Techniques for reconfiguring spectral features stored in a medium based on a two-state atomic system with transition dipole moment .mu. includes causing a chirp to pass into the medium. The chirp includes a monochromatic frequency that varies in time by a chirp rate .kappa. over a frequency band B.sub.R during a time interval T.sub.R. The amplitude A.sub.R of the chirp is constant over B.sub.R and equal to A.sub.R=(hbar/.mu..pi.) {square root over ((.kappa. ln [2/.epsilon.]))}, The term hbar is reduced Plank's constant, ln is a natural logarithm function, and .pi. is a ratio of a circumference of a circle to a diameter of the circle. For .epsilon.<<1, the atomic-state populations in the two states are inverted. For .epsilon.=1, prior atomic-state populations are erased, with final populations equal in the two states, regardless of populations before erasure.