Dispersion management in femtosecond laser oscillators with highly dispersive mirrors.

Recently the manufacture of highly dispersive mirrors with -1300 fs(2) group delay dispersion per reflection was reported. Here we demonstrate the intracavity applicability of these novel mirrors in Ti:sapphire oscillators for the first time, as well as their capability of compensating a substantial amount of material dispersion in the cavity (40 mm fused silica). We also studied the influence of net negative cavity dispersion, realized with these mirrors, on the achievable maximum pulse energy in long-cavity femtosecond oscillators before the onset of anomalous behavior (e.g. multi-pulsing). In addition, we demonstrate a 0.5 GHz Ti:sapphire oscillator the dispersion compensation of which is realized with a single highly dispersive mirror.

Femtosecond time-resolved saturation dynamics of BDN-doped polycarbonate.

In this paper we report on optical pump-probe measurements on BDN-doped polycarbonate irradiated with laser pulses ranging from 25fs to 1.2ps in duration and up to fluences of 0.1 J/cm(2) at 800nm wavelength. Transient change of the transmission has been measured as a function of pump-probe delay and pump fluence. Pulse duration dependent channels of saturation have been identified and the ground state repopulation (GSR) time has been determined.

Reliability of laser safety eye wear in the femtosecond regime.

Appropriate eye protection is a prerequisite for the safe operation of ultrashort laser systems in industrial and laboratory environments. In this paper we report on the measurement of the transmission of ion-doped phosphate glass filters for pulses having a center wavelength of 800nm, a duration of 10fs to 1.2ps and a fluence range of 0.01 to 30J/cm(2). The measurements suggest, that the filter material preserves its protective features over the whole range. Saturation of absorption was only observed in the picosecond pulse duration range.

Protective materials for subpicosecond Ti:sapphire lasers.

The high intensities provided by short-pulse Ti:sapphire laser systems call for the utilization of appropriate eye-protecting materials. We summarize the representative results of our characterization measurements on optical filters employed for laser radiation protection. Physical effects are discussed that influence the transmission (and thus the protective properties) of the investigated materials. Potential hazard factors have been recognized and characterized. We make recommendations to the extension of the current characterization methods and illustrate the acquired information in the form of operation charts.

Sub-10-fs, terawatt-scale Ti:sapphire laser system.

A three-stage, 1-kHz amplifier system delivering pulses shorter than 10 fs with a peak power in excess of 0.3 TW is reported. Passive and active spectral intensity and phase control allows the preservation of a bandwidth of 120 nm (FWHM) to as high as multimillijoule energy levels and temporal compression of the broadband pulses close to their Fourier limit. The system is scalable to peak powers well beyond 1 TW and holds promise for substantially advancing the state of the art of coherent laboratory soft-x-ray sources.