THEORY OF INTERBAND COHERENCE AND INVERSIONLESS BISTABILITY IN SEMICONDUCTOR LASERS

• 来源期刊: 中国物理(海外版)
• 关键词: interband coherence inversionless bistability semiconductor laser
• 年，卷（期）: 2000,（11）
• 所属期刊栏目: CLASSICAL AREAS OF PHENOMEN
• 页码范围: 813-823
• 页数: 11页
• 分类号: 4250,4265,4262
• 语种: 英文

摘要

Coherent transitions of charge carriers between the conduction and valence bands of a semiconductor medium are essential for the operation of a semiconductor laser.In this paper,we study how such interband coherence can be set up by an injection current and a coherent pump-field.In the absence of the pump-field,the injection current is the only source to establish the interband coherence in a semiconductor laser system.A laser threshold is obtained,which shows that a strongly coupled high-Q microcavity has a low threshold value.However,when an external pump-field serving as another mechanism to create the interband coherence is applied,the threshold value of the injection current can be lowered and it vanishes for sufficiently strong field.Besides,if the pump-field exceeds a threshold value,it is even possible to achieve a bistability in the inversionless region.Some fundamental macroscopic properties,including polarization,absorption and dispersion for the semicoductor system,are also obtained analytically.