• Ge Substrate
• Ø1" (25.40 mm)
• Broadband AR Coating for the 8-12 µm Range
• Focal Length: 75 mm

Thorlabs' Ø1" Germanium (Ge) Plano-Convex Lens is available with a broadband AR coating for the 8-12 µm spectral range deposited on both surfaces. This coating greatly reduces the high surface reflectivity of the substrate, yielding an average transmission in excess of 90% over the entire AR coating range.

Plano-Convex lens has a positive focal lengths and approach best form for infinite and finite conjugate applications. This lens focuses a collimated beam to the back focus and collimates light from a point source. It is designed with minimal spherical aberration and have a focal length given by f= R/(n-1), where R is the radius of curvature of the convex portion of the lens and n is the index of refraction. To minimize the introduction of spherical aberration, a collimated light source should be incident on the curved surface of the lens when being focused and a point light source should be incident on the planar surface when being collimated.

Due to its broad transmission range (2 - 16 µm) and opacity in the visible portion of the spectrum, Germanium is well suited for IR laser applications. It is also inert to air, water, alkalis, and acids (except nitric acid). Germanium's transmission properties are highly temperature sensitive; in fact, the absorption becomes so large that germanium is nearly opaque at 100 °C and completely non-transmissive at 200 °C

• Material: Germanium
• Wavelength Range: 2.0 - 16.0 µm
• AR Coating Range: 8-12 µm
• Reflectance over Coating Range (Avg.): <1.5%
• Diameter Tolerance: +0.00/-0.10
• Thickness Tolerance: ±0.2 mm
• Focal Length Tolerance: ±1%
• Surface Quality: 60-40 Scratch-Dig
• Surface Flatness (Plano Side): λ/2
• Spherical Surface Power (Convex Side): 3λ/2
• Surface Irregularity: λ/2
• Centration: ≤3 arcmin
• Clear Aperture: 80% of Diameter
• Design Wavelength: 10.6 µm
• Diameter: Ø1" (25.40 mm)
• f: 75 mm
• R: 225.5 mm
• t_c: 4 mm
• t_e: 3.6 mm
• f_b: 73.7 mm
• Suggested Mount: LMR1