Spectroscopic Analysis of Nd$^{3+}$:Y$_{2}$O$_{3}$ Nanocrystals for Photonic and Biomedical Applications

Spectroscopic properties are investigated for Nd$^{3+}$ in nanocrystalline Nd$^{3+}$:Y$_{2}$O$_{3}$. Room temperature absorption intensities of Nd$^{3+}$(4$f^{3})$ transitions in synthesized Nd$^{3+}$:Y$_{2}$O$_{3}$ nanocrystals have been analyzed using the Judd-Ofelt (J-O) approach in order to obtain the phenomenological intensity parameters. The J-O intensity parameters are used to calculate the spontaneous emission probabilities, radiative lifetimes, and branching ratios of the Nd$^{3+}$ transitions from the upper multiplet manifolds to the corresponding lower-lying multiplet manifolds $^{2S+1}L_{J}$ of Nd$^{3+}$(4$f^{3})$. A comparison between the spectroscopic properties of the Nd$^{3+}$ nanocrystals suspended in epoxy, Chitosan, and 2-hydoxyethyl methacrylate (HEMA) has been performed. This study suggests that synthesized Nd$^{3+}$:Y$_{2}$O$_{3}$ nanocrystals could be an excellent alternative to single-crystal Ho$^{3+}$:Y$_{2}$O$_{3}$ for various photonic applications, in particularly biosensors, when used in the near infrared (0.8 to 0.9 $\mu $m ) region. *This research was supported in part by the National Science Foundation Grant No. DMR-0602649 and the NSF-sponsored CBST at UC Davis under the cooperative agreement No. PHY-0120999.