Scattering Type Near Field Optical Microscopy (neaspec s-SNOM)
Near-field microscopy has much higher spatial resolution than conventional microscopes, that is limited to half the wavelength (Abbe Diffraction limit). With this technique we study the nanoscale optical properties of samples, light-matter interaction, and material composition. Electronic and vibrational properties (phonons) are studied with near-field spectroscopy, all with a resolving power down to 10 nm.
In our group, we developed a unique setup that combines a near-field microscope with near-field spectroscopy, allowing tunable excitation (dual s-SNOM). It records high-resolution images, tip-enhanced Raman scattering, photoluminescence, and absorption, and to measure the dielectric function, chemical compositions, determine optical transitions, and light-matter coupling strength.
Currently, our research focuses on van der Waals materials, such as graphene, MoS2 and WS2, as well as other advanced materials for novel optical devices, such as LEDs, detectors and laser diodes. We study how excitons (strongly bound electron-hole pairs) are coupled with light and move through the material. We want to know how the environment affects the optical and electronic properties of nanoscale materials.