B I Denker

50 mJ/30 ns FTIR Q-switched diode-pumped Er:Yb:glass 1.54 μm laser

Abstract 50 mJ Q-switched output at 30 ns pulse duration was demonstrated with a transversely diode-pumped bulk Er 3+ :Yb 3+ :glass 1.54 μm laser system of uncomplicated and compact design, using a piezoelectrically driven FTIR shutter. In long-pulse operation, 360 mJ output was obtained for 2.65 J incident optical pump energy. Maximum optical slope efficiencies of 20.5% and 5.4% were measured in long-pulse and Q-switched operation, respectively. Optimum Q-switch timing was studied taking into account the Yb 3+ →Er 3+ energy transfer process and was correlated with free-running delay parameters.

Laser performance of Yb:GdCa4O(BO3)3 compared to Yb:KGd(WO4)2 under diode-bar pumping

A study of Yb:GdCOB under diode-bar pumping has been performed and the results are compared, experimentally and theoretically, with Yb:KGW in the same cavity. An output power of 7.3 W and a slope efficiency of 57.4% were obtained. Self-frequency-doubling experiments are also discussed.

The IR emitting centers in Bi-doped Mg-Al-Si oxide glasses

The properties of IR emission centers are investigated in Bi-doped Mg-Al-silicate glasses having moderate melting temperatures to be fabricated by routine melting in alumina crucibles. The quadratic concentration dependence of absorption in the visible range indicates that the considered optical centers can be Bi2 dimers forming in a balanced chemical reaction in the glass melt. Their formation enthalpy is evaluated from their concentration variations with the synthesis temperature. The high (up to 85% at low concentrations) luminescence quantum yield and wide emission spectrum makes this glass a promising material for tunable lasers.

Activation of color centers in bismuth glass by femtosecond laser radiation

The activation of color centers in the bismuth aluminum-boron-phosphate glass by high-intensity femtosecond laser radiation is experimentally studied. The dynamics of the laser-induced emitting centers in the bulk of sample is characterized. The photoactivation of bismuth glasses is possibly related to the recharging of structural precursors, which serve as effective electron traps and whose possible configuration is discusses. The effect of the femtosecond irradiation involves the initiation of the nonlinear ionization of the glass matrix and the generation of plasma with the concentration of carriers that is sufficiently high to provide almost complete recharging of precursors over several laser pulses.

Alternative ways to form IR luminescence centers in bi-doped glass

It was shown that identical Bi-associated emission centers can be formed in aluminophosphate glass either by high-temperature melting or by γ-irradiation. Some conclusions on the structure of the nearinfrared emission centers were made. 1 The article is published in the original.

High-beam quality, high-efficiency laser based on fiber with heavily Yb(3+)-doped phosphate core and silica cladding.

We have fabricated and tested a composite fiber with an Yb(3+)-doped phosphate glass core and silica cladding. Oscillation with a slope efficiency of 74% was achieved using core pumping at 976 nm with fiber lengths of 48-90 mm in a simple laser configuration, where the cavity was formed by a high-reflectivity Bragg grating and the cleaved fiber end. The measured M(2) factors were as low as 1.05-1.22 even though the fiber was multimode at the lasing wavelength.

A Passive Q-Switched Microchip Er/Yb Glass Laser Pumped by Laser Diode

A laser-diode-pumped 1.54-μm passive Q-switched erbium doped glass laser was reported. We utilize a laser diode with wavelength of 973 nm to pump a 1-mm Er/Yb co-doped phosphate glass with the erbium and ytterbium concentrations of 1 wt.% and 21 wt.%, respectively. A Co2+:MgAl2O4 slab crystal was used as a passive Q-switcher. Q-switched pulses with repetition frequency of 800 Hz, width of 7.4 ns, peak power of 2.2 kW and average power of 13.3 mW were obtained when absorbed pump power was 475 mW. A sandwich structure of the Q-switched microchip Er/Yb glass laser was demonstrated, which shows shorter pulse width of 6.8 ns. Dependences of pulse duration and repetition frequency on pump power were also investigated.

Co2+:MgAl2O4 crystal passive Q-switch performance at 1.34, 1.44, and 1.54 μm

Passive Q-Switch characteristics of Co2+:MgAl2O3 sample were evaluated in a diode pumped QX/Er Erbium glass laser at 1535 nm, a flashlamp pumped Nd:YAG laser at 1.44 micrometers and Nd3+:KGd(WO4)2 laser at 1.34 micrometers .

Efficiency of an Li–Nd–La phosphate glass laser at low pump energies. Free lasing

An investigation was made of the free-lasing regime in a high-concentration Li–Nd–La phosphate glass pumped in the energy range 1–15 J. A laser efficiency of 2.9% was obtained for a pump energy of 14.5 J. Estimates were made of the intracavity losses and the maximum attainable efficiency was determined. An investigation was made of the laser performance in the giant pulse regime and at pulse repetition frequencies of up to 25 Hz.

GeO2 influence on the formation of near-infrared emitting centers in Bi-doped multicomponent silicate glasses

A meaningful increase in the number of NIR emission centers was experimentally observed in bismuth-doped multicomponent silicate glasses additionally doped with germanium dioxide. The emission and excitation spectra of the glass sets were monitored and compared with the spectra of radiative oxygen-deficient centers in vitreous silica and germania.