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  1. Surface plasmon polaritons (SPPs) are traditionally excited by plane waves within the Rayleigh range of a focused transverse-magnetic (TM) Gaussian beam. Here we investigate and confirm the coupling between SPPs and two-dimensional Gaussian and Bessel–Gauss wave packets, as well as one-dimensional light sheets and space-time wave packets. We encode the incoming wavefronts with spatially varying states of polarization; then we couple the respective TM components of radial and azimuthal vector beam profiles to confirm polarization-correlation and spatial-mode selectivity. Our results do not require material optimization or multi-dimensional confinement via periodically corrugated metal surfaces to achieve coupling at a greater extent, hereby outlining a pivotal, yet commonly overlooked, path towards the development of long-range biosensors and all-optical integrated plasmonic circuits.

    Free, publicly-accessible full text available August 26, 2023
  2. For active beam manipulation devices, such as those based on liquid crystals, phase-change materials, or electro-optic materials, measuring accumulated phase of the light passing through a layer of the material is imperative to understand the functionality of the overall device. In this work we discuss a way of measuring the phase accumulation through a switched layer of Ge2Sb2Te5, which is seeing rapid use as means to high speed dynamic reconfiguration of free space light. Utilizing an interferometer in the switching setup and modulating the phase of one arm, the intensity of a probe beam can be captured and phase data pulled from it. Simulations were used to discover the connection between the intensity modulations and the phase information. The technique was tested experimentally and it was found that within error, the measurement was robust and repeatable.

  3. Phase change material Ge2Sb2Te5 tilted and helical nanorods films featuring 25 nm diameters are grown using the oblique and glancing angle deposition techniques. We provide insights on the growth process, structural integrity and optical responses
  4. Abstract

    Bound states in the continuum (BICs) are widely studied for their ability to confine light, produce sharp resonances for sensing applications and serve as avenues for lasing action with topological characteristics. Primarily, the formation of BICs in periodic photonic band gap structures are driven by symmetry incompatibility; structural manipulation or variation of incidence angle from incoming light. In this work, we report two modalities for driving the formation of BICs in terahertz metasurfaces. At normal incidence, we experimentally confirm polarization driven symmetry-protected BICs by the variation of the linear polarization state of light. In addition, we demonstrate through strong coupling of two radiative modes the formation of capacitively-driven Freidrich-Wintgen BICs, exotic modes which occur in off-Γpoints not accessible by symmetry-protected BICs. The capacitance-mediated strong coupling at 0° polarization is verified to have a normalized coupling strength ratio of 4.17% obtained by the Jaynes-Cummings model. Furthermore, when the polarization angle is varied from 0° to 90° (0° ≤ϕ < 90°), the Freidrich-Wintgen BIC is modulated until it is completely switched off at 90°.

  5. We created a system for the characterization of Ge2Sb2Te5 starting with a 1550 nm CW laser and utilizing second harmonic generation through a PPLN crystal in order to achieve full pulse control at 775 nm.
  6. We present an advancement towards high speed (sub ps) phase change material based spatial light modulators by electrically addressing single pixels with high-speed optical monitoring at 1550nm light.