Malus-metasurface-assisted polarization multiplexing

Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields.

Zero-order-free meta-holograms in a broadband visible range

The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction-related optical devices such as holograms,gratings,beam shapers,beam splitters,optical diffusers,and diffractive microlenses.Here,inspired by the unique characteristic of nano-polarizer-based metasurfaces for both positive and negative amplitude modulation of incident light,we propose a general design paradigm to eliminate zero-order diffraction without burdening the metasurface design and fabrication.The experimentally demonstrated metahologram,which projects a holographic image with a wide angle of 70°×70°in the for field,presents a very low zero-order intensity(only 0.7%of the total energy of the reconstructed image).More importantly,the zero-orderfree meta-hologram has a large tolerance limit for wavelength variations(under a broadband illumination from520 to 660 nm),which brings important technical advances.The strategy proposed could significantly relieve the fabrication difficulty of metasurfaces and be viable for various diffractive-optics-related applications includingholography,laser beam shaping,optical data storage,vortex beam generation,and so on.