Tackling misconceptions in geometrical optics

Matrix Methods in Geometrical Optics

As well as the geometrical methods used for solving lens problems, and locating the size and position of images in optical systems, there is an alternate, perhaps more versatile, method involving matrix manipulation. Many of you will be familiar with the use of simple 2x2 matrices. Firstly, however, before I consider the use of matrices in optics, I will review the matrix solution of two simult...

Multiphase Computations in Geometrical Optics

In this work we propose a new set of partial diierential equations (PDEs) which can be seen as a generalization of the classical eikonal and transport equations, to allow for solutions with multiple phases. The traditional geometrical optics pair of equations suuer from the fact that the class of physically relevant solutions is limited. In particular, it does not include solutions with multipl...

Electromagnetic Scintillation I. Geometrical Optics

Geometrical optics and chessboard pebbling

Recently Chung. Graham, Morrison and Odlyzko [l] studied some combinatorial and asymptotic enumeration aspects of chessboard pebbling. In this problem, we start with a single pebble, placed at the origin (0,O) of an infinite chessboard. At each step we remove a pebble from (i,j) and repIace it with two pebbles at positions (a + 1,j) and (i.j + I). provided the latter are unoccupied. After m ste...

WKB-Methods in Multivalued Geometrical Optics

We consider the Cauchy problem for a class of scalar linear dispersive equations with rapidly oscillating initial data. The problem of the high-frequency asymptotics of such models is reviewed, in particular we highlight the difficulties in crossing caustics when using (time-dependent) WKB-methods. Using Wigner measures we present an alternative approach to such asymptotic problems. We first di...