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Anisotropic Optical-Response of Eu-doped Yttrium OrthosilicateEu-doped yttrium orthosilicate (Eu(3+) : Y2SiO5) had been a subject being investigated for coherent time-domain optical memory and information processing applications since its ultraslow optical dephasing was discovered several years ago. In this crystal the weakly allowed (7)F0 - (5)D0 transition of europium ions exhibits a sufficient long dephasing time and no spectral difli.usion on a time scale of several hours at low temperature, thus an information pattern or data can be stored as a population grating in the ground state hyperfine levels. On the other hand, the study on photon-echo relaxation shows that the dephasing time T2 of Eu (3+) and other rare-earth ions doped YAG, YAlO3 strongly depends on the intensity of the excitation pulses. In Eu (3+) :YAlO3, an exponential decay of photon-echo with T2 = 53 microseconds if the excitation pulses are weak (5 vJ/pulse) was observed. However, when the excitation pulses are strong (80 pJ/pulse) they observed a much shortened T2 with a highly nonexponential decay pattern. The conclusion they derived is that the intensity-dependent dephasing rate effects are quite general, and it depends on how much the excitation intensity varies. In this paper we use transient grating formation technique showing that a temporal lattice distortion may only occur along crystal c axis, caused by EU (3+) excitation. At high excitation level the produced exciton in conduction band may also couple to the dynamical lattice relaxation process, giving rise to an apparently much shortened dephasing time.
Document ID
20000032310
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Liu, Huimin
(Puerto Rico Univ. Mayaguez, Puerto Rico)
Santiago, Miguel
(Puerto Rico Univ. Mayaguez, Puerto Rico)
Jia, Weiyi
(Puerto Rico Univ. Mayaguez, Puerto Rico)
Zhang, Shoudu
(Academia Sinica Shanghai, China)
Date Acquired
August 19, 2013
Publication Date
February 22, 1998
Publication Information
Publication: NASA University Research Centers Technical Advances in Aeronautics, Space Sciences and Technology, Earth Systems Sciences, Global Hydrology, and Education
Volume: 2 and 3
Subject Category
Optics
Report/Patent Number
98URC151
Funding Number(s)
CONTRACT_GRANT: NCCW-88
CONTRACT_GRANT: NSF EHR-91-08775
CONTRACT_GRANT: DE-FRO2-94ER-757640
CONTRACT_GRANT: DAAH04-96-1-0416
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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