A NEW ELLIPSOIDAL MIRROR-TYPE REFLECTOMETER FOR MEASURING NORMAL-INCIDENT HEMISPHERICAL REFLECTANCE SPECTRUM

A new reflectometer system is developed to measure the radiation chara cteristics of solid materials from a heat transfer science point of vi ew. This system employs an ellipsoidal mirror in a simple optical alig nment, and measures the spectrum of the normal-incident hemispherical reflectance in the wavelength region of 0.35 to 1.10 mum. A single spe ctral scanning gives a hemispherical reflectance spectrum which comple tely covers both the specular and diffuse components of reflection. Th e reflectance is directly interpreted in terms of the absorptance for the normal incidence. The system also readily measures the angular cha racteristics of reflection. The system is applied to a systematic stud y of the reflection characteristics of rough metal surfaces. The predo minant contribution of the specular component to the angular character istics is demonstrated.