The rate equations for a continuous four level laser are solved in this letter, taking into account the finite lower level lifetime and the crystal field splitting of the laser levels.

在考虑了有限的下能级寿命和激光能级与晶格场的相互作用的基础上，对四能级激光的速率方程组进行了求解。

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With a lifetime rating of 82.3 percent, McCain would rate "on the lower level of what we would consider to be conservative, " Keene tells Steve Inskeep.

NPR: David Keene: McCain Must Prove GOP Allegiance