Gaussian-mode Analysis of "Thin" Mirrors

The 4th International Symposium on Space Terahertz Technology

S. Withington

Others  :  http://www.nrao.edu/meetings/isstt/papers/1993/1993211222.pdf
PID  :  36709

来源: CEUR

【 摘 要 】

We have developed a technique for calculating the Gaussian bean -mode scattering matrices of a shaped, off-axis mirrors. In its simplest form, the technicue gives the coupling efficiency between the incoming and outgoing lowest-order Gaussia i modes. In its more complete form, the technique gives the full scattering matrix between zigher-order modes, which in turn characterises the aberrative behaviour of the mirror. I this paper, we model a mirror as a thin phase-transforming surface located at the tang 3nt plane to the centre of the mirror. The scattering matrix is determined in the usual manner by evaluating the overlap integrals across some surface in the system for which e amplitude and phase of the field are known. Because, however, the modes are not ortho lormal over the surface of the mirror a system of linear equations has to be solved. The shape of the mirror is simply described by the height of the surface above the tangent plan, and therefore, the technique is particularly flexible and can be used for a variety of ( pplications. Eventually, we hope to use the technique for synthesising systems of shaped nirrors.