![]() ![]() 12, 22įor the present report, we probed the low-frequency modes of ytterbium-doped ternary aluminoborosilicate glasses through the combined analysis of low-temperature heat capacity, low-frequency Raman scattering, and THz time domain spectroscopy. 20 Elastic heterogeneity is intrinsically related to the intermediate range order, 21 therefore, investigations of the low-frequency vibrations and their interaction with acoustic waves provide a suitable method for examining structural features of glasses on such length scales. 12 It has been established that the spatial variability of elastic properties plays a central role in defining the Bp. 12- 17 It can be traced experimentally through optical spectroscopy techniques such as low-frequency Raman scattering 18 and THz time domain spectroscopy (THz-TDS), 19 but also, for example, via low-temperature specific heat capacity measurements. Most prominently, the so called “Boson peak” (Bp, an excess in the low-frequency VDoS), has gained considerable research interest as a universal feature of glassy materials. In this report, we consider the effect of B 2O 3 additions on the intermediate-scale structural heterogeneity in Al 2O 3-doped silica as a host material for lasing Yb 3+ centers.Īnalyzing the vibrational density of states g( ω) (VDoS) and its low-frequency anomalies provides a means for probing structural heterogeneity. 11 Direct measurements of the intermediate-range structure of glasses remain challenging: the length scales of interest surpass the typical scale of pair distribution analysis, but are still below the capabilities of contemporary analytical imaging methodology. ![]() 2- 4 Due to the experimental difficulties of obtaining homogeneous glasses consisting only of glass-forming oxides, 5- 10 network modifiers are frequently added to the base composition, which facilitate conventional melt-quenching of glass samples, but fundamentally change the chemical behavior of the glass system due to their strong interactions with the network-forming oxides. Despite several studies made in the SiO 2-Al 2O 3-B 2O 3 (SAB) glass system, there are still unanswered questions regarding structure, dynamic features, and mixing of the network-forming cations. ![]() More systematic design strategies require an improved understanding of the specific interactions of minor components within the backbone of vitreous silica. 1 Specific formulations are often found in empirical ways, mostly subject to the constraints of high-purity synthesis routes in terms of achievable dopant levels and material homogeneity. #Boson x crack Activator#g., reducing activator interactions at maximum activator concentration). Additions such as Al 2O 3 or B 2O 3 are used in order to modify the silica backbone towards tailored optical performance ( e. Depending on operation wavelength, they may incorporate a variety of rare-earth activator species such as Yb or Tm ions. Vitreous silica and silica derivatives are benchmark materials for high-power fiber lasers. ![]()
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