Negative Meniscus(Convex-Concave) lens
| Focal Lengths Available | from -100.0 to -1000.0 mm |
| Focal Lengths Tolerance: | ±1% |
| Diameter: | 3.0mm ~200.0mm |
| Scratch & Dig: | 80/50~20/10 |
| Spherical Surface Power: | 5 Fringes~1 Fringes |
| Spherical Surface Irregularity: | λ/2~λ/8 |
| Center Error: | 5arc min ~ 30 arc Sec |
Negative meniscus (convex-concave) lenses, with center thickness smaller, are designed to minimize spherical aberration in optical systems. When used in combination with another lens, a negative meniscus lens will increase the focal length and decrease the numerical aperture (NA) of the system. When used to diverge light, as shown in the diagram above, the convex surface should face the beam to minimize spherical aberration.
The focal length of each lens can be calculated using the following equation:
f= (R1*R2)/((n-1)*(R2-R1)).
where n is the index of refraction and R1,R2 is the radius of curvature for each surface of the lens.
They can be also coated with MgF2 to protect the surface or AR coated to increase the transmission.
