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An erbium-doped Lu3Ga5O12(LuGG) single crystal was grown by the Czochralski method. The crystalline phase in the grown crystal was analyzed by powder X-ray diffraction. The erbium-ion emission spectra of the crystal were acquired. The erbium-ion emission cross-section (ECS) spectrum was computed from the acquired emission spectrum. The erbium-ion absorption cross-section (ACS) spectrum was computed using the McCumber relationship. The results are discussed in contrast to those computed from the acquired absorption spectrum, and the comparison shows that both methods give consistent results. The temporal characteristics of the emissions were also studied based on 0.98 μm pulse pumping. The study shows that the infrared emissions at 1.0, 1.5, and 2.8 μm show mono-exponentially temporal behavior. Instead, the decays of two visible emissions at 0.56 and 0.67 μm show considerable non-exponential features; each trace can be fitted double-exponentially. The non-exponential behavior is associated with those erbium ions that are present in the form of clusters, which enables non-radiative upconversion depopulation and hence additional contribution to the decay through cross relaxation between the erbium ions in clusters. The study also shows that about half of the erbium ions are present in the cluster state in the studied crystal. [ABSTRACT FROM AUTHOR]

Fluorescence and absorption spectra at 530 nm (2H11/2→4I15/2), 560 nm (4S3/2→4I15/2), 660 nm (4F9/2→4I15/2), 980 nm (4I11/2→4I15/2), 1530 nm (4I13/2→4I15/2), and 2710 nm (4I11/2→4I13/2) of Er3+ in Gd3Ga5O12 single‐crystal codoped with Pr3+ have been measured. Judd‐Ofelt analysis yields the intensity parameters Ω2 = (0.68 ± 0.03) × 10−20 cm2, Ω4 = (0.60 ± 0.07) × 10−20 cm2, and Ω6 = (0.90 ± 0.17) × 10−20 cm2. A comparison with previously reported values of Er3+‐only doping case shows that Pr3+‐codoping causes slight change of both Ω2 and Ω4, while onefold increase of Ω6. From calculated radiative rates and measured fluorescence spectra, Er3+ emission cross‐section spectra were calibrated at first. Then, the absorption cross‐section spectra were calculated using McCumber relation. In parallel, the absorption cross‐section spectra were also obtained from the measured absorption spectrum, and compared with those obtained from the McCumber relation. The comparison shows that both methods give consistent result of absorption cross‐section spectrum. Further comparison with Er3+‐only doping case shows that Pr3+‐codoping causes considerable change of Er3+ cross‐section value. In spectrally mixing regions of Er3+ and Pr3+, Pr3+ emission affects little the determination of Er3+ emission cross‐section as Pr3+ fluorescence is much weaker than Er3+ fluorescence due to low Pr3+ concentration. [ABSTRACT FROM AUTHOR]

Er3+‐doped strontium gadolinium gallium garnet (SrGdGa3O7) single‐crystal was grown by Czochralski method. The Er3+ concentration in the crystal was determined as 4.2 × 1021 ions/cm3 by inductively coupled plasma atomic absorption spectroscopy. Refractive index of the crystal was measured at the wavelengths of 633, 1311 and 1553 nm by prism coupling technique. The results show that the crystal is a positive uniaxial crystal with a birefringence of ~0.01, and the Sellmeier equation reported previously for the crystal doped with Nd3+ is also valid for the one doped with Er3+. Unpolarized absorption spectrum of the crystal was measured at room temperature and the Er3+ absorption cross‐section spectrum was calibrated from it. The Er3+ spectroscopic properties were studied by Judd‐Ofelt theory. Some fundamental spectroscopic parameters were obtained that include absorption coefficient and cross‐section spectral distributions, electronic transition oscillator strength, Judd‐Ofelt parameters, fluorescence branch ratio, transition probability, radiative and fluorescence lifetimes, and quantum efficiency. [ABSTRACT FROM AUTHOR]

The mutual influence of co-diffused Ti and Sc in LiNbO single-crystal was studied. Sc/Ti co-doped LN plates were prepared by annealing (at 1060 °C in wet O) Z-cut congruent LiNbO substrates coated with stacked ScO and Ti films, which have different thicknesses and coating sequences. After the annealing, the refractive index and composition at the undoped and Sc-only doped surface parts were characterized by prism coupling technique. The Sc and Ti profiles were analyzed by secondary ion mass spectrometry. The results show that the Sc-doping has little contribution to the LiNbO refractive index. LiO out-diffusion is not measurable. In the only diffusion case, the Sc diffuses five times slower than the Ti. In the Sc/Ti co-diffusion case, the Ti assists and controls the Sc diffusion. The Sc diffusivity increases linearly with the initial Ti-metal thickness. In contrast, the Sc affects the Ti diffusion little. Neither the ScO film thickness nor the coating sequence influences the diffusivity of the two ions. The co-diffusion features are explained. A model for the co-diffusion system is suggested and verified experimentally. The Ti:Sc:LiNbO planar and strip waveguide are optically characterized. The results show that the Sc presence does not affect the waveguide characteristics and the waveguide is optical-damage-resistant. [ABSTRACT FROM AUTHOR]

Abstract Optical and spectroscopic properties of Er3+/Pr3+-codoped Gd 3 Ga 5 O 12 single-crystal grown by Czochralski method have been studied. Absorption spectrum of the crystal was measured at room temperature and Er3+ absorption cross-section spectral distributions were calibrated from it. The Er3+ spectroscopic properties were analyzed on the basis of the Judd-Ofelt theory. Fundamental spectroscopic parameters were obtained that include absorption coefficient, cross-section spectral distribution, electronic transition oscillator strength, Judd-Ofelt parameters, fluorescence branch ratio, transition probability, radiative and fluorescence lifetimes, and quantum efficiency as well. Study shows that Pr3+-codoping results in substantial change of Er3+ spectroscopic properties, in qualitative consistent with the previous fluorescence studying result. In addition, refractive index of the crystal was measured at different wavelengths using prism coupling method, and the Sellmeier equation reported previously for Er3+-only doped Gd 3 Ga 5 O 12 crystal is corrected. Highlights • Juud-Ofelt spectroscopic properties of Er3+/Pr3+:Gd 3 Ga 5 O 12 crystal were studied. • Pr codoping results in substantial increase of the Judd-Ofelt parameters. • Pr codoping induces shortening of Er3+ 2.7 and 1.5 μm lifetimes from ms to sub-ms. • The effect is related to two resonant energy transfers from Er3+ to Pr3+. • Different efficiencies of the two transfers enable to realize 2.7 μm lasing. [ABSTRACT FROM AUTHOR]