B. Broers

Rubidium electronic wavepackets probed by a phase-sensitive pump-probe technique

Abstract A phase-sensitive pump-probe technique has been developed to study the dynamics of electron wavepackets. The wavepacket population is modulated by the relative phase of the pump and probe pulses. The time autocorrelation of electron wavepackets in rubidium subject to an electric field above the classical field-ionization energy has been measured.

Large interference effects of small chirp observed in two-photon absorption

Abstract It is shown that the populations of excited levels after a multi-photon excitation process are strongly influenced by the exact phase relations between the different frequency components within the excitation pulse (the ‘chirp’ of the pulse). This general effect, which can already show up dramatically if chirp has lengthened the pulse by only 10%, is experimentally demonstrated two systems: two-photon absorption in an atom and frequency-doubling in a nonlinear crystal.

High-power femtosecond dye laser with tunable wavelength, pulse duration and chirp

Abstract We present a high-power femtosecond dye-laser system based on a CPM oscillator. The pulses have an energy up to 0.6 mJ and a variable pulse duration between 70 fs and 5 ps. The wavelength of the pulses is tunable throughout the visible, and the chirp of the pulses can be varied continuously.

Excess-photon detachment of negative chlorine ions with 100 fs laser pulses

Multiphoton detachment spectra of Cl-, showing excess-photon absorption, have been obtained using short (100 fs) and intense (up to 5*1016 W m-2) optical pulses with a wavelength of 620 nm. In the short-pulse regime the shifts in the electron spectrum can be related directly to shifts of the continuum states. In this way, it is shown experimentally that excess-photon detachment can occur in the absence of channel closure.

Similarities between atomic wave packets and optical pulses

Abstract We consider the similarities between short optical pulses and atomic electron wave packets. The atomic potential acts in a similar way on the electron wave function as an optical cavity does on electromagnetic waves. It is shown that effects well known in optics, such as creation of pulsed light, dispersion, and shortening of optical pulses, can also occur for matter waves.

Population transfer in ladder systems by means of frequency‐swept ultrashort laser pulses

We report on experiments in which 100% population transfer is obtained in an atomic three‐level ladder system by means of frequency‐swept ultrashort laser pulses. Application to bond‐selective vibrational excitation and dissociation of molecules is discussed.