In this work, we will present two techniques for extracting the wavefront and polarization structure of optical fields. The first being a digital analogy to Stokes polarimetry involving only four measurements, as opposed to the usual six. Here, we implement static polarisation optics, such as a Polarization Grating (PG) to project a mode into left- and right-circular states, which are subsequently directed to a Digital Micro-mirror Device (DMD) to impart a phase retardance for full phase and polarisation reconstruction. The second approach uses the transport-of-intensity which harnesses the connection between observed energy flow in optical fields and their wavefronts. We present a simple scheme using a DMD to perform angular spectrum propagation and extract the wavefront of optical fields. Finally, we demonstrate these approaches by spatially resolving complex polarization structures such as metasurfaces, liquid crystal devices and chiral materials.
Skyrmions are topologically stable fields that cannot be smoothly deformed into any other field configuration that differs topologically or possesses a different integer topological invariant, the Skyrme number. They have been studied as full skyrmions in magnetic spin systems, and more recently as baby skyrmions in optical systems. Here, we introduce an optical analogy to magnetic skyrmions and demonstrate their dynamics within a magnetic field. Our optical skyrmions and synthetic magnetic field are both engineered using superpositions of Bessel-Gaussian beams, with time dynamics observed over propagation distance. We show that the Skyrmionic form changes during propagation, exhibiting controllable periodic precession over a well defined range, analogous to time varying spin precession in homogeneous magnetic fields. This local precession manifests as the global beating between skyrmion types, while still maintaining the invariance of the Skyrme number.
In this work we generate optical fields whose polarisation structures not only rotate about the propagation axis, but can be tailored to accelerate, independently from their spatial profiles. Here we will demonstrate how this can be achieved with orthogonal, scalar fields, represented by weighted superpositions of oppositely charged Bessel beams, through path interference with a beam-splitter. In addition to their creation, we investigate various aspects of these generated modes, such as their angular accelerating Stokes vectors and optical current or intensity transport between various local positions within the field. Finally, we present a digital analogy to measure such fields in order to reconstruct their state of polarisation via Stokes polarimetry. undefined In this work we generate optical fields whose polarisation structures not only rotate about the propagation axis, but can be tailored to accelerate, independently from their spatial profiles. Here we will demonstrate how this can be achieved with orthogonal, scalar fields, represented by weighted superpositions of oppositely charged Bessel beams, through path interference with a beam-splitter. In addition to their creation, we investigate various aspects of these generated modes, such as their angular accelerating Stokes vectors and optical current or intensity transport between various local positions within the field. Finally, we present a digital analogy to measure such fields in order to reconstruct their state of polarisation via Stokes polarimetry.
In this work, Stokes polarimetery is used to extract the polarization structure of optical fields from only four measurements as opposed to the usual six measurements. Here, instead of using static polarization optics, we develop an all-digital technique by implementing a Polarization Grating (PG) which projects a mode into left- and right-circular states which are subsequently directed to a Digital Micromirror Device (DMD) which imparts a phase retardance for full polarization acquisition. We apply our approach in real-time to reconstruct the State of Polarization (SoP) and intra-modal phase of optical modes.
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