JGS3 is an "infrared-grade" fused silica glass, characterized by low hydroxyl content (OH? ≤ 5 ppm), absence of a 2.73 μm absorption peak, and high transmittance across a broad wavelength range (260 nm–3.5 μm). It serves as a critical window and lens material in optical systems ranging from deep ultraviolet to far infrared, high-power lasers, aerospace, and semiconductor equipment. Below is a systematic introduction covering its composition, properties, manufacturing process, and applications.

In China, fused silica is categorized into three grades based on ultraviolet-to-infrared transmission capability:

• JGS1: CVD synthesized, high hydroxyl content (800–1400 ppm), transmission starting at 185 nm, used for excimer lasers.

• JGS2: Flame-fused natural crystal, OH? 150–400 ppm, transmission starting at 220 nm, general-purpose for visible to near-infrared.

• JGS3: Vacuum-electromelted or plasma-melted crystal powder, OH? < 5 ppm, high transmission from 260 nm to 3.5 μm, known as "infrared quartz."