Optical Quartz Glass & Fused Silica Optics

Fused silica is the workhorse of demanding optics. Six properties explain why optical quartz glass is specified where ordinary optical glass cannot survive.

Broadband UV–IR Transmission

Fused silica transmits from deep-UV (around 170 nm) through the visible into the near-infrared. Few materials cover this range, which makes it the default for UV and broadband optics.

High Laser-Damage Threshold

Pure fused silica withstands high power densities with minimal absorption. This makes it the standard substrate for laser windows, beam optics and excimer-laser components.

Low Thermal Expansion

A very low expansion coefficient keeps surface figure stable as temperature changes. Optics hold their shape under thermal load, which protects wavefront quality.

High Homogeneity, Low Striae

Good index homogeneity and low striae keep wavefront distortion small. This is essential for imaging optics, interferometry and precision metrology.

Chemical & Radiation Durability

Fused silica resists most acids and tolerates UV and ionising radiation far better than ordinary glass. Optics keep their performance over long service life.

Polishable to Tight Specs

Fused silica polishes to high surface quality and tight flatness — down to λ/10 figure and 20-10 scratch-dig. This supports laser-grade and metrology-grade surfaces.

FGQuartz machines and polishes optical quartz glass into finished optics and blanks. Standard windows and discs ship quickly; custom geometries are made to drawing from the same facility. For grade and surface-spec guidance, see our fused silica optics guide.

UV fused silica windows transmit from deep-UV through near-IR with high uniformity. FGQuartz supplies round and rectangular windows, sight glasses and laser windows, with optional wedge, bevels and anti-reflection coatings. Both UV-grade (JGS1) and UV-Vis grade (JGS2) are available.

Round / rectangular · Wedged · AR-coat option · JGS1 / JGS2

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Fused silica lenses hold focus across the UV and visible bands where coated glass lenses absorb or fluoresce. FGQuartz makes plano-convex, plano-concave, bi-convex and cylindrical lenses to your radius, focal length and tolerance. UV fused silica is ideal for excimer and DUV systems.

Plano / bi-convex / cylindrical · Custom R & f · UV-grade

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Fused silica prisms steer and disperse UV and laser beams with low absorption. FGQuartz makes right-angle, equilateral and wedge prisms, plus beamsplitter substrates, with polished and angled faces held to tight angular tolerance for stable beam paths.

Right-angle / equilateral / wedge · Tight angles · Low absorption

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Low thermal expansion makes fused silica an excellent mirror substrate for stable surface figure. FGQuartz supplies polished blanks and substrates for dielectric or metallic coating, in round and custom shapes, finished to your flatness and parallelism spec.

Coat-ready blanks · Stable figure · Custom flatness

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Clear fused silica rods carry UV and visible light with low loss. FGQuartz makes polished rods, light guides and homogeniser rods with fire-polished or precision-ground surfaces, used in illumination, UV curing and analytical instruments.

Polished / fire-polished · UV transmission · Custom lengths

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Many systems need optics no catalogue lists. FGQuartz machines and polishes fused silica to your drawing — special windows, flow cells, light pipes and bespoke shapes. Send DXF, STEP or IGES files, or a sample. Single-piece prototypes are welcome.

DXF / STEP / IGES · Prototype to volume · Single-piece OK

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Optical fused silica is graded by the spectral band where it performs best. The three common Chinese-standard grades — JGS1, JGS2 and JGS3 — map directly to UV, UV-visible and infrared use. FGQuartz supplies all three; the right choice depends on your wavelength.

Exact transmission curves and tolerances are confirmed per order. Custom grades and coatings available on request. See full data on our technical specifications page.

Specifying optics well means matching grade, OH content and surface quality to the job. These notes cover the choices that most affect optical performance. For the full treatment, read our fused silica optics guide.

OH content sets the spectral sweet spot. High-OH (synthetic) fused silica such as JGS1 transmits deep-UV very well but absorbs in part of the IR around 2.7 µm. Low-OH fused silica such as JGS3 transmits the IR better but is weaker in the deep-UV. Choose by your working wavelength: UV and excimer work wants high-OH UV fused silica, while IR laser and sensing work wants a low-OH IR grade.

Two numbers describe an optic’s finish. Surface flatness (figure), given in fractions of a wavelength such as λ/4 or λ/10, controls wavefront distortion. Scratch-dig, such as 60-40 or 20-10, describes cosmetic and functional surface defects. Imaging and metrology optics need tight figure; high-power laser optics need a low scratch-dig to avoid damage initiation. FGQuartz polishes to the spec your application requires.

Bare fused silica reflects about 4% per surface, which wastes light and can create stray reflections. Anti-reflection coatings cut this loss at your design wavelength, while mirror and beamsplitter coatings tune reflectance and transmittance. FGQuartz supplies coat-ready substrates polished to coating-grade surfaces, so the optic performs as designed once coated.

For UV and laser systems, two purity-driven effects matter. Fluorescence — light re-emitted at a longer wavelength — adds noise in fluorescence and Raman instruments, so low-fluorescence synthetic grades are preferred there. Laser-induced damage threshold sets how much power a surface can take; it depends on purity, surface quality and any coating. FGQuartz advises on grade and finish to match your power and wavelength budget.

Send us your optical drawings, wavelength and tolerance. The FGQuartz team will review your requirements and respond with a detailed quotation within 24 hours. Explore related fiber optic quartz or the full application library.