Definitions of Optical Instrumentation and Measurement

In this chapter we turn our attention to the definitions, terms, quantities and units most commonly employed in optical instrumentation and measurements. For example, in the planning and construction of experimental arrangements and, in particular, in the application of light sources and detectors there is a need for a basic understanding of radiometry and photometry. We will also define some basic concepts such as absorptance, transmittance and reflectance. There is still a plethora of terms in use in this field of science. Indeed, terminology developed for use in one discipline is sometimes carelessly applied in another. Our treatment of this subject follows the thorough expositions by Zalewski [178] and Palmer [179].