The Optical Society of America (OSA) is hosting the Optics and Photonics Congress: Renewable Energy & the Environment, which will be held at the Omni Austin Hotel Nov. 2 to 3, in Austin, Texas. Scientists and engineers from around the world will gather to discuss recent advances in optics and photonics affecting renewable energy and environmental research. Four colocated meetings will cover optics for solar energy, solid-state and organic lighting, photovoltaics, and instrumentation for energy and environmental applications. Featured will be seven plenary session keynote speakers from institutions such as the US National Renewable Energy Lab and Stanford University. Research presentations at the meeting will focus on the most cutting-edge discoveries in renewable energy and photonics, including new designs for solar cells and LEDs. Highlighted presentation topics include: Thousands of Sensors to Keep Watch on Earth's Climate Science is only as good as the data on which it is based, the saying goes. To help meet the forecasting challenges of climate-change science, the US National Ecological Observatory Network (NEON) plans an ambitious network of more than 45,000 sensors to monitor climate indicators such as temperature, precipitation, carbon dioxide concentration and soil characteristics. Researchers will present a strategy for automating and managing this vast array of climate sentinels. Looking for CO2 Leaks One proposed method to slow anthropogenic climate change is to capture carbon dioxide emissions and store them underground. But the solution won't work if the CO2 escapes. Researchers have designed and tested an imaging system that may be able to spot leaks by the telltale way the CO2 feeds vegetation growth. Let the Sunshine In Natural light is free and aesthetically pleasing, but it can't reach basements or windowless offices. Novel day-lighting systems, called core sunlighting, that bring light into these building areas might solve this problem by piping the sunshine through cost-effective, mirror-lined tubes. Studying Space Debris: NASA Uses Optics to Help Reveal Size, Composition of Space Junk NASA is using new optical techniques to study the ever-growing cloud of space debris encircling the Earth. NASA uses the information it gathers to help develop space debris mitigation standards and collision avoidance maneuvers for spacecraft, making space a little safer. Novel LED Design May Boost Efficiencies LEDs are vastly more efficient than incandescent lightbulbs and even compact fluorescent bulbs, but they still have design constraints that limit their potential. Researchers at the National Institute of Advanced Industrial Science and Technology (AIST) in Japan have used a new ridge-shaped design that is 10 to 16 times more efficient than the current flat design. "Inverted Pyramid" Design Makes Thinner Wafers, Cheaper Solar Cells The battle between solar power and fossil fuels can be fought on many fronts, but a big one is cost. Researchers at MIT will discuss their newly designed prototype silicon solar cell that promises to be just as efficient as a standard silicon cell, but that uses much less material, making it theoretically cheaper to produce. "Power Droop" Challenges of LEDs for High-power Lighting The US is currently in a transition from old and familiar incandescent lightbulbs to vastly more efficient solid-state LEDs, or light-emitting diodes. There remain, however, formidable challenges facing LED technologies, particularly for high-power lighting applications. One of the major hurdles is the so-called "efficiency droop" that occurs when attempting to ramp up LEDs to high current densities. Researchers from Rensselaer Polytechnic Institute in New York will discuss the origin of this droop as well as ways to reduce it. Toward a Simpler White Organic LED Design Organic light emitting diodes (OLEDs), because of their remarkable efficiency and low energy consumption, show great promise in meeting home and business lighting needs. One of the remaining hurdles to deploying these more broadly, however, is the challenge of producing white light, which is currently generated through a complex design that combines multiple color emitters. Research is under way to develop an efficient white OLED that uses a single broadband emitter. Improving Efficiency with Photonic Crystal Sandwiches "Tandem" solar cells can increase energy efficiency by combining multiple materials that absorb different frequencies of light. However, they are difficult to manufacture because only certain materials are compatible, and minor defects can have a major impact on the ability of two adjacent materials to work together. Researchers in Germany have discovered that 3-D photonic crystals sandwiched between two different absorbing materials can manage the flow of photons within a tandem solar cell, preventing one material from interfering with the light-absorbing abilities of the other, and making it easier to manufacture tandem solar cells on a large scale. Plasmonics for Better Light Trapping In their quest for more efficient sunlight-to-energy converters, scientists are exploring the light-controlling properties of metals in the burgeoning field of plasmonics, which examines the flow of a special type of light wave along the surface of metals. Stanford University materials scientist Mark Brongersma will discuss recent progress in the development of plasmonic and other nano-sized structures that can increase the efficiency of light absorption and trapping in solar cells. For more information, visit: www.osa.org