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Enhancing far-field thermal emission with thermal extraction.
Zongfu Yu1, Nicholas P Sergeant, Torbjørn Skauli
1Department of Electrical Engineering and Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
Nature Communications
|April 18, 2013
Summary
Researchers demonstrate a novel thermal extraction scheme to significantly enhance thermal radiation. This method boosts thermal emission from blackbody emitters, crucial for energy conversion and radiative cooling applications.
Area of Science:
- Thermodynamics
- Optics
- Materials Science
Background:
- Controlling thermal radiation is vital for energy conversion and radiative cooling.
- Existing methods for thermal emission control have limitations.
Purpose of the Study:
- To theoretically and experimentally investigate a thermal extraction scheme for enhancing thermal emission.
- To demonstrate enhanced far-field thermal emission from a blackbody emitter.
Main Methods:
- Theoretical modeling of a thermal extraction scheme involving an emitter and a transparent extraction device.
- Experimental setup using a carbon-black emitter in optical contact with an extraction device.
- Measurement of far-field thermal emission enhancement.
Main Results:
- Theoretically, enhanced thermal emission is achievable when the emitter and extraction device have a higher internal density of states than vacuum.
- The extraction device must be larger than the emitter and possess a geometry facilitating light extraction.
- Experimentally observed a four-fold enhancement in far-field thermal emission from a carbon-black emitter (emissivity 0.85).
Conclusions:
- The thermal extraction scheme effectively enhances thermal radiation.
- This approach offers a promising pathway for improving energy conversion and radiative cooling technologies.
- The findings highlight the importance of internal density of states and geometric factors in thermal emission control.
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