ABSTRACT
This chapter reviews the main methods of spectroscopy, concentrating mainly on covering general concepts of spectroscopy. Optical spectroscopy is an invaluable tool for the characterization of many physical and chemical components and processes. Important spectroscopic methods and types of spectrometers will be mentioned together with a brief description of some interesting case studies of optical sensor systems. The technique of absorbance spectroscopy, or spectrophotometry, monitors attenuation of a beam of light by matter and is one of the most commonly applied methods in spectrometry, particularly in the infrared (IR), visible (VIS), and ultraviolet (UV) regions. Electromagnetic radiation in the UV, visible, and IR wavelength range is especially interesting in spectroscopy. Electromagnetic radiation is characterized by its amplitude, frequency, state-of-polarization, phase, and in the case of modulated light, the time dependence of its amplitude, phase, or frequency. The most usual and important interaction with matter for use in spectroscopy involves the electric field vector.
