Optimizing Energy Efficiency with Solid State Thermoelectric Devices

LY13235 - Conservation laws are certainly one of the most elementary and fundamental principles of mechanics. The surprise is that they may play a basic role to solve one of the main problems of future society. Providing a sustainable supply of energy to the world’s population will become a major societal problem for the 21^st century. Thermoelectric phenomena provide a method for heating and cooling,  with no moving parts, possible miniaturization  and absence of emission. They could play a crucial role in a global sustainable energy solution but the  main problem is that in spite of 60 years of research, the efficiency of thermoelectric devices is too low. A breakthrough - allowing increase of efficiency- would have a substantial economic and environmental relevance. In  this letter  we show that total momentum conservation property allows thermoelectric efficiency to reach the ideal Carnot limit.

Engineering a Light Touch

LY13471 - Researchers have found a way to enhance the force of light on matter. Most of the time the momentum of light and the associated forces are too small to notice, but at the nanoscale the effect can be quite large, and researchers have used these forces to dynamically manipulate optical waveguides at the nanoscale. However, these optical forces decay significantly as the distance between the waveguides increases and become too small for all-optical device actuation at larger separation distances.

The new method amplifies the optical forces and thus extends them to larger separations between waveguides by using a novel way to alter the perceived distance between them. This is done with thin layers of engineered structures known as metamaterials, which can manipulate light in ways not seen in conventional materials, extending its influence to greater distances from the surfaces of the waveguide. This work paves the way for the production of optical forces with unprecedented amplitude and eventually the design of mechanical devices activated entirely by light.