Control of spatial phase empowering spectral splitting and concentration of solar spectrum


Gün B. N. , Yüce E.

PVCON 2020, Ankara, Turkey, 30 November - 02 December 2020, pp.39

  • Publication Type: Conference Paper / Summary Text
  • City: Ankara
  • Country: Turkey
  • Page Numbers: pp.39

Abstract

Harvesting energy from a broad-spectrum light with high efficiency is a long-standing endeavor given the increasingly important energy source yet to be exploited further: sunlight. No material alone can derive energy from a broadband light with high efficiency. That being the case, the methods benefitting from spectral sub-bands together with concentration are in demand to utilize record level efficiency in photovoltaic cells. It is possible to get these sub-bands by portioning a broadband light through spectral splitting. Spectral splitters are generally realized via computational methods. Here, we present an experimental method to spectrally split and concentrate broadband light via controlling the wavefront of the incident light. We have chosen particular concentration spots for red (560 nm - 875 nm), green (425 nm – 620 nm), and blue (420 nm – 535 nm) frequency bands within the broad-spectrum. Encoding different diffractive patterns onto the SLM, we manage to generate dynamic phase plates that enable experimental control on the spatial phase of the incident light. The concentration of light is achieved with a total enhancement factor of 564 %. The spectral splitting ratios that we obtain are 43 %, 37 % and 34 % for red, green, and blue channels, respectively. The method that we offer is faster than the computational methods given the fast response time of the spatial light modulator within 17 ms. This duration is much shorter than the time spent for calculating diffractive optical elements. We provide an experimental method that can increase the impact of diffractive optical elements (DOE) by providing the means to design efficient and effective DOEs within a very short time. Thereby, the output intensity profile of light that passes through the phase plate is measured and altered within this short duration providing a faster total computational time than a calculation of the output intensity distribution at the target plane. This study is financially supported by The Scientific and Technological Research Council of Turkey (TÜBİTAK), grant no 118F075.