Babak Vosoughi Lahijani

Near-field characterization of a Bloch-surface-wave-based 2D disk resonator.

We present, to the best of our knowledge, the first experimental investigation of a two-dimensional disk resonator on a dielectric multilayer platform sustaining Bloch surface waves. The disk resonator has been patterned into a few tens of nanometer thin (∼λ/25) titanium dioxide layer deposited on the top of the platform. We characterize the disk resonator by multi-heterodyne scanning near-field optical microscopy. The low loss characteristics of Bloch surface waves allowed us to reach a measured quality factor of 2×103 for a disk radius of 100 μm.

Investigation of the Propagation Length of Bloch Surface Waves on One Dimensional Photonic Crystals, 2018 International Conference on Optical MEMS and Nanophotonics (OMN)

A 1D photonic crystal structure sustaining optical surface waves is investigated. The propagation length of the surface mode is studied both using an eigenmode model and a rigorous time domain solver. The two models show good convergence. Our results demonstrate that by a carefully designed 1D photonic crystal, dielectric surface waves may propagate over several millimeters, even if a Kretschmann-type coupling configuration is used.

Waveguide grating as a Bragg mirror on Bloch surface waves based platform for 2D integrated optics applications

We study and demonstrate a Bloch-surface-wave-based nano-thin waveguide grating. The waveguide grating is characterized as a Bragg mirror at telecommunication wavelengths. The structure is a dielectric multilayer platform designed to sustain a Bloch surface wave. Such a platform is regarded as a foundation for in-plane integrated optics. The Kretschmann coupling configuration, as the most widely used approach, is utilized to excite the optical surface waves. We use multi-heterodyne scanning near-field optical microscopy to characterize the waveguide gratings in the near-field. The fabricated waveguide grating shows the expected Bragg mirror behavior with a measured reflectivity of approximately 72 % inside the photonic band gap at λ = 1553 nm.

Bloch Surface Waves Fabry- Pérot Nanocavity

We demonstrate the first cavity confinement of Bloch surface waves in the fundamental mode of a Fabry–Perot cavity. The cavity consists of two distributed Bragg mirrors separated by a spacer of dimensions smaller than the wavelength (633nm). The cavity mode exhibits quality factor of 400. This quality factor is the highest recorded thus far for a subwavelength optical surface waves cavity.