The Plano-Concave Lens has one concave surface and one flat surface, featuring a negative focal length. It is commonly used for beam collimation, increasing (or decreasing) the focal length, or enlarging (or reducing) images. To minimize spherical aberration, when the incident beam is collimated, it should be directed onto the concave surface of the plano-concave lens. N-BK7 is the most common lens material, widely used in visible and near-infrared applications. In addition to N-BK7 plano-concave lenses, LBTEK also offers N-SF11, UV fused silica, and calcium fluoride plano-concave lenses. Due to its lower Abbe number, N-SF11 is often used to produce lenses with shorter focal lengths. UV fused silica exhibits excellent transmittance in the ultraviolet range and a low coefficient of thermal expansion, while calcium fluoride boasts an extremely high damage threshold and chemical inertness. LBTEK provides uncoated plano-concave lenses as well as lenses with three types of anti-reflection coatings: 400 nm-700 nm, 700 nm-1100 nm, and 1100 nm-1650 nm. All our lenses undergo precision machining and strict quality control, ensuring that LBTEK delivers high-quality lens products to customers at reasonable prices.