Open AccessTerahertz spectra and soft optical phonons of PbB4O7 crystal
Author(s) -
侯碧辉,
菅彦珍,
王雅丽,
张尔攀,
傅佩珍,
汪力,
钟任斌
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.4640
Subject(s) - phonon , crystal (programming language) , polariton , raman spectroscopy , materials science , terahertz radiation , raman scattering , optics , resonance (particle physics) , dispersion (optics) , dielectric , dispersion relation , spectral line , attenuation coefficient , molecular physics , condensed matter physics , physics , atomic physics , optoelectronics , astronomy , computer science , programming language
The terahertz(1012Hz)spectra, Raman spectra and infrared-visible-UV spectra are analyzed for PbB4O7 crystal sample. A resonance peak appears in the curve of the dielectric function ε(ν) in the frequency range of 0.25—2.5 THz. The analysis supports that soft optical phonons exist in PbB4O7 crystal from four aspects: 1) the change curve ε(ν) of the dielectric function satisfies the Lyddane-Sachs-Teller relation; 2) a strong Raman scattering peak appears in the vicinity of resonance frequency (3.10 THz); 3) absorption coefficient curve α(ν) meets the characteristics of polaritons; 4) the dispersion relation curve ν(k) of the photon transmitting from the crystal reveals a frequency gap. The soft optical phonon exists in PbB4O7 crystal, which means that the frequency curve of the photon transmitting from the crystal will suffer splitting when the condition of producing polariton is satisfied. And the dispersion curve splits a higher branch and a lower one. This may help us find a new method of changing the frequency of the photon.