On Application of 2D Metasurfaces for light guiding and manipulation

Abstract

In the last decade, technological evolutions and developments have pushed the boundaries of science. This has led to the development of small scale and faster processing units. Newer ways are developed and techniques are made to perform information processing at unparallel speeds. Photonics is the field of science that combines the benefits of the optical technologies with electronics system and is fast proving innovative ways of processing. In this regard controlling, guiding, focusing and manipulating the light field is of utmost importance. For these purposes, novel class of materials are designed and developed by artificial arrangement of building blocks (meta-atom) of sub-wavelength thickness in a specific repetitive manner at nanometers precision. One special class of such materials is 2D meta-structures known as metasurfaces. These meta-atoms, usually consisting of plasmonic or dielectric nano-antennas, can directly alter certain properties of light such as phase, amplitude, and polarization. The varied modulation of polarization is essential since it plays a significant role in 2D metamaterials. However, current polarization optics are limited to polarization control in a single transverse plane. Here, regardless of the incidence polarization, we present a new class of wave plates and polarizers based on metasurfaces that can impart a freely selected polarization response along the propagation path. The basic technique depends on splitting an incident waveform into a collection of pencil-shaped beams with various polarization states that beat along the optical axis, allowing the polarization of the resulting light as it travels to be changed at whim, locally. Surprisingly, the desired propagation-dependent polarization response may be implemented utilizing birefringent metasurface in conjunction with matrix-based holography without prior knowledge of the incident polarization. a behavior that, if achieved, would need three polarization-sensitive holograms. Single metalens contains multiple meta-atoms depends size and thickness of metalens. In this research metalens used is made of sub atoms called meta-atoms. Metalens shape and size will depends on the arrangements, Size and shape of meta-atoms. In this case cylindrical shape meta-atom are used where its diameter varies from edge to center in the increasing order, although its height remains same through the lens area. Polarization is the key factor of this research, by changing the polarization intensity of converge to a single peak, where its effects come across from 80̊ to 90̊. Our research broadens the application of polarization in the construction of multifunctional metasurfaces and will find applications in optically switchable electronics, controllable structured light, and flexible light-matter interactions.