Who: Javier Alfaro, Nanooptics Group
Place: nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
Date: Monday, 10 September 2018, 11:00
Periodically patterned dielectrics -photonic crystals- provide opportunities to shape and control the flow of light. However, they are not suitable for deeply subwavelength scale applications, since the size of their unit cell is comparable to the wavelength of light. We overcome this difficulty by engineering a nanoscale hole array in a slab of a van der Waals material (hexagonal boron nitride, h-BN) supporting ultra-confined phonon-polaritons -atomic lattice vibrations coupled to electromagnetic fields. Such a hole array represents a phonon-polaritonic crystal. We demonstrate both theoretically and experimentally that the h-BN hole array presents angle- and polarization-independent sharp Bragg resonances. Our results could be used for the design of novel tunable infrared narrow-band couplers, absorbers and thermal emitters based on van der Waals materials.