利用速率方程理论，得到包含激光增益介质反转密度、光子密度和饱和吸收介质基态布居数密度的速率方程组。

Using rate equation theory, the equation group including the population inversion density of the gain medium, photon density and the absorber ground state population density is acquired.

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当上能级粒子数处于未反转分布态时，具有较大的发射截面与吸收截面比值的波长信道拥有相对较大的增益竞争优势。

When the upper state population is not reversed, the channel with greater ratio of emission and absorption cross-section has greater competitive advantage.

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