Thermal Emission from Nanoplasmonic Structures in Near-and-Far-Fields: Numerical Simulation, Device Fabrication, and Characterization

Thermal radiation originates from photons which are spontaneously emitted by different points in a thermal source. All matter with a temperature greater than 0K emits thermal radiation, which in turn can extract temperature distribution for all optical and electronic materials and devices. The classic model was found by Max Planck, which describes the spectral density of electromagnetic radiation emitted by a blackbody in the thermal equilibrium at a given temperature. A blackbody is an ideal emitter which absorbs all incident electromagnetic radiation from all frequencies and angles of incidence. All other emissions are studied with the reference of the blackbody following the properties of emission and absorption. Emissivity is core in thermal devices, both source and receiver. Thermal emission is a fundamental phenomenon for which any object with temperature greater than absolute zero emits energy in the form of electromagnetic waves. The thermal emission from a blackbody (an ideal thermal emitter) only depends on its temperature, as described by Planck’s law. For a nonideal thermal emitter, i.e., a gray body, thermal emission also depends on how effectively the emitter can radiate, quantified as its emissivity.

In this dissertation, I systematically investigate the thermal emission from nanoplamonic structures in both near- and far-field regimes such as metasurfaces, 2D materials, single plasmonic emitter, etc. I implement numerical simulations to investigate the directional control of narrow-band perfect thermal emission using a nanoscale Yagi–Uda antenna consisting of an array of nanowires. Then I fabricate single plasmonic device and plasmonic structures via the state-of-the-art micro and nanofabrication techniques including electron beam (e-beam) lithography, photolithography, e-beam evaporation, reactive ion etching (RIE), wet etching, focused ion beam (FIB), etc. Finally, I demonstrate the unique properties of the nanoplasmonic structures we fabricate via thermal and optical characterization.