Complex degree of mutual polarization in randomly scattered fields

Random electromagnetic fields resulting from light-matter interaction have strong intensity fluctuations and are characterized by various statistical parameters. The local polarization of these fields can also vary randomly leading to different degrees of global depolarization. Here we demonstrate that the spatial variability of the vectorial properties contains information about the origins of randomly scattered fields. In particular, we show that the complex degree of mutual polarization provides the high-order polarization correlations necessary to identify the sources of different random fields. Scattered fields with similar global properties but different origins can be efficiently discriminated from one single realization of the light-matter interaction

On the asymptotic evolution of finite energy Airy wavefunctions

In general, there is an inverse relation between the degree of localization of a wavefunction of a certain class and its transform representation dictated by the scaling property of the Fourier transform. We report that in the case of finite energy Airy wavepackets a simultaneous increase in their localization in the direct and transform domains can be obtained as the apodization parameter is varied. One consequence of this is that the far field diffraction rate of a finite energy Airy beam decreases as the beam localization at the launch plane increases. We analyse the asymptotic properties of finite energy Airy wavefunctions using the stationary phase method. We obtain one dominant contribution to the long term evolution that admits a Gaussian-like approximation, which displays the expected reduction of its broadening rate as the input localization is increased

Correlations of polarization in random electromagnetic fields

Random electromagnetic fields have a number of distinctive statistical properties that may depend on their origin. We show here that when two mutually coherent fields are overlapped, the individual characteristics are not completely lost. In particular, we demonstrate that if assumptions can be made regarding the coherence properties of one of the fields, both the relative average strength and the field correlation length of the second one can be retrieved using higher-order polarization properties of the combined field

Polarization Correlations In Backscattering From Media With Different Optical Densities

Random electromagnetic fields have a number of distinctive statistical properties that may depend on their origin. We show that, when two mutually coherent fields overlap, their individual characteristics are not completely lost. If assumptions can be made regarding the coherence properties of one of the fields, then the correlation length of the second one can be retrieved using the higher-order polarization properties of the combined field. We demonstrate experimentally that colloidal particles of different sizes can be identified based on polarization correlations measured even in situations of strong multiple scattering. © 2014 Optical Society of America

Polarimetric Filtering Of Time-Reversal In Multiple Scattering

Time-reversed trajectories in multiple scattering produce constructive interference. Ensemble averaging leads to enhancement of backscattered intensity. We demonstrate that polarization analysis identifies time-reversed contributions even within a single realization of wave-matter interaction. © 2007 Optical Society of America

Fluctuations of scattered waves: going beyond the ensemble average

The interaction between coherent waves and random media is a complicated, deterministic process that is usually examined upon ensemble averaging. The result of one realization of the interaction process depends on the specific disorder present in an experimentally controllable interaction volume. We show that this randomness can be quantified and structural information not apparent in the ensemble average can be obtained. We use the information entropy as a viable measure of randomness and we demonstrate that its rate of change provides means for discriminating between media with identical mean characteristics

Ballistic Dynamics Of Airy Beams

We demonstrate both theoretically and experimentally that optical Airy beams propagating in free space can perform ballistic dynamics akin to those of projectiles moving under the action of gravity. The parabolic trajectories of these beams as well as the motion of their center of gravity were observed in good agreement with theory. The possibility of circumventing an obstacle placed in the path of the Airy beam is discussed. © 2008 Optical Society of America

Observation Of Accelerating Airy Beam Ballistics

We demonstrate experimentally that Airy beams can perform ballistic dynamics in a way totally analogous to that of projectiles moving under the action of gravity. The possibility of circumventing opaque obstacles is discussed. © 2008 Optical Society of America