title: Direct observation of quasi-coherent thermal emission by a three-dimensional metallic photonic crystal.
abstract: We report a direct observation of a quasi-coherent thermal emission from a heated three-dimensional photonic-crystal sample. While the sample was under Joule heating, we observed multiple oscillations in its emission interferogram and deduced a coherent length of L(coh)≅(20-40) μm, 5-10 times longer than that of a blackbody at comparable wavelengths. The observed, relatively long coherent length is attributed to coupling of thermal emission into lossy Bloch modes that oscillate coherently over a distance determined by decay length and the slow light nature of Bloch modes at the band-edges.
authors.affiliation: Department of Photonics, National Chiao-Tung University, Hsinchu, Taiwan.
authors.forename: Mei-Li
authors.initials: ML
authors.lastname: Hsieh
authors.forename: James
authors.initials: J
authors.lastname: Bur
authors.forename: Yong-Sung
authors.initials: YS
authors.lastname: Kim
authors.forename: Shawn-Yu
authors.initials: SY
authors.lastname: Lin