Introduction to JGS1, JGS2, and JGS3 Fused Silica

“Fused Silica” or “Fused Quartz” which is the amorphous phase of quartz (SiO2). When contrasted to borosilicate glass, fused silica has no additives; hence it exists in its pure form, SiO2. Fused silica has a higher transmission in the infrared and ultraviolet spectrum when compared to normal glass. Fused silica is produced by melting and re-solidifying ultrapure SiO2. Synthetic fused silica on the other hand is made from silicon-rich chemical precursors such as SiCl4 which are gasified and then oxidized in a H2 + O2 atmosphere. The SiO2 dust formed in this case is fused to silica on a substrate. The fused silica blocks are cut into wafers after which the wafers are finally polished.

JGS1, JGS2, and JGS3 are three specialized grades of high-purity fused silica, each designed for optimal performance in different wavelength ranges. Produced under stringent manufacturing standards, they provide excellent optical transmission, thermal stability, and resistance to environmental degradation. These materials are widely used in laser systems, spectroscopy, semiconductor processing, infrared imaging, and precision metrology.

While all three grades are based on amorphous SiO₂ with superior purity and homogeneity, their key difference lies in the spectral range and OH content control, making them ideal for different UV, visible, and IR applications.

UV Grade Fused Silica- JGS1, JGS2, and JGS3

JGS1 – UV Grade Fused Silica

Wavelength Transmission Range: 185–2500 nm
Core Advantage: Exceptional deep ultraviolet (DUV) transmission.

JGS1 is a premium UV-grade fused silica designed for applications that require superior transmission in the deep ultraviolet spectrum. Produced with ultra-low metallic impurities and controlled hydroxyl (OH) content, it offers minimal absorption and high stability under UV laser exposure.

Key Optical Properties of JGS1:

• High transmission (>90%) from 200 nm upward.

• Very low fluorescence and minimal solarization.

• High laser damage threshold for excimer laser wavelengths.

• Excellent surface quality achievable after precision polishing.

Typical Applications of JGS1:

• Excimer laser optics (193 nm, 248 nm systems).

• Photolithography projection lenses and masks.

• UV-grade windows and prisms for spectroscopic equipment.

• High-performance UV beam splitters.

• Scientific instrumentation for ultraviolet analysis.

JGS2 – Optical Grade Fused Silica

Wavelength Transmission Range: 220–3500 nm
Core Advantage: Balanced performance from visible (VIS) to near-infrared (NIR) regions.

JGS2 is a general-purpose optical-grade fused silica optimized for visible and near-infrared applications. It still retains moderate UV transmission, but its main strength lies in the high transmittance and low wavefront distortion in the VIS–NIR spectrum.

Key Optical Properties of JGS2:

• High transmittance across visible light spectrum.

• Good UV transparency down to ~220 nm.

• Excellent thermal shock resistance and mechanical strength.

• Uniform refractive index with minimal birefringence.

Typical Applications of JGS2:

• Precision imaging lenses and windows.

• Laser system optics for VIS–NIR wavelengths.

• Optical microscopes and projection systems.

• Beam splitters, filters, and prisms for measurement devices.

• Protective optics in high-energy laser environments.

JGS3 – IR Grade Fused Silica

Wavelength Transmission Range: 260–3500 nm
Core Advantage: Enhanced infrared (IR) transmission with reduced OH absorption peaks.

JGS3 is specifically engineered for IR-related applications. The production process minimizes hydroxyl group content, reducing absorption bands at ~2.73 μm and ~4.27 μm, which are common in standard fused silica. This makes JGS3 particularly valuable in IR spectroscopy and thermal imaging.

Key Optical Properties of JGS3:

• High IR transmission with low absorption losses.

• Reduced OH-related absorption bands.

• Excellent thermal and chemical resistance.

• Stable optical characteristics during repeated heating cycles.

Typical Applications of JGS3:

• IR spectrometer windows and cuvettes.

• Thermal imaging camera optics.

• IR sensor protection windows.

• Industrial high-temperature viewing ports.

• Fiber-optic IR communication components.

Comparative Overview – JGS1 vs JGS2 vs JGS3

To help select the right grade, here’s a comparative summary:

Manufacturing Quality of JGS1, JGS2, and JGS3
 

Production of JGS-series fused silica involves:

Raw Material Purification – Only ultra-high purity SiO₂ feedstock is used.

Controlled Melting – Ensures minimal inclusions and bubbles.

Annealing – Removes internal stresses to maintain low birefringence.

Precision Shaping – Using diamond tools for accurate dimensions.

Ultra-Fine Polishing – Achieving surface roughness <5 Å RMS.

Spectral Testing – Using spectrophotometers to confirm transmission curves.

FAQ – JGS1, JGS2, and JGS3 Fused Silica

Q1: What are the main differences between JGS1, JGS2, and JGS3 fused silica?
A:

• JGS1 is a UV-grade fused silica with excellent deep-UV transmission (185–2500 nm), ideal for excimer lasers, lithography, and UV spectroscopy.

• JGS2 is an optical-grade fused silica optimized for visible to near-infrared (220–3500 nm) applications, perfect for general-purpose precision optics.

• JGS3 is an IR-grade fused silica with enhanced infrared transmission (260–3500 nm) and minimal OH absorption peaks, used for IR spectroscopy and thermal imaging.

Q2: How should I choose between JGS1, JGS2, and JGS3?
A: Match the grade to your primary wavelength range:

• Choose JGS1 if your system operates mainly in the UV spectrum (<250 nm).

• Choose JGS2 if your application is in the visible or near-infrared range.

• Choose JGS3 for infrared-focused designs, especially when OH absorption reduction is important.

Q3: Can JGS1, JGS2, and JGS3 be used in high-power laser systems?
A: Yes. All three grades have a high laser damage threshold (>20 J/cm² at 1064 nm, 10 ns pulses) and excellent thermal resistance. However, for excimer lasers (193 nm, 248 nm), JGS1 is the preferred choice due to its superior UV resistance.

Q4: Are there differences in chemical durability among JGS1, JGS2, and JGS3?
A: All three grades share the same chemical stability inherent to fused silica, with excellent resistance to acids, water, and most chemicals, except hydrofluoric acid and hot concentrated alkalis.