Thorlabs' plano-convex lenses have a positive focal length and can be used to focus collimated light, to collimate a point source, or reduce the divergence angle of a diverging source. Our plano-convex lenses are fabricated from N-BK7, UV fused silica, N-SF11, vacuum-grade calcium fluoride, magnesium fluoride, silicon, barium fluoride, zinc selenide, germanium, PTFE, or HRFZ-Si. For more information on most of these substrates, please visit our Optical Substrates page.