Measuring grazing-angle DHR with the infrared grazing angle reflectometer

摘要

The Infrared Grazing Angle Reflectometer allows measurement of Directional Hemispherical Reflectance (DHR)at very high angles of incidence (30 to 85 degrees) and at wavelengths ranging from 4.3 to 10.8 microns. Ahemi-ellipsoidal mirror redirects the reflected light and reflects it on to a novel five-sided pyroelectric detector.The incident light intensity is measured and used in calculating the DHR of the sample. In this paper, the theoryof operation of this detector is derived, and used to simulate the operation of the system. This simulation of thedetector shows errors of 3% or less for both diffuse and specular samples, compared to the theoretical DHR. Thecalibration method defined in this paper allows for high accuracy and ease of use without knowing the specificattributes of the optics used in the system. Finally, collected DHR data is compared with the simulated datafor comparison. Comparing the measured data to the simulation shows that the model correctly predicts thelocations and trends of the scattered energy.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.