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The shaded region represents the recommended wavelength range for the uncoated acrylic.

Features

• Ø3 mm and Ø6 mm Sizes
• Focal Lengths Available from 3.02 mm to 24.20 mm
• Numerical Apertures Available from 0.10 to 0.38
• Available Uncoated or with an AR Coating for 400 - 700 nm or 650 - 1050 nm
• Substrate: Acrylic
• Excellent for use in OEM Applications
• Volume Pricing is Available by Contacting Technical Support

Aspheric lens are designed to eliminate spherical aberration, which allows for the spot size and collimation of a monochromatic beam of light to be diffraction limited. The Molded Acrylic Aspheric Lenses offered here are available uncoated or with an antireflection coating deposited on both sides for either the 400 - 700 nm or 650 - 1050 nm range. In addition, these aspheres are fabricated from acrylic, which is half as dense as N-BK7, making them ideal for weight-sensitive applications.

In laser diode systems, difficulties with aberration correction are compounded by the beam's high divergence angle. Since individual spherical lenses can refract light at only small angles before spherical aberration is introduced, three or four elements are often required to collimate laser diode light. In contrast, a single aspheric lens collimates without introducing spherical aberration. When used to collimate light, the lens should be oriented so that the side with a larger radius of curvature (i.e., the flatter surface) faces the point source.

Conversely, when coupling into fiber, it is often necessary to focus the laser light to a diffraction-limited spot. Single spherical elements are typically not capable of achieving such a small spot size because spherical aberration is the limiting factor. Since the aspheric lenses are corrected to eliminate the spherical aberration, only diffraction limits the size of the focal spot. For focusing applications, the lens should be oriented so that the side with a smaller radius of curvature (i.e., the more curved surface) faces the source.

These high-performance multilayer AR coatings have an average reflectance of less than 0.5% (per surface) across the specified wavelength ranges. These coatings are designed for angles of incidence between 0 and 30 degrees (0.5 NA). For optics intended to be used at large incident angles, consider using a custom coating optimized at a 45° angle of incidence; these coatings are effective from 25° to 52°. 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 reflectivity plots.

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