SAN DIEGO, CA--In last year’s review of the 2008 SPIE (Bellingham, WA) Optics + Photonics conference (see “Optics + Photonics continues nano, solar emphasis” in Optoelectronics Report, August 1, 2008), the staff at Optoelectronics Report was hoping that the 2009 attendance figures would exceed 5100, the peak attendance figure for 2007. But what a difference a year makes. Despite the economic storm that began building early last year and continues to rage in the optics and photonics industry, official 2009 SPIE Optics + Photonics attendance figures came in at 4837, slightly above the official 4812 attendee count for 2008, but slightly below projections considering that the 2009 event included the SPIE Astronomical Telescopes and Instrumentation conference that should have driven up attendance. Nonetheless, attendance figures were quite respectful for the 2009 event, held August 2–6 in San Diego, CA, and most of the exhibitors I spoke with were pleased at the level of booth traffic. SPIE even reported that the number of walk-in visitors to the exhibition was up over last year.
Conference organizer SPIE continued in 2009 with the NANO, SOLAR, PHOTONICS, and OPTICS conference topical areas, and Plenary sessions were plentiful for each; in total, there were 39 Plenary sessions, including the two symposium-wide plenaries that focused on astronomy. After all, the International Year of Astronomy 2009 commemorates 400 years of the telescope (see www.laserfocusworld.com/articles/365502 and www.laserfocusworld.com/articles/339877), and Optics + Photonics 2009 included an antique telescope/monocular/binocular display on the exhibit floor, an Astro-Photo Wall with photos of our universe, and a “Star Gazing” event at the Monday Welcome Reception.
Solar stays hot
While most of the Plenary sessions were well attended, the Monday Solar Energy Plenary Sessions were filled to capacity if you include all the people standing at the rear of the room waiting to take a seat.
David S. Ginley, research fellow and group manager in Process Technology and Advanced Concepts at the National Renewable Energy Laboratory (NREL; www.nrel.gov) in the National Center for Photovoltaics, began the Solar Energy Plenary with a talk on “Progress in Organic Photovoltaics Toward Low Cost PV.” He described how organic thin-film solar cells from Plextronics (Pittsburgh, PA) were now achieving 6% optical-to-electrical conversion efficiencies, whereas values were at 4% only a year ago. Based on photo-induced charge separation in polymer materials, these organic solar cells offer flexibility, potentially lower fabrication cost due to their ability to conform to roll-to-roll processing and printing techniques, and lower material costs. However, degradation mechanisms still exist, and lifetimes for these products are from months to just a few years, compared to decades in some cases for crystalline silicon photovoltaics.
One of the more interesting Plenary presentations in terms of its historical content related to the tremendous technological growth in solar-cell technology was “Thin-Film Silicon PV Modules: Status and Prospects” by Arvind Shah from the University of Neuchâtel in Switzerland. Shah reminded the audience that the first amorphous silicon solar cell demonstrated back in 1976 had a conversion efficiency of only 1.1%. Today, amorphous silicon (a:Si) module efficiencies are around 6.3% and improving, thanks to techniques such as texturing the transparent conductive oxide layers of the cell to improve electron capture.
A Plenary from Sarah R. Kurtz, manager of the Reliability Group at NREL, focused on the need for PV reliability in order to achieve a solar-powered world. Kurtz says that reliability is paramount if solar technology is to gain the widespread acceptance needed to penetrate the energy markets. She described how many of the solar system failures are not caused by the cells, but by the inverters (many of them failing after only two years of service). When solar-cell failures do occur, Kurtz noted that unfortunately, many of the manufacturers are reluctant to provide data on failure mechanisms. The need for this transparency, says Kurtz, is critical for the continued improvement in solar-cell efficiencies and elimination of system failures.
David Eaglesham, VP Technology at First Solar (Tempe, AZ), also emphasized the need for reliability, touting the cadmium telluride technology of First Solar (actually CdTe/CdS/TCO/glass) as having a 25 year warranty with 11% conversion efficiency values. Eaglesham pointed out that in addition to reliability, the real challenge to the solar community is the 5 TW renewable goal by 2020 from the Intergovernmental Panel on Climate Change (IPCC)--a goal that would require the solar market to grow each year up to 2020 at a 70% compound annual growth rate. Although First Solar plans to reach a $0.52 to $0.63/Watt target by 2014, he believes that all solar PV systems need to have a one-year payback time for the terawatt world to be realized.
Metamaterials: closer to commercialization?
With their strange attribute of negative refractive index, metamaterials continue to spark the imagination with such possibilities as optical invisibility cloaking (see www.laserfocusworld.com/articles/363446). But can the tremendous research and development momentum in metamaterials continue? Martin Wegener, professor and nanostructures expert at Universität Karlsruhe (Karlsruhe, Germany) thinks so, provided metamaterials begin to deliver commercial applications. In his Wednesday Photonic Devices and Applications Plenary entitled “Photonic Metamaterials: Optics Starts Walking on Two Feet,” Wegener has identified such an application: a 3-D chiral metamaterial that can be used as a broadband circular polarizer. This material, says Wegener, is one of the first demonstrations of how metamaterials exploit the manipulation of both the electric and magnetic field contributions of light--hence the reference to light propagation (walking) in the z direction with the orthogonal electric and magnetic fields acting as the two feet.
Exhibition
In total, 248 companies and institutions exhibited in 2009--down from the record number of 279 for Optics + Photonics 2008. A large share of exhibit space was devoted to finished optics, coatings, optical fabrication, and optical metrology equipment. And in addition to the historical telescopes display, a portion of the exhibit hall was devoted to the Prism Innovations Product Lab. Silicon CMOS photonics company Luxtera (Carlsbad, CA), as a winner of the 2008 Prism Award, demonstrated its 40 Gigabit Active Optical Cable (AOC), Blazar, that integrates optics directly with silicon electronics on a monolithic CMOS chip.
Noticeably lacking from the exhibit floor were new products. If you are aware of any, please contact [email protected]. Unfortunately, new product development is an area that is suffering in the current economic storm. Here’s hoping that next year is better for all of us. And be sure to mark your calendars for SPIE’s Optics + Photonics 2010, to be held again in San Diego, CA, from August 1–5.
--Gail Overton
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