光束截面的能量守恒及能量衍射发散度

证明了任何一个在真空中稳态传输的单色标量光束，在忽略了瞬逝波的条件下，其光束截面能量的径向分量Ｅ及轴向定量Ｅ都与轴坐标无关，它们都为不变量，文中还进一步给出了光束能量衍射分散度的Ｘ，Ｙ分量的表达式。

Energy Conservation of Beam Cross-Section and Energy Diffraction Divergence

We prove that, for any stable propagating monochromatic scalar beam in vacuum, the radial component E and the z component E of the beam cross-section energy are invariances and independent of the position of the cross- section if the evanescent waves of the plane-wave spectrum of the beam are ignored. The expressions of x and y component of beam energy diffraction divergence are derived.