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Magnesium Fluoride Plano-Convex Lenses, Uncoated
LA6004 Lens Shown Mounted
Thorlabs' MgF2 Plano-Convex lenses are popular for many applications in the UV and IR. These lenses are an ideal choice for applications from 200 nm to 6.0 μm. Magnesium Fluoride is extremely durable in comparison to other materials that reach this far down into the UV or out into the IR. The C-axis is oriented to minimize birefringence.
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:
where n is the index of refraction and R is the radius of curvature of the lens surface. To minimize the introduction of spherical aberration, a collimated light source should be incident on the curved surface of the lens when being focused and a point light source should be incident on the planar surface when being collimated.
Plano-Convex Lens kits are also available - please click here for information.
Transmission Curve for Magnesium Fluoride: 10 mm Thick Uncoated Sample, Surface Reflections are Included in the Transmission Plot
Mounting High-Curvature Optics
Thorlabs' retaining rings are used to secure unmounted optics within lens tubes or optic mounts. These rings are secured in position using a compatible spanner wrench. For flat or low-curvature optics, standard retaining rings manufactured from anodized aluminum are available from Ø5 mm to Ø4". For high-curvature optics, extra-thick retaining rings are available in Ø1/2", Ø1", and Ø2" sizes.
Extra-thick retaining rings offer several features that aid in mounting high-curvature optics such as aspheric lenses, short-focal-length plano-convex lenses, and condenser lenses. As shown in the animation to the right, the guide flange of the spanner wrench will collide with the surface of high-curvature lenses when using a standard retaining ring, potentially scratching the optic. This contact also creates a gap between the spanner wrench and retaining ring, preventing the ring from tightening correctly. Extra-thick retaining rings provide the necessary clearance for the spanner wrench to secure the lens without coming into contact with the optic surface.