Polarized sunglasses are a pair of sunglasses. Polarization can be divided into three types, namely linear polarization, elliptically polarized light and circularly polarized light. Generally speaking, polarized light refers to linear polarized light, also known as planar polarized light. The vibration of this light wave is fixed in a specific direction, the propagation path in space is sinusoidal, and the projection on the plane of the vertical propagation direction is a straight line.
A plane composed of a linear polarization vibration direction and a propagation direction is called a vibration surface, and a plane perpendicular to the vibration direction and including a propagation direction is called a polarization plane. Linear light can be obtained by passing natural light through a polarizer, which is often used in crystal optics research.