Maximum-performance photovoltaic concentration with unfolded aplanatic optics

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


Some current high-concentration photovoltaic designs are based on folded mirror optics, i.e., the optical path is reversed via reflection in order to achieve minimal aspect ratio. One apparently overlooked class of aplanats is the unfolded dualmirror aplanat explored in this presentation. The confluence of practical constraints presented by many highconcentration photovoltaic systems creates a niche for unfolded aplanatic optics that permit the elimination of optical bonds between dielectric elements and solar cells while achieving an angular tolerance near the fundamental limit. The long-term material integrity of the optical bonds - especially at high irradiance - remains to be established and has been viewed as potentially precarious. Furthermore, the unfolded optic and the target can be decoupled. The disadvantage of unfolded optics is depth: concentrator aspect ratios far larger than the fundamental compactness bound realizable with folded optics. However, with high-concentration photovoltaics evolving to millimeter-scale cells, the corresponding depth of the concentrator would be only a few centimeters: compatible with precision large-volume fabrication techniques. We also show how a lens at the center of the aplanat's glazing permits a noticeable reduction in concentrator depth. A fringe benefit is the paucity of hot spots on the optical elements, creating the option of coated polymeric reflectors, which reduces mass and cost.

Original languageEnglish
Title of host publicationHigh and Low Concentration for Solar Electric Applications III
StatePublished - 21 Nov 2008
EventHigh and Low Concentration for Solar Electric Applications III - San Diego, CA, United States
Duration: 11 Aug 200812 Aug 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceHigh and Low Concentration for Solar Electric Applications III
Country/TerritoryUnited States
CitySan Diego, CA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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