Applications / Optical
Optical Quartz Glass
JGS1 · JGS2 · JGS3 fused silica optics
Precision windows, optical flats, plates, lens blanks, prisms, viewports, cuvettes and custom CNC optics — produced in JGS1, JGS2 and JGS3 grades for deep-UV, visible and near-infrared systems. High laser damage threshold, low thermal expansion, controlled homogeneity. Engineering quote within 24 business hours.
Transmission
185–3500 nm
UV @ 254 nm
> 90 %
Grades
JGS1 · 2 · 3
1 pc
Minimum custom prototype
185 nm
Deep-UV edge (JGS1)
LIDT ready
High laser damage threshold
15 000 m²
ISO 9001 plant, Lianyungang
Since 2005
Optical fused silica specialist
Why optical fused silica
When ordinary optical glass reaches its limit
Optical quartz glass — fused silica — is specified when the system must transmit deep ultraviolet, survive high laser fluence, or hold figure through rapid thermal change. Standard optical glasses become opaque below roughly 300 nm. They also expand more under heat and damage more easily under high peak power. Fused silica closes those gaps in a single material.
It combines an exceptionally wide transmission window (deep UV through near-IR), very low thermal expansion, high laser damage threshold, chemical durability and high internal homogeneity. Those properties make it the default substrate for high-performance laser optics, UV lithography, spectroscopic instruments, semiconductor process windows and precision optical systems that demand both clarity and thermal stability.
Deep UV
Transmission where glass goes dark
JGS1 transmits from approximately 185 nm. Borosilicate is effectively opaque below ~300 nm. That single difference decides material choice for ArF, KrF, germicidal UV and deep-UV spectroscopy.
LIDT & CTE
Survive power and temperature
High laser damage threshold and near-zero expansion (5.5 × 10⁻⁷ /°C) keep figure and wavefront stable under high average power, pulsed lasers and thermal cycling that would degrade ordinary optical glass.
Optical grades
JGS1, JGS2 and JGS3 — match the grade to the wavelength
Under China’s GB/T 18371 standard, optical fused silica is classified into three grades. The practical difference is how the material is made and how much hydroxyl (OH) and metallic impurity it carries — which decides the usable spectral window. Choose the grade for the working wavelength; do not over-specify purity you will never use.
Deep-UV
JGS1
Synthetic fused silica produced by flame hydrolysis of a silicon precursor. High OH content (~1000–2000 ppm) extends transmission into the deep UV. Very low bubble and inclusion content. Comparable to Heraeus Suprasil and Corning 7980 UV grades.
Band: ~185–2500 nm
Best for: ArF 193 nm · KrF 248 nm · UV lithography · deep-UV spectroscopy · germicidal UV
Trade-off: OH absorption band near 2.7 µm limits deep NIR/IR
UV–Visible
JGS2
Natural fused quartz melted from high-purity crystal. Medium OH (~100–200 ppm). Good transmission from about 220 nm across the visible. The cost-effective workhorse for general optical windows, flats, microscope slides and laboratory optics where deep-UV is not required.
Band: ~220–2500 nm
Best for: Nd:YAG 355 / 532 / 1064 nm · general UV–VIS windows · lab optics · UV sterilisation sleeves
Note: Possible striae in large pieces; confirm quality class for critical wavefront work
Infrared / low-OH
JGS3
Vacuum-electric fused material with very low OH (<5–20 ppm). Removes the water absorption band around 2.7 µm, opening clean transmission further into the infrared. Preferred for IR systems, thermal imaging and broadband UV–VIS–IR designs.
Band: ~260–3500 nm
Best for: IR windows · high-power IR lasers · thermal imaging · broadband optics
Note: Deep-UV performance is limited compared with JGS1
Selection rule of thumb: Working below ~250 nm → JGS1. Need clean transmission beyond ~2.5 µm or high-power IR → JGS3. Mainly 220 nm–visible / NIR and cost-sensitive → JGS2. We stock all three grades and advise on grade selection from the operating wavelength and wavefront requirements.
Product range
Optical quartz components we manufacture
From standard optical windows and flats to lens blanks, prisms, viewports, spectroscopy cells and fully custom CNC optics — in JGS1, JGS2 or JGS3 as required by the wavelength and surface specification.
Plane optics
Optical Windows & Flats
Precision fused silica windows and optical flats with controlled flatness, parallelism and surface quality. Used as laser windows, protective covers, beam entry/exit ports and reference surfaces.
Options: Circular / rectangular · viewport grade · pressure-rated · AR coating ready
Substrates
Optical Plates & Substrates
High-purity quartz plates and substrates for optical instruments, semiconductor process monitoring, laser systems and high-temperature viewing ports. Cut, ground, lapped or double-side polished.
Finish: As-cut · ground · commercial polish · precision optical polish
Formed optics
Lens Blanks & Prisms
Optical-grade fused silica blanks for plano-convex, plano-concave and cylindrical lenses; right-angle, equilateral, Dove and Porro prisms. Suitable for further polishing and coating by optical fabricators.
Scope: Diameter from a few mm to several hundred mm
Process access
Viewports & Observation Windows
High-temperature and vacuum viewports that combine optical transmission with thermal and mechanical reliability for process chambers, furnaces and sealed systems.
Related: High-temperature quartz assemblies available from the same plant
Spectroscopy
Cuvettes & Optical Cells
UV-grade quartz cuvettes and flow cells for spectroscopic analysis — high transmission in the ultraviolet and excellent chemical resistance for analytical and research work.
Path length: Standard and custom · compatible with lab quartz programme
Built to print
Custom Optical Components
CNC-machined and polished fused silica optics to customer drawings: complex shapes, drilled windows, stepped plates, mirror blanks, etalon substrates and coated assemblies.
Input: DXF · STEP · IGES · dimensioned sketch · sample photo
Applications
Where optical quartz is specified
Laser and photonic systems, UV lithography and semiconductor process monitoring, spectroscopy, scientific research, high-temperature viewing and UV lighting / curing all rely on the same core material properties — only the grade, surface finish and geometry change.
- Laser & photonic systems — Excimer, Nd:YAG, harmonic generation, beam delivery and high-power laser windows
- UV lithography & semiconductor — Process monitoring windows, inspection optics and UV optical components
- Spectroscopy & analytical instruments — Cuvettes, flow cells, optical windows and sample cells for UV-Vis and IR analysis
- Scientific research — Precision optics for laboratories, universities and R&D facilities
- High-temperature viewing — Observation windows and viewports for furnaces and process equipment
- UV lighting & curing — Envelopes and windows for UV lamps and photochemical systems
Optical data
Transmission and index at a glance
Typical values for high-purity clear fused silica. Exact transmission depends on grade, thickness and surface quality; request a certificate of analysis for critical wavelength bands.
Refractive index (589 nm, 20 °C)1.4585
Refractive index (1060 nm)1.4496
Transmission range (grade dependent)185–3500 nm
UV transmission (254 nm, 10 mm)> 90 %
Abbe number67.8
Stress optical coefficient3.5 × 10⁻⁶ MPa⁻¹
Thermal & purity
Stability under load and heat
The same low expansion and purity that protect optical figure also support high-temperature viewports and process windows.
SiO₂ content≥ 99.99 %
Thermal expansion (20–300 °C)5.5 × 10⁻⁷ /°C
Continuous service temperature1 200 °C
Softening point≈ 1 680 °C
Total metal impurities (typical)< 20 ppm
Laser damage thresholdHigh (grade & polish dependent)
Fabrication
From blank to optical surface under one roof
Optical quartz is cut, ground, polished and CNC-machined in the same 15 000 m² ISO 9001 facility that produces structural fused silica. That integration shortens lead time when an order mixes optical windows with process hardware, and it keeps material pedigree under one quality system.
Surface finish can range from commercial polish to precision optical quality. Flatness, parallelism and scratch-dig are specified to the drawing. AR and HR coatings can be arranged through partner coating houses when required.
01
Precision cutting & grinding
Accurate sizing of optical blanks and plates with controlled thickness, edge quality and stock removal for subsequent polish.
02
Optical polishing
Surface finishing from commercial polish to precision optical quality — supporting flatness, parallelism and surface-quality requirements for laser and imaging use.
03
CNC machining & custom geometry
Complex shapes, drilled windows, stepped components and custom geometries produced to drawing, with optional coating support.
04
Inspection & documentation
Dimensional metrology, surface inspection and material certification. CoC and grade documentation available on request.
Laser compatibility
Wavelengths optical fused silica supports
Fused silica works across a very wide laser wavelength range. Grade selection follows the line, not the other way around. CO₂ at 10.6 µm is outside the transmission window — use ZnSe, germanium or other mid-IR materials for that wavelength.
UV lasers — typically JGS1
- ArF excimer · 193 nm
- KrF excimer · 248 nm
- XeCl excimer · 308 nm
- Nd:YAG 4th harmonic · 266 nm
Visible / NIR — typically JGS2
- Nd:YAG 3rd harmonic · 355 nm
- Nd:YAG 2nd harmonic · 532 nm
- Nd:YAG fundamental · 1064 nm
- Telecom · 1310 nm / 1550 nm
Infrared emphasis — consider JGS3
- Broadband UV–VIS–IR systems
- Thermal imaging and IR sensing windows
- High-power IR laser optics where OH absorption must be minimised
State the laser wavelength, pulse regime and required surface quality on the RFQ. We will recommend grade, blank size and finish, and flag when a partner coating is the practical next step.
FAQ
Questions optics and procurement actually ask
Grade selection, laser wavelengths, drawings, surface quality and product scope. If the answer is not here, put it on the RFQ.
Fused silica works across a very wide laser wavelength range. For UV lasers: ArF excimer at 193 nm, KrF excimer at 248 nm, XeCl excimer at 308 nm, and Nd:YAG fourth harmonic at 266 nm (all requiring JGS1 grade). For visible and NIR lasers: Nd:YAG third harmonic at 355 nm, second harmonic at 532 nm, and fundamental at 1064 nm; and telecom lasers at 1310 nm and 1550 nm (JGS2 for NIR applications). For CO₂ lasers at 10.6 µm, fused silica is not transparent — ZnSe, germanium, or other mid-infrared materials must be used instead.
Yes. FGQuartz accepts formal drawings in DXF, STEP, or IGES format and also works from dimensioned sketches, photographs of sample parts, or verbal descriptions of the required optical function. For new designs, the FGQuartz engineering team produces a manufacturing drawing for customer approval before production begins. Prototype quantities starting from a single piece are accepted with no minimum order requirement on custom components.
FGQuartz manufactures UV and optical windows in standard and custom geometries; plano-convex, plano-concave, and cylindrical lenses; right-angle, equilateral, Dove, and Porro prisms; mirror blanks and etalon substrates; optical flats and reference surfaces; UV cuvettes and spectroscopy flow cells in standard and custom path lengths; UV lamp envelopes and discharge tube bodies; optical rods and line diffusers; ICP plasma torch tube assemblies; and fully custom CNC-machined optical assemblies from customer drawings. The same facility also manufactures structural quartzware, so mixed orders can be fulfilled from a single source.
JGS1 is a synthetic high-OH fused silica with the deepest UV transmission, produced by flame hydrolysis of a silicon precursor. The high hydroxyl content enables good transmission at wavelengths below 250 nm, making it the standard for excimer laser optics, deep-UV spectroscopy, and germicidal UV applications. The trade-off is a near-infrared absorption feature around 2.7 µm from the OH groups. JGS2 is natural fused silica with much lower OH content, providing good transmission from approximately 260 nm through to beyond 2.5 µm and lower near-infrared absorption. JGS2 is the standard for Nd:YAG laser optics, telecom wavelength components, NIR spectroscopy, and general-purpose visible optics. FGQuartz stocks both grades and advises on grade selection based on the operating wavelength.
Fused silica transmits deep ultraviolet light at wavelengths where standard optical glasses are completely opaque. Its transmission window extends from approximately 150 nm in the deep UV through the visible spectrum and into the near infrared — a breadth that no common optical glass matches. Standard borosilicate glass becomes opaque below approximately 300 nm, ruling it out for germicidal UV, excimer laser systems, and deep-UV spectroscopy. Combined with very low chromatic dispersion, exceptional resistance to laser-induced damage, near-zero thermal expansion, and high chemical purity, fused silica is the default choice for any optical system that must function below 300 nm or that will be exposed to high-power laser radiation.
RFQ
Source optical quartz matched to your wavelength
Tell us the required grade (JGS1 / JGS2 / JGS3), dimensions, surface quality, coating needs and application wavelength. DXF, STEP, IGES, a dimensioned sketch or a photo of a sample are enough to start. Prototype quantity: one piece.
- Quote within 24 business hours
- File formats: DXF, STEP, IGES, PDF
- JGS1, JGS2 and JGS3 in stock programme
- Commercial to precision optical polish
- Prototype through production volume