TY - JOUR
T1 - Comparison of Brillouin Light Scattering and Density of States in a Supported Layer
T2 - Analytical and Experimental Study
AU - El Abouti, Ossama
AU - Cuffe, John
AU - El Boudouti, El Houssaine
AU - Sotomayor Torres, Clivia M.
AU - Chavez-Angel, Emigdio
AU - Djafari-Rouhani, Bahram
AU - Alzina, Francesc
N1 - Publisher Copyright:
© 2022 by the authors.
PY - 2022/9
Y1 - 2022/9
N2 - We provide a detailed analytical calculation of the Brillouin light scattering (BLS) intensity of a layer on a substrate, taking into account both photoelastic and moving boundary (ripple effect) mechanisms, and give a comparison between BLS intensity and density of states (DOS) to determine the dispersion curves of longitudinal guided modes in the supported layer. In particular, in the case where the mismatch between the elastic parameters of the substrate and the adsorbed layer is high, such as in a PMMA layer on a Si substrate, we derive closed-form expressions of BLS and DOS and demonstrate a simple relationship between these two quantities. A very good agreement between experimental and theoretical BLS spectra was found and compared to theoretical DOS spectra. In particular, we show that while the peaks in the DOS present a uniform behavior, the BLS spectra follows a sine cardinal (sinc) function shape around a given frequency fixed by the chosen laser wavelength. The theoretical calculation is performed within the framework of the Green’s function approach.
AB - We provide a detailed analytical calculation of the Brillouin light scattering (BLS) intensity of a layer on a substrate, taking into account both photoelastic and moving boundary (ripple effect) mechanisms, and give a comparison between BLS intensity and density of states (DOS) to determine the dispersion curves of longitudinal guided modes in the supported layer. In particular, in the case where the mismatch between the elastic parameters of the substrate and the adsorbed layer is high, such as in a PMMA layer on a Si substrate, we derive closed-form expressions of BLS and DOS and demonstrate a simple relationship between these two quantities. A very good agreement between experimental and theoretical BLS spectra was found and compared to theoretical DOS spectra. In particular, we show that while the peaks in the DOS present a uniform behavior, the BLS spectra follows a sine cardinal (sinc) function shape around a given frequency fixed by the chosen laser wavelength. The theoretical calculation is performed within the framework of the Green’s function approach.
KW - Brillouin light scattering
KW - density of states
KW - Green’s function
KW - supported layer
UR - https://www.scopus.com/pages/publications/85139565274
U2 - 10.3390/cryst12091212
DO - 10.3390/cryst12091212
M3 - Article
AN - SCOPUS:85139565274
SN - 2073-4352
VL - 12
JO - Crystals
JF - Crystals
IS - 9
M1 - 1212
ER -