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Antonio Zelaquett Khoury

Publications and source records attributed to Antonio Zelaquett Khoury.

5 recordsLinked to original sources

Structured light under turbulence

Structured light has emerged as a promising resource for high-capacity and secure free-space optical communication, where atmospheric turbulence remains a major source of signal degradation. In this work, we investigate the resilience of different transverse mode structures of an optical beam with respect to the random action of turbulence. A spatial light modulator (SLM) is programmed to apply amplitude and phase modulation corresponding to the desired transverse mode, which is then transmitted through a turbulent medium emulated by a second SLM. Laguerre-Gauss, Hermite-Gauss, and Airy beams are investigated through the resulting intensity distributions measured with a camera. Different figures of merit are used to evaluate and compare the resilience of these modes.

physics.optics↗

All-optical saddle trap as a platform for mesoscopic quantum experiments

We investigate the quantum dynamics of a levitated nanoparticle in a structured light rotating saddle-like optical potential consisting of a superposition of Gaussian and Laguerre-Gauss modes with detuned frequencies. This rotating saddle trap offers unique opportunities for quantum experiments, such as reduced decoherence due to photon recoil and absorption, the possibility of large delocalization of the particle's center-of-mass motion, particle recovery protocols, the generation of motional entanglement and momentum squeezing. As an application, we show that this saddle-trap architecture enables force detection with sensitivity in the zepto-Newton regime.

quant-ph↗

All-optical Saddle Trap

The superposition of frequency-shifted Laguerre-Gauss modes can produce a rotating saddle-like intensity profile. When spinning fast enough, the optical forces produced by this structured light saddle generate a dynamically stable equilibrium point capable of trapping nanoparticles in a high vacuum, akin to a Paul trap but with its unique characteristics. We analyze the stability conditions and center-of-mass motion, dynamics and cooling of a nanoparticle levitated in the optical saddle trap. We expect the optical saddle to find applications in levitated optomechanics experiments requiring fast parametric modulation and inverted squeezing potential landscapes.

physics.optics↗

Poincaré sphere symmetries in four-wave mixing with orbital angular momentum

We explore a degenerate four-wave mixing process induced by transversely structured light beams in a rubidium vapor cell. In particular, we consider the nonlinear interaction driven by optical modes contained in the orbital angular momentum Poincaré sphere, which can be parametrized in terms of a polar and an azimuthal angle. In this context we investigate the transfer of spatial structure to two distinct four-wave mixing signals, possessing different propagation directions in space. We show that under usual assumptions, the output fields can also be described by modes belonging to Poincaré spheres, and that the angles describing the input and output modes are related according to well-defined rules. Our experimental results show good agreement with the calculations, which predict intricate field structures and a transition of the FWM transverse profile between the near- and far-field regions.

physics.optics↗

Reconstructing the full modal structure of photonic states by stimulated emission tomography

Stimulated emission tomography is a powerful and successful technique to both improve the resolution and experimentally simplify the task of determining the modal properties of biphotons. In the present manuscript we provide a theoretical description of SET valid for any quadratic coupling regime between a non-linear medium and pump fields generating photons by pairs. We use our results to obtain not only information about the associated modal function modulus but also its phase, for any mode, and we discuss the specific case of time-frequency variables as well as the quantities and limitations involved in the measurement resolution.

quant-ph↗