Azimuthal modulation of electromagnetically induced grating using structured light

Abstract

We propose a theoretical scheme for creating a two-dimensional Electromagnetically Induced Grating in a three-level $$\Lambda $$ Λ -type atomic system interacting with a weak probe field and two simultaneous position-dependent coupling fields—a two dimensional standing wave and an optical vortex beam. Upon derivation of the Maxwell wave equation, describing the dynamic response of the probe light in the atomic medium, we perform numerical calculations of the amplitude, phase modulations and Fraunhofer diffraction pattern of the probe field under different system parameters. We show that due to the azimuthal modulation of the Laguerre–Gaussian field, a two-dimensional asymmetric grating is observed, giving an increase of the zeroth and high orders of diffraction, thus transferring the probe energy to the high orders of direction. The asymmetry is especially seen in the case of combining a resonant probe with an off-resonant standing wave coupling and optical vortex fields. Unlike in previously reported asymmetric diffraction gratings for PT symmetric structures, the parity time symmetric structure is not necessary for the asymmetric diffraction grating presented here. The asymmetry is due to the constructive and destructive interference between the amplitude and phase modulations of the grating system, resulting in complete blocking of the diffracted photons at negative or positive angles, due to the coupling of the vortex beam. A detailed analysis of the probe field energy transfer to different orders of diffraction in the case of off-resonant standing wave coupling field proves the possibility of direct control over the performance of the grating.

Electromagnetically induced grating in azimuthal dependent three-level quantum dot system

“…Due to electromagnetically induced transparency (EIT) [1] promising applications in slow light [2], optical switching * Author to whom any correspondence should be addressed. [3,4], optical storage [5], enhanced Kerr-nonlinearity [6,7], four-wave mixing (FWM) [8,9], optical soliton [10,11], and others [12][13][14][15] the EIT opens a new way to manipulate the optical properties of atomic medium via light, has been extensively studied. By applying a standing-wave coupling field to atoms, an all-optical device known as an electromagnetically induced grating (EIG) based on EIT can be created [16].…”

“…Many applications based on EIG have been proposed, such as optical bistability [17], optical switching and routing [18], beam splitting and fanning [19], stationary light pulse [20], coherently induced photonic bandgap [21] and surface solitons [22]. EIG was first put forth in a three-level system by Ling and colleagues [16], after that many groups [12][13][14][23][24][25] observed it. The diffraction efficiency that can be achieved is, however, quite low because EIG is typically a hybrid grating with simultaneous amplitude and phase modulations.…”

Recent Progress in Nonlinear Frequency Conversion of Optical Vortex Lasers

“…Researchers found that due to the low diffraction limit, the vortex beam could replace the trivial Gaussian beam to improve the resolution of imaging, e.g., stimulated emission depletion, which can be of great use to biological and clinical medicine research [24]. Other recent applications in 2021 point to high-dimension OAMentanglement, and phase-gradient protection was also reported [25][26][27][28]. Many other exciting applications with regard to optical vortices are yet to be found.…”

Asymmetric two-dimensional electromagnetically induced grating controlled by a vortex field

“…However, all the research schemes described above were to realize 1D or 2D symmetric EIG. Very recently, some interesting proposals were reported to realize asymmetric EIG via different methods [33][34][35][36][37][38]. Some research groups used optical PT-symmetric structure to demonstrate 1D and 2D asymmetric diffraction gratings in atomic media, double quantum wells, and Rydberg atomic gas respectively [33][34][35].…”

“…Combining Hermitian, PT-symmetry, and non-Hermitian modulations, Liu et al [36] investigated lopsided diffractions of distinct symmetries in 2D non-Hermitian optical gratings. Utilizing a 2D SW field and an optical vortex beam interacting with Λ-type atomic system, Asadpour et al [38] proposed a theoretical scheme to create asymmetric 2D EIG.…”