**1. Introduction**

Optically active materials are the fundamental constituents of the human body and its nutrients. Major part of the daily human diet is comprised of OAMs, and has a strong impact upon wellness and performance of the human body. The monitoring of OAMs in everyday nutrition is of vital importance for being healthy, lean and active. Therefore, a strong check of quality control is always the matter of concern is the

industries including food, chemical, pharmaceutical, beverages etc. The OAMs cause the rotation in the angle of polarization of linearly polarized light when it pass through them. The variation in plane of polarization is different for different materials at different concentrations. OAMs are not limited to sugar (glucose, sucrose, fructose, maltose etc.), proteins, acids (tartaric acid, lactic acid etc.), cholesterol, etc.

A number of prescribed analytical techniques have been employed such as Ultra-voilet visible (UV–vis) absorption spectroscopy [1, 2], thin-layer chromatography (TLC) [3], infrared (IR) and Fourier transform infrared (FTIR) spectroscopy [4, 5] and Raman spectroscopy [6, 7]. However, optical techniques such as polarimetry [8, 9], interferometry [10, 11] and refractrometry [12] are commonly used in most of the practical applications for quantitative determination of OAMs due to their rapidity, noninvasiveness and non-destructive nature of their method of analysis.

OAMs are usually comprised of at least one asymmetric atom inside their molecular structure. The list of those atoms include carbon, sulfur, phosphorous, silicon etc. The asymmetric nature of these molecules result in the formation of two different types of isomers. The isomer of the same substance which rotates the plane of polarization of the light clockwise is called dextrorotatory or right-handed. However, those molecules which cause anti clock wise rotation of the polarization is called levorotatory or left-handed. Optical activity is the result of left–right asymmetry around the central carbon atom in the case of amorphous substances. The geometrical shape and chemical composition of both the molecules are same but left-handed isomer is mirror image of right-handed isomer and both of them are called enantiomers, as shown **Figure 1** for the D and L configuration of glucose molecule. Both of the enantiomorphs rotate the plane of polarization of light exactly by same magnitude but in opposite directions.

*A Review of Optical Interferometry Techniques for Quantitative Determination of Optically… DOI: http://dx.doi.org/10.5772/intechopen.104937*
