VUV-UV 5d-4f interconfigurational transitions of Nd3+ in BaMgF4 ferroelectric crystals

BaMgF4 single crystals doped with Nd3+ are of great interest as possible active media for VUV-UV and mid-IR all solid-state lasers. The luminescence spectroscopy and the excited state dynamics of these crystals are investigated for the first time upon VUV excitation using synchrotron radiation. The material shows fast Nd3+ 5d-4f emission upon direct VUV excitation into Nd3+ 5d levels. The decay kinetics of the Nd 3+ 5d-4f emission in this host lattice upon direct VUV excitation of 5d levels is characterized by a lifetime of about 14 ns with no significant rise after the excitation pulse. No significant temperature dependence of the lifetime is observed within the range 8-300 K. © 2014 Elsevier B.V

Spectroscopic study of Yb3+ centres in the YAl3(BO3)4 nonlinear laser crystal

A spectroscopic study of Yb3+ ions in YAl3(BO3)(4) laser crystals is presented. Polarized absorption and site selective spectroscopy experiments at low temperature have been used to determine the presence of two different Yb3+ centres in this host crystal in the concentration range 0.2-9 at.%. The contribution of these centres to the absorption spectra has been found to be dependent on the total Yb3+ concentration, and the Stark energy level diagrams corresponding to the different Yb3+ centres have been determined. The importance of electron-phonon coupling, in the optical transitions of Yb3+ ions has been also pointed out

Yb3+ sites in YAl3(BO3)4 nonlinear crystals

In this work the optical properties of Yb:YAl3(BO3)(4) have been studied for a concentration of 2 at %. The low temperature polarized absorption and emission spectra, together with site selective spectroscopy, show the presence of different Yb3+ sites in the YAB crystal host

Thermal lens and heat generation of Nd : YAG lasers operating at 1.064 and 1.34 mu m

We report on a simple and accurate method for determination of thermo-optical and spectroscopic parameters (thermal diffusivity, temperature coefficient of the optical path length change, pump and fluorescence quantum efficiencies, thermal loading, thermal lens focal length, etc) of relevance in the thermal lensing of end-pumped neodymium lasers operating at 1.06- and 1.3-mu m channels. The comparison between thermal lensing observed in presence and absence of laser oscillation has been used to elucidate and evaluate the contribution of quantum efficiency and excited sate absorption processes to the thermal loading of Nd: YAG lasers. (c) 2008 Optical Society of America

Thermal hysteresis in the luminescence of Yb3+ ions in Sr0.6Ba0.4Nb2O6

The optical spectra of Yb(3+) ions in congruent, Sr(0.6)Ba(0.4)Nb(2)O(6) (SBN) crystals have been systematically investigated in a broad temperature range (10-420 K). Laser site selective low temperature fluorescence spectra have shown that Yb(3+) ions enter in four different cationic lattice sites. A thermal hysteresis in both bandwidth and luminescence intensity of Yb(3+) ions has been detected in the temperature range (300-400 K) around the ferro to paraelectric phase transition. This behavior has been explained as a result of the local structural modifications that take place around the Yb(3+) ions when the crystal becomes nonpolar, which affect in a different way the luminescence of Yb(3+) ions located in the different sites. Off-congruent SBN crystals activated with Yb(3+) ions have been grown and investigated in order to examine the possibilities of extending the detected hysteretic behavior to other temperature ranges