arXiv subjects

Verónica Vicuña-Hernández

Publications and source records attributed to Verónica Vicuña-Hernández.

3 recordsLinked to original sources

arXiv2024

Generation of heralded vector-polarized single photons in remotely controlled topological classes

We demonstrate an experimental protocol for the preparation and control of heralded single photons in inhomogeneously polarized states, such as Vector Vortex and Full Poincaré beam states. A laser beam is shaped by a voltage-controlled spin-to-orbital angular momentum converter q-plate device which eliminates the need for an interferometer for the robust preparation of high-quality inhomogeneously polarized beams. Such a beam is then used as pump in a spontaneous parametric downconversion (SPDC) photon-pair source. We demonstrate the full pump to heralded single photon transfer of the intensity/phase distributions, as well as of the vector polarization structure. Additionally, we show that by controlling the polarization to which the heralding idler photon is projected before detection, we can toggle between the direct and basis-switched pump-single photon transfer. We show that this non-local control of the heralded single photon pertains also to the topological class of the resulting heralded single photon. We believe that our work will lead to new opportunities in photons-based quantum information processing science.

quant-ph↗

arXiv2020

A quantum-inspired Fredkin gate based on spatial modes of light

Distinguishing between strings of data or waveforms is at the core of multiple applications in information technologies. In a quantum language the task is to design protocols to differentiate quantum states. Quantum-based technologies promises to go beyond the capabilities offered by technologies based on classical principles. However the implementation of the logical gates that are the core of these systems is challenging since they should overcome quantum decoherence, low probability of success and are prone to errors. One unexpected contribution of considering ideas in the quantum world is to inspire similar solutions in the classical world (quantum-inspired technologies), protocols that aim at mimicking particular features of quantum algorithms. This is based on features of quantum physics also shared by waves in the classical world, such it is the case of interference or entanglement between degrees of freedom of a single particle. Here we demonstrate in a proof-of-concept experiment a new type of quantum-inspired protocol based on the idea of quantum fingerprinting (Phys. Rev. Lett. 87, 167902, 2001). Information is encoded on optical beams with orbital angular momentum (OAM). These beams allow to implement a crucial element of our system, a new type of Fredkin gate or polarization-controlled SWAP operation that exchange data between OAM beams. The protocols can evaluate the similarity between pairs of waveforms and strings of bits and quarts without unveiling the information content of the data.

physics.optics↗

arXiv2019

Knotting fractional-order knots with the polarization state of light

The fundamental polarization singularities of monochromatic light are normally associated with invariance under coordinated rotations: symmetry operations that rotate the spatial dependence of an electromagnetic field by an angle $θ$ and its polarization by a multiple $γθ$ of that angle. These symmetries are generated by mixed angular momenta of the form $J_γ= L + γS$ and they generally induce Möbius-strip topologies, with the coordination parameter $γ$ restricted to integer and half-integer values. In this work we construct beams of light that are invariant under coordinated rotations for arbitrary $γ$, by exploiting the higher internal symmetry of 'bicircular' superpositions of counter-rotating circularly polarized beams at different frequencies. We show that these beams have the topology of a torus knot, which reflects the subgroup generated by the torus-knot angular momentum $J_γ$, and we characterize the resulting optical polarization singularity using third-and higher-order field moment tensors, which we experimentally observe using nonlinear polarization tomography.

physics.optics↗