Begin with Maxwell Equation>>Eikonal Function E(,t)(E( iot Hr D ( Ho(r)) S(r=ns.r =2。2z no 27 real scalar function 元444 of position 0 Ho(r) Are/ir0 0 E(r,t) E (r) H(r,t) H (r) i t e −          =     0 0 0 E (r) H (r) e e ik r ik ns r e e h h               = =       0 0 0 2 2 2 k s s ns         = = = S r ns r ( ) =  real scalar function of position