25mm Dia x 20mm FL 3-5μm Coated, Hybrid Ge Aspheric Lens

Product Details Color Corrected for 3 – 5μm Near Diffraction Limited Focusing Performance Full Prescription Data Available Due to material supply chain disruptions with germanium, there may be increased lead times and price changes on our germanium products. For more information, please contact our customer service team . Edmund Optics has limited remaining inventory of this part number and no raw material available to supply more once this is depleted. Please contact our Product Support Engineers to help with an alternate solution for your needs. Customer Service can provide you the latest price and availability. Our TECHSPEC Germanium Infrared (IR) Hybrid Aspheric Lenses provide diffraction limited focusing performance at any wavelength in the 3 – 5μm region, and near diffraction limited performance when used over the entire 3 -5μm spectral range. They are ideal for integration into imaging applications, FTIR spectrometers, or any Mid-Wave IR application utilizing a broad band light source. Each hybrid aspheric lens is coated for >95% transmission for the most efficient use of costly infrared illumination. However, transmission is limited by the inherent diffraction efficiency of the aspheric surface, yielding lower overall transmission at the extremes of the design spectral band. For custom design or coating options, please contact our Sales Department . Specifications General Type: Aspheric Lens Physical & Mechanical Properties Diameter (mm): 25.00 +0.0/-0.1 Center Thickness CT (mm): 2.80 ±0.10 Edge Thickness ET (mm): 1.36 Clear Aperture CA (mm): 24.0 Centering (arcmin): ≤5 Shape of Back Surface: Concave Edges: Diamond Turned Bevel: Protective as needed Optical Properties Effective Focal Length EFL (mm): 20.00 @ 4000nm Back Focal Length BFL (mm): 18.21 Substrate: Many glass manufacturers offer the same material characteristics under different trade names. Learn More Germanium (Ge) f/#: 0.79 Numerical Aperture NA: 0.63 Index of Refraction (n d ): 4.002 @ 11µm Coating: BBAR (3000-5000nm) Coating Specification: R avg <3.0% @ 3 - 5μm Wavelength Range (nm): 3000 - 5000 Focal Length Specification Wavelength (nm): 4000 Aspheric Design Wavelength (nm): 4000 Surface Quality: 60-40 Radius R 2 (mm): 35 Asphere Figure Error, RMS @ 632.8nm: λ/6 Surface Accuracy, P-V (μm): 0.3 Conjugate Distance: Infinite Material Properties Coefficient of Thermal Expansion CTE (10 -6 /°C): 6.1 Regulatory Compliance RoHS 2015: Compliant × Certificate of Conformance: View × Reach 235: Compliant ×