Aplicações do Momento Angular Orbital da luz à Computação e Informação Quântica

Abstract

It presents a detailed study about the Orbital Angular Momentum of the light. Its theoretical description, the experimental method for the production of the beams carrying OAM and the procedure to measure the OAM will be presented. The spin and orbital angular momentum were associated to produce states described by two degrees of freedom representing two-qubit systems. This association enabled the description of original Quantum Information and Computation experiments, namely: an experiment that showed for the first time the topological phase associated to two cyclical paths in the space represented by SO[3] rotation group, a new design of a CNOT quantum logic gate that uses polarization as the control qubit and the transverses modes as the target qubit, and a mode sorter. These last two experiments were based on a Single Lense Mode Converter, originally proposed in this thesis. Besides, a device that implements the BB84 quantum key distribuition protocol without the need of a shared referencial frame was conceived. Finally, we present the procedure to stabilize the Optical Parametric Oscillator, that constitutes a source of twin beams to study continuous variable entanglement at UFF. A proposal to measure this entanglement is discussed as well.