A spectrum splitter can be used to spatially multiplex different solar cells that have high efficiency in mutually exclusive parts of the solar spectrum. We investigated the use of a surface-relief grating made of dielectric materials for specularly transmitting one part of the solar spectrum while the other part is transmitted nonspecularly and the total reflectance is very low. A combination of (i) the rigorous coupled-wave approach for computing the reflection and transmission coeffients of the grating and (ii) the differential evolution algorithm for optimizing the grating shape was devised as a design tool. We used this tool to optimize two candidate gratings and obtained denite improvements to the initial guesses for the structural and constitutive parameters. Signicant spectrum splitting can be achieved if the angle of incidence does not exceed 15.

Date Published: 5 September 2014
PDF: 10 pages
Proc. SPIE 9191, Nonimaging Optics: Efficient Design for Illumination and Solar Concentration XI, 91910I (5 September 2014); doi: 10.1117/12.2064026

Published in SPIE Proceedings Vol. 9191:
Nonimaging Optics: Efficient Design for Illumination and Solar Concentration XI
Roland Winston; Jeffrey M. Gordon, Editor(s)