Access to SPIE eBooks is limited to subscribing institutions. Access is not available as part of an individual subscription. However, books can be purchased on SPIE.Org
Chapter 3:
Performance of Optical Filters
Author(s): James D. Rancourt
Published: 1996
DOI: 10.1117/3.242743.ch3
Conservation of energy requires an accounting of all of the energy in the incident light beam. Generally, a consideration of the reflectance and transmission intensities and of the absorption accounts for most of the incident light. In some instances, scattering also plays a role; this is not considered here, but is covered in the next section. If there is no absorption in the spectral range of interest, then reflectance and transmittance must equal unity, or 100 percent if the values are given as percentages. In this text, we deal with the ratio form of these values in equations, unless otherwise noted, and the percentage form is used in the narrative because of its clearer meaning. The mathematical derivations of the equations governing the behavior of thin film interference filters indicate that the transmission of a coating is independent of the direction of the arrival of the light (Heavens, 1965, p. 77). This is well established in practice, and it simplifies the measurement of transmission, as the side of incidence of the filter is unimportant.
Online access to SPIE eBooks is limited to subscribing institutions.

Optical filters



Interference filters

Laser scattering

Light scattering


Back to Top