Observation of Thermal Beaming from Tungsten and Molybdenum Bull’s Eyes

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• 作者：Jong Hyuk Park ; Sang Eon Han ; Prashant Nagpal ; David J. Norris
• 刊名：ACS Photonics
• 出版年：2016
• 出版时间：March 16, 2016
• 年：2016
• 卷：3
• 期：3
• 页码：494-500
• 全文大小：634K
• ISSN：2330-4022

文摘

Although losses in plasmonic films can be detrimental for optoelectronics, they can be exploited to create novel thermal emitters. Surface plasmon polaritons that are thermally excited on a heated metal surface can be converted to photons with useful properties. We demonstrate highly tailored thermal emission from tungsten and molybdenum films patterned with a series of circular concentric grooves (i.e., a bull’s eye). At 900 °C our structures emit an infrared beam normal to the film that is spectrally narrow (tens of nanometers) and highly directional (∼2° angular divergence). The peak wavelength (3.5 μm) can be tuned with groove periodicity. To enhance the thermal stability of the structures, we add a thin layer of HfO₂. Such devices, with their simple design and low thermal mass, provide interesting incandescent light sources for various applications.