An additional impressive diamond property is it's high transparency over an extremely broad optical range, extending from the far infrared down to 220nm (deep ultra violet) with only a slight distortion between 2 - 6 µm. These properties remain almost constant even under high temperatures. In combination with the high thermal conductivity and the low thermal expansion coefficient, diamond is an ideal material for windows and lenses designed for high power radiation.
Other interesting fields of application arise when combining the wide band transparency with the extraordinary mechanical and chemical stability of diamond. For example, windows for extremely harsh environmental conditions can be made.