Light field

About: Light field is a research topic. Over the lifetime, 5357 publications have been published within this topic receiving 87424 citations.

Experimental Verification of Position-Dependent Angular-Momentum Selection Rules for Absorption of Twisted Light by a Bound Electron

Abstract: We analyze the multipole excitation of atoms with twisted light, i.e., by a vortex light field that carries orbital angular momentum. A single trapped $^{40}$Ca$^+$ ion serves as a localized and positioned probe of the exciting field. We drive the $S_{1/2} \to D_{5/2}$ transition and observe the relative strengths of different transitions, depending on the ion's transversal position with respect to the center of the vortex light field. On the other hand, transition amplitudes are calculated for a twisted light field in form of a Bessel beam, a Bessel-Gauss and a Gauss-Laguerre mode. Analyzing experimental obtained transition amplitudes we find agreement with the theoretical predictions at a level of better than 3\%. Finally, we propose measurement schemes with two-ion crystals to enhance the sensing accuracy of vortex modes in future experiments.

Magneto-optical resonance of electromagnetically induced absorption with high contrast and narrow width in a vapour cell with buffer gas

Abstract: The method for observing the high-contrast and narrow-width resonances of electromagnetically induced absorption (EIA) in the Hanle configuration under counterpropagating light waves is proposed. We theoretically analyze the absorption of a probe light wave in presence of counterpropagating one with the same frequency as the function of a static magnetic field applied along the vectors of light waves, propagating in a vapour cell. Here, as an example, we study a "dark" type of atomic dipole transition Fg=1-->Fe=1 in D1 line of 87Rb, where usually the electromagnetically induced transparency (EIT) can be observed. To obtain the EIA signal one should proper chose the polarizations of light waves and intensities. In contrast of regular schemes for observing EIA signals (in a single travelling light wave in the Hanle configuration or in a bichromatic light field consisted of two travelling waves), the proposed scheme allows one to use buffer gas to significantly enhance properties of the resonance. Also the dramatic influence of atomic transition openness on contrast of the resonance is revealed, that gives great advantage in comparison with cyclic atomic transitions. The obtained results can be interesting in high-resolution spectroscopy, nonlinear and magneto-optics.

Storage and retrieval of thermal light in warm atomic vapor

Abstract: We report slowed propagation and storage and retrieval of thermal light in warm rubidium vapor using the effect of electromagnetically induced transparency (EIT). We first demonstrate slowed propagation of the probe thermal light beam through an EIT medium by measuring the second-order correlation function of the light field using the Hanbury-Brown-Twiss interferometer. We also report an experimental study on the effect of the EIT slow-light medium on the temporal coherence of thermal light. Finally, we demonstrate the storage and retrieval of the thermal light beam in the EIT medium. The direct measurement of the photon number statistics of the retrieved light field shows that the photon number statistics are preserved during the storage and retrieval processes.

Large Kerr nonlinearities on cavity-atom polaritons

Abstract: I analyze a scheme that is capable of producing large Kerr nonlinearities on cavity-atom polaritons in a cavity quantum electrodynamics system consisting of multiple three-level atoms confined in a cavity mode. A weak control laser coupled to the atoms from free space induces destructive quantum interference in the polariton excitation of the coupled cavity-atom system and creates large Kerr nonlinearities on the intra-cavity light field. The scheme can be used for optical switching or cross-phase modulation of the cavity-atom polariton at ultralow light levels.

Intrinsic Light Fields.

Abstract: We present the first method to automatically decompose a light field into its intrinsic shading and albedo components. Contrary to previous work targeted to 2D single images and videos, a light field is a 4D structure that captures non-integrated incoming radiance over a discrete angular domain. This higher dimensionality of the problem renders previous state-of-the-art algorithms impractical either due to their cost of processing a single 2D slice, or their inability to enforce proper coherence in additional dimensions. We propose a new decomposition algorithm that jointly optimizes the whole light field data for proper angular coherency. For efficiency, we extend Retinex theory, working on the gradient domain where new albedo and occlusion terms are introduced. Results show our method provides 4D intrinsic decompositions difficult to achieve with previous state-of-the-art algorithms.