Spectroscopy and upconversion ofCsCdBr3:Pr3+

Abstract

In CsCdBr3 the trivalent Pr ions substitute the divalent Cd ions. Charge compensation leads to Pr vacancy centers. By selective excitation and fluorescence spectroscopy and by annealing the crystals, three different Pr centers could be identified. The first one is the well-known symmetric pair center Pr'+-Cd + vacancy-Pr'+, the second one is the asymmetric pseudopair center Pr'+-Pr +-Cd + vacancy, and the third one finally is a Pr'+ single ion with a Cs+ vacancy nearby. Energy-level schemes of all three centers were deduced from polarized site-selective spectra including the symmetries of the crystalfield states. Only the Pr'+-Pr'+-Cd'+ vacancy center showed upconversion emission from 'Po and 'P, under pulsed 'D2 excitation.keeping in mind that the highest phonon frequencies in CsCdBr3 are of the order of 160 cm ' (Ref. 18) or, maybe, 200 cm ' because the crystal consists of heavy ions only. Doping with 1% Pr + did not change the known Raman spectra' as found experimentally. ' Therefore we ' proposed another process to be responsible for the upconversion: cooperative energy transfer

High-resolution infrared absorption spectra, crystal-field levels, and relaxation processes inCsCdBr3:Pr3+

“…In particular, symmetries of the third ( 2 Γ 3 ) and fourth (Γ 1 ) sublevels of the 3 H 5 multiplet and of the second ( 1 Γ 3 ) and third (Γ 2 ) sublevels of the ground 3 H 4 multiplet are inverted in [2,8] (it should be noted that our scheme of crystal field energies of the ground state agrees with the assignment of Ref. [4]). Additional measurements of polarized spectra are to be carried out to check our predictions.…”

“…1 shows low temperature transmittance spectra of CsCdBr 3 :Pr 3+ (0.2 %) corresponding to different infrared transitions. The first excited state of the ground multiplet 3 H 4 lies at about 170 cm −1 [1][2][3][4] and is not populated at helium temperatures. So, low temperature absorption spectra display crystal field levels of the excited multiplets directly.…”

“…This makes them a promising material for up-conversion lasers. The structure of CsCdBr 3 belongs to the D were intensively studied before [1][2][3][4][5], crystal field energies of the lowest excited multiplets were not investigated in absorption. The positions of crystal field levels for the main center, as reported by different authors, differ by 2-14 cm −1 .…”

Rare-Earth-Doped Low Phonon Energy Halide Crystals for Mid-Infrared Laser Sources

“…In the near future, such systems will also be pumped at 4.6 m by means of high power quantum cascade laser (QCL) diodes for the emission at 5 m from the 3 H 5 level, particularly in KPb 2 Cl 5 because the pumping strategy involving ETU seems more favourable than in CsCdBr 3 , not only because of lower phonon energies but also because the one dimensional crystal structure of the latter compounds favours ion pairing of Pr 3+ [Amedzake et al, 2008;An & May, 2006;Balda et al, 2002Balda et al, , 2003Bluiett et al, 2008;Chukalina, 2004;Ferrier et al, 2009aFerrier et al, , 2009bGafurov et al, 2002;Guillot-Noël et al, 2004;Neukum et al, 1994;Rana & Kaseta, 1983]. Absorption and emission spectra recorded as a function of temperature at low temperature (10-50 K) over a broad spectral range allows for the determination of Pr 3+ ions crystal field sublevels dissolved in KPb 2 Cl 5 , and to match them with the eigenvalues of a parameterized crystal field model hamiltonian taking into account 74 sublevels of the 12 first multiplets.…”

“…Table 1. Laser-related crystallographic, thermal, mechanical, optical and spectroscopical properties of selected low phonon energy halide crystals [Aleksandrov et al, 2005;Atuchin et al, 2011;Cockroft et al, 1992;Doualan & Moncorgé, 2003;Ferrier et al, 2006aFerrier et al, , 2007Ferrier et al, , 2008aFerrier et al, , 2008bFerrier et al, , 2009aFerrier et al, , 2009bHeber et al, 2001;Isaenko et al, 2008Isaenko et al, , 2009aIsaenko et al, , 2009bMalkin et al, 2001;Mel'nikova et al, 2005;Merkulov et al, 2005;Neukum et al, 1994;Nostrand et al, 2001;Okhrimchuk et al, 2006;Popova et al, 2001;Quagliano et al, 1996;Ren et al, 2003;Singh et al, 2005;Velázquez et al, 2006aVelázquez et al, , 2006bVirey et al, 1998;Vtyurin et al, 2004Vtyurin et al, , 2006. (*) per lead type of crystallographic site.…”