Abstract: A lens is fabricated of an array of parallel rod-shaped dielectric waveguides extending from a generally planar front surface of the array, this front surface constituting a front surface of the lens, to a concave back surface of the array, this back surface constituting a back surface of the lens. The wavguides vary in length, from a maximum length at an outer region of the lens to a minimum length at a central region of the array, to provide the concave back surface. The back lens surface envelops a receptor of radiant energy located at a focus of the lens. This configuration of lens provides an increased spherical angle of impingement of the incident radiation upon the receptor.