The CaF₂ double-concave lens diverges a collimated beam from a virtual focus and are commonly used in beam expanders. These lenses have a negative focal length and negative spherical aberration, which can be used to balance out aberrations of other lenses in the system. These lenses are all made of vacuum grade UV material, the uncoated lenses have high transmission (>90%) from 200-7000nm. If the application needs even higher transmission at 3~5μm, IR1 AR coating (R<1.5%@ 3~5μm) is available.
Material: UV grade CaF₂ |
Design Wavelength: 587.6nm |
Dimension Tolerance: +0.0/-0.1mm |
CT tolerance: ±0.1mm |
EFL Tolerance: ±1% |
Centration: <3' |
Surface Quality: 60/40 |
Bevel : 0.2mmX45° |
Coating : See details in the list |