Orbital Angular Momentum Eigenstates Research Articles

Superposition of helical beams by using a Michelson interferometer

Orbital angular momentum (OAM) of a helical beam is of great interests in the high density optical communication due to its infinite number of eigen-states. In this paper, an experimental setup is realized to the information encoding and decoding on the OAM eigen-states. A hologram designed by the iterative method is used to generate the helical beams, and a Michelson interferometer with two Porro prisms is used for the superposition of two helical beams. The experimental results of the collinear superposition of helical beams and their OAM eigen-states detection are presented.

Study on holographic grating diffraction for Laguerre–Gaussian beam generation

Laguerre–Gaussian beams, as a special model with spiral phase structure, have been intensively investigated. Holographic grating method is a convenient method of generating Laguerre–Gaussian beams and measuring their orbital angular momenta. But due to some inevitable adverse factors such as lateral displacement, angular deflection and elliptical incident profile of incident beam, the practical effectiveness should be reevaluated. This paper is devoted to the study on the influences of the abovementioned three adverse factors on the holographic grating method. The characteristics of the mode decomposition of diffractive order and the relative powers of the orbital angular momentum eigen-states are also given.

Spin‐adapted states: A basis for quantum dot structure calculation

AbstractThe exact diagonalization method using a spin‐adapted basis is employed to calculate the electronic structure of a multi‐electron quantum dot. By isolating spin and orbital angular momentum eigenstates, we have significantly reduced the size of the matrices required in comparison with the standard configuration interaction method. A novel approach to the simplification of the interaction integrals that arise in the calculation is also presented, which allows exact evaluation of the Hamiltonian matrix required in the calculations. This Mathematica package permits accurate calculation of energy levels and wave functions for both ground and excited states of multiple electrons confined in a circular quantum dot. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006

Merons in a finite quantum Hall system

We study quasiparticle states in a finite $\ensuremath{\nu}=1$ spin (as an additional degree of freedom) quantum Hall system. The skyrmion (topological) quasiparticle states are well established in the infinite system, but in finite systems, in the effective mean-field pictures that we have, as a rule, they are not eigenstates of hamiltonian and some other generators of the system symmetries. We present a class of states, which are eigenstates of certain combinations of the generators and are similar in structure to the orbital angular momentum eigenstates of the Laughlin quasihole in the same system. We refer to the states as states of a meron. They have an upper limit on the mean orbital angular momentum, and the limit defines an effective edge, at a distance less than the system radius, in an effective quasiparticle description of the meron. Remarkably, the meron edge (as the usual quasihole edge) is characterized by a power-law decay of the single-particle, static correlator defined between positional coherent states of the meron.