Optical methods of investigation are based on application of the laws of optics, i.e. the laws describing the nature and mechanisms of optical radiation, its propagation and phenomena observed as a result of interaction of light with a substance. In other words, optical methods are physical-chemical methods of analysis that are based on the optical range of the scale of electromagnetic waves.
The optical methods of analysis include:
- Molecular-absorbing spectral analysis, which is based on the measurement of the luminous flux decay due to selective absorption of light by the analyzed substance;
- Atom spectroscopy, which uses the spectra of radiation or absorption of the substance after the substance being transformed into atomic state by the external high-energy impact;
- Refractometric analysis, which is based on the light refraction index versus nature and concentration of the substance;
- Fluorometric analysis, which is based on the intensity of the substance light emission, when absorbing external energy, versus its composition.