A general expression for the optical theorem for probe sources given in terms of propagation invariant beams is derived. This expression is obtained using the far field approximation for Rayleigh regime. In order to illustrate this results is revisited the classical and standard scattering elastic problem of a dielectric sphere for which the incident field can be any arbitrary invariant beam.

中文翻译：

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瑞利散射近似的广义光学定理

导出了根据传播不变光束给出的探测源光学定理的一般表达式。该表达式是使用瑞利方案的远场近似获得的。为了说明这一结果，我们重新审视了电介质球的经典和标准散射弹性问题，其中入射场可以是任意不变的光束。