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UV Fused Silica Plano-Convex Lenses, Uncoated
These uncoated UV-Grade Fused Silica Plano-Convex lenses are available in sizes ranging from Ø2 mm to Ø75 mm. UV-grade fused silica offers high transmission in the deep UV and exhibits virtually no laser-induced fluorescence (as measured at 193 nm), making it an ideal choice for applications from the UV to the near IR. In addition, UV fused silica has better homogeneity and a lower coefficient of thermal expansion than N-BK7.
Plano-convex lenses can focus a collimated beam or collimate light from a point source. 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. When image quality is not critical, plano-convex lenses can also be used as a substitute for achromatic doublets.
The focal length of each lens can be calculated using a simplified thick lens equation:
f = R/(n-1),
where n is the index of refraction and R is the radius of curvature of the lens surface. These lenses are fabricated from UV-Grade Fused Silica, which has an Abbe Number of 67.82; this value is an indicator of the dispersion.
When deciding between a plano-convex lens and a bi-convex lens, both of which cause collimated incident light to converge, it is usually preferable to choose a plano-convex lens if the desired absolute magnification is either less than 0.2 or greater than 5. Between these two values, bi-convex lenses are generally preferred.
Thorlabs offers fixed lens mounts that can be used for mounting the lenses sold here. For mounting high-curvature lenses in select sizes, extra-thick retaining rings with SM05 (0.535"-40), SM1 (1.035"-40), or SM2 (2.035"-40) threading are available that provide extra clearance for spanner wrenches (see the Lens Mounting Guide tab for more information).
UV Fused Silica lens kits are also available. Please click here for information.
Below is the transmission curve for UV Fused Silica. Total transmission is shown for a 10 mm thick, uncoated sample and includes surface reflections. The uncoated UV Fused Silica plano-convex lenses sold on this page can also be ordered with one of the following AR coatings: YAG AR V-Coating (532/1064 nm), -UV (245 - 400 nm), -A (350 - 700 nm), -B (650 - 1050 nm), and -C (1050 -1700 nm).
Our high-performance multilayer AR coatings have an average reflectance of less than 0.5% (per surface) across the specified wavelength ranges. These coatings provide good performance for angles of incidence (AOI) between 0° and 30° (0.5 NA). The plot shown below indicates the performance of the standard coatings in this family as a function of wavelength. Broadband coatings have a typical absorption of 0.25%, which is not shown in the reflectance plots.
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.