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SQ Fused Silica

ultrapure fused silica In 5 quality grades


SQ Fused Silica —  Especially for the production of optical and photonic devices in the fiber optic, semiconductor and display technology markets, as well as for optical applications and laser applications. The particularly inclusion- and bubble-free material features excellent optical and physical properties:

  • Laser durability
  • Refractive index homogeneity
  • Thermal stability and temperature shock resistance
  • Low stress birefringence
  • Small thermal expansion coefficients

Due to the high OH and H2 content our fused silica SQ shows extremely low fluorescence and high stability under high-energy UV and laser radiation.


Excimer laser optics and beam guiding systems

  • DUV and UV optics components
  • Standard optics (VIS and NIR)
  • UV rods, preforms and optical fibers
  • Laser fusion
  • Technical applications
    • Fused silica vessels, windows
  • Lithography and microlithography applications
    • stepper lenses, photo mask blanks, wafers and lithography optics

Design / quality

LEONI offers SQ Fused Silica as ingot or semi-finished product (round disc, rod, plate, block etc.) in five quality grades concerning homogeneity, absence of striae and application type. The quality grades are adjusted to individual customer needs in proven measuring and selection procedures. Thus, the fused silica can be used in the optical application range from DUV to NIR.

Quality grades (according to customer-specific needs / applications)

SQ0: is a 3D material free of striae and striations in any functional direction. It is recommended for requirements in optical elements with several light directions such as prisms and lenses.

SQ1: With high homogeneity and free of striae and striations in the functional direction. Typical applications are optical elements such as lenses, discs, wafers and rods / fibers.

SQT: not specified concerning homogeneity, striations and striae. This quality level is recommended for technical applications.

Excimer grade Fused Silica – available as SQ1 or SQ0: Excellent transmission at 193 nm / 248 nm. Lowest level of laser-induced fluorescence (LIF).

  • SQ0-E193 / SQ1-E193 (ArF  excimer grade)
  • SQ0-E248 / SQ1-E248 (KrF  excimer grade)