CaF2 Fused Silica CaF2 Triplet Lenses

Triplet achromatic lenses offer excellent performance in chromatic and aberration correction and are suitable for high precision optical systems, but have higher cost, weight and assembly complexity. The choice needs to be weighed against the specific needs of the application.

Triplet achromatic lenses made of fused silica(SiO2) and calcium fluoride(CaF2) materials are used to correct chromatic aberration mainly through the different dispersion characteristics of these two materials.

Fused Silica (SiO2):

Abbe number: High (about 67.8), a low dispersion material.
Refractive index: moderate (about 1.46 in the visible range).
Transparent range: good from ultraviolet to near infrared.

Calcium Fluoride (CaF2):

Abbe number: low (about 95.3), a high dispersion material.
Refractive index: low (about 1.43 in the visible range).
Transparent range: from UV to IR, especially excellent in the UV region.