Crystallization kinetics and enhanced Bi NIR luminescence of transparent silicate glass‐ceramics containing Sr₂YbF₇ nanocrystals

Abstract

Bismuth‐doped glasses and crystals have been widely investigated due to their intriguing potential applications in superbroadband fiber amplifier and lasers in new NIR spectral range. However, few reports have been devoted so far to bismuth‐doped transparent glass‐ceramics. Here, this work reports on bismuth‐doped silicate glasses and glass‐ceramics, which were prepared by melt‐quenching and consequent annealing processes, respectively. On the basis of the analyses on crystallization kinetics, nucleation and growth rate of crystalline phase can be modulated and Sr2YbF7 nanophase can, therefore, be precipitated uniformly inside the glass matrix in a controlled way to maintain proper transparence especially in optical telecommunication windows. Once the nanophase comes into being, enhanced bismuth NIR luminescence can be observed by more than 40 times upon excitation of 470 nm. Similar enhancement can appear upon different excitation schemes and the mechanism is discussed accordingly. Such Bi doped transparent glass‐ceramics with improved luminescence efficiency might find application in fiber lasers for future optical fiber communication.

The origin of the heterogeneous distribution of bismuth in aluminosilicate laser glasses

“…Bismuth (Bi)‐doped silicate glasses and fibers have been garnering more and more interests for their super broadband 1000‐1600 nm near‐infrared (NIR) emission from the 6p electronic configuration of low valence state Bi . This spectra range cannot be fully covered by single rare‐earth ions doped photonic materials . Thus, Bi‐doped glass and fibers offer us a new platform for tunable fiber lasers and super broadband optical amplifier.…”

“…When it comes to the distribution of bismuth, all glass components should be taken into account considering the super sensitive feature of Bi NIR centers to the slight change in local structure . Especially, the influence of aluminum should be paid more attention since it plays a major role in the enhancement of Bi NIR emission and local glass structure, which eventually results in the optical heterogeneities of Bi‐doped glasses.…”

“…When it comes to the distribution of bismuth, all glass components should be taken into account [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] considering the super sensitive feature of Bi NIR centers to the slight change in local structure. [14][15][16][17][18] Especially, the influence of aluminum should be paid more attention since it plays a major role in the enhancement of Bi NIR emission and local glass structure, 7,17,36 which eventually results in the optical heterogeneities of Bi-doped glasses. Yet, up to now, no direct evidence or conclusion is provided to reveal the origin of optical heterogeneity in Bi-doped glass.…”

Predictable tendency of Bi NIR emission in Bi‐doped magnesium aluminosilicate laser glasses

“…Traditional erbium fiber amplifier can work only in a narrow spectral range, [8][9][10][11] i.e., 36 nm in width around 1.53 lm, and it is physically impossible to fully utilize the low loss window of silica fiber such as 1000-1600 nm. 7,[16][17][18] Since bismuth NIR luminescence is known from the outmost 6p electrons, [19][20][21][22][23] it is highly sensitive to the changes of local crystal field bismuth resides. Bismuth [12][13][14][15] doped NIR glasses and fibers recently appeared as a new family of laser materials for this purpose, and they have aroused increasing interests since the beginning of 21st century due to its super broadband luminescence in 1000-1600 nm, and the success in tunable fiber lasers.…”

“…Bismuth [12][13][14][15] doped NIR glasses and fibers recently appeared as a new family of laser materials for this purpose, and they have aroused increasing interests since the beginning of 21st century due to its super broadband luminescence in 1000-1600 nm, and the success in tunable fiber lasers. 7,[16][17][18] Since bismuth NIR luminescence is known from the outmost 6p electrons, [19][20][21][22][23] it is highly sensitive to the changes of local crystal field bismuth resides. Therefore, it becomes very difficult to predict bismuth NIR luminescence.…”