Designs of Diffractive Optical Elements for Solar Energy Harvesting

Solar energy has been chosen as "the source of energy" given its effectiveness and promises that push researchers forward for developing enhanced solar panels. Diffractive optical elements promise efficient spatial and spectral control of the sunlight that can fulfill the need for increased conversion efficiency. Here, we present designs of diffractive optical elements that can spectrally split broadband sunlight as well as serving as a solar concentrator. We show that a single wavelength can be concentrated with almost 1200-fold at the target position. Moreover, our results indicate that a single diffractive optical element can guide two different wavelengths to two distinct target planes with 89% average spectral optical efficiency. We observe that a diffractive optical element that is optimized for two wavelengths can provide 5.3% excess spectral optical efficiency under broadband illumination. The increased output at limited computation costs enables the design of diffractive optical elements for various settings that require broad angle response which is extremely costly in terms of computation.