0000000000754716
AUTHOR
Alfons Schulte
showing 3 related works from this author
Inelastic neutron and low-frequency Raman scattering in niobium-phosphate glasses: the role of spatially fluctuating elastic and elasto-optic constan…
2011
We investigate the low-frequency enhancement of vibrational excitations ('boson peak') in niobium-phosphate glasses through the combination of inelastic neutron and polarization-resolved Raman scattering. The spectra of these glasses reveal an enhancement of the vibrational density of states and of the cross section for spontaneous Raman scattering in the frequency range below 150?cm ? 1. A recent theoretical model that is based on fluctuating elastic and elasto-optic (Pockels) constants provides a unified description of the measured neutron and Raman spectra, including the depolarization ratio.
Rayleigh and Brillouin scattering in a lysozyme–water mixture: An unusual behavior around 343K
2011
Abstract This article describes Rayleigh and Brillouin light scattering studies on a lysozyme–water mixture from 293 K to 355 K. The scattering intensities from this system are compared with those from a sodium acetate buffer used to dissolve the lysozyme. It is found that in the vicinity of 343 K the lysozyme–water mixture becomes opalescent, and the intensity of the Brillouin peaks decreases and almost vanishes, to be restored at temperatures above 343 K. Around the same temperature the intensity of the central, unshifted Rayleigh peak, however, increases strongly. No such behavior was observed for the sodium acetate buffer. The analysis of the experimental data indicates an irreversible …
Inelastic neutron and low-frequency Raman scattering in a niobium-phosphate glass for Raman gain applications
2011
Abstract We present measurements of the vibrational spectrum of a binary niobium-phosphate glass in the THz frequency range using inelastic neutron and Raman scattering. The spectra of these glasses show a low-frequency enhancement of the vibrational density of states (“boson peak”). Using a recently developed theory of vibrational excitations in disordered solids we are able to reconcile the measured neutron and Raman spectra using fluctuating elastic and Pockels constants as a model concept. As the spontaneous Raman susceptibility is a key parameter for Raman amplification our results suggest a significant gain profile for application of niobium-phosphate glasses in Raman amplifiers.