High quality GGG:Cr,Ca crystal for passive Q-switching Nd:garnet lasers has been grown by the Czochralski method. Thermal treatment of GGG crystals co-doped with Cr4+ and Ca2+ at different temperatures is investigated. The absorption spectra were resolved into different peaks, of modified Gaussian line-shape. Transition from octahedral sites to tetrahedral ones is thermally activated. An...

The influence of self-phase modulation (SPM) and group-velocity dispersion (GVD) on pulse development in a passive mode-locked dye laser is investigated numerically by using fast Fourier transformations. The situation of positive SPM is considered. Four regions of laser performance may be distinguished: (i) In the positive GVD region pulse broadening by GVD must be balanced by the pulse-shorten...

Unabsorbed pump light in passively Q-switched microlasers leads to suboptimal pulse generation by bleaching the saturable absorber. This mechanism increases the effective unsaturated transmission of the absorber, which leads to a change in the system dynamics that results in increased pulse durations and decreased pulse energies. We report experimental evidence of pump-induced bleaching of the ...

The interaction of an optical pulse with a quantum well saturable absorber is simulated using a semi-classical two-level-atom model which has been modified to approximate spectral hole burning in the carrier distribution. Saturable absorption behaviour is examined in the limit where pulse duration approaches the carrier-carrier scattering time. For long pulses bleaching dominates the absorber r...

After advent of graphene as a saturable absorber many experiments have been conducted to produce short pulse duration pulses. Here, we have measured the properties of flake-graphene saturable absorber mirrors of various flake sizes dependent on fabrication technique. These mirrors enabled us to obtain a large mode-locking bandwidth of 16nm in an erbium-doped fiber laser. Mirrors with large flak...

Mathematical description of a passively Q-switched laser and the way it works are presented. Both theoretical and experimental model of this laser have been worked out. Moreover, numerical analysis of saturable absorber influence on laser efficiency was made. It is the saturable absorber characterized by excited state absorption (ESA) that has been taken into account. The optimization procedure...