What are the applications of Balls?
Optical experiments: for focusing, collimating and shaping of light beams to support various optical studies.
Laser processing: for laser cutting, welding and marking to improve processing precision and efficiency.
Medical equipment: for endoscopy and laser therapy to improve imaging quality and treatment effects.

Comparison of fused silica balls and BK7 balls
1. Material Characteristics
Fused silica (SiO₂) has high UV transmittance, low thermal expansion coefficient, high temperature resistance and good chemical stability.
BK7 is borosilicate glass with high visible light transmittance, easy to process, low UV transmittance and high coefficient of thermal expansion.

2. Optical Performance
Fused Silica Balls
Transmittance: high transmittance from UV to NIR wavelengths
Refractive index: approx.1.46 (@587.6 nm)
Chromatic dispersion: low dispersion

BK7 Balls
Transmittance: high transmittance mainly in the VIS to NIR wavelengths
Refractive index: approx.1.52 (@587.6 nm)
Chromatic dispersion: high dispersion

3. Application Scenarios
Fused silica ball applications: ultraviolet optical systems, laser systems, high-temperature environments, chemical corrosive environments
BK7 ball applications: visible optical systems, microscopes, camera lenses, general optical experiments

4. Cost
Fused silica balls cost more than the BK7 balls

Highly Recommended Ball Lenses from Yutai Optics:
Optical Balls
N-SF11 (H-ZF13) Balls
Optical BK7 Glass Balls
Sapphire Optical Glass Balls