• Ø1" Negative Meniscus Lenses
• Uncoated
• Focal Length: -300 mm
• Fabricated from UV Grade Fused Silica
• Spherical Surface Power: 3 Fringes
• Spherical Surface Irregularity: λ/4

Thorlabs' UV-Grade Fused Silica Negative Meniscus Lens is uncoated. Compared to N-BK7, UV-grade fused silica offers high transmission deeper into the UV (down to 185 nm), better homogeneity, and a lower coefficient of thermal expansion. In addition, UV-grade fused silica exhibits virtually no laser-induced fluorescence (as measured at 193 nm), making it an ideal choice for applications from the UV to the near IR.

The additional UV antireflection coating available on this negative meniscus lens is particularly desirable for applications with multiple optical elements. Since approximately 4% of the incident light is reflected at each surface of an uncoated substrate, the application of a UV AR coating improves transmission, which is particularly important in low-light applications, and prevents the undesirable effects (e.g., ghost images) associated with multiple reflections.

Negative meniscus (convex-concave) lenses, which are thinner in the middle than at the edges and cause light rays to diverge, are designed to minimize third-order spherical aberration. When used to diverge light, the convex surface should face the beam to minimize spherical aberration. It is often used in conjunction with other lenses to increase the focal length, and therefore decrease the numerical aperture (NA), of an optical assembly.

• Lens Shape: Negative Meniscus
• Substrate material: UV Grade Fused Silica
• Diameter: Ø1"
• Diameter Tolerance: +0.00 mm / -0.10 mm
• Wavelength Range: 290-370 nm
• Focal Length Tolerance: ±1%
• Surface Quality: 40-20 Scratch-Dig
• Clear Aperture: >90% of Diameter
• Design Wavelength: 588 nm (n=1.460)
• Index of Refraction (@ Design λ): 1.460
• Centration: ≤3 arcmin
• Diameter: 25.4 mm
• f: -300 mm
• R₁: 150 mm
• R₂: 71.4 mm
• t_c: 3.5 mm
• t_e: 4.1 mm
• f_b: -297.8 mm
• Suggested Mount: LMR1