Broadband transmission properties of multilayered structures

The formalism of the scattering matrix is applied to describe the transmission properties of multilayered structures with deep variations of the refractive index and arbitrary arrangements of the layers. We show that there is an exact analytical formula for the transmission spectrum, which is valid for the full spectral range and which contains only a limited number of parameters for structures satisfying the quarter-wave condition. These parameters are related to the poles of the scattering matrix, and we present an efficient algorithm to find them, which is based on considering the ray propagation inside the structure and subsequent application of the harmonic inversion technique. These results are significant to analyze the reshaping of ultrashort pulses in multilayered structures. OCIS codes: 290.5825, 230.4170, 310.6860, 320.5540. Multilayered structures with periodic arrangement of the layers represent the simplest example of photonic crys-tals. Such structures are widely used as distributed re-flectors, spectral filters and can be applied for compres-sion or reshaping of ultrashort pulses [1]. A lot of at-tention has been paid to the question of how to mod