Zigzag analysis of interference effects in an arbitrarily oriented biaxial single layer

A wave-vector zigzag analysis is developed to investigate the complicated interference effects among the four extraordinary waves in a biaxial slab with general principal-axes orientation; the four corresponding zigzag Poynting vectors have distinct walk-off directions. Expressions for transmission and reflection coefficients, analogous to Airy’s summation for isotropic slabs, are determined for an arbitrarily oriented linearly polarized monochromatic plane wave at oblique incidence. A KTP slab is analyzed with the derived method, and the results are compared with those obtained with the 4 × 4 matrix method. Some common applications of this theory include analysis of multilayer structures and waveguides.