We investigate the nonlinear refraction and absorption related to holographic\nwriting in rubidium vapor at resonance with 87Rb D2 transition. The numerical\nmodel based on time-dependent density matrix formalism is used. The\ntheory adequately describes nonlinear optical rotation and absorption at light\nintensities in 0.1− 30mW / cm2 range.\nWe discuss two principal mechanisms. The first is based on absorption grating\nwriting and another grating formation mechanism based on Faraday rotation. It is\npromising for applications because it gives phase holograms with higher diffraction\nefficiency. The theory for both cases was developed.\nThe basic configurations for obtaining amplitude and phase gratings for nearly\nequal frequencies of writing beams are investigated experimentally, and the writing\ntime is estimated.\nWe also proposed a rapid solution algorithm for the calculation of the full density\nmatrix evolution for a multi-level atom. The calculation principle is similar to the\nsplit-step algorithm widely used for modeling the nonlinear propagation in media\nwith Kerr-type nonlinearity. The spectrum of nonlinear Faraday rotation in the D2\nnatural rubidium line is calculated and compared with the experiment. Good\nagreement is obtained.