At infrared frequencies, silicon carbide possesses very interesting optical properties due to the resonant excitation of optical phonons. Silicon Carbide structures support a variety of electromagnetic resonances that can be exploited for infrared sensing, near field microscopy, and metamaterials. To learn more about the Brongersma Lab’s investigations into phonon-polaritons, please click [http://brongersma.stanford.edu/main/PhononPolariton here]
Dielectric Function of SiC
Near-field Infrared Microscopy
Conventional optical microscopy is limited in resolution by diffraction to about a half of the wavelength used. Near-field microscopy can overcome this limitation by locally probing the sample with tiny light source. The use of infrared light offers the additional advantage of chemical and structural sensitivity to molecular and atomic vibrations. In the Brongersma Lab we a currently setting up a scattering-type near-field infrared microscope:
This technique uses the electromagnetic field enhancement at the sharp tip of a Atomic Force Microscope (AFM) to locally probe the samples (infrared) optical properties. The resolution depends on tips radius of curvature (typically around 20-30 nm) and not primarily on the wavelength of the light used.
A superlens is a novel device that allows for subwavelength imaging with a flat “lens” made from a material that support surface waves (here: Phonon-Polaritons) .