Multi-wave-mixing-induced nonlinear modulation of diffraction peaks in an opto-atomic grating

Abstract

We propose an atomic model in close-loop configuration, which exhibits controllable symmetric and asymmetric evolution of significantly enhanced diffraction peaks of the weak probe beam in an opto-atomic grating at far-field regime. Such results are obtained by the linear and nonlinear modulation of the intensities of the diffraction peaks as a result of multi-wave-mixing-induced modification of spatially modulated coherence in a closed four-level atomic system. Novelty of the results lies in predicting the diffraction pattern with uniform peak height due to the dominance of the amplitude part of the grating-transfer-function at the condition of exact atom-field resonance, which is unique to the present model. Efficacy of the present scheme is to apply it in producing nonlinear light generated by four-wave-mixing-induced control of spatially modulated coherence effect. The work also finds its importance for its applicability in the field of all-optical devices.

Generation of optical  -antisymmetry in a coherent N-type atomic medium

“…With the advent of electromagnetically induced transparency (EIT) [1] of a weak coherent field probing the coherence evolved in a laser-driven multilevel atom, it has been possible to introduce spatially dependent coherence effects like electromagnetically induced focusing and waveguiding [2][3][4], coherent control of optical image transfer via EIT [5][6][7], electromagnetically induced grating (EIG) [8][9][10], atom localization in EIT-related systems [11][12][13][14][15] and so on. In such phenomena, spatially modulated coherence plays a vital role, which is to be controlled by varying the system parameters.…”