ABSTRACT
We report the observation of non-Gaussian reflected and transmitted laser spatial profiles resulting from the excitation of resonant modes below the critical angle for total reflection in a Fabry-Perot cavity formed by a thin ~7 um air film between two glass prisms. The observations of an interference minimum in the reflected profile and exponential decay in the transmitted profile are new and in excellent agreement with a complex pole theory. Extension of the theory to a larger ~0.7 m cavity at normal incidence predicts similar reshaped profiles.
ABSTRACT
We report the observation of novel interference patterns in reflected beam profiles resulting from the excitation with a focused laser beam of both the long-range surface plasmon mode and leaky waveguide modes in a prism-coupled thin-film geometry. Many new features of the observation are in good agreement with the theory; namely, the greater than unity normalized peak interference intensities, the monotonically decreasing spacing between the periodic intensity variations, and the reshaping of the reflected profile due to propagation. Implications of these results for submicrometer patterning in nanoscience are pointed out.
ABSTRACT
The temporal reshaping of short optical pulses reflected from a metal film under the condition of surface-wave excitation of single- and multiple-boundary surface-plasmon modes is theoretically investigated. Reflected pulse shapes are calculated through evaluation of Fourier transform integrals both by direct numerical integration and by approximate pole expansion. The latter is particularly useful for the interpretation of the simple exponential time decay of the trailing edge of the pulse. Emphasis is placed on determination of the range of parameters for which pulse reshaping may be experimentally observed. Diffraction of the incident beam is a limiting factor.
