Polarization-Independent Silicon Metadevices for Efficient Optical Wavefront Control.

We experimentally demonstrate a functional silicon metadevice at telecom wavelengths that can efficiently control the wavefront of optical beams by imprinting a spatially varying transmittance phase independent of the polarization of the incident beam. Near-unity transmittance efficiency and close to 0-2π phase coverage are enabled by utilizing the localized electric and magnetic Mie-type resonances of low-loss silicon nanoparticles tailored to behave as electromagnetically dual-symmetric scatterers. We apply this concept to realize a metadevice that converts a Gaussian beam into a vortex beam.

Quantum-size-controlled photoelectrochemical fabrication of epitaxial InGaN quantum dots.

We demonstrate a new route to the precision fabrication of epitaxial semiconductor nanostructures in the sub-10 nm size regime: quantum-size-controlled photoelectrochemical (QSC-PEC) etching. We show that quantum dots (QDs) can be QSC-PEC-etched from epitaxial InGaN thin films using narrowband laser photoexcitation, and that the QD sizes (and hence bandgaps and photoluminescence wavelengths) are determined by the photoexcitation wavelength. Low-temperature photoluminescence from ensembles of such QDs have peak wavelengths that can be tunably blue shifted by 35 nm (from 440 to 405 nm) and have line widths that narrow by 3 times (from 19 to 6 nm).

Near-infrared surface plasmon polariton dispersion control with hyperbolic metamaterials.

We demonstrate experimentally signatures and dispersion control of surface plasmon polaritons from 1 to 1.8 µm using periodic multilayer metallo-dielectric hyperbolic metamaterials. The fabricated structures are comprised of smooth films with very low metal filling factor.