ABSTRACT
A spectrum is a representation of a phenomenon in terms of its frequency of occurrence. A spectrometer is any device that measures a spectrum. Prism spectrometers were improved little by little by the introduction of better sources, better detectors, and better optics. Grating spectrometers had these improvements, but were also improved in very substantial ways by the improvements in grating manufacture. Resolution is a measure of the fineness with which the width of a spectral line can be measured. A filter spectrometer in concept is a device that consists of a number of filters, each of which passes a small portion of the spectrum. Laser spectrometers are different from classical spectrometers in that there is no monochromator; the source is a tunable laser. Grating and prism spectrometers come in a variety of configurations: single and double pass, single and double beam, and double monochromator versions.
