Ультракороткие импульсы с широким спектром излучения в волоконных лазерах с пассивной синхронизацией мод

On basis of numerical simulation and analytical calculations, the generation of fiber lasers in the regime of stationary ultrashort pulses with an extremely wide radiation spectrum is studied. It is shown that the spectral width of the generated pulses can be several times greater than the gain bandwidth of the laser active medium.

Sm3+-Doped Molybdenum Gadolinium Borate Glasses for Orange Emission Laser Active Medium

Room temperature visible and near infrared optical absorption and emission spectra of Sm3+-doped molybdenum gadolinium borate (MGB) glasses with molar composition 25MoO3-20Gd2O3–(55 − x)B2O3−xSm2O3 (x = 0.05, 0.1, 0.5, 1.0, 2.0 mol.%) have been analyzed. The experimental oscillator strengths of absorption bands have been used to determine the Judd–Ofelt (J–O) parameters. Fluorescence spectra were recorded by exciting the samples at 402 nm. Using the J–O parameters and luminescence data, the radiative transition probabilities (AR), branching ratios (BR), and stimulated emission cross-sections oe) are obtained. The decay curves of the 4G5/2 - 6H7/2 transition exhibit a non-exponential curve fit for all concen-trations. The concentration quenching has been attributed to the energy transfer through the cross-relaxation between Sm3+ ions. 4G5/2 level and its relative quantum efficiencies are measured. Intense reddish-orange emission corresponding to the 4G5/2−6H7/2 transition has been observed in these glasses at the 487-nm excitation, From the values of the radiative parameters, it is concluded that the 1.0-mol% Sm3+-doped MGB glass may be used as a laser active medium with the emission wavelength at 599 nm. The analysis of the non-exponential behavior of decay curves through the Inokuti–Hirayama model indicates that the energy transfer between Sm3+ ions is of dipole–dipole type. The quantum efficiency for the 4G5/2 level of MGBSm10 glass is found to be 67%. The co-related color temperature obtained from CIE (Commission International de L’Eclairage) for these glass samples is ∼1620 K for the indicated orange emission at the 402-nm excitation.

Influence of nitrogen on CO-laser characteristics

The role of the addition of nitrogen to the discharge plasma of CO lasers on plasma-chemical processes is discussed here. It is shown that nitrogen addition improves laser characteristics and changes the composition of the laser active medium. A reduction of CO highly-excited vibrational-states populations with current is smaller in the case of mixtures with nitrogen additions. The addition of nitrogen significantly decreases CO dissociation level and concentrations of C atoms created in plasma-chemical reactions of laser discharge. Full Text: PDF ReferencesG.M. Grigorian and I.V. Kochetov, "Balance of CO molecules in the plasma of a sealed-off CO laser", Plasma Phys. Rep. 30, 788 (2004). CrossRef V.S. Aleinikov and V.I. Masychev, CO Lasers (Moscow, Radio i Svyaz' 1990).A. Cenian, A. Chernukho, V. Borodin and G.Śliwiński, "Modeling of Plasma-Chemical Reactions in Gas Mixture of CO2 Lasers I. Gas Decomposition in Pure CO2 Glow Discharge", Contr. Plasma Phys. 34, 25 (1994). CrossRef A. Cenian, A. Chernukho, V. Borodin, "Modeling of Plasma-Chemical Reactions in Gas Mixture of CO2 lasers. II. Theoretical Model and its Verification", Contrib. Plasma Phys. 35, 273 (1995). CrossRef A. Cenian, A. Chernukho, P. Kukiełło, R. Zaremba, V. Borodin and G. Śliwiński, "Improvement of self-regeneration of gas mixtures in a convection-cooled 1.2 kW laser", J.Phys. D: Appl.Phys. 30, 1103 (1997). CrossRef E.A. Trubacheev, Trudy FIAN 102, 3 (1977).G.M. Grigorian, B.M. Dymshits and Yu.Z. Ionikh, "Influence of oxygen on the parameters of the active medium in an electric-discharge CO laser", Sov J Quant Electron 19, 889 (1989). CrossRef V.N. Ochkin, S.Yu. Savinov, N.N. Sobolev and E.A. Trubacheev, Kvant. Elektr. 1, 573 (1974).

Influence of nitrogen on thermodynamic properties and plasma composition in discharge tube of CO-laser

The role of the addition of nitrogen to the discharge plasma of CO lasers on thermodynamic properties and composition of the laser active medium is discussed here. It is shown that nitrogen addition improves laser characteristics and changes the composition of the laser active medium. The addition of nitrogen significantly decreases CO dissociation level and concentrations of C atoms created in plasma-chemical reactions of laser discharge.

Laser Effect on Spherical Nanoparticles with Thin Surface Layer

It is shown that metal nanoparticles with thin atomic surface layer can be used as laser active medium. Significant narrowing of the emission band in the spectrum of the particle with a surface layer was found.