S E Sverchkov

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.

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 .

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.

Spectral and luminescent properties of Bi-doped bulk glasses and factors acting on them

The properties near infrared (NIR) - emitting centers were investigated in Bi-doped Mg.Al-silicate and phosphate glasses. The NIR-emitting optical centers containing a pair of bismuth ions were shown to be formed in a reversible redox chemical reaction. The common electric charge (+5) of bismuth ions in such centers was determined. The NIR-emission saturation measurements have made it possible to calculate the ground-state absorption cross-section (~4.4×~10-19 cm2) of these centers at 532 nm and their absolute concentration in the glass. It was found that similar emitting centers can also be formed in a colorless and non-luminescent Bi-doped glass by γ-irradiation. This fact allowed deriving some conclusions on an optical center structure.

Diode-Pumped and FTIR Q-Switched Laser Performance of Novel Yb-Er Glass

Diode-pumped slope efficiencies of 14% with output energies up to 18 mJ have been obtained from highly concentrated Yb,Er:boro-silico-phosphate glass. FTIR Q-switched pulses of 10 mJ, 50 ns have been obtained with 15 J flashlamp pulses.

Influence of synthesis conditions on optical losses in aluminoborophosphate laser glass

The influence of the duration of melting, the purity of the reagents used for synthesis, and the material of crucibles on the optical losses in laser neodymium high-strength aluminoborophosphate glass has been investigated. The obtained results have demonstrated that the main reason of emerging of optical losses at the lasing wavelength in the glass under study is the interaction of the crucible material with the aluminoborophosphate melt which is aggressive at a synthesis temperature of 1350°C.