Optical Quartz Glass Plate Factory & Suppliers for Ireland

In high-precision optical engineering, optical quartz glass plates represent the ultimate substrate when conventional borosilicate (BK7/B270) or soda-lime glass succumbs to thermal degradation, optical phase distortion, or chemical clouding. Fused quartz and fused silica consist of pure silicon dioxide ($SiO_2$) in an amorphous, non-crystalline solid matrix. The absence of long-range crystalline order, combined with tight covalent silicon-oxygen bonding, delivers unique physical constants: an extremely low coefficient of thermal expansion ($5.5 \times 10^{-7}/\text{K}$), broad-spectrum transmission ranging from the deep ultraviolet ($185\text{ nm}$) to the mid-infrared ($3500\text{ nm}$), and outstanding chemical resistance against virtually all mineral acids, excluding hydrofluoric and hot phosphoric acids.

A frequent point of confusion among procurement engineers is distinguishing between Synthetic Fused Silica and Fused Natural Quartz. While both exhibit a chemical composition of $\ge 99.99\%$ $SiO_2$, their manufacturing pathways yield profoundly different optical behaviors:

1. JGS1 (Synthetic Fused Silica / Excimer Grade): Fabricated through chemical vapor deposition (gas-phase hydrolysis of high-purity silicon tetrachloride $SiCl_4$ in an oxygen-hydrogen flame). This grade features negligible metallic trace impurities ($<1\text{ ppm}$ total metals), zero gas bubbles or inclusions (Class 0 under DIN ISO 10110-3), and exceptional internal transmittance in the Deep Ultraviolet (DUV) range down to $185\text{ nm}$. It exhibits practically no fluorescence under UV excitation and demonstrates superior laser-induced damage thresholds (LIDT), making it the mandatory standard for excimer lasers ($193\text{ nm}$ ArF, $248\text{ nm}$ KrF), photolithography stepper optics, and fluorescence microscopy windows.

2. JGS2 (Optical Fused Quartz / UV-Visible Grade): Produced by melting naturally occurring high-purity crystalline quartz sands under oxy-hydrogen or electric flame refining. JGS2 exhibits outstanding transmission across the UV-visible-near IR spectrum ($220\text{ nm} - 2500\text{ nm}$). It retains exceptional mechanical rigidity and thermal resilience (continuous working temperature of $1100^\circ\text{C}$, short excursions to $1450^\circ\text{C}$). It is the industry standard for high-temperature furnace viewports, plasma etching chamber viewports, spectrophotometer windows, and solar simulator covers.

3. JGS3 (Electrically Fused Silica / Infrared Grade): Synthesized by melting natural quartz in a vacuum or high-temperature electric furnace with dry gas purging. By stripping out the hydroxyl radical content ($[OH^-] \le 5\text{ ppm}$), JGS3 completely eliminates the deep optical absorption dip at $2.73\,\mu\text{m}$. It achieves uniform, crystal-clear infrared transmission up to $3500\text{ nm}$, serving thermal imaging lenses, infrared pyrometer sight glasses, CO2 laser beam expanders, and optical sensor substrates for harsh marine telemetry.

Sub-Surface Damage and Chemical-Mechanical Planarization (CMP): At Nivra Quartz, all optical quartz glass plates are produced under class-certified planetary double-sided grinding and chemical-mechanical planarization (CMP). Standard precision flat stock achieves a surface roughness $Ra \le 0.5\text{ nm}$ with scratch-dig specifications of 20/10 or 10/5 per MIL-PRF-13830B. Optical parallelism can be maintained under $\le 5\text{ arcseconds}$ and transmitted wavefront distortion controlled to $\lambda/10$ at $632.8\text{ nm}$, eliminating optical aberrations across beam-splitter plates, high-energy laser windows, and photolithography reticle blanks.