We present a robust interferometric method to generate arbitrary vector beam modes by diffracting a Gaussian laser beam from a spatial light modulator consisting of a high-resolution reflective nematic liquid crystal display. Vector beams may have the same intensity cross-section as the more common scalar Laguerre–Gaussian (LG) or Hermite–Gaussian (HG) beams, but with a spatially modulated polarization distribution. Special cases are the radially or azimuthally polarized 'doughnut' modes, which have superior focusing properties and promise novel applications in many fields, such as optical trapping, spectroscopy and super-resolution microscopy. Our system allows video rate switching between vector beam modes. We demonstrate the generation of high quality Hermite–Gaussian and Laguerre–Gaussian vector beam modes of different order, of vectorial anti-vortices, and of mode mixtures with interesting non-symmetric polarization distributions.

https://iopscience.iop.org/article/10.1088/1367-2630/9/3/078/pdf

Tailoring of arbitrary optical vector beams

Spin optics provides a route to control light, whereby the photon helicity (spin angular momentum) degeneracy is removed due to a geometric gradient onto a metasurface. The alliance of spin optics and metamaterials offers the dispersion engineering of a structured matter in a polarization helicity-dependent manner. We show that polarization-controlled optical modes of metamaterials arise where the spatial inversion symmetry is violated. The emerged spin-split dispersion of spontaneous emission originates from the spin-orbit interaction of light, generating a selection rule based on symmetry restrictions in a spin-optical metamaterial. The inversion asymmetric metasurface is obtained via anisotropic optical antenna patterns. This type of metamaterial provides a route for spin-controlled nanophotonic applications based on the design of the metasurface symmetry properties.

http://science.sciencemag.org/content/sci/340/6133/724.full.pdf

Spin-Optical Metamaterial Route to Spin-Controlled Photonics

We present a system employing a dynamic diffrac- tive optical element to control properties of two counter- propagating beams overlapping within a sample chamber. This system allows us to eliminate optical aberrations along both beam pathways and arbitrarily switch between various num- bers of laser beams and their spatial profiles (i.e. Gaussian, Laguerre-Gaussian, Bessel beams, etc.). We successfully tested various counter-propagating dual-beam configurations includ- ing optical manipulation of both high and low index particles in water or air, particle delivery in an optical conveyor belt and the formation of colloidal solitons by optical binding. Furthermore, we realized a novel optical mixer created by particles spiraling in counter-propagating interfering optical vortices and a new tool for optical tomography or localized spectroscopy enabling sterile contactless rotation and reorientation of a trapped living cell. CP Bessel beams in a form of optical conveyor belt

/pdf/the-holographic-optical-micro-manipulation-system-based-on-4stasctzwg.pdf

The holographic optical micro‐manipulation system based on counter‐propagating beams

Nondiffracting vector Bessel beams are of considerable interest due to their nondiffracting nature and unique high-numerical-aperture focusing properties. Here we demonstrate their creation by a simple procedure requiring only a spatial light modulator and an azimuthally varying birefringent plate, known as a q-plate. We extend our control of both the geometric and dynamic phases to perform a polarization and modal decomposition on the vector field. We study both single-charged Bessel beams as well as superpositions and find good agreement with theory. Since we are able to encode nondiffracting modes with circular polarizations possessing different orbital angular momenta, we suggest these modes will be of interest in optical trapping, microscopy, and optical communication.

Generating and measuring nondiffracting vector Bessel beams

Methods for generating beams with arbitrary polarization based on the use of liquid crystal displays have recently attracted interest from a wide range of sources. In this paper we present a technique for generating beams with arbitrary polarization and shape distributions at a given plane using a Mach-Zehnder setup. The transverse components of the incident beam are processed independently by means of spatial light modulators placed in each path of the interferometer. The modulators display computer generated holograms designed to dynamically encode any amplitude value and polarization state for each point of the wavefront in a given plane. The steps required to design such beams are described in detail. Several beams performing different polarization and intensity landscapes have been experimentally implemented. The results obtained demonstrate the capability of the proposed technique to tailor the amplitude and polarization of the beam simultaneously.

http://diposit.ub.edu/dspace/bitstream/2445/43312/1/622621.pdf

Reconfigurable beams with arbitrary polarization and shape distributions at a given plane

We demonstrate the experimental generation at optical frequencies of the lowest- and first-order Bessel beams with TE and TM polarizations in free space by means of a Mach-Zehnder interferometer. The polarization and angular momentum properties of these waves are analyzed and discussed.

Experimental generation and analysis of first-order TE and TM Bessel modes in free space.

We present a theoretical analysis and an experimental demonstration of a wave field constituted by an axial array of vortices consecutively inverting the topological charge over distances of one-quarter of a wavelength It exhibits a periodic gradient of the orbital angular momentum density along a single axis, although the field is created by the superposition of counter-propagating waves possessing no angular momentum themselves The experiment is carried out with acoustic waves, whose wavelength is sufficiently large to allow a three-dimensional mapping of the field in amplitude and phase

Wave fields with a periodic orbital angular momentum gradient along a single axis: a chain of vortices

The experimental generation of vector Bessel beams of different orders with TE and TM polarizations is demonstrated in the optical frequencies domain and in free space by means of a Mach-Zehnder interferometer. For the zero order beams, these modes correspond to the well known azimuthal and radial polarization states, whereas higher order versions become vector vortices, thus carrying orbital angular momentum. The case of the lowest order TE and TM vector vortices, corresponding to a topological charge of l=1, is particularly interesting due to their off-axis location and the non-null intensity at the beam center, unlike the case of topological charges l>1. The polarization and angular momentum properties of these waves are thoroughly analyzed and discussed for different cases. Keywords : Vector beams, vortices, Bessel beams, polarization 1. INTRODUCTION Since they were first introduced in 1987 1 , Bessel beams (BBs) have attracted considerable attention due to their properties of propagation invariance and self-reconstruction, which have found interesting applications in fields like optical trapping and manipulation of microparticles and atoms

A. Flores-Peréz

Papers

Experimental generation and analysis of first-order TE and TM Bessel modes in free space.

Wave fields with a periodic orbital angular momentum gradient along a single axis: a chain of vortices

Transverse electric (TE) and transverse magnetic (TM) vector vortices in free-space: analysis and experimental generation