Low-frequency vibrational excitations in a niobium-phosphate glass for Raman gain applications

    Authors

    A. Schulte; Y. Guo; W. Schirmacher; T. Unruh;T. Cardinal

    Comments

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    Abbreviated Journal Title

    Vib. Spectrosc.

    Keywords

    Raman spectroscopy; Boson peak; Raman gain; neutron scattering; INELASTIC NEUTRON-SCATTERING; AMORPHOUS SOLIDS; BOSON PEAK; DENSITY; SYSTEMS; SILICA; STATES; MODEL; Chemistry, Analytical; Chemistry, Physical; Spectroscopy

    Abstract

    Raman gain for all-optical amplification depends significantly on the cross section for spontaneous Raman scattering. We present measurements of the Raman spectrum of binary niobium-phosphate glasses in the frequency range from 5 to 1300 cm(-1). The spectra of these glasses show a low-frequency enhancement of the vibrational density of states ('Boson peak') suggesting a significant gain profile for application in Raman amplifiers as well as providing an additional mechanism for Raman gain. To separate the effects of density of states from the light-vibration coupling we carried out an inelastic neutron scattering investigation of 40Nb(2)O(5)-60NaPO(3) using the time-of-flight spectrometer (TOFrOF) at the FRM II neutron source in Munich. The Boson peak appears between 40 and 70 cm(-1) as an increase of the reduced density of states over the flat Debye approximation. Possible mechanisms contributing to the low-frequency excitations such as disorder-induced irregular vibrational states are discussed. (C) 2008 Elsevier B.V. All rights reserved.

    Journal Title

    Vibrational Spectroscopy

    Volume

    48

    Issue/Number

    1

    Publication Date

    1-1-2008

    Document Type

    Article; Proceedings Paper

    Language

    English

    First Page

    12

    Last Page

    15

    WOS Identifier

    WOS:000259283100004

    ISSN

    0924-2031

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