Substrate: N-BK7 (Grade A Optical Glass) Diameter (Ø): 6mm & Effective Focal Length (EFL): -9.8mm Radius (R): -5.069mm & Center Thickness (CT): 1.0mm Edge Thickness (ET): 1.98mm & Back Focal Length (BFL): -10.05mm Precision N-BK7 plano-concave lens with excellent wavefront accuracy. Ideal for beam expansion, projection systems, and aberration correction. Features negative focal length design, broadband transmission, and serves as coating substrate. Quality-inspected for reliable performance. Our high-precision plano-concave lenses are core components engineered for demanding applications that require exceptional optical performance. Through meticulous manufacturing processes and stringent quality control, we ensure that each lens delivers superior surface figure accuracy and optical consistency, effectively minimizing wavefront distortion to guarantee precise beam propagation and clear imaging. In laser processing, precision measurement, scientific research experiments, and advanced imaging systems, our plano-concave lenses demonstrate outstanding stability and reliability, providing solid support for complex optical designs. They represent the ideal choice for enhancing your system's performance.