Search results for "orbital angular momentum of light"

Generation of Non-Classical States through QND-like Processes

2007

In the spirit of quantum nondemolition measurement we show that repeatedly measuring the atomic state of a trapped ion subjected to suitable vibronic couplings it is possible to extract interesting nonclassical states. The possibility of generating angular momentum Schrödinger cat is demonstrated.

Regression of high-dimensional angular momentum states of light

2023

The Orbital Angular Momentum (OAM) of light is an infinite-dimensional degree of freedom of light with several applications in both classical and quantum optics. However, to fully take advantage of the potential of OAM states, reliable detection platforms to characterize generated states in experimental conditions are needed. Here, we present an approach to reconstruct input OAM states from measurements of the spatial intensity distributions they produce. To obviate issues arising from intrinsic symmetry of Laguerre-Gauss modes, we employ a pair of intensity profiles per state projecting it only on two distinct bases, showing how this allows to uniquely recover input states from the collect…

Angular Momentum Coupling

2007

In nuclear physics, as also in atomic and molecular physics, the entities to be described consist of sub-entities with some orbital angular momentum and spin. The angular momentum of the entity is built, then, of the angular momenta of the sub-entities. This building process leads to quantum-mechanical angular momentum coupling. This chapter presents the basic machinery for treating angular momentum and its coupling. Clebsch-Gordan coefficients and 3j symbols are introduced. It is shown that Clebsch-Gordan coefficients and 3j symbols relate to the coupling of two angular momenta. Increasing the number of angular momenta to be coupled leads to more complicated coupling patterns. Transformati…

Symmetry-induced forces on phase singularities

2010

We show the existence of external forces acting on phase singularities whose origin can be attributed to the presence of short-term discrete-symmetry potentials. These special forces can break highly charged phase singularities into single-charged ones and provide them with non-zero orbital angular momentum even when the potential no longer acts.

Distilling angular momentum nonclassical states in trapped ions

2004

In the spirit of Quantum Non-Demolition Measurements, we show that exploiting suitable vibronic couplings and repeatedly measuring the atomic population of a confined ion, it is possible to distill center of mass vibrational states with well defined square of angular momentum or, alternatively, angular momentum projection Schr\"odinger cat states.

Electric-Field-Induced Symmetry Breaking of Angular Momentum Distribution in Atoms

2006

We report the experimental observation of alignment to orientation conversion in the 7D_3/2 and 9D_3/2 states of Cs in the presence of an external dc electric field, and without the influence of magnetic fields or atomic collisions. Initial alignment of angular momentum states was created by two-step excitation with linearly polarized laser radiation. The appearance of transverse orientation of angular momentum was confirmed by the observation of circularly polarized light. We present experimentally measured signals and compare them with the results of a detailed theoretical model based on the optical Bloch equations.

Transfer of optical orbital angular momentum to a bound electron

2016

Photons can carry angular momentum, not only due to their spin, but also due to their spatial structure. This extra twist has been used, for example, to drive circular motion of microscopic particles in optical tweezers as well as to create vortices in quantum gases. Here we excite an atomic transition with a vortex laser beam and demonstrate the transfer of optical orbital angular momentum to the valence electron of a single trapped ion. We observe strongly modified selection rules showing that an atom can absorb two quanta of angular momentum from a single photon: one from the spin and another from the spatial structure of the beam. Furthermore, we show that parasitic ac-Stark shifts from…

Angular momentum and transition dipole moment

1995

Electric-field-induced symmetry breaking of angular momentum distribution in atoms

2007

We report the observation of alignment to orientation conversion in the 7,9 D3/2states of Cs in the presence of an electric field without the influence of magnetic fields or collisions. Initial alignment of angular momentum was created by two-step excitation with linearly polarized light. The appearance of transverse orientation was confirmed by the observation of circularly polarized fluorescence. We present measured signals and compare them with the results of a theoretical model based on the optical Bloch equations. The effect is odd under time reversal and should be taken into account in searches for an electron electric dipole moment.

A new technique in the theory of angular distributions in atomic processes: the angular distribution of photoelectrons in single and double photoioni…

1996

Special reduction formulae for bipolar harmonics with higher ranks of internal spherical functions are derived, which will be useful in problems involving multiple expansions in spherical functions. Together with irreducible tensor operator techniques these results provide a new and effective approach, which enables one to extract the geometrical and dynamical factors from the cross sections of atomic processes with polarized particles with an accurate account of all the polarization effects. The angular distribution of polarized electrons and the circular dichroism in photoionization of polarized atoms with an arbitrary angular momentum are presented in an invariant vector form. A specific…