Optical amplification in the gain medium of a laser or laser amplifier arises from stimulated emission, where the input light induces transitions of laser-active ions from some excited state to a lower state.
Three-Level Systems
In a three-level system, the laser transition ends on the ground state. The unpumped gain medium exhibits strong absorption on the laser transition. Only by pumping more than half of the ions (or atoms) into the upper laser level do a population inversion and consequently net laser gain result; the threshold pump power is thus fairly high.
从这段话看不像是电子阿作者: qyxhhl 时间: 2008-10-18 21:07
课本上说是原子。。。。。。作者: zemax 时间: 2008-10-19 02:27
说 电子,离子都可以吧,对搞激光的来说,只要把它理解为可以吸收或发射光子的最小单位就可以了。作者: duyinchao 时间: 2008-10-24 23:09
非常同意楼上的意见~~~~~作者: craftboy 时间: 2008-10-25 11:00
电子在能级跃迁的时候发射电磁波啊!应该是带不同电子数的离子?作者: zcc03023 时间: 2008-12-20 14:06 1#laserpad