Which Harmful UV Wavelengths Do Cerium-Doped Quartz Tubes Primarily Filter?

When developing medical or sterilization devices, engineers often prioritize safety measures against harmful exposure from medical light sources. This is considered a high-compliance issue during product development.

However, options for UV-blocking encapsulation materials are limited. The material must allow high visible light transmission without interfering with therapeutic laser performance, while also filtering harmful UV radiation. It must also be durable and resistant to high temperatures and radiation — for example, CO₂ lasers (10,600 nm) and Er:YAG lasers (2940 nm) used in tumor ablation or scar removal typically operate at 100–300°C, vaporizing tissue through intense absorption by water molecules.

One of the best commercially available materials is the cerium-doped quartz tube, such as those offered by totalquartzworks.com under their UV Block Quartz Tube series. These tubes utilize cerium ions (Ce³⁺/Ce⁴⁺) to strongly absorb harmful UV bands.

1. UV Wavelengths Filtered

UV Type	Wavelength Range	Associated Risk	Filtration Effect
UVC	100–280 nm	Causes severe skin and eye damage; DNA disruption	High absorption, especially at 200–280 nm; nearly complete blockage
UVB	280–315 nm	Leads to sunburn and increases risk of skin cancer	Partial absorption; strong effect from 280–300 nm, weaker above 300 nm
UVA	315–400 nm	Penetrates deep, causing skin aging and pigmentation	Weak absorption; often supplemented with coatings such as TiO₂

2. Key Applications

Medical and sterilization devices:
Used as observation windows in germicidal lamps (e.g., 254 nm), allowing visible light transmission while blocking UVC to protect users.

Semiconductor lithography:
Filters shortwave UV from excimer or mercury lamps (e.g., 193 nm, 248 nm) to reduce stray light damage.

Aerospace and nuclear industries:
Shields harmful UV radiation in high-radiation environments while maintaining optical transparency.

3. Advantages and Limitations

Advantages:

• High visible light transmittance (400–700 nm)
• Excellent resistance to heat and radiation
• Longer lifespan compared to organic UV filters like PMMA

Limitations:

• Weak UVA blocking; often requires co-doping or surface coatings
• Filtration performance depends on doping uniformity, requiring precise manufacturing

4. Comparison with Other UV Filter Materials

Material	Effective Filtering Range	Limitations
Cerium-doped quartz tube	100–300 nm	Weak for UVA
Standard quartz glass	Below 200 nm	Ineffective for UVC/UVB
Borosilicate glass	Below 300 nm	Low absorption, needs high thickness
Organic UV filters	Tunable by formula	Age rapidly, low temperature resistance

Summary

Cerium-doped quartz tubes are ideal for blocking shortwave ultraviolet radiation (UVC and part of UVB), particularly in high-temperature and high-radiation environments. For broader protection, such as full-range UV shielding in personal care or consumer applications, combining with other materials is recommended.