An In-situ and Direct Confirmation of Super-Planckian Thermal Radiation Emitted From a Metallic Photonic-Crystal at Optical Wavelengths

Planck’s law predicts the distribution of radiation energy, color and intensity, emitted from a hot object at thermal equilibrium. The Law also sets the upper limit of radiation intensity, the blackbody limit. Recent experiments reveal that micro-structured tungsten can exhibit significant deviation...

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Bibliographic Details
Published in:Scientific reports 2020-03, Vol.10 (1), p.5209-5209, Article 5209
Main Authors: Lin, Shawn-Yu, Hsieh, Mei-Li, John, Sajeev, Frey, B., Bur, James A., Luk, Ting-Shan, Wang, Xuanjie, Narayanan, Shankar
Format: Article
Language:English
Subjects:
639/301
639/624
639/766
ASTRONOMY AND ASTROPHYSICS
Equilibrium
Humanities and Social Sciences
Materials science
multidisciplinary
NUCLEAR PHYSICS AND RADIATION PHYSICS
Optics and photonics
Oscillators
Physics
Science
Science (multidisciplinary)
Tungsten
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Summary:Planck’s law predicts the distribution of radiation energy, color and intensity, emitted from a hot object at thermal equilibrium. The Law also sets the upper limit of radiation intensity, the blackbody limit. Recent experiments reveal that micro-structured tungsten can exhibit significant deviation from the blackbody spectrum. However, whether thermal radiation with weak non-equilibrium pumping can exceed the blackbody limit in the far field remains un-answered experimentally. Here, we compare thermal radiation from a micro-cavity/tungsten photonic crystal (W-PC) and a blackbody, which are both measured from the same sample and also in-situ . We show that thermal radiation can exceed the blackbody limit by >8 times at λ = 1.7 μm resonant wavelength in the far-field. Our observation is consistent with a recent calculation by Wang and John performed for a 2D W-PC filament. This finding is attributed to non-equilibrium excitation of localized surface plasmon resonances coupled to nonlinear oscillators and the propagation of the electromagnetic waves through non-linear Bloch waves of the W-PC structure. This discovery could help create super-intense narrow band thermal light sources and even an infrared emitter with a laser-like input-output characteristic.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-020-62063-2