Brewster's main contribution
Brewster's greatest contribution was the development of the "Blues Specific Law" in optics. It follows from this law: "When a beam of light is projected at the interface of two media (such as air and glass), if the tangent of the angle of incidence of the light in the first medium (such as air) is equal to the second medium (such as glass) ), Then the reflected light becomes fully linearly polarized. " The angle of incidence at this time is called the "Brewster angle," or the angle of polarization.
Brewster's law: When the incident angle i satisfies tani = n2 / n1, only reflected light is normal to the vibration of the incident surface, and there is no light vibration parallel to the incident surface. At this time, the reflected light is polarized light, and Refracted light is still partially polarized. i is called the "Brewster angle", or the angle of polarization.
Bruce's law is of great significance in modern optical technology. When the angle of incidence is Brewster's angle, 100% of the light energy in the polarization state can be injected into another medium. This transmissivity of light can be used to prepare a non-consumption laser window. The external cavity gas laser uses this principle.