Every material below is sourced through a qualified global network, prepared for yield, and carried with full batch and lot traceability. Pick by wavelength first, then by environment and cost.
Typical published values for common grades. Confirm against a grade-specific datasheet before design freeze.
| Material | Transmission | Refractive index | Density | Knoop hardness | Typical use |
|---|---|---|---|---|---|
| MgF₂ | 0.12 – 7 µm | 1.3777 @ 0.6 µm | 3.18 g/cm³ | 415 | Deep-UV and excimer windows |
| CaF₂ | 0.13 – 10 µm | 1.4338 @ 0.6 µm | 3.18 g/cm³ | 158 | Broadband UV–IR, FTIR cells |
| Sapphire | 0.17 – 5.5 µm | 1.7682 @ 0.6 µm | 3.98 g/cm³ | 2200 | Abrasion and pressure windows |
| Fused Silica | 0.18 – 2.5 µm | 1.4585 @ 0.59 µm | 2.20 g/cm³ | 500 | UV/VIS/NIR laser optics |
| N-BK7 | 0.35 – 2 µm | 1.5168 @ 0.59 µm | 2.51 g/cm³ | 610 | General visible optics |
| ZnS (multispectral) | 0.4 – 14 µm | 2.2008 @ 10.6 µm | 4.09 g/cm³ | 160 | Dual-band VIS + LWIR |
| ZnSe | 0.6 – 21 µm | 2.4028 @ 10.6 µm | 5.27 g/cm³ | 120 | CO₂ laser optics |
| Chalcogenide (AMTIR-1) | 0.7 – 12 µm | 2.5109 @ 10.6 µm | 4.40 g/cm³ | 170 | Athermal thermal imaging |
| GaAs | 1 – 15 µm | 3.278 @ 10.6 µm | 5.32 g/cm³ | 731 | High-power CO₂ delivery |
| Silicon | 1.2 – 8 µm | 3.4223 @ 5 µm | 2.33 g/cm³ | 1150 | MWIR windows, mirror blanks |
| Germanium | 2 – 14 µm | 4.0032 @ 10.6 µm | 5.33 g/cm³ | 780 | Thermal imaging objectives |
| Copper (mirror) | R > 98% @ 10.6 µm | — | 8.96 g/cm³ | — | High-power beam steering |
Knoop hardness is a relative guide to handling and cleaning risk — ZnSe and CaF₂ are soft and scratch easily; sapphire and silicon tolerate far more.
CVD-grown, laser grade with ≤ 80 µm inclusions. Very low absorption at 10.6 µm makes it the default focusing and window material for CO₂ systems, and its visible transmission gives you a red alignment channel through the same optic.
Handle with care: the low hardness means fingerprints and aggressive cleaning leave permanent marks. Specify AR both surfaces for a real transmission gain.
The highest refractive index of the common IR set, which buys you shorter, more compact lens designs. Opaque in the visible, so alignment must be handled on a separate path.
Less than half the density of germanium and a much better thermal conductor — the right call whenever mass or heat dissipation drives the design. Also our standard blank for laser mirror substrates.
Note the strong lattice absorption band near 9 µm — silicon is a MWIR material, not an LWIR one.
Mechanically robust with a high damage threshold — chosen for high-power CO₂ delivery optics and protective windows that live in dirty, high-flux environments where ZnSe would not survive handling.
Available as Cleartran® and multispectral grades. The unusually wide window — visible right through long-wave IR — makes it the natural substrate for dual-band assemblies that must image and align through one element.
A germanium–arsenic–selenium glass with a very low thermo-optic coefficient. If a thermal imager has to hold focus across its whole operating temperature range without an active compensation mechanism, this is how it is done.
Alignment paths, beam combiners, visible channels in dual-band assemblies, and everything that has to survive an excimer source.
Low thermal expansion and excellent UV transmission. The default for Nd:YAG harmonics and any high-stability visible path.
The widest single window we stock — deep UV all the way to 10 µm. Standard for FTIR cells and broadband spectroscopy.
Transmits further into the vacuum UV than anything else here, and is birefringent — specify orientation if that matters.
Knoop 2200 — effectively unscratchable in service. The answer for abrasive, high-pressure or chemically hostile windows.
Past a certain power density no transmissive optic survives the thermal load. Diamond-turned copper reflects more than 98% at 10.6 µm and carries the remaining heat away through the substrate — with a water-cooled option for continuous-duty industrial sources.
Send the source wavelength, power, environment and quantity. We will recommend a substrate and coating design before you commit to a drawing.