Enhanced transient effects due to saturated absorption of recoillessγradiation

Prominent nonlinear transient effects due to thickness saturation are presented for the Mössbauer resonance of ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$. Short and intense pulses of resonant $\gamma$ radiation, resembling those obtained with synchrotron radiation, are produced using fast stepwise phase modulation. A $\gamma$-ray interferometer, based on the 0.86-Å wavelength of Mössbauer radiation, is described. Transient methods revealed the properties of a ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}_{0.1}^{}{}_{}{}^{}$ ${\mathrm{Rh}}_{0.9}$ absorber with an improvement of one order of magnitude in the statistical accuracy compared with conventional measurement techniques.