Abstract We theoretically investigated the tuning of subluminal to superluminal propagation of light pulse in four-level N-type atomic medium. The dynamics of the atomic system are derived using the density matrix method. The group index ng=±1×106documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$n_g=pm 1times 10^6$$end{document} is significantly modified in four-level atomic medium. The medium shows subluminality and superluminality of group velocity vg=c/1×106documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$v_g=c/1times 10^6$$end{document} and vg=-c/1×106documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$v_g=-c/1times 10^6$$end{document}. The intensity of the output pulse is both positive and negative phase shifts in time and have undistorted shape with Rabi frequencies of the driving fields. The minimum distortion in subluminality and superluminality is useful in communication technology to propagates pulse with large phase shift and without energy loss.
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