Borghi R, Santarsiero M
Opt Lett. 1998 Mar 1;23(5):313-5. doi: 10.1364/ol.23.000313.
We present a simple mathematical model giving a possible description of a partially coherent light beam exhibiting a flat-topped transverse intensity profile. Such a model allows us to deduce the modal distribution inside a multimode stable optical cavity, assuming that the modes are of the Hermite-Gauss type. The analytical expression used to represent flat-topped profiles is of the flattened Gaussian type and leads to an exact, closed-form expression for the M(2) factor of the output beam. An analogous procedure could be used to treat the general problem of deducing the modal distribution inside a laser cavity starting from intensity measurements of the output beam.
我们提出了一个简单的数学模型，它可能描述了具有平顶横向强度分布的部分相干光束。假设模式为厄米 - 高斯型，这样的模型使我们能够推导出多模稳定光学腔内的模式分布。用于表示平顶分布的解析表达式是扁平高斯型的，并能得出输出光束的M(2)因子的精确闭式表达式。可以使用类似的过程来处理从输出光束的强度测量推导激光腔内模式分布的一般问题。
