Materials Science & Engineering Program
Sunmi Shin is a PhD candidate in the Materials Science and Engineering Program at the University of California, San Diego. She received her BS and MS degrees in Chemical Engineering from Hanyang University in 2011 and 2014, respectively. Her research interests include experimental investigation of fundamental heat transport for thermal management and development of energy harvesting devices such as thermoelectrics and solar-thermal absorbers. Her recent paper on wearable thermoelectrics funded by ARPA-E was selected in the Top 100 Scientific Reports (Sci. Rep.) Physics papers in Sci. Rep. in 2017. Currently she has developed a new measurement platform to study fundamental heat transfer by optical phonon polaritons. She aims to manipulate heat as light source.Coherent Thermal Emission from Polaritonic Resonance in Individual Anisotropic Nano-Ribbon
We exploited the large disparity in the two length scales pertaining to thermal emission in polar dielectrics: skin-depth and resonance wavelength of surface phonon polariton (SPhP). Designed anisotropic nanoribbons made of polar dielectrics (e.g. SiO2) enabled independent control of the incoherent and coherent behaviors. We observed over 16-fold enhancement in the emissivity of the nanoribbons with respect to the thin film limit. Importantly, this enhancement is attributed to the coherent resonant effect of SPhP and hence, is more pronounced at lower temperature. A novel thermometry platform was devised to extract, for the first time, thermal emissivity from such nanoscale dielectric thermal emitters with exceedingly low emitting power (0.1-10 nW). The demonstrated coherent heat source provides a new insight on realization of spatial and spectral distribution control for thermal energy. Also, this work provides an experimental platform to measure the far-field radiative heat transfer coefficient from an individual nanoscale-object.