Lagrangian Optics

In geometrical optics, light propagation is analyzed in terms of light rays which define the path of propagation of light energy in the limit of the optical wavelength tending to zero. All of geometric optics can be derived from Fermat's principle. The counterpart in classical mechanics is of course Hamilton's principle. There is a very close analogy between mechanics of particles and optics of light rays. In this text, the authors begin with Fermat's principle and obtain the Lagrangian and Hamiltonian pictures of ray propagation through various media. The analysis of light propagation in inhomogeneous media is dealt with in great detail.