Superior photoluminescence (PL) of Pr^3+-In, compared to Pr^3+-Ga, selenide-chalcogenide bulk glasses and PL of optically-clad fiber

Abstract

The photoluminescent-(PL)-properties of Pr³⁺-ions in indium-containing selenide-chalcogenide bulk-glasses are found to be superior when compared with gallium-containing analogues. We observe circa doubling of mid-infrared (MIR) PL intensity from 3.5 to 6 μm for bulk glasses, pumped at 1.55 μm wavelength, and an increased excited state lifetime at 4.7 μm. PL is reported in optically-clad fiber. Ga addition is well known to enhance RE³⁺ solubility and PL behavior, and is believed to form ([RE³⁺]-Se-[Ga(III)]) in the glasses. Indium has the same outer electronic-structure as gallium for solvating the RE-ions. Moreover, indium is heavier and promotes lower phonon energy locally around the RE-ion, thereby enhancing the RE-ion PL behavior, as observed here.

Promising emission behavior in Pr 3+ /In selenide-chalcogenide-glass small-core step index fiber (SIF)

“…Plotted for each of (a) and (b) are the output pump-power collected from the opposite fiber end to that pumped (blue solid squares), and fluorescent-intensity at 4.7 µm collected from the same fiber-end as that pumped (black solid squares) (see Fig.3(c)), plotted as a function of the incident input pump-power. Fig.1(ii) and (ii), respectively) at 4.7 m wavelength, when pumping at 1.55 m or 2.013 m compared to 'Pr 3+ /In bulk-glass' from prior work [25].…”

“…From Table 1, the Pr 3+ fluorescent-lifetime at 4.7 m in the presence of an In solubilizer tends to decrease from bulk glass (10.1 ± 0.3 ms) [25], to intermediate fiber ( Below, we argue that the decrease in Pr 3+ fluorescent-lifetime in the presence of an In solubilizer goes hand-in-hand with an increase in the cumulative-processing required to prepare each type of sample.…”

“…Fig.1(b)) and (c) undoped cladding-tube (section 2.2(a) and Fig.1(ii)). Fig.1(i)), which underwent glass-distillation, compared to a Pr 3+ /In large-core intermediate SIF, from previous work [25] ( core /cladding = 498 ppmw Pr 3+ -Ge-As-In-Se / Ge-As-In-Se (fiber OD = 270 ± 30 μm; core diameter = 80-85% fiber OD). Fig.1(ii)) across 3.5-6 µm, when end-pumped at 2.013 µm / 25 mW, with emission collected from the same fiber-end as that pumped (as Fig.…”

“…9. Normalized fluorescence-emission at 3.5-6 µm: (a) prior work: bulk glass (531 ppmw Pr 3+ -Ge-As-InSe) with orthogonal pump (1.55 µm/50.2 mW), fluorescent-emission collection across a sharp corner [25]; (b) 20 µm core-diameter 'Pr 3+ /In small-core SIF' (section 2.2, Fig.1(ii)) end-pumped at 2.013 µm /25 mW with fluorescent-emission collection from same fiber-end as pumped (cf. Fig.…”

“…3(c); (c) from prior work [25]: Pr 3+ /In large-core intermediate SIF (core/cladding = 498 ppmw Pr 3+ -Ge-As-In-Se/Ge-As-In-Se (fiber OD: 270 ± 30 μm, 80-85% core-diameter)) end-pumped at 1.55 µm/50.84 mW with fluorescent-emission collection at side of fiber (Fig. 3(b) and (d) fiber same as (c) [25], but end-pumped, at 1.55 µm / 24.5 mW with fluorescent-emission collection at opposite end of fiber to that pumped ( Fig. 3(a).…”