Glass, including fused silica, phosphate glass, fluorophosphate glass, zirconium fluoride (ZrF 4 ) (CAS 7783-64-4) and hafnium fluoride (HfF 4 ) (CAS 13709-52-9) and having all of the following: 1. A hydroxyl ion (OH – ) concentration of less than 5 ppm; 2. Integrated metallic purity levels of less than 1 ppm; and 3. High homogeneity (index of refraction variance) less than 5 × 10 – 6 ; (e) Synthetically produced diamond material with an absorption of less than 10 – 5 cm – 1 for wavelengths exceeding 200 nm but not exceeding 14 000 nm.