As a modern culture, we crave artificial white lights -- the brighter the better, and ideally using less energy than ever before. To meet the ever-escalating demand for more lighting in more places and to improve the bulbs used in sports stadiums, car headlights and street lamps, scientists are scrambling to create better light-emitting diodes (LEDs) -- solid state lighting devices that are more energy efficient than conventional incandescent or fluorescent light sources.
Photograph of bright white light (right) achieved using lasers in combination with phosphors next to an image of the phosphor with no illumination.
Just one thing stands in the way: "droop," the term for a scientific problem related to LEDs currently in use. Droop refers to the fact that LED efficiency falls as operating currents rise, making the lights too hot to power in large-scale applications. Many scientists are working on new methods for modifying LEDs and making progress toward cooler, bigger and brighter bulbs.
Now investigators at University of California, Santa Barbara, led by material scientists Kristin A. Denault and Michael Cantore, have devised an alternative means of creating high-power white light by using a different excitation source -- a laser diode in combination with inorganic phosphors, instead of the traditional LEDs.
Their laser-based lighting options are high in efficiency and high in performance metrics, according to their study, which is described in the journal AIP Advances, which is produced by AIP Publishing.
"We found two ways to create high-intensity ‘cool’ white light, explained Denault. "In one we used a blue laser diode and yellow-emitting phosphor powder with a luminous flux of 252 lumens, which is comparable to current high-brightness white LEDs. For our second method, we used a near-ultra-violet laser diode and a combination of red-, green-, and blue-emitting phosphors."
They also achieved a variety of other color temperatures with high color rendition, broadening the range of applications for these new lights, she said.
The article, "Efficient and stable laser-driven white lighting" by Kristin A. Denault, Michael Cantore, Shuji Nakamura, Steven P. DenBaars, and Ram Seshadri appears in the journal AIP Advances. See: http://dx.doi.org/10.1063/1.4813837ABOUT THE JOURNAL
Jason Socrates Bardi | Newswise
Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH
To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences