Optical Quartz Glass JGS1 / JGS2 / JGS3 for UV, Visible and Infrared Optical Systems

Product Overview

Optical Quartz Glass, also known as fused silica, is an amorphous and isotropic form of silicon dioxide (SiO₂). It is characterized by extremely high purity, excellent optical transparency, low thermal expansion, high thermal stability, and outstanding chemical resistance. These properties make optical quartz glass a critical material for precision optical systems operating across ultraviolet (UV), visible, and infrared (IR) wavelength ranges.

Depending on the raw materials and manufacturing processes, optical quartz glass is commonly classified into JGS1, JGS2, and JGS3. Each grade exhibits distinct hydroxyl (OH) content, impurity levels, internal structure, and spectral transmission characteristics. Proper selection of the JGS grade is essential to ensure optimal optical performance and long-term system stability.

Key Features

• Wide optical transmission range from deep ultraviolet to infrared

• High-purity SiO₂ with excellent chemical and corrosion resistance

• Very low coefficient of thermal expansion

• High thermal shock resistance and dimensional stability

• Good mechanical strength and surface finish capability

• Compatible with optical coatings (AR, reflective, interference coatings)

• Available in standard and custom optical component geometries

Optical Quartz Glass Grades Comparison

JGS1 – Far UV Optical Quartz Glass

JGS1 is a synthetic fused silica produced using high-purity silicon tetrachloride (SiCl₄) as the raw material and melted by an oxyhydrogen flame. This process results in extremely high material purity and excellent optical homogeneity.

Due to its high hydroxyl (OH) content of approximately 2000 ppm, JGS1 exhibits outstanding transmission in the deep ultraviolet region. Its transmittance at 185 nm can exceed 90%, making it the preferred choice for demanding UV optical systems. However, the high OH content leads to a strong absorption peak at 2730 nm, limiting its infrared performance.

Typical applications include:

• Deep UV laser optics

• Semiconductor lithography systems

• UV lenses, windows, prisms, and mirrors

• UV analytical and inspection instruments

JGS2 – UV Optical Quartz Glass

JGS2 is manufactured from natural quartz crystal using an oxyhydrogen flame fusion process. Compared with JGS1, it contains slightly higher levels of metallic impurities and a lower hydroxyl content, typically in the range of 100–200 ppm.

JGS2 offers good ultraviolet and visible light transmission within the 220–2500 nm wavelength range. While minor striations or particle structures may be present, it provides a cost-effective solution for many general-purpose optical applications. In small dimensions and thin components, JGS2 can be fabricated with excellent optical quality and minimal bubbles.

Typical applications include:

• Optical windows and viewports

• Condenser optics

• Optical flats and substrates

• Microscope slides

• Sight glasses and high-temperature optical components

JGS3 – Infrared Optical Quartz Glass

JGS3 is produced from natural quartz using a vacuum electric fusion process, resulting in extremely low hydroxyl content and excellent infrared transmission performance. Unlike JGS1 and JGS2, JGS3 exhibits minimal OH-related absorption near 2730 nm.

Although minor bubbles, striations, or particle structures may be present, JGS3 provides superior performance in the infrared region and supports a wide spectral range extending to approximately 3500 nm. This makes it suitable for applications requiring infrared transparency or wide-band optical coverage.

Typical applications include:

• Infrared optical windows

• IR sensors and detectors

• Thermal imaging systems

• Multi-spectral optical systems

Available Forms

• Optical windows and plates

• Lenses and prisms

• Optical flats and substrates

• Filter substrates (bandpass, cutoff, ND, notch filters)

• Custom-machined optical components based on drawings

Selection Guide

• Choose JGS1 for deep UV applications below 200 nm or high-performance UV laser systems

• Choose JGS2 for general UV–visible optical applications with balanced performance and cost

• Choose JGS3 for infrared optics or systems requiring extended IR transmission

FAQ

Q1: What is the main difference between JGS1, JGS2, and JGS3?
A: The differences lie in raw materials, manufacturing processes, hydroxyl content, impurity levels, and spectral transmission ranges.

Q2: Why is hydroxyl (OH) content important in optical quartz glass?
A: OH groups improve deep UV transmission but introduce absorption around 2730 nm, which affects infrared performance.

Q3: Can optical quartz glass be coated?
A: Yes. Anti-reflection, reflective, and interference coatings can be applied depending on the operating wavelength.

Q4: Is optical quartz glass the same as ordinary glass?
A: No. Optical quartz glass has much higher purity, lower thermal expansion, and significantly better UV and IR transmission than ordinary glass.

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