Chemical pressure effects on the spectroscopic properties of Nd3+-doped gallium nano-garnets

[EN] Nd3+-doped RE3Ga5O12 (RE = Gd, Y, and Lu) nano-crystalline garnets of 40-45 nm in size have been synthesized by a sol-gel method. With the decrease of the RE atom size, the chemical pressure related to the decreasing volumes of the GaO4 tetrahedral, GaO6 octahedral and REO8 dodecahedral units drive the nano-garnets toward a more compacted structure, which is evidenced by the change of the vibrational phonon mode frequencies. The chemical pressure also increases the crystal-field strength felt by the RE3+ ions while decreases the orthorhombic distortion of the REO8 local environment. These effects alter the absorption and emission properties of the Nd3+ ion measured in the near-infrared luminescence range from 0.87 to 1.43 ¿m associated with the 4 F3/2¿4 IJ (J = 9/2, 11/2, 13/2) transitions. The 4 F3/2 luminescence decay curves show non-exponential behavior due to dipole-dipole energy transfer interactions among Nd3+ ions that increases with pressure.Authors are grateful to The Governments of Spain and India for the Indo-Spanish Joint Programme of Bilateral Cooperation in Science and Technology (PRI-PIBIN-2011-1153/DST-INT-Spain-P-38-11). Dr. Venkatramu is grateful to DAE-BRNS, Government of India for the award of DAE Research Award for Young Scientist (No. 2010/20/34/5/BRNS/2223). This work have been partially supported by MINECO under The National Program of Materials (MAT2013-46649-C4-2-P/-3-P/-4-P), The Consolider-Ingenio 2010 Program (MALTA CSD2007-00045), by Fundacion CajaCanarias (ENER-01), and by the EU-FEDER funds. V. Monteseguro wishes to thank MICINN for the FPI grant (BES-2011-044596). 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An efficient synthesis of 2,5-diaryl-1,3,4-oxadiazoles

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Engineering of TeO2-ZnO-BaO-Based Glasses for Mid-Infrared Transmitting Optics

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