Silicon mirror：The substrate silicon, which has good optical and thermal properties, can greatly increase its reflectivity after being coated with a reflective film on the surface of the silicon, which is about 98-99%, almost avoiding the loss of light caused by reflection.
Molybdenum reflective lens：The molybdenum substrate is directly polished, the surface is not coated, it is resistant to scrubbing, and has a long service life. However, because the molybdenum mirror is not coated, its reflectivity is low, about 88%-90%, and there is light loss after reflection.