Optical activity describes molecules possessing at least one chiral center, resulting in a non-superimposable mirror image.
An illustrative example is the molecule presented below:
$$ \text{CH}_3\text{-CH}_2\text{-C}^*\text{-CH}_3 $$ (Chiral center - optically active)
The carbon atom designated as the chiral center is bonded to four distinct substituents, conferring optical activity upon the molecule. Consequently, this molecule has the capacity to rotate plane-polarized light.
