Best of Green Photonics

Best papers at SPIE Green Photonics show how to save money and resources.

01 July 2013

Research papers showing ways that solar energy, solid-state lighting (SSL), and optical interconnects can improve standards of living while saving money and resources were recognized at the Green Photonics symposium during SPIE Photonics West this year.

“Each of the winning papers provides new information to help solve existing problems using photonics,” says SPIE Fellow Stephen Eglash of Stanford University (USA), founder and chair of the symposium. “Photonics innovations enable improved sustainable products and services worldwide. The winners of this year’s Green Photonics Awards are exemplary in this regard.”

The four prize-winning papers are open-access in the SPIE Digital Library through 31 July.

Stephen Eglash awards best paper prize in Green Photonics to Ruth Houbertz-Krauss and Sönke Steenhusen from Fraunhofer ISC.
Paper on next-generation lighting from Denmark researchers

SSL utilizing light-emitting diodes (LEDs) is the new industry standard for energy efficiency, and the rapid development of LEDs has flooded the lighting market, Eglash noted.

However, there are large variations in the quality of these products, so Carsten Dam-Hansen and Technical University of Denmark colleagues Anders Thorseth, Dennis Corell, and Peter B. Poulsen tested more than 300 LED lamps on the Danish market to evaluate quality and lifetime. They reported their results in “Light quality and efficiency of consumer grade solid state lighting products.

Thorseth, who accepted the award in February, said the group hoped to work with other researchers on test and characterization “so the data can be shared all over the world to benefit the individual nation importing or producing the products.”

German researchers on less electricity for computing

Another photonics technology driving sustainable development is optical interconnects, considered a good solution for the challenges of designing and building computing systems. Eglash noted these devices can reduce the electrical power needed for communication and computation but board-level integration of optical interconnects is problematic.

In their winning paper, “Hybrid polymer optical waveguides written by two-photon processing for 3D interconnects,” SPIE members Ruth Houbertz-Krauss and Sönke Steenhusen, along with Timo Grunemann, of Fraunhofer-Institut für Silicatforschung (Germany) illustrated how they were able to considerably simplify the fabrication of optical interconnects, resulting in both environmental and energy-saving benefits.

A summary of their paper is available from SPIE as a PDF file.

USA and French researchers on cheap solar power

Two papers discussing solar power received Green Photonics awards.

Authors of “The photovoltaic potential of femtosecond-laser textured amorphous silicon” explain how they used femtosecond laser texturing to reduce reflection and enhance light absorption, enabling high efficiency from thin absorbers.

High-efficiency solar cells are needed to decrease the cost of solar energy, Eglash said. Solar cells that use thin absorber layers cost less and require fewer materials. But inefficiencies of conventional light-trapping techniques limit the ability to reduce the thickness of thin-film solar cells.

Authors were Kenneth Hammond and SPIE members Meng-Ju Sher and Eric Mazur of Harvard University (USA) and Lysander Christakis of the Cambridge School of Weston (USA).

Clément Colin of the Lab de Photonique et de Nanostructures, CNRS (France), an author of the other winning paper in the solar energy category, explained that his team of French researchers used new light-trapping strategies for broadband absorption in ultra-thin solar cells.

“These results allow at least a tenfold thickness reduction of the absorber and pave the way to novel architectures for thin-film and high-efficiency photovoltaic technologies,” he said. Colin’s team showed light enhancement for CIGSe, GaAs, and other PV materials, demonstrating the potential of their technique for crystalline or poly-crystalline solar cells.

Colin’s co-authors for “Broadband light trapping in ultra-thin nano-structured solar cells” are Inés Massiot, Andrea Cattoni, Nicolas Vandamme, Christophe Dupuis, Nathalie Bardou, Jean-Luc Pelouard, and Stéphane Collin of the Lab de Photonique et de Nanostructures; Isabelle Gérard of Institut de Recherche et Développement sur l’Energie Photovoltaique, CNRS; and Negar Naghavi and Jean François Guillemoles of Université de Versailles.

Call for papers

LOGO FOR Green PhotonicsAbstracts are due 22 July for next year’s SPIE Green Photonics virtual symposium.

Green Photonics, part of SPIE Photonics West, highlights papers from OPTO, LASE, and MOEMS-MEMS that showcase the latest photonics and optoelectronic tools and materials that reduce power consumption, enable cleaner manufacturing, and create new energy generation for a broad range of applications.

SPIE Photonics West 2014 will be held 1-6 February 2014 in San Francisco.

Green photonics special sections in Journal of Photonics for Energy

The Journal of Photonics for Energy (JPE) featured recent special sections on high and low concentrator systems for solar electric applications, guest edited by Kaitlyn VanSant of the National Renewable Energy Laboratory (NREL) (USA), and on reliability of photovoltaic cells, modules, components, and systems.

The latter special section was guest edited by SPIE member Neelkanth G. Dhere of the University of Central Florida (USA), John H. Wohlgemuth of NREL, and Kevin Lynn of the U.S. Department of Energy.

Special sections scheduled for 2014 will cover:

  • Smart photonic systems
  • Solid-state lighting
  • Nanophotonics and cell technologies for solar energy conversion

SPIE Fellow Zakya Kafafi is editor-in-chief.

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