Tomasz Kardaś

Study of phenomena connected with propagation of ultrashort pulse in different media

Tomasz Kardaś, UW
Supervisor: prof. Bożena Gadomska (UW)

An extended cavity Ti : Sapphire femtosecond laser was build and lead into automodulations. The stability of modulations was studied to reveal complicated laser dynamics involving period doubling and chaos. The behaviour of laser pulses spectrum in stable automodulations and in period doubling was measured. This is the first study of those effects in Ti:Sapphire femtosecond laser.
The transient reflection and setup was prepared and used for measurement of saturable absorber mirrors (SAM). SAM are used in lasers for starting pulsed action. Their intensity dependent absorption and absorption decay can be measured.
The Time Resolved Stimulated Raman setup was builed and tested. The Raman scattering of 800 nm pumping beam stimulated by 600 - 1050 nm supercontinuum probe is measured as a function of delay after sample electronic activation with 400 nm pump.
The supercontinuum generation in diamond was studied. Propagation of ultrashort energetic pulse though diamond can lead to broadening of pulse spectrum. This broadening is caused by nonlinear electronic and ionic response of medium to high intensity light. The broadening of spectrum of pulses travelling through diamond was measured as a function of laser light intensity.
A model of cross-phase modulation of ultrashort pulses in alexandrite crystal was created. The effect of cross-phase modulation involves two pulses. Pulses affect each other spectra via medium nonlinear electronic response. The case of two pulses with the same time characteristic and different energies was studied theoretically and the results were found to agree with experimental results.

Chairman - prof. Adam Proń (WUT)

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