Patent ID: 6904069

Claim:
A laser that controls amplified spontaneous emission and/or parasitic light, comprising: a laser gain medium having polished surfaces that are used to transport pump light by internal reflection throughout said laser gain medium, a light source directing laser pump light into said laser gain medium, a layered coating on at least some of said polished surfaces that are used to transport pump light by internal reflection of said laser gain medium, said layered coating comprising a first inner material coating layer, said first inner material coating layer comprising a transparent coating, and a second absorptive scattering outside material coating layer, said second absorptive scattering outside material coating layer comprising an absortive layer or a scattering layer or both an absorptive layer and a scattering layer, wherein said layered coating is configured to substantially reflect the pump light that strikes the layered coating so as to direct the pump light back into said laser gain medium, and substantially transmit said amplified spontaneous emission and/or parasitic light that strikes the layered coating so as to let this light strike said outside material coating layer of said layered coating where it is scattered or absorbed or both scattered and absorbed.