Date of Award
Doctor of Philosophy (PhD)
Markus B. Raschke
Thomas R. Schibli
Novel optical phenomena emerge on nanometer length scales which determine the macroscopic material response. By bringing a sharp atomic force microscopy tip close to a surface and illuminating with either a laser, a broadband light source, or the intrinsic thermal fields of the material itself, we can probe near-field optical properties with spatial resolution only limited by the apex radius of the tip. These properties include the spectral, spatial, and coherence properties of the thermal near-fields that emerge at sub-wavelength distances from any matter at non-zero temperature that affect thermal emission and nanoscale heat transfer. I also apply near-field imaging to correlated electron and 2D materials where nanoscale properties strongly influence the bulk properties. The nanoscale heterogeneity of the metal-insulator transition of vanadium dioxide and the strong light confinement provided by polaritons of boron nitride and graphene may lead to novel electronic or photonic devices, however application of these materials requires additional insight and understanding. Nano-imaging and -spectroscopy can provide the needed spatial resolution and specificity to interrogate these phenomenon on their natural length scales.
O'Callahan, Brian Thomas, "Nanoscale and Ultrafast Imaging and Spectroscopy to Probe Heterogeneity of Novel Materials and Coherence of Thermal Near-Fields" (2017). Physics Graduate Theses & Dissertations. 256.