A diffraction‐limited geodesic lens was demonstrated in a polyurethane film‐glass substrate waveguide structure. The lens has an aspherical depression and a rounded edge. The measured focal length remained at 10 mm up to 92% of the aperture. Diffraction‐limited focal spot size was measured for an input beam width of 2 mm. For larger input beamwidth, the spot size measurement was limited by the optical resolution of the detection system.