• Best Possible Performance from a Spherical Singlet
• C Coating
• Ideal for High Power Applications
• Diffraction-Limited Performance at Small Input Diameters
• Spherical Surface Power: 3 Fringes
• Spherical Surface Irregularity: ?/4

Thorlabs' N-BK7 Best Form lens is designed to have minimum spherical aberration. This is achieved by polishing both sides to different radii optimized for an infinite conjugate source. For best performance in focusing applications, the surface with a larger radius of curvature should face the collimated source. The lens is optimized for minimum spot size and can theoretically reach diffraction-limited performance for small input beam diameters. An Antireflection Coating can reduce the amount of light reflected from each surface of the lens. Thorlabs' N-BK7 Best Form Lenses are available with our standard -A, -B, or -C Broadband Antireflection Coating.

• Lens Shape: Convex/Convex
• Material: N-BK7
• Design Wavelength: 587.6 nm
• Index of Refraction: 1.5167 at Design Wavelength
• Centration: <3 arcmin
• Clear Aperture: =90% of Diameter
• Focal Length Tolerance: ±1% @ Design Wavelength
• Surface Quality: 20-10 Scratch Dig
• Diameter Tolerance: +0.0 mm / -0.1 mm
• Wavelength Range: (-C Coating) 1050 - 1620 nm
• Diameter: 25.4 mm
• f: 40 mm
• R₁: 24.02 mm
• R₂: -134.6 mm
• t_c: 6.5 mm
• t_e: 2.3 mm
• f_b: 36.3 mm
• Suggested Mount: LMR1
• Input Diameter for Diffraction Limited Performance @ 632.8 nm: 5 mm
• Input Diameter for Diffraction Limited Performance @ 1064 nm: 6 mm