深圳大学电子科学与技术学院 In chapter 3 we found that an atomic medium of amplifying an electromagnetic wave if the o with an inverted population (n2>Ni is capable latter 's frequency falls within the transition lineshape. Consider next the case in which the laser medium is placed inside an optical resonator深圳大学电子科学与技术学院 • In chapter 3 we found that an atomic medium with an inverted population (N2>N1 ) is capable of amplifying an electromagnetic wave if the latter’s frequency falls within the transition lineshape. Consider next the case in which the laser medium is placed inside an optical resonator