Plano Concave Lens
Understanding Plano-Concave Lenses
Star-Optics manufactures plano concave lenses that bend parallel input rays so they diverge on the output side, creating a negative focal length. These lenses are essential components in beam expanders, optical systems requiring light divergence, and applications where aberration correction is needed.
The spherical aberration of plano concave lenses is negative, making them valuable for balancing aberrations created by other optical elements in multi-lens systems. Like plano convex lenses, the curved surface should face the largest object distance or infinite conjugate to minimize spherical aberration and optimize performance.
Specifications
| Parameter | Specification |
|---|---|
| Material | Optical glass, Fused silica, Sapphire, etc. |
| Diameter | 2 mm ~ 300 mm |
| Diameter Tolerance | ±0.05 mm (≤50 mm) ±0.1 mm (>50 mm) |
| Focal Length | -50 mm ~ -2000 mm |
| Focal Length Tolerance | ±0.2% (<10 mm) ±0.5% (10 mm – 1000 mm) ±1% (>1000 mm) |
| Edge Thickness | 2 mm ~ 20 mm |
| Surface Quality | 60/40, 40/20, 20/10 |
| Surface Accuracy | λ/2 ~ λ/10 @ 632.8 nm, 532 nm, etc. |
| Clear Aperture | >85% of diameter |
| Centration | <3 arc min ~ 30 arc sec |
| Chamfer | <0.2 mm × 45° |
| Coating | AR, BBAR, V-coat, or custom per request |
Plano-Concave Lenses Design, Coatings, and Manufacturing
Plano concave lenses diverge collimated light to form a virtual focal point on the input side, making them suitable for beam expansion when combined with positive optics. The flat surface simplifies mounting, while the curved surface is typically oriented toward the collimated or distant light source to reduce aberrations.
At Star-optics, plano concave lenses are engineered for real system conditions. Focal length, clear aperture, and surface orientation are defined based on actual beam parameters rather than nominal designs.
Anti-reflection coatings are used to minimize surface reflections and improve transmission. Options include MgF₂ for visible wavelengths, broadband multilayer AR coatings, and V-coatings for single-wavelength laser use, with protective overcoats available as required. Custom coating designs support non-standard wavelengths, angles of incidence, and high-power laser applications.
Lenses are manufactured using precision CNC grinding and polishing, achieving surface quality down to 20/10 scratch-dig and centration tolerances as tight as 30 arc seconds, depending on lens geometry.
Custom Plano Concave Lenses
In addition to the standard specifications, we also offer custom plano-concave lenses tailored to specific optical requirements, including non-standard focal lengths, special materials suitable for a wide wavelength range, and geometric shapes optimized for system integration. Customized edge treatment, installation features, and coating designs can also be provided to support seamless assembly. Please contact us to discuss your application needs.
