Prisms are polyhedra made of transparent materials such as glass and crystal. It is widely used in Optical instrument. According to the working principle of different optical prisms, the application range is also different, mainly including the color Dispersive prism used in spectral instruments, the total reflection prism used in Periscope, binoculars, etc. to change the direction of light and adjust its imaging. Today, we will mainly look at the working principle of Dispersive prism?
The plane from which light enters is called the side of an optical prism. The plane perpendicular to the side is called the main section of the prism. According to the shape of the main section, it can be divided into Dispersive prism, right angle prism, pentagonal prism, etc.
The main section of a Dispersive prism is a triangle. A Dispersive prism has two refracting surfaces. Their included angle is called the vertex angle. The plane opposite the vertex angle is the bottom. According to the refraction law, the light passes through the Dispersive prism and deflects twice to the bottom. The included angle q between the outgoing light and the incoming light is called the deflection angle. The size is determined by the refractive index n of the prism medium and the incidence angle i. When i is fixed, light of different wavelengths has different deflection angles. In visible light, the largest deflection angle is purple light and the smallest is red light.