METHOD OF MAKING OPTICAL LENSES FROM LEUCOSAPPHIRE Russian patent published in 2009 - IPC G02B1/02 B29D11/00 

FIELD: physics; optics.

SUBSTANCE: method involves making concave-convex workpieces via plastic deformation by bending plane-parallel plates from the Z-section of AI₂O₃ crystals using a die, the surface of which is a surface of revolution with a profile described by the equation of a parabola y^c = αx+b, where c=0.7369n+1.0110, α∈[2.85; 4.26] b∈ [-1.93; -0.55] depending on n - refraction index, δ₀ - thickness of the lens along the axis of symmetry and R - radius of the hemispherical surface. Further, the input surface of the lens is formed by removing from the workpiece a hemispherical layer of material with radius R to a given thickness δ₀, which allows for passage of a beam along optical axes after refraction. The optical axis of the lens is aligned with the axis of symmetry of the workpiece.

EFFECT: making hemispherical lenses from leucosapphire for a parallel light beam without double refraction, which are transparent in the 25000-2000 cm^-1 region.

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