Abstract

The amplitude and phase of the reflectivity vary strongly near the Brewster angle. Strongly focused beams or ultrashort pulses can thus undergo dramatic distortions on reflection from the surface of a solid. In particular, femtosecond pulses, which have a large bandwidth, may be reshaped after reflection from a bare surface in a way that is reminiscent of the reshaping produced after reflection from multilayer dielectric mirrors, provided that the wavelength is close to a resonance. We present calculations of the temporal reshaping of femtosecond optical pulses as a function of the pulse duration, angle of incidence, and dielectric properties of the reflector. In a related study, we calculated and measured the angular distribution of a strongly focused Gaussian beam after reflection near the Brewster angle. Here the spread in k vectors plays the role of the spread in frequency that produces the temporal reshaping observed with femtosecond pulses.

© 1987 Optical Society of America