Corning® HPFS® 7979 and 7980 are families of high-purity fused silica, not interchangeable single grades. The correct selection depends on wavelength, hydroxyl content, laser exposure, index homogeneity and the certification level required for the finished optic.
HPFS® 7979 or 7980: Start With the Optical Band
HPFS® 7979 IR Grade
Designed for infrared use and specified with very low hydroxyl content. It is a practical starting point when the 2.7 µm OH absorption region or other IR loss mechanisms matter.
Do not specify “7979” alone: add the working wavelength, optical path length, homogeneity class and required certificate.
HPFS® 7980 Grades
The 7980 family includes Standard, KrF, ArF, Mirror and Industrial grades. These options do not carry the same impurity, fluorescence, homogeneity or striae certifications.
Select the grade against the application—general UV-visible optics, excimer-laser exposure, mirror substrates or non-certified tooling.
Certified Optical Quality Is Part of the Material Specification
For precision optics, material quality is defined by more than chemistry. Corning’s grade system can include inclusion class, refractive-index homogeneity, striae class and birefringence. Those values should be selected in the direction and clear aperture used by the finished component.
Homogeneity is commonly reported in parts per million over a certified aperture. Inclusion class describes the permitted inclusion population, while striae and birefringence address wavefront distortion that may not be visible during a basic cosmetic inspection.
What to Put on the Drawing or RFQ
- Corning HPFS glass code and exact grade
- Finished dimensions and clear aperture
- Operating wavelength or full spectral band
- Transmission requirement at finished thickness
- Homogeneity grade and measurement direction
- Inclusion and striae class
- Maximum birefringence
- Surface quality, flatness and parallelism
- Edge finish, chamfer or bevel geometry
- Coating, cleaning, packaging and certificate needs
Fabrication Into Finished Components
We review available HPFS stock against the required blank size before cutting. Finished parts may include optical windows, wafers, discs, substrates, light-guide components and CNC-machined quartz features. Grinding, lapping and optical polishing are planned around the certified material orientation and clear aperture.
For laser or semiconductor use, identify every surface that must remain free of chips, subsurface damage or process contamination. Cleaning and packaging requirements should be agreed before final inspection, not added after machining.
Data Qualification
The numerical values on this page are reference values reproduced from Corning technical data. Grade availability and certification limits vary by form, size and current manufacturer specification. The purchase specification and current Corning certificate take precedence.
Send the glass code, working wavelength, drawing and optical requirements for stock and manufacturability review.
Request a Material Review
Grade-Qualified Material Purity
Electric-fused / flame-fused quartz: SiO₂ ≥99.99%; synthetic JGS1-grade fused silica: ≥99.999%. Grade and lot certificate govern supplied material.
