Direct observation of plasmonic index ellipsoids on a deep-subwavelength metallic grating

We constructed a metallic grating on a deep-subwavelength scale and tested its plasmonic features in visible frequencies. The deep-subwavelength metallic grating effectively acts as an anisotropic homogeneous uniaxial form-birefringent metal, exhibiting different optical responses for polarizations along different optical axes. Therefore, this form-birefringent metal supports anisotropic surface plasmon polaritons that are characterized by directly imaging the generated plasmonic index ellipsoids in reciprocal space. The observed plasmonic index ellipsoids also show a rainbow effect, where different colors are dispersively distributed in reciprocal space

Folded shift multiplexing

Shift multiplexing is a holographic recording method that uses a spherical reference wave. We extend the principle to a thin slab of holographic material that acts as a waveguide. Total internal reflection folds the reference spherical beam in one dimension. We demonstrate that the shift selectivity with the folded spherical beam is independent of the slab thickness but depends instead on the numerical aperture of the coupled spherical wave. A shift selectivity of 0.5 µm has been achieved with a 1-mm-thick LiNbO3 crystal and 50 high-definition data pages are recorded with this method

Metamaterials for Enhanced Polarization Conversion in Plasmonic Excitation

Surface plasmons efficient excitation is typically expected to be strongly constrained to transverse magnetic (TM) polarized incidence, as demonstrated so far, due to its intrinsic TM polarization. We report a designer plasmonic metamaterial that is engineered in a deep subwavelength scale in visible optical frequencies to overcome this fundamental limitation, and allows transverse electric (TE) polarized incidence to be strongly coupled to surface plasmons. The experimental verification, which is consistent with the analytical and numerical models, demonstrates this enhanced TE-to-plasmon coupling with efficiency close to 100%, which is far from what is possible through naturally available materials. This discovery will help to efficiently utilize the energy fallen into TE polarization and drastically increase overall excitation efficiency of future plasmonic devices

A systematic evaluation of Silicon-rich Nitride Electro-optic Modulator design and tradeoffs

We present a study of linearized \c{hi}^((3)) based electro-optic modulation beginning with an analysis of the nonlinear polarizability, and how to linearize a modulator based on the quadratic third order DC-Kerr effect. Then we perform a numerical study, designing a linearized \c{hi}^((3)) phase modulator utilizing Silicon-rich Nitride where we show that a phase modulator with a V_{\pi} L_{\pi} metric of 1 Vcm or a V_{\pi} L_{\pi} {\alpha} metric of 37VdB is achievable and a V_{\pi} L_{\pi} as low as 0.5Vcm in a push-pull Mach Zehnder Interferometer. This numerical study argues that linearized modulation exploiting the \c{hi}^((3)), and \c{hi}^((2)) as applicable, is possible and can allow for high-speed modulation using a CMOS compatible material platform