Introducing Brewster angle
The Brewster angle, also known as the polarization angle, when incident natural light enters the interface at this angle, the reflected light is linearly polarized and perpendicular to the refracted light. This perspective is named after Scottish physicist David Brewster (1781--1868).
When natural light is reflected and refracted on the dielectric interface, generally the reflected light and refracted light are partially polarized light. The reflected light is linearly polarized only when the incident angle is a certain angle, and its vibration direction is perpendicular to the incident surface. The specific angle is called the Brewster angle or deflection angle. This law is called Bruce's specific law. When light is incident at the Brewster angle, the reflected light and the refracted light are perpendicular to each other.
The essence of the Brewster's angle is that when the light and the medium interact, it stimulates the optical intrinsic resonance mode at this angle, so that it can be completely refracted.