Diffraction Management by using Coherent control fields in Optical Media

Jun Ye, R. Jason Jones, Kevin W. Holman +6 more

Lu Zhao, Wenhui Duan, Susanne F. Yelin

We theoretically explore an all-optical method for generating tunable diffractive Fresnel lenses in coherent media based on electromagnetically induced transparency. In this method, intensity-modulated images in coupling light fields can pattern the coherent media to induce the desired modulo-2π quadratic phase profiles for the lenses to diffract probe light fields. We characterize the focusing and imaging properties of the induced lenses. In particular, we show that the images in coupling fields can flexibly control the images in probe fields by diffraction, where large focal length tunability from 1 m to infinity and high output (∼ 88% diffraction efficiency) can be achieved. Additionally, we also find that the induced Fresnel lenses can be rapidly modulated with megahertz refresh rates using image-bearing square pulse trains in coupling fields. Our proposed lenses may find a wide range of applications for multimode all-optical signal processing in both the classical and quantum regimes.

Ірина Василівна Солтис

The media of layered crystals as a possible element of memory in the storage systems were analyzed, the manipulation mechanisms of which are carried out with polarization of incident radiation. The phenomenon of polarization optical bistability in the medium of layered crystals was obtained, in which the transmission band is managed with only the change of polarization of incident radiation. On the basis of the mechanism of polarization control of nanoparticles motion in the tasks of polarization diagnostics of optical fields, the estimation of the coherent features of mutually orthogonal linearly polarized optical fields was performed that also enables to analyze the terms of storage of information about the structure of an optical field.

S. H. Lee

Muhammad Safeer Sadiq, Haleema Sadia Qureshi, Shakir Ullah +1 more

We demonstrate coherence-controlled azimuthal modulation of electromagnetically induced transparency (EIT) and all-optical switching in a four-level atomic ensemble coupled to a Laguerre-Gaussian beam, a control field, and a microwave field. The spatial EIT patterns exhibit doublet, quartet, and sextuplet structures, evolving into more complex structures with increasing orbital angular momentum (OAM). These structures can be dynamically switched between EIT and absorption patterns, preserving mirror image symmetry (with even OAM) and rotation symmetry (with odd OAM) by adjusting the relative phase of the coupling fields. By creating two-dimensional electromagnetically induced gratings (EIGs), we find that the diffractive patterns are influenced by probe field detuning, OAM, and relative phase. Specifically, the diffraction patterns of a probe field exhibit complex behavior across first to fourth orders, with intensities influenced by topological charge and azimuthal angle. The diffraction patterns are further modulated by the relative phase, with patterns at 0 and π being mirror images of each other, while the pattern at π /2 exhibits distinct behavior. These findings highlight the potential for precise control over structural EIT, all optical switching and diffraction patterns in coherent atomic media.

Debabrata Goswami