Abstract

Commercially available spectrophotometers, designed to obtain spectra for chemical analysis, are commonly used to characterize optical components with interference coatings. In this application, they exhibit several shortcomings: the sample compartments do not accomodate large components, particularly at off-normal incidence; beam deviation introduces error in off-normal transmittance measurements; rigid beam geometry makes reflectance measurements at arbitrary angles of incidence difficult; reflectance measurements must be referenced to a standard; reflectance measurements at normal incidence are not possible; and the beam’s conic angle in the sample chamber introduces error in off-normal measurements and in the measurement of narrow bandpass filters. Previous attempts to alleviate these shortcomings^1,2 have resulted in instruments which are mechanically complex, fail to address all the problems stated above, or are sensitive to the optical alignment.

© 1988 Optical Society of America