ABSTRACT
Intense, multi-color laser fields permit the control of the ionization of atoms and the steering of electron dynamics. Here, we present the efficient collinear creation of the second and third harmonic of a 790 nm femtosecond laser followed by a versatile field synthesizer for the three color fields' composition. Using the device, we investigate the strong-field ionization of neon by fields composed of the fundamental, and the second or third harmonic. The three-color device offers sufficient flexibility for the coherent control of strong-field processes and for time-resolved pump-probe studies.
ABSTRACT
We have studied the effect of transient vibrational inversion of population in trans-ß-apo-8(')-carotenal on the time-resolved femtosecond stimulated Raman scattering (TR-FSRS) signal. The experimental data are interpreted by applying a quantum mechanical approach, using the formalism of projection operators for constructing the theoretical model of TR-FSRS. Within this theoretical frame we explain the presence of transient Raman losses on the Stokes side of the TR-FSRS spectrum as the effect of vibrational inversion of population. In view of the obtained experimental and theoretical results, we conclude that the excited S2 electronic level of trans-ß-apo-8(')-carotenal relaxes towards the S0 ground state through a set of four vibrational sublevels of S1 state.
ABSTRACT
We report on experimental results of supercontinuum generation in bulk diamond. The spectrum of supercontinuum generated with 800 nm pump extends up to 600 nm towards short wavelengths. We present the numerical model explaining the phenomenon, in which the role of different nonlinear effects including stimulated Raman scattering is discussed. Unlike in other materials, in diamond the feature of supercontinuum due to stimulated Raman response is apparently visible.
