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2.3" x 2.3", FL 1.2", IR Fresnel Lens

Infrared (IR) Fresnel Lenses

Stock #32-798 3-4 days
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Qty 11+
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Effective Focal Length EFL (mm):
Substrate: Many glass manufacturers offer the same material characteristics under different trade names. Learn More
Poly IR
Fresnel Lens
Wavelength Range (nm):
8000 - 14000
Center Thickness CT (inches):
Coefficient of Thermal Expansion CTE (10-6/°C):
11 - 13
Dimensions (inches):
2.3 x 2.3
Dimensions (mm):
58.42 x 58.42
Effective Diameter (inches):
Effective Focal Length EFL (inches):
Flexural Modulus (psi):
(100-260) x 103
Groove Density (grooves/inch):
Index of Refraction nd:
Visible (Sodium D Line): 1.52
8-14µm: 1.53
15µm+: 1.48
Operating Temperature (°C):
Shore Hardness:
Wavelength Range (μm):
8 - 14
Young's Modulus (GPa):
0.40 - 1.24

Regulatory Compliance

RoHS 2015:
Reach 224:
Certificate of Conformance:

Product Family Description

  • Excellent Collecting Optics for Infrared Detectors
  • Minimal Absorption Loss in the 8-14μm Region

IR Fresnel lenses are molded in a flexible, 0.015" (0.457mm) thick, milky white plastic. Advantages of this product are: least absorption loss in the 8-14μm region, extremely thin with consistent thickness across the lens, large apertures and minimal thermal expansion. The design of an infrared-transmitting Fresnel lens involves many complex considerations. The grooved side of a Fresnel lens should face the longer conjugate (away from the detector when used to collect radiation). If the smooth side needs to face the longer conjugate for some nonoptical reason, the maximum aperture of the lens should be f/1.0. In this case, total internal reflection keeps all radiation from the area of the lens past f/1.0 from reaching the image. Even when the grooves face the longer conjugate, the portion of the lens past f/1.0 contributes a diminished amount and there is no significant contribution past f/0.5.

Technical Information

Durability Specifications
Effect of Sunlight None to Slight
Effect of Ultraviolet UV Stabilized
Effect of Weak Acids Very Little
Effect of Strong Acids Attacked by Oxidizing Acids
Effect of Weak Alkalies Very Little
Effect of Strong Alkalies Very Little
Effect of Organic Solvents Little below 60°C (140°F)