A plano convex lens fits exactly into a plano concave lens.Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive index u1 and u2 and
Quartz lenses & glass lenses | Quantum Design
Plano Concave BK7 Lens - 25.4mm dia - Opto4U
Plano-Concave Cylindrical Lenses, N-BK7, AR Coating: 650-1050 nm