Concentration depolarization and concentration quenching of fluorescence under saturation of excited states

V. T. Koyava, Владимир Иванович Попечиц, A. M. Sarzhevskii

Edward H. Piepmeier

Anatoly I. Burshtein

Liliana O. Martínez-Martínez, E. Hernández-Hernández, Serguei I. Stepanov

Depolarization of the fluorescence excited at 1492, 1526, and 1568nm in EDF with concentrations 600-5600ppm proved to be in good qualitative agreement with earlier reported reduction in population gratings recorded via saturation of absorption.

Nikolay V Znamenskiy, Eduard A. Manykin, Yurii V Orlov +6 more

Anti-Stokes fluorescence from the 3 P 0 level of impurity ions was detected in Pr 3+ : Y 2 SiO 5 , Pr 3+ : Lu 2 SiO 5 , and Pr 3+ : Gd 2 SiO 5 crystals non-resonantly pumped by laser radiation with a certain power density. The integrated intensity of the anti-Stokes fluorescence depends nonlinearly on the pump power density. As the atomic concentration of impurity ions was increased from 0.3% to 0.6% and 1.8%, the anti-Stokes fluorescence intensity was saturated due to the concentration quenching of the 1 D 2 term of the impurity Pr 3+ ions. The anti-Stokes fluorescence and quenching of the 1 D 2 term occur due to the cross relaxation of the electronic energy of excited terms of the Pr 3+ ions.

E. Hernández-Hernández, Liliana O. Martínez-Martínez, Serguei I. Stepanov

In this paper we analyze the influence of a spatial migration of the excited states on suppression of the population gratings recorded in erbium-doped optical fibers (EDF). Such dynamic Bragg gratings are formed via saturation of the optical transition between the fundamental and the meta-stable states of the active ions and are observed experimentally via transient two wave mixing (TWM) of the phase-modulated counter-propagating recording waves. The reported experiments were performed in the spectral range 1492-1568nm, which covers the absorption region of the fundamental transition 4I15/2→4I13/2 of Er3+ ions. Significantly stronger grating suppression is observed at the central/long-wavelength regions of the above-mentioned spectral region. A set of similar fibers with essentially different Er3+ ions concentrations with maximum attenuation of 4, 9, 17 and 35 ± 1 dB/m at 1531 nm was investigated and a clear concentration dependence of the grating suppression was observed. The TWM measurements are supported by the original experimental data on the fluorescence depolarization. The observed spectral dependence of the grating reduction factor is explained using the model of the vacant states limited spatial migration of the excitation among the Er3+ ions.