Optical vortex production mediated by azimuthal index of radial polarization

Abstract

Special light beams are becoming more and more interesting due to their applications in particle manipulation, micromachining, telecommunications or light matter-interaction. Both spin and orbital angular momenta of light are exploited often in combination with spatially varying linear polarization profiles (e.g. radial or azimuthal distributions). In this work we study the interaction between those polarization profiles and the spin-orbit angular momenta, finding the relation involved in the mode coupling. We find that this manipulation can be used for in-line production of collinear optical vortices with different topological charges, which can be filtered or combined with controlled linear polarization. The results are valid for continuous wave and ultrashort pulses, as well as for collimated and focused beams. We theoretically demonstrate the proposal, which is further confirmed with numerical simulations and experimental measurements with ultrashort laser pulses.

Ultraestable spatiotemporal characterization of optical vortices in the visible and near infrared

“…We used a Ti:Sapphire ultrashort laser (central wavelength around 800 nm) as light source and the optical vortices were generated using a nanostructured plate known as s-waveplate [4,6]. As explained in [6], depending on the incident beam properties, the s-waveplates can generate two circularly polarized optical vortices of different orbital angular momentum (OAM or ℓ). Then, using linear polarizers and zero order waveplates we can manipulate them and select only one of the vortices or a combination of both [4].…”

Optical Vector Vortex Generation by Spherulites with Cylindrical Anisotropy

“…A beam of circular polarization with spin angular momentum can be treated as a linear combination of two orthogonal polarized vectors of equal magnitudes but π/2 out-of-phase in Cartesian coordinates with fundamental vectors of e x and e y . In a cylindrical coordinate, where the fundamental vectors are e r and e θ , the circular polarization can be expressed as a linear combination of the radially polarized optical vortex and an azimuthally polarized optical vortex with a topological charge of ±1 while π/2 out-of-phase between each other − where P ( r ) is the amplitude distribution of the beam in the cylindrical coordinates and e r and e θ are the unit vectors along the radial and azimuthal directions, respectively. θ is the azimuthal angle.…”

Detecting the orbital angular momentum from speckle via convolutional neural network

“…V ortex beams carrying OAM lħ per photon, where l is the topological charge, have demonstrated tremendous success in applications ranging from optical communication [1][2][3] to particle manipulation. 4,5) The infinite OAM modes of vortex beam can extend the channel capacity of the communication system and improve the data transmission capability. The effective recognition of OAM modes is the key to an OAM-based communication system.…”