Using continuous and time-resolved spectroscopy, we investigate Raman and luminescence signals from synthetic hydroxylapatites doped with trivalent REE including Dy3+, Eu3+, Nd3+, and Sm3+, as well as REE in natural apatites, with laser excitations at 532 and 785 nm. We demonstrate that time-resolved spectroscopy is an efficient method to reduce luminescence from Raman spectra or, alternatively, to investigate the luminescence signals without interference from the Raman contribution. Time-resolved luminescence spectroscopy is a powerful technique for generating specific high-quality luminescence spectra for the REE emission activators in apatites by using appropriate combinations of delay and gate width for time synchronization of the laser pulse and ICCD detector. This allows the unambiguous detection and identification of the activators by avoiding overlapping of various emission signals in the luminescence spectra. This is particularly useful in the case of natural samples, which often have several activators for luminescence. In the case of synthetic REE-doped apatites, a quenching process for luminescence due to activator concentration is seen for Eu3+ and Sm3+, i.e., the higher the concentration, the shorter the luminescence decay time. The interpretation of luminescence decay time in natural apatites is promising but more complex because of energy transfers between the various luminescence activators present in the crystal lattice. Luminescence is a powerful technique for detecting the presence of REE in apatites down to parts per million levels, though quantifying the concentration is still a challenge.

中文翻译：

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合成稀土掺杂羟基磷灰石和天然磷灰石的时间分辨拉曼和发光光谱

使用连续和时间分辨光谱，我们研究了掺杂三价 REE（包括 Dy3+、Eu3+、Nd3+ 和 Sm3+）以及天然磷灰石中的 REE 的合成羟基磷灰石的拉曼和发光信号，激光激发波长为 532 和 785 nm。我们证明时间分辨光谱是减少拉曼光谱发光的有效方法，或者，在不受拉曼贡献干扰的情况下研究发光信号。时间分辨发光光谱是一种强大的技术，通过使用延迟和栅极宽度的适当组合来实现激光脉冲和 ICCD 检测器的时间同步，为磷灰石中的 REE 发射活化剂生成特定的高质量发光光谱。这允许通过避免发光光谱中各种发射信号的重叠来明确检测和识别活化剂。这在天然样品的情况下特别有用，天然样品通常具有多种发光激活剂。在合成稀土掺杂磷灰石的情况下，Eu3+ 和Sm3+ 的活化剂浓度导致发光的猝灭过程，即浓度越高，发光衰减时间越短。由于晶格中存在的各种发光激活剂之间的能量转移，天然磷灰石中发光衰减时间的解释是有希望的，但更复杂。发光是一种强大的技术，可以检测磷灰石中 REE 的含量低至百万分之几的水平，