Abstract

Spectrometers with a spectral resolution of better than 1 nm are capable of resolving the interference effects in substrates with thicknesses of <100 µm. The absolute reflection accessory that uses the John Strong VW method measures the product of the reflection or transmission at two different locations on the sample. The spectra of a silicon wafer polished on both sides showed some unusual and unexpected interference effects. Other thin substrates of glass and polyester films also showed unusual effects. Computer calculations were made to investigate the nature of the interference effects when two thicknesses are used in a calculation of the reflection or transmission squared.

© 1987 Optical Society of America