Transient reflection from a multilayer with a time jump in the sublayer permittivities

A theoretical investigation of the wave reflection from a 1-D quasiperiodic dielectric multilayer with a transient permittivity of sublayers is presented. The problem of field interaction with such a structure is reduced to the Volterra integral equations for the field in a transient medium, and is solved by convergent iterations. Numerical analysis shows a considerable modifications of the reflected field spectrum. This modification depends on the incident wave frequency, and can result in the appearance of not only additional harmonics, but also a continuous spectrum over a wide waveband for some values of the incident wave frequency. Therefore, the considered time-varying structures provide rich opportunities for spectrum transformation. (C) 2001 John Wiley & Sons, Inc.