• Ø2" Mounted Positive IR Achromatic Doublet
• AR Coated for the 1050-1620 nm Range
• Engraved Threaded Housing Includes Part Number, Focal Length, and Coating
• Housing Enables Easy Integration into Thorlabs' Optomechanics
• Focal Length: 75 mm

Thorlabs' most popular cemented IR achromatic doublet is available pre-mounted in an engraved threaded mount, making it easy to incorporate this optic into your setup.

The engraving on the mount clearly indicates the part number, focal length, antireflection coating deposited onto the surface, an arrow indicating the direction of light propagation to collimate a point source, and an infinity symbol denoting that this lens has an infinite conjugate ratio (i.e., if a diverging light source is placed one focal length away from the flat side of the lens, the light rays emerging from the curved side will be collimated).

Achromatic doublets are useful for controlling chromatic aberration and are frequently used to achieve a diffraction-limited spot when using a monochromatic source like a laser.

• Design Wavelengths: 1016 nm, 1330 nm, and 1550 nm
• Diameter Tolerance: +0.00/-0.10 mm
• Focal Length Tolerance: ±1%
• Surface Quality: 40/20 Scratch/Dig
• Spherical Surface Power: 3?/2
• Spherical Surface Irregularity: ?/4
• Centration: =3 arcmin
• Clear Aperture: >90% of Diameter
• C Coating Range R_avg: < 0.5% (1050 - 1620 nm)
• Damage Threshold: 5 J/cm² (1542 nm, 10 ns, 10 Hz, Ø0.181 mm)
• Operating Temperature: -40 °C to 85 °C
• Diameter: 50.8 mm
• f: 75 mm
• f_b: 63 mm
• r₁: 49.89 mm
• r₂: -39.09 mm
• r₃: -230.7 mm
• t_c1: 19 mm
• t_c2: 2.5 mm
• t_e: 13.1 mm
• Materials: N-BAF10/N-SF6HT
• Mounting Thread: SM2 (2.035"-40)