... efficiency, the second, plano (flat) surface should face the desired focal plane. Plano Convex lenses are commonly used in a wide range ... emitters, detectors, lasers, and fiber optics.Specifications:Material: BK7, Fused Silica, SF10, CaF2, Sapphire, etc. Paraxial Focal Length Tolerance: ±2% Dimension Tolerance ...