Femtosecond Photon Echo Spectroscopy in Single Laser Shot

We take advantage of extreme spatial thinness of 100-femtosecond pulse of an amplified femtosecond laser and measure for the first time the homogeneous spectrum of a strongly inhomogeneously-broadened solid with a single laser shot. This is achieved by combining causality-related diffraction asymmetry of twoand three-pulse photon echo with oblique excitation pulse wave fronts, which are creating a space-variable time delay. We show that by focussing the resulting photon echo image with a Fourier-transforming lens, we can directly record the autocorrelation function of the homogeneous spectrum. We measure the homogeneous line shape of dye-doped polymer at different temperatures, with spectral resolution up to 0.2 cm –1 , such that each measurement requires only one single laser pulse.