractive index variations.