Time dependence in stimulated gamma-ray emission: Implications for GRASERs

Summary We discuss the limitations of the cross-section concept in estimating the performance of a GRASER and the implications of this for evaluating conceptual systems and for experimental detection of stimulated gamma-radiation. We derive the time-dependent cross-section for stimulating emission of gamma-radiation from a nucleus and show, not only that the asymptotic cross-section is extremely small for transitions from a long-lived isomeric state to a shorter-lived excited lower state, but also that, forany transition from a long-lived state, the cross-section remains small compared with its asymptotic value for a time of the order of the reciprocal linewidth.