An optical device including a metamaterial layer having a negative index of refraction for at least one wavelength in the visible range of 400-700 nm, a photovoltaic cell, and an optical waveguide arranged between the metamaterial layer and the photovoltaic cell. The optical waveguide has a first face and second face arranged opposite the first face, the first face having a larger area than the second face, the metamaterial layer positioned at the first face of the optical waveguide and the photovoltaic cell positioned at the second face of the optical waveguide. The optical device can be a solar collector. The optical waveguide can have a trapezoidal cross section, with the side faces of the waveguide having an angle of tilt sufficient to ensure total internal reflection for all incidence angles within the metamaterial's acceptance cone.