| The scientific research of quantum optics is advancing rapidly,with extensive research being done on a variety of topics ranging from the study of atoms on surfaces to the development of quantum devices for quantum optical networks.I explore two research directions from this broad range of topics and describe my Ph.D.research goals.My first objective is to investigate techniques based on a novel four-level tripod((?))type atomic scheme for high-precision position measurement of an atom,and my second objective is to investigate the performance of a two-dimensional(2D)electromagnetically induced grating(EIG)produced in a(?)-type system.In the first part of the thesis,we mainly focus on two-dimension(2D)and threedimension(3D)atom localization in a rh type scheme via a single and Double electromagnetically induced transparency(DEIT).Our(?)type atomic scheme is coherently controlled using a signal field,a weak probe field,and two orthogonal standing-wave fields(OSWFs)for 2D localization and the three OSWFs for 3D localization.We also consider that each standing wave(SW)is the superposition of two SWFs oriented in the same direction.The presence of SWFs results in a position-dependent interaction between atom and field,which gives a position-dependent Rabi frequency.We consider that the system is initially constructed at lower levels and investigate the atom localization via manipulation of the probe absorption spectrum.We study the influence of field detuning,intensities,and phase shifts on 2D and 3D atom localization.We show that by appropriately adjusting the system parameters,we can obtain an atom’s single position information in a 2D plane and 3D space,with significantly higher spatial resolution.We also observed the effect of Doppler broadening on atom localization and established that Doppler broadening has a significant impact on the precision of an atom’s spatial position information.We found that our(?)type novel scheme has two main advantages;first,the atom is initially prepared in the ground state,which can easily be accomplished experimentally,second,it does not need spontaneous emission(SE)control,which is difficult to perform experimentally.Our scheme may be useful in a variety of possible applications,including laser cooling,atom nano-lithography,computing the center of the mass wave function for moving atoms,and Bose-Einstein condensation.In the second part of the thesis,we investigate the coherent control of 2D EIG that switches between zeroth-order diffraction to a distinct higher-order diffraction pattern by driving a planar gaseous medium of four-level(?)atoms with three laser beams:modulation of SW control beam propagating nearly perpendicular to the planar medium.In contrast,vortex and weak plane probe beams are directed perpendicular to the medium.By the variation of the field detunings and orbital angular momentum(OAM)number of the composite vortex light beam,diffraction of probe beam has been observed that are interacting with a gaseous atomic medium,which acts as grating by applying SW control beam.Specifically,in the off-resonant case,probe and vortex fields may each have coherent gain,resulting in large diffraction efficiencies in the zeroth and higherorder directions.Due to the azimuthal modulation of the structure light,we find a twodimensional asymmetric grating,resulting in an increase of the zeroth and high orders of diffraction and a subsequent transfer of probe energy to the high order direction.The asymmetry is especially seen in the case of combining a resonant SW control field and an off-resonant probe and vortex fields.We believe that the proposed 2D EIG scheme will be experimentally achievable in a typical EIG setup,with useful applications in various fields of science to study,for example,diffracting and switching a quantized probe field,probing the optical properties of a material,all-optical switching and routing,and an optical memory devices via storage of information to diffraction orders of the atomic grating. |
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