Influence of Lu content on (LuxGd1-x)2SiO5 oxyorthosilicates grown by Laser Floating Zone: Structural studies and transparency

Laser Floating Zone: General Overview Focusing on the Oxyorthosilicates Growth

“…Regarding structural properties, the silicates having the formula RE 2 SiO 5 are all monoclinic, presenting P2 1 /c (Gd 2 SiO 5 , [18]) or C2/c (Lu 2 SiO 5 , [45]) space groups depending on the rare earth ions present (Figure 3) [46,51]. This structure provokes their biaxial character that compromises their crystallization, resulting in internal crack formation when LFZ processing is carried out in air and the cooling is not gradually performed [18,47].…”

“…It should be noted Following the structural overview about oxyorthosilicates, the Raman spectroscopy analysis can be divided in two groups or families considering the total number of vibrational modes together with the shape of the high frequency region. Thus, assuming the Voron'ko et al [8] notation, oxyorthosilicates can be distinguished among A-type and B-type silicates depending on whether a triplet or a doublet, respectively, appears inside the (ν 1 + ν 3 ) region [8,9,18,[45][46][47]. This way, the Raman spectra can be divided in four vibrational regions denoted as ν 3 , (ν 1 + ν 3 ), ν 4 and ν ext + ν 2 ( Figure 5) [8].…”

“…Furthermore, other approaches for oxyorthosilicates production have been employed during the last years using different methods, like pulsed laser deposition [42], sol-gel [43] or solid-state diffusional process [44]. On the other hand, their production by the LFZ technique is more recent [18,[45][46][47]; besides, there are two experiments performed in the 1980s decade by de la Fuente et al [33] and Black et al [34], who produced GdNdSiO 5 and 7Gd 2 O 3 •9SiO 2 :Nd materials applying a high laser power (~185 W).…”

“…Aiming to develop new laser materials, Rey-García et al [18,46,47] have recently produced a sort of gadolinium-lutetium oxyorthosilicate materials at low laser powers (<100 W) and pulling rates two to three times faster than those used by Czochralski or other standard methods (1-3 mm h −1 ). Thus, transparent fibers of Gd 2 SiO 5 [18], (Gd 0.3 Lu 0.7 ) 2 SiO 5 [46] and 5 mol% Y 3+ :(Gd 0.3 Lu 0.7 ) 2 SiO 5 [47] have been obtained at 10 mm h −1 in air under atmospheric pressure presenting high crystallinity degree.…”

“…Aiming to develop new laser materials, Rey-García et al [18,46,47] have recently produced a sort of gadolinium-lutetium oxyorthosilicate materials at low laser powers (<100 W) and pulling rates two to three times faster than those used by Czochralski or other standard methods (1-3 mm h −1 ). Thus, transparent fibers of Gd 2 SiO 5 [18], (Gd 0.3 Lu 0.7 ) 2 SiO 5 [46] and 5 mol% Y 3+ :(Gd 0.3 Lu 0.7 ) 2 SiO 5 [47] have been obtained at 10 mm h −1 in air under atmospheric pressure presenting high crystallinity degree. These single crystals present excellent photonic properties that make them useful to be employed as laser host materials due to the Gd 3+ charger transfer band (CTB) that favors the transfer processes with 4f 7 transitions from the 8 S 7/2 ground state to energy levels of the dopant element [48][49][50].…”