The Nobel Prizes in Physics and Chemistry have been awarded to scientists working in areas of photonics. The Nobel Prize in Physics was presented to the inventors of the blue light-emitting diode, while the developers of super-resolved fluorescence microscopy techniques won the Nobel Prize in Chemistry.
Both teams were chosen by the Royal Swedish Academy of Science and will each receive eight million Swedish Krona.
Nobel Prize for Chemistry
The Nobel Prize for Chemistry, announced on 8 October, was awarded to Eric Betzig, Stefan Hell and William Moerner for having bypassed the physical limit for optical microscopy.
Two separate principles have been rewarded. One enables the method stimulated emission depletion (STED) microscopy, developed by Stefan Hell in 2000. The STED technique involves the use of an excitation laser pulse closely followed by a doughnut-shaped pulse that is termed the STED beam. First, all of the fluorescence molecules are depleted using a laser, but because the STED beam is set to a doughnut shape, only the fluorescence molecules at the edge of the excitation focus are depleted, so the fluorescence molecules in the centre of the doughnut remain unaffected and can be detected.
Eric Betzig and William Moerner, working separately, laid the foundation for the second method, single-molecule microscopy. The method relies upon the possibility to turn the fluorescence of individual molecules on and off. Scientists image the same area multiple times, letting just a few interspersed molecules glow each time. Superimposing these images yields a dense super-image resolved at the nano-level. In 2006 Eric Betzig utilised this method for the first time.
Before the work of the Laureates, traditional fluorescence microscopy was diffraction-limited, meaning that the highest achievable resolution for optical microscopes was 200nm. In 1873, the microscopist Ernst Abbe stipulated this physical limit for the maximum resolution of traditional optical microscopy.
But thanks to the Laureates achievements, Abbe's diffraction limit of 200nm can now be overcome. Their ground-breaking work has brought optical microscopy into the nano-dimension, and microscopes can now achieve resolutions ten times greater than was previously possible.
Increasing the resolution by a factor of ten creates new possibilities for fluorescence microscopy. As most biological structures are much smaller than the previous 200nm limit, scientists can now image biology that could not be seen before.
This includes being able to see how molecules create synapses between nerve cells in the brain, enabling scientists to track proteins involved in Parkinson’s, Alzheimer’s and Huntington’s diseases as they aggregate.
Image: The dotted line represents the limit of what could be visualised before the diffraction limit was overcome. Credit: Johan Jarnestad/The Royal Swedish Academy of Sciences
Nobel Prize for Physics
The 2014 Nobel Prize for Physics was awarded to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura, the team behind the blue light-emitting diode, first demonstrated in 1994, which has enabled bright and energy-saving white light sources.
In order to create a white light source, red, green, and blue LEDs are required. Red and green LEDs had been around for around 30 years before the team managed to produce blue light from a semiconductor in the early 1990s. The work was carried out while Akasaki and Amano worked at the University of Nagoya and Nakamura was employed at Tokushima-based Nichia Chemicals.
The LED lamp holds great promise for increasing the quality of life for over 1.5 billion people around the world who lack access to electricity grids - due to low power requirements LEDs can be powered by cheap local solar power.
Commenting on the announcement, the Optical Society's CEO Elizabeth Rogan said: 'Lighting accounts for approximately one-quarter of all electricity consumption in industrialised nations. The invention of blue LEDs has led to new lighting solutions that will have a significant impact on energy efficiency and the potential to reduce electricity consumption on a large scale over time. How very fitting that on the cusp of the 2015 International Year of Light, the Nobel Prize in Physics is awarded for this critical light-based technology. Congratulations to Drs. Amano, Akasaki and Nakamura for this well-deserved honour.'
The most recent record for luminous flux for white LED lamps is just over 300 lm/W, which can be compared to 16 for regular light bulbs and close to 70 for fluorescent lamps. As about one fourth of world electricity consumption is used for lighting purposes, the LEDs contribute to saving the Earth’s resources. Materials consumption is also diminished as LEDs last up to 100,000 hours, compared to 1,000 for incandescent bulbs and 10,000 hours for fluorescent lights.
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