• Ø1" (25.40 mm) Plano-Convex Lens
• Substrate: Barium Fluoride
• AR-Coated for the 3 – 5 µm Range
• Focal Length: 75 mm
• Surface Quality: 40-20 Scratch-Dig

The LA0270-E Barium Fluoride (BaF₂) Plano-Convex Lens has an AR coating deposited on both surfaces that is optimized for the 3.0 to 5.0 µm spectral range. The lens has an average transmission in excess of 95% over the wavelength range. Due to its transparency from 200.0 nm to 11.0 µm, Barium Fluoride is commonly chosen for applications that require transmission into the ultraviolet. Although its properties are similar to those of Calcium Fluoride, BaF₂ offers the benefits that it is more resistant to high energy radiation. However, it is less resistant to water damage. Pronounced degradation of the BaF₂ substrate occurs at 500 °C when exposed to water, but in dry environments, it can be used in applications requiring exposure to temperatures up to 800 °C.

Plano-convex lenses focus a collimated beam to the back focus and collimate light from a point source. This lens has a positive focal length and near-best-form shape for infinite and finite conjugate applications.

• Lens Shape: Plano / Convex
• Substrate: Barium Fluoride
• AR Coating Range: 3.0 - 5.0 µm
• Design Wavelength: 4 µm
• Reflectance over Coating Range (Avg.): <2.0%
• Surface Quality: 40-20 Scratch-Dig
• Surface Flatness (Plano Side): ?/2
• Spherical Surface Power (Convex side): 3?/2
• Centration: =3 arcmin
• Clear Aperture: >90% of Diameter
• Thickness Tolerance: ±0.2 mm
• Diameter Tolerance: +0.00 mm / -0.10 mm
• Focal Length Tolerance: ±1%
• Diameter: 1" (25.40 mm)
• f: 75 mm
• R: 34.3 mm
• t_c: 4.4 mm
• t_e: 2 mm
• f_b: 72 mm
• Suggested Fixed Lens Mount: LMR1