Abstract

Surface coherent Raman scattering (SCRS) is a powerful technique for obtaining vibrational Raman spectra of surface species with submonolayer sensitivity. This sensitivity is achieved by using incident and scattered fields in the form of guided waves. A planar optical waveguid (1 µm) of a transparent oxide is deposited upon a silica substrate. Dye laser beams of frequencies ω₁ and ω₂ are coupled into the waveguide via coupling prisms in optical contact with the surface. The allowed TE and TM modes (electric field and magnetic field in the plane of the surface, respectively) for guided waves are characterized by a discrete set of wavevectors which depend upon the indices of refraction and the film thickness. The guided wave fields extend beyond the film into the surrounding media, and hence nonlinear interactions such as coherent anti-Stokes Raman Scattering (CARS) can occur on the surface of a waveguide. The field distribution functions exhibit an exponentially decaying evanescent tail outside the film.

© 1985 Optical Society of America