Planar dielectric waveguide
= Planar dielectric waveguide
= Slab waveguide
{synonym}
A <dielectric> slab surrounded by lower-index material confines waves with an oscillatory core profile and evanescent exterior tails. In an isotropic, nonmagnetic symmetric slab, an even transverse-electric field has core profile $\cos Kz$ and matches to exponential tails through $K\tan(Kd)=K'$. The transverse constants also satisfy $K^2+K'^2=(\epsilon_r-1)\omega^2/c^2$ for vacuum exterior.