Principle of Dichroic Glass:
When a bundle of monochromatic light is refracted on the surface of the crystal (as picture show), commonly two beams of refracted light are produced. This phenomenon is called birefringence. One of the two refracted lights always according the rule of refraction, called normal light, which is represented by the mark o; the other beam generally does not according the rule of refraction, called extraordinary light, and is represented by the mark e. Both o and e are linearly polarized. Most crystals produce equal intensity of o and e light in the natural light. However, some crystals have a large difference in the absorption of two refracted lights. This property is called dichroism. HHG offer three kinds of colors, including blue, green, yellow and orange.