CaF2 is commonly used for applications requiring high transmission in the infrared and ultraviolet spectral ranges. Its extremely high laser damage threshold allows it to be used with excimer lasers. The material exhibits a low refractive index, varying from 1.35 to 1.51 within its usage range of 180 nm to 8.0 μm. Calcium fluoride is also fairly chemically inert and offers superior hardness compared to its barium fluoride, magnesium fluoride, and lithium fluoride cousins.
Plano-Convex lenses have a positive focal length and approach best form for infinite and finite conjugate applications. These lenses focus a collimated beam to the back focus and collimate light from a point source. They are designed with minimal spherical aberration and have a focal length which can be calculated using a simplified thick lens equation:
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f = R/(n-1)
where n is the index of refraction and R is the radius of curvature of the lens surface.
To minimize the introduction of spherical aberrations, light should be bent gradually as it propagates through the lens. Therefore, when using a plano-convex lens to focus a collimated light source, the collimated light should be incident on the curved surface. Similarly, when collimating a point source of light, the diverging light rays should be incident on the planar surface of the lens.
0.18 - 8.0 μm
+0.0 mm / -0.1 mm
Focal Length Tolerance
Surface Flatness (Plano Side)
>90% of Diameter