Determination of specular reflectances in a liquid medium with a variable angle of incidence

S. Gil, G. A. Clarke, L. McGarry, C. E. Waltham
1995 Applied Optics  
We present a technique we developed to measure specular reHectances ofmirrors immersed in liquids and in air. The methad warks with a bread unge of angles of incidence (0 = 15-75"). Tbe wavelength range used in this reseaxcb was fram 250 to SOO nm, and the state ofpolarizatian ofthe incident rays could be eontinuously varied with respect to the phase afineidence. The teehnique used in this study is based on a low-cost variable-angle reflectometer and a eommercial spectrophotometer. Here we
more » ... ss the protocol we devised to extraet reHectanees with this instrument. This procedure was tested with samples that were measured through the use of ellipsometric teehniques. The main advantages of the method diseussed here are versatility, speed, and the availability af the equipment used; these are partieularly useful for cantrolling the quality of a large number of samples. We present the results of reHectanee measurements in water for dielectric coated aluminum intended for use in ligbt eoneentrators for the Sudbury Neutrino Observatoly. The error in our estimate of the overall reflectance, weighted over operatianal distributions of wavelength and incident angle. is t3?4 for ene sample and +5%> far the
doi:10.1364/ao.34.000695 pmid:20963171 fatcat:jju2tx6hd5bgzljnfhecl6nocm