Title

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

Authors

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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