Influences of polarization and relative phase of laser fields on the optical properties of three-level cascade atomic medium

In this work, we study the influences of interference parameter of spontaneously emissions (generated by the polarization of light and the non-orthogonal orientation of electric dipole moments) p and relative phase of the laser fields  on the absorption and dispersion coefficients of 85Rb three-level cascade atomic medium by analytical method. The results show that the influence of parameter p leads to a narrower of the transparent window, while the absorption spectrum on both sides of the transparent window is enhanced. This increases the slope of normal dispersion curve inside the transparent spectral domain; the absorption and dispersion coefficients vary according to the phase difference with the period of 2. At  = 0 and  = 2, the absorption coefficient is largest, while at  = , the absorption coefficient is smallest. For dispersion coefficient, at  = 0,  = 2 and  = , the dispersion coefficient is vanished, while it reaches the extreme value when  = /2 and  = 3/4. Analytical results are useful for experimental observation and related applications.