2009-12-16

Photonic Crystals Material More Insulating than the Vacuum

clipped from www.physorg.com

Scientists Create Material More Insulating than the Vacuum

clipped from www.physorg.com
http://www.physorg.com/newman/gfx/news/hires/vacuumflask.jpg
clipped from www.physorg.com
(PhysOrg.com) -- With its complete lack of atoms, a vacuum is often considered to be the best known insulator. For this reason, vacuums are regularly used to reduce heat transfer, such as in the lining of a thermos to keep beverages hot or cold. However, in a recent study scientists have found a material even less able to conduct heat: a stack of photonic crystals layered within a vacuum can create a material with a thermal conductance just half that of empty space alone.
clipped from focus.aps.org

Photonic Thermos

thermos with hot liquid

Not the best. A complete theoretical analysis shows why a photonic crystal should insulate better than the vacuum jacket of a thermos. The photonic crystal would insulate by blocking much of the infrared radiation a warm object emits--radiation that can cool the object even when it's surrounded by vacuum.


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clipped from www.smartplanet.com

Scientists create material more insulating than a vacuum; smart windows on horizon

A new material made of photonic crystals may be more insulating than a vacuum that completely lacks atoms.

Led by Shanhui Fan, the researchers set out to create a material that addressed that pesky third source of heat transfer: infrared radiation. Photonic crystals, which consist of bands of nanostructures that affect how light travels through them, were the solution.

So what’s the importance of a better vacuum? As I mentioned above, smarter windows on cars, homes and offices is a start. With photonic crystals, smart windows could capture the sun’s heat for use as an energy source while allowing visible light to pass through uninterrupted.


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Sources:
  1. Scientists Create Material More Insulating than the Vacuum
  2. vacuumflask.jpg (JPEG Image, 200x346 pixels)
  3. Photonic Thermos | Physical Review Focus
  4. Scientists create material more insulating than a vacuum; smart windows on horizon - SmartPlanet
Related:
  1. Fan Group at Stanford University
  2. Wah Tung Lau's Homepage
  3. Universal features of coherent photonic thermal conductance in multilayer photonic band gap structures
  4. Photonic Crystal Research
  5. Photonic Crystals Tutorial