Plasmonic wave plate based on subwavelength nanoslits

Abstract

We propose a quarter-wave plate based on nanoslits and analyze it using a semianalytical theory and simulations. The device comprises two nanoslits arranged perpendicular to one another where the phases of the fields transmitted by the nanoslits differ by λ/4. In this way, the polarization state of the incident light can be changed from linear to circular or vice versa. The plasmonic nanoslit wave plate is thin and has a subwavelength lateral extent. We show that the predictions for the phase shift obtained from a semianalytical model are in very good agreement with simulations by the finite difference time domain method.

A subwavelength slit as a quarter-wave retarder

“…Our experimental results contradict a recently published proposal for a quarter-wave retarder using perpendicular metallic nanoslits [20], where the width of the slits is varied purely to control the TM transmission. Varying the width of the slit also changes the TE transmission of the incident light and the phase difference between the TM and TE components.…”

Realizing full visible spectrum metamaterial half-wave plates with patterned metal nanoarray/insulator/metal film structure

“…As one of the most important optical components, wave plate has attracted much attention and various metamaterial wave plates have been proposed and realized [5][6][7]. However, in those designs with single resonant layer [5,8,9], abrupt phase shift introduced by plasmonic resonance is generally coupled with resonant amplitude, resulting in a narrow operation band or low efficiency for polarization conversion.…”

Optical Manipulation with Plasmonic Beam Shaping Antenna Structures

“…Linearly polarized light can be converted into circularly polarized one (that possesses the spin angular momentum of h/2π per photon), for example, by passing through an elliptical metal hole-groove structure (Figure 4(a)) [20] or coupled orthogonal metal slits [21]. These structures effectively work as a plasmonic quarter waveplate.…”

“…Metal nanoslit or nanohole arrays were used for focusing a beam into a small spot [17][18][19]. Metal nanostructures were also studied for angular momentum control of light [20][21][22]. Previously, such beam shaping has been achieved with elaborate wavefront and beam control (such as Bessel, Airy, or Laguerre-Gaussian beams) involving bulky diffractive or holographic components [5].…”