My research on phonon-polaritonic materials involves the exploration of sub-wavelength modes at mid-infrared wavelengths (~10 μm), where there is no strong plasmonic response from either metals or semiconductors. Yet, enhancing transmission in this wavelength range is still very important. It is known as the biological finger-print regime because many organic molecules exhibit distinctive vibrational resonances in this range. Efficient detection of molecular "finger prints" is important for a wide range of spectroscopic applications.
In my research on phonon-polaritonic materials, I investigate the confinement and concentration of mid-infrared radiation in subwavelength holes. As an example, I numerically and experimentally demonstrate extra-ordinary transmission through subwavelength hole arrays in silicon carbide (SiC). Many molecules have unique spectral signatures in the mid-infrared. Field concentration, associated with enhanced transmission through subwavelength holes in an otherwise opaque medium, can be very beneficial for infrared spectroscopic studies where highly localized fields are required in the vicinity of the film to achieve the required sensitivity to detect trace elements.