68-257 25mm Dia. Germanium Infrared Aspheric Lens; EFL=50mm; NA=0.25 BBAR 8-12µm
- Type
- Lens
- Subtype
- Aspheric Lens
- Brand
- Edmund Optics
Properties
- Shape
- Circular
- Diameter
- 25 mm
- EFL
- 50 mm
- BFL
- 48.44 mm
- R1
- 74.64 mm
- R2
- 142.9 mm
Material
- Name
- Germanium
- Dispersion Equation
- Sellmeier
- n (λ)
- 4.024720747638282
- λ
- 4000 nm
- B1
- 0.4886331
- C1
- 1.393959 μm2
- B2
- 14.5142535
- C2
- 0.1626427 μm2
- B3
- 0.0091224
- C3
- 752.19 μm2
68-257 25mm Dia. Germanium Infrared Aspheric Lens; EFL=50mm; NA=0.25 BBAR 8-12µm
This is the 68-257 model from Edmund Optics, a 25mm diameter Germanium Aspheric Lens designed for infrared applications with a wavelength of 4000nm. The lens boasts an effective focal length (EFL) of 50mm and a numerical aperture (NA) of 0.25, making it suitable for a wide range of optical systems.
The lens is made from Germanium burnett, a material known for its excellent transmission properties in the infrared spectrum. It features a precision-ground aspheric surface, which helps to minimize spherical aberration and distortion, thereby improving image quality.
The lens has a center thickness of 3mm and an edge thickness of 2.45mm, providing robustness and durability. The front and back surfaces of the lens are coated with EDMD ARCEDGERMANIUM81, a broadband anti-reflection coating that enhances transmission and reduces surface reflections in the 8-12µm range.
The lens geometry includes an inner radius of 0mm, an outer radius of 0mm, and a clear aperture of 25mm. The back focal length (BFL) is 48.44mm, and the lens has a shape factor of aspheric.
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