Features

• 4 Different Diameters Available: 6 mm, 8 mm, 1/2", or 1"
• Wavelength Range: 185 nm - 2.1 μm (Uncoated)
• Focal Lengths Available from -10.0 to -200.0 mm
• Fabricated from UV Grade Fused Silica
• Form Virtual Images

Thorlabs' UV Grade Fused Silica Plano-Concave lenses are uncoated 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-concave lenses have negative focal lengths, making them useful for a wide range of applications. They are commonly used to diverge a collimated incident beam; in such cases the collimated light source should be incident on the curved surface to minimize spherical aberrations. Plano-concave lenses, which produce virtual images, are used as the entrance optic in Galilean-type beam expanders; this lens provides the desired divergence and then a doublet is used to recollimate the beam. In optical systems, it is common for researchers to choose their optics carefully so that the aberrations introduced by the positive- and negative-focal-length lenses approximately cancel. Still others use these lenses in pairs to increase the effective focal length of a converging lens.

When deciding between a plano-concave lens and a bi-concave lens, both of which cause collimated incident light to diverge, it is usually preferrable to choose a plano-concave lens if the desired absolute magnification is either less than 0.2 or greater than 5. Between these two values, bi-concave lenses are generally preferred.

Thorlabs offers these plano-concave lenses in sizes ranging from Ø6 mm to Ø1". Each size is compatible with a multitude of Thorlabs lens mounts. Please see the Mounting Options tab for details.