Optical quartz glass is graded by spectral transmission. The JGS system defines three classes — deep-UV (JGS1), UV (JGS2) and infrared (JGS3) — used for cuvettes, windows and precision optics. This guide compares their transmission ranges, purity and best-fit applications so you can choose the right grade.
| Grade | Class | Transmission | Purity (OH) | Max temp | Best for |
|---|---|---|---|---|---|
| JGS1 | Deep-UV | 190–2500 nm | OH < 5 ppm, metals < 1 ppm | 1100 °C | Far/deep-UV spectroscopy; highest-purity optics |
| JGS2 | UV-Vis | 360–1100 nm | — | — | UV optical components, precision windows |
| JGS3 | Infrared | 260–3500 nm | — | High-temp stable | IR optics, high-temperature use |
Transmission ranges as specified on Scuvette's JGS product pages. JGS2/JGS3 list class and application; full impurity and tolerance data are published for JGS1.
JGS1 is the highest-purity synthetic fused silica grade, with OH content below 5 ppm and metal impurities below 1 ppm. It transmits from about 190 nm (some lots) through 2500 nm and serves continuously up to 1100 °C (softening point 1680 °C). With ±0.05 mm tolerance and a 40–60 scratch-dig optical surface, it is the reference grade for deep-UV and far-UV spectroscopy. See JGS1 quartz plates →
JGS2 is the UV-Vis optical quartz glass for components and precision windows, transmitting in the 360–1100 nm band. It is the standard choice when deep-UV performance is not required. See JGS2 quartz plates →
JGS3 is the infrared-grade quartz for IR optics and high-temperature use, with transmission extending to 3500 nm. See JGS3 quartz plates →
Most UV-Vis cuvettes are made from JGS1 because it covers the full 190–2500 nm working range and gives the cleanest UV cut-off. If your instrument works only in the visible or near-IR, JGS2/JGS3 equivalents are sufficient. Browse our quartz cuvettes, fluorescence cuvettes and flow cells.
What is the difference between JGS1, JGS2 and JGS3 quartz?
They are three transmission classes of optical quartz glass. JGS1 is deep-UV grade (190–2500 nm, highest purity, OH below 5 ppm); JGS2 is the UV-Vis grade (360–1100 nm); JGS3 is the infrared grade (260–3500 nm) for IR and high-temperature optics.
Which JGS grade should I use for UV-Vis spectroscopy?
JGS1. It covers the full 190–2500 nm working range and has the cleanest UV cut-off, which is why most quartz cuvettes are made from JGS1 fused silica. JGS2 or JGS3 are sufficient only if your instrument works purely in the visible or near-IR.
Is JGS1 the same as fused silica?
JGS1 is a highest-purity grade of synthetic fused silica (made by vapor-phase hydrolysis of silicon tetrachloride), with OH below 5 ppm and metal impurities below 1 ppm. All JGS grades are fused silica; JGS1 is simply the purest, deepest-UV-transmitting class.
What transmission range does each JGS grade cover?
As specified on Scuvette product pages: JGS1 190–2500 nm, JGS2 360–1100 nm, JGS3 260–3500 nm. JGS1 also runs continuously up to 1100 °C (softening point 1680 °C).