Optical Instruments

This article describes some complex devices which are commonly used in the laboratory for analysis of condensed matter, instruments which measure the fundamental quantity of light, and use the interaction between light radiation and matter. It is assumed, that the reader is confident with simple optical instruments such as lenses, mirrors, prisms, and diffraction gratings. A complete description of the fundamental optical phenomena is given elsewhere in this encyclopedia and can be easily found in literature on fundamental optics. Before describing optical instruments in detail, a brief overview of light behavior is given. Among the instruments commonly used in the laboratory, the spectrometer or devices based on scattering, absorption, and reflection are widely described in other sections of this encyclopedia. Also interferometric methods used in microscopy are illustrated elsewhere. Here, the focus is on the following instruments: refractometer, interferometer, polarimeter, ellipsometer, and radiometer.