Plan Apochromatic Objective

Optical glass such as K9, fused silica, sapphire, MgF2, silicon (Si), ZnSe, ZnS, etc. These materials possess high transmittance, low absorption, low scattering, uniform refractive index, and specific dispersion characteristics.

Precisely hemispherical. The machining precision of the center and radius of curvature of the sphere is extremely high.

The surface is precision polished to an optical grade of 10-5 to ensure image quality and reduce scattering and aberrations.

An AR coating is typically applied to the concave surface to maximize the transmittance of specific wavelengths of light (e.g. visible light) and reduce reflection loss.