SLB-25B-30NIR1 Biconcave Lens

[Features]
· With both faces concave, this lens can efficiently refract light in a restricted space, and spread the light widely.
· It can be used in cases where the irradiation area of the illuminating light is expanded.
· A BK7 lens for the visible range to the near infrared range.
· Three types of lenses with antireflection coating in the visible range, near-infrared range, and infrared range are available.
· Selection can be made from a wide range of variations subdivided by outer diameter, focal distance, and so on, to suit the specifications.
· * A concave lens itself cannot concentrate light or form an actual image.
· * Use in combination with a convex lens.
· * Spherical surface biconcave lenses have chromatic aberration, resulting in focal lengths changing with wavelength.
· * If a high-energy pulse laser is used, a focal point may be created on the optical path due to reflected light from the concave surface and sparking may occur.
· * Use a planoconcave lens when using a pulse laser.
[Product Specifications]
· [ Common Specifications]
· Material: BK7
· Design Wavelength: 546.1 nm
· Refractive Index: n e = 1.519
· Coating: Anti-reflective Film (633-1,064 nm)
· Laser Yield Strength (Reference Value): Anti-reflection Coating 4 J/cm^2 (Pulse Width 10 ns, Repetition Frequency 20 Hz)
· Effective Diameter: 85% of External Diameter
· Scratch-Dig: 20-10
· [Individual Specifications]
· Antireflection Film Coating Wavelength Region: 633-1,064 nm
· Outer diameter φD: φ25 mm
· Focal distance f: -29.7 mm
· Rim thickness te: 7.2 mm
· Central thickness tc: 2 mm
· Back focus fb: -30.3 mm
· Radius of the curvature r: 31.14 mm
· Eccentricity: < 1'