Common Laser Optics Materials
This is Section 1.9 of the Laser Optics Resource Guide.
Understanding the most commonly used laser optics materials will allow for easy navigation of EO’s wide selection of laser optics components. Table 1 below lists common substrates used for laser optics, along with their key properties, followed by transmission curves for each material. All values in Table 1 are at 1064nm and 20° C and all transmission curves show the internal transmission of 5mm thick substrates without Fresnel reflections. Transmission data was gathered using Edmund Optics’ spectrophotometers.
|Material||Transmission Range (nm)||Index of Refraction (n)||Abbe Number (v)||Group Velocity Dispersion (fs2/mm)||dn/dT
|Coefficient of Thermal Expansion (10-6/K)||Relative Price|
200nm - 7μm
|UV Grade Fused Silica (Corning HPFS® 7980)2||185nm - 2.1µm||1.450||67.8||16.476||9.6||0.55||$$|
|KrF Grade Fused Silica (Corning HPFS® 7980)2||185nm - 2.1µm, T ≥ 99.9% @ 248nm||1.450||67.8||16.476||9.6||0.55||$$$
|IR Grade Fused Silica (Corning HPFS® 7979)2||300nm - 3.5µm||1.451||67.8||16.476||9.7||0.55||$$($)|
|N-BK73||350 - 2000nm||1.507||64.2||22.369||3.0||7.1||$|
|N-SF53||330 - 2500nm||1.651||32.3||77.779||3.4||7.9||$|
|Sapphire*4||200 - 5500nm||1.755||72.2||28.588||13.1||5.4||$$$|
|N-SF113||400 - 2500nm||1.754||25.8||118.44||2.4||8.5||$|
*Sapphire is a birefringent material and all specifications correspond parallel to C-Axis
Table 1: Common laser optics substrates and their key properties (all values at 1064nm and 20° C). Materials are listed from smallest refractive index to largest refractive index. The small dollar sign by KrF grade fused silica indicates that it is slightly more expensive than UV grade fused silica. SImilarly, the small dollar sign in parentheses by IR grade fused silica indicates that it is sometimes slightly more expensive than UV grade fused silica, but it is almost never cheaper
Figure 1: CaF2 has excellent transmission in the UV and IR spectra, making it a great choice for both UV and IR laser optics applications
Figure 2: Sapphire is highly durable and can be used across a broad wavelength range from the UV to the IR
Figure 3: Fused Silica is available in UV and IR grades, which are differentiated by the amount of OH content in the material
Figure 4: While Fused Silica is more common in laser optics, CaF2, Sapphire, N-BK7, N-SF5, and N-SF11 are also used in some transmissive laser optics
Figure 5: The transmission of N-BK7, N-SF5, and N-SF11 decreases rapidly in the IR spectrum
- I. H. Malitson. “A redetermination of some optical properties of calcium fluoride,” Appl. Opt. 2, 1103-1107 (1963)
- “Corning HPFS® 7979, 7980, 8655 Fused Silica.” Corning, February 2014.
- “Optical Glass Data Sheets.” Schott, February 2014.
- I. H. Malitson. “Refraction and dispersion of synthetic sapphire,” J. Opt. Soc. Am. 52, 1377-1379 (1962)
- Collier, David, and Rod Schuster. “Superpolishing Deep-UV Optics.” Photonics Spectra, February 2005.