摘要:

Numerical solutions of electromagnetic fields are presented for the scattering by pits and guide grooves on optical disks. The boundary element method can be applied to pit scattering of various pit forms under different conditions of the incident beam. Scattering characteristics from concave or convex pits with a section of trapezoid shapes are calculated as functions of the width or the depth (height) of pits. The maximum interference effects due to disk pits are discussed, and optimum pit shapes are found. Near‐field and induced currents are also studied for different polarization

ISSN:0048-6604    

DOI:10.1029/90RS01874

年代:1991

数据来源: WILEY

摘要:

In this paper a numerical method for computations of electromagnetic fields is presented, which has been developed by the authors and their colleagues since 1978 under the name of the multiple multipole (MMP) method. In the meantime several groups are working independently on similar methods (with sometimes different approaches and different names). The majority of them agreed to use the name generalized multipole technique (GMT) in the future (Ludwig, 1989). The main advantages are as follows: (1) Only the boundaries of the domains have to be discretized (even in the case of lossy bodies). (2) No integrals have to be solved numerically which reduces the computation time and simplifies the codes. (3) Plotting errors on the boundaries and fields allows an excellent control of the results. (4) The fields may be computed accurately in the near‐field region and even on boundaries for closed and open problems. (5) Efficient programs including graphic input and output routines (also animated pictures) are available even for personal computer

ISSN:0048-6604    

DOI:10.1029/90RS00931

年代:1991

数据来源: WILEY

摘要:

It is shown that the equations of resonant nonlinear optics can be studied entirely within the framework of an underlying Lie algebra, in which the 2x2 su(2) Hamiltonian and density matrices of the quantum mechanical description of the atomic system transform directly to the 2x2 sl(2,R) matrices of the Ablowitz‐Kaup‐Newell‐Segur (AKNS) scheme, and the AKNS eigenvalue is introduced naturally as a free parameter. The Lie algebra sl(2,R) is also the symmetry algebra of transformations between equivalence classes of AKNS systems under SL(2,R) gauge transformations. The Lie algebra formalism condenses much algebraic manipulation, and provides a natural basis for the perturbation theory of “nearly integrable” nonlinear wav

ISSN:0048-6604    

DOI:10.1029/90RS01149

年代:1991

数据来源: WILEY