Phase-controlled Optical PT symmetry and asymmetric light diffraction in one- and two-dimensional optical lattices

Abstract

We propose a novel scheme for asymmetric light diffraction of a weak probe field into a one-dimensional (1D) and two-dimensional (2D) lattice occupied with cold atoms. The atoms are driven into the double lambda-type configuration by a standing wave, two coupling laser fields and a probe. Our study suggests the proposed scheme is capable of forming an asymmetric diffraction as a result of inducing optical paritytime symmetry in both 1D and 2D lattices. Moreover it is demonstrated that the asymmetric pattern of diffraction can be dynamically manipulated by means of adjusting the relative phase. Furthermore it is revealed that in the case of 1D lattice (grating), variation of the intensities of the coupling fields has a significant impact on the intensity of diffraction orders in the uneven distribution of diffraction.

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

“…The experiment has been performed in an 87 Rb atomic vapour cell with the temperature set at about 40 °C. A number of works have been reported to exhibit EIG with the azimuthal variation of diffraction peaks relating to  -symmetry [41][42][43][44][45][46][47] or  -antisymmetry [48,49].…”

Azimuthal modulation of electromagnetically induced grating using structured light

“…In recent years it has been demonstrated, that in the PT-symmetric media it is possible to observe an asymmetric diffraction pattern since light undergoes spatially modulated refractive index 13 . The realization of one-and two-dimensional asymmetric gratings in optical PT-symmetric structures has drawn the attention of many research groups [14][15][16][17][18][19][20][21][22][23][24][25] .…”