Negative Focal Length: The double concave lens has a negative focal length, which allows it to diverge collimated light beams to the virtual focal point.

Versatile Applications: Biconcave lenses are versatile and can be used for divergence of collimated or focused light beams, beam diameter modulation, correction of spherical aberration in optical assemblies, and increasing the focal lengths of a lens group.

Optimal Performance: Due to its symmetric structure, the double concave lens works best when the conjugate ratio is close or equal to 1:1, providing minimal distortion, spherical/chromatic aberration, and coma.

Cost-Effective: N-BK7 glass is known for its low cost, making it an economical choice for manufacturing optical components.

High Optical Transmission: N-BK7 glass offers high optical transmission across the visible spectrum and into the near-infrared region (350-2200nm).

Durability: The material is known for its high hardness and resistance to scratches and abrasions, as well as its ability to withstand changes in temperature without significant expansion or contraction.

Applications: Beam Divergence, Beam Diameter Modulation, Spherical Aberration Correction, Focal Length Adjustment, Custom Optical Solutions, etc.