We have made in situ measurements of attenuated total reflection (ATR) and Raman scattering from a layered structure consisting of a glass prism, a thin silver film, an ${\mathrm{MgF}}_2$ spacer, and a liquid mixture whose refractive index is matched to that of ${\mathrm{MgF}}_2$. When the incident angle of the laser beam coincides with the ATR angle, the surface-plasmon polariton (SPP) of the silver film is excited resonantly and the Raman scattering intensity of the liquid shows a maximum. The same effect is observed at the frequency of the Stokes scattered light. By measuring the decrease of the Raman scattering intensity of the liquid with increase of the thickness of the ${\mathrm{MgF}}_2$ spacer layer, we have determined the decay length ($l_d$) of the SPP field into the liquid. The measured value of $l_d$=1539 Å agrees with the calculated value, 1534 Å.

• Received 30 August 1985

DOI:https://doi.org/10.1103/PhysRevB.33.789