UV Grade Fused Silica is synthetic amorphous silicon dioxide of extremely high purity providing maximum transmission from 195 to 2100 nm. This non-crystalline, colorless silica glass combines a very low thermal expansion coefficient with good optical qualities, and excellent transmittance in the ultraviolet region. Transmission and homogeneity exceed those of crystalline quartz without the problems of orientation and temperature instability inherent in the crystalline form. It will not fluoresce under UV light and is resistant to radiation. For high-energy applications, the extreme purity of fused silica eliminates microscopic defect sites that could lead to laser damage. For more information, refer to our optical materials Technical Note

Our precision UV Fused Silica plano-convex lenses are polished to tight tolerances minimizing wavefront distortion. Tight surface quality tolerances minimize scatter and unwanted diffraction effects. These lenses have a 20-10 scratch-dig surface quality, and a 1.5 λ surface power accuracy. For more information, refer to the optical surfaces technical note.

Our AR.14 broadband multilayer antireflection coating markedly improves the transmission efficiency of these lenses by reducing surface reflections over a 430-700 nm wavelength range. This visible AR coating performs effectively for multiple visible wavelengths and tunable lasers eliminating the need for several sets of optics.

Standard effective focal lengths across a variety of newport lens sizes, materials and shapes provide a systematic approach allowing for lenses of different sizes to be interchanged without requiring other changes to your optical system. Collimating a point light source coming from the planar surface or focusing a collimated light source which is incident on the curved surface will help to minimize the spherical aberration.

Plano-Convex lenses are the best choice for focusing parallel rays of light to a single point. They can be used to focus, collect and collimate light. The asymmetry of this lens shape minimizes spherical aberration in situations where the object and image are located at unequal distance from the lens. The optimum case is where the object is placed at infinity with parallel rays entering lens and the final image is a focused point.

For an application example, let’s look at the case of the output from a Newport R-31005 HeNe laser focused to a spot using a KPX043 Plano-Convex Lens. This Hene laser has a beam diameter of 0.63 mm and a divergence of 1.3 mrad. Note that these are beam diameter and full divergence, so in the notation of our figure, y₁ = 0.315 mm and θ₁ = 0.65 mrad. The KPX043 lens has a focal length of 25.4 mm. Thus, at the focused spot, we have a radius θ₁f = 16.5 µm. So, the diameter of the spot will be 33 µm.

Since a common application is the collimation of the output from an Optical Fiber, let’s use that for our numerical example. The Newport F-MBB fiber has a core diameter of 200 µm and a numerical aperture (NA) of 0.37. The radius y₁ of our source is then 100 µm. NA is defined in terms of the half-angle accepted by the fiber, so θ₁ = 0.37. If we again use the KPX043 , 25.4 mm focal length lens to collimate the output, we will have a beam with a radius of 9.4 mm and a half-angle divergence of 4 mrad.

The lenses can be mounted in LT series lens tube for constructing a complex optical system or quickly connecting to other threaded lens mounts: A-Line™ series fixed lens mount, or adjustable lens positioner (with thread adapter). Use LT-WR series spanner wrench for easy lens installation.