RESUMEN
Amplification of femtosecond pulses through spatial expansion and recompression in a temporally nondispersive grating apparatus is demonstrated. The system used does not lengthen the pulse, provides higher gain than conventional amplifiers, and separates effectively the amplified spontaneous emission from the signal. The output pulse duration is easily controlled from tau(min) = 50 fs to several hundred femtoseconds by fine adjustment of the components used in the spatially dispersive scheme.
RESUMEN
Polarization nondegenerate nonstationary coherent anti-Stokes Raman spectroscopy was used in measurements of pulse responses for separate electronic multipole moments. The 6P(1/2)-6P(3/2) transition of Tl atoms was investigated. Doppler dephasing conditions, quantum beats of the hyperfine components of this transition are clearly seen when pure anisotropic scattering is registered, but they are small in the case of purely antisymmetric scattering. Under collisional dephasing conditions the relaxation rates of anisotropic and antisymmetric scattering agree with existing theory within +/-5%.