Reflection and transmission of plane waves at the interface of pyroelectric bi-materials

A simple reflection and transmission theory of plane waves at the interface of pyroelectric media is studied in this paper. In an infinite homogeneous pyroelectric medium, there are four bulk wave modes: quasi-longitudinal (QL), two quasi-transversal (QT) and one temperature (T) waves, whose velocities depend on the frequency and incident angle. Simultaneously, a quasi-surface (QS) wave on each side of the interface of pyroelectric bi-materials will appear in the general reflection and transmission problem. The quasi-surface wave has the same wave vector component with the incident waves along the interface plane. So, the reflection and transmission problem is different with the propagation wave in the infinite homogeneous space, but it is still solvable. In the reflection and transmission problem, there are ten complex continuous conditions on the interface, which are satisfied by the bulk and quasi-surface waves together. Numerical calculations are performed for bi-material PZT-6B/BaTiO3. Incidences of the quasi-longitudinal and quasi-transversal waves from the side of PZT-6B or BaTiO3 medium are discussed. The reflection and transmission amplitude coefficients and energy flow ratios varying with the incident angle are examined.