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Product Information

High quality synthetic fused silica LITHOSIL® with excellent optical properties is particularly suitable for the highly demanding applications found in the optical industry. The different quality levels (offered in different grades: Q0, Q1, Q2, QT) can be adapted to all kinds of individual customers' needs, from NIR (IR) to DUV. Synthetic fused silica LITHOSIL® from SCHOTT North America has the following outstanding properties: Free of inclusions and bubbles (eg. grades Q0 + Q1) Excellent UV transmittance from 185 nm to 2.5 µm High laser durability High refractive index homogeneity: additional 3D option High temperature stability Low stress birefringence Very low thermal expansion coefficient Very low fluorescence

Benefits

The amorphous synthetic fused silica LITHOSIL® of high purity completes the application range of optical materials from DUV to IR with a very good transmission ranging from 185 nm to 2.5 µm.

Key Applications

Fused silica is widely used in applications such as: Micro-/Lithographic applications: stepper lenses, photo mask blanks DUV laser components Standard optics Excimer laser optics Litho optics Beam deliveries Light pipes Laser fusion Technical usage

Forms of Supply

SCHOTT North America offers LITHOSIL® components and blanks in different grades along with different surface qualities (raw, cut, ground or polished), depending on the individual requirements of the customers.

Specifications

Grades: Different material grades are characterized in the functional direction by: Very low inclusion / bubble levels Low levels of refractive index variations and local in-homogeneities especially striae Excimer Grades: Excimer laser optics require fused silica of the following exceptional qualities: High internal transmission, wide spectral UV-range Very low fluorescence (qualified by laser induced fluorescence at 193 nm). Excimer grades are available in LITHOSIL® Q0 and Q1 grade 3D Material Refractive index homogeneity qualified in all 3 dimensions depending on geometry Available in LITHOSIL® Q0 grade 3D Material is available on request

Quality Assurance

SCHOTT North America offers fused silica with 100% control of homogeneity, stress birefringence, striae, bubbles, and inclusions. We utilize statistical control of refractive index, transmittance, laser induced fluorescence, trace-elements and OH-content. Quality levels: Q0: is characterized by its high three-dimensional optical homogeneity. Free of striations in any functional direction, it is recommended for high-end resolution requirements in optical elements such as prisms and lenses. Q1: exhibits high homogeneity and has no striations in the functional direction. Typical applications are optical elements such as lenses, windows and wafers. Q2: is not specified concerning homogeneity. This grade is recommended for optics in the visible spectral range or optics in the UV with less stringent demands on transmission. QT: is not specified concerning homogeneity, striae and striations. This grade is recommended for technical applications.

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