Doron Bar-Lev

Plasmonic metasurface for efficient ultrashort pulse laser-driven particle acceleration

A laser-driven particle accelerator based on plasmonic nano-antennas is proposed and analyzed. The concept utilizes the enhancement and localization of the electric field by nano-antennas to maximize the acceleration gradient and to overcome potential metallic losses. The structure is optimized for accelerating relativistic particles using a femto-second laser source operating at 800nm, and is shown to support the bandwidth of ultra-short laser pulses (up to 16fsec) while providing a high acceleration gradient potentially reaching 11.6GV/m.

Efficient second harmonic generation using nonlinear substrates patterned by nano-antenna arrays

We study theoretically various design considerations for efficient generation of second harmonic using a nonlinear substrate patterned with nano-antennas. The analysis is focused on a gap Bowtie nano-antenna array recessed in LiNbO₃ which is shown to be preferable over on surface structures due to field enhancement, field profile and linear and non-linear polarization considerations. In addition, we develop the nano-antenna counterpart of the Boyd-Klienmann model in order to analyze the impact of a Gaussian shaped fundamental beam on the generated second harmonic. Finally, we show that the dielectric properties of the substrate lead to preferable directions for the incident fundamental harmonic and the emission of the second harmonic. Our analyses lead to several design rules which can enhance second and high harmonic generation from nano-antennas arrays by several orders of magnitude.

High load sensitivity in wideband infrared dual-Vivaldi nanoantennas.

Dual-Vivaldi nanoantenna (DVA) arrays were designed, fabricated, and optically characterized in the infrared (IR) and visible regimes. The antenna arrays were characterized by measuring the scattered light at IR (1450-1640 nm) and visible (780 nm) spectral ranges. The radiation efficiency and the spectral response of the antennas were found to be in good agreement with numerical simulations. The results presented here demonstrate the extremely wideband nature of the DVAs and the strong impact of load at the antenna terminals on its scattering response. These properties, as well as their many degrees of freedom for design, render the DVAs excellent candidates for optical sensing applications.

Metasurfaces for Particle Manipulation and Radiation Generation

Metasurfaces offer a new approach for manipulation of particle beams traveling in the vicinity of the surface. We discuss their utilization for efficient laser-driven particle acceleration and for shaping and enhancing Smith-Purcell radiation.

Plasmonic metasurface for efficient laser-driven particle acceleration

A laser-driven particle accelerator based on plasmonic metasurfaces is proposed and analyzed. The concept utilizes a unique slot-patch nanoantennas combination and is shown to support ultra-short laser pulses while providing high acceleration gradients reaching 11.6GV/m.

Controlling surface plasmon propagation by tilted optical beams incident on a 1D grating

Tailoring the properties of an optical beam incident on a one dimensional metallic grating can attain a substantial control over the excited surface plasmon polariton wave. In this work we derive the complete analytical relations between the optical angles of incidence and the resulting surface plasmon propagation angle. These relations are demonstrated both numerically and experimentally. Following we show that there is an optimal grating that can excite any surface plasmon propagation angle between ±82.46 degrees and efficient polarization schemes which lead to negligible losses. Finally we introduce a formalism that relates general surface plasmon beams to corresponding incident optical beams and using it we demonstrate numerically a varying position surface plasmon hotspot generation.

UWB Dual-Vivaldi nano-antenna and load effect on the reflection properties

Dual-Vivaldi nanoantenna arrays were designed, fabricated and optically characterized in the infrared (IR) and visible regimes. The antenna arrays were characterized by measuring the scattered light at IR (1450-1640 nm) and visible (780 nm) spectral ranges. The radiation efficiency and the spectral response of the antennas were found to be in good agreement with numerical simulations. The results presented here demonstrate the extremely wide-band nature of the dual-Vivaldi antennas and the strong dependence of the scattering response on the load at the antenna terminals. These properties, as well as their many degrees of freedom for design, render the dual-Vivaldi antennas excellent candidates for optical sensing applications.