Quantum-limited phase-matching effect in a Λ-type laser system
Quantum-limited phase-matching effect in a Λ-type laser system
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DOI：
10.1103/physreva.83.063846
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发表时间：
2011-06
影响因子：
2.9
通讯作者：
Deshui Yu;Jingbiao Chen
中科院分区：
文献类型：
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作者：
Deshui Yu;Jingbiao Chen
在量子朗之万法的基础上，详细研究了量子有限位相匹配效应的理论基础。基于两次激光跃迁直接产生两个准单色场。我们发现，两个激光之间的相干性可以远远超过任何一个激光场的线宽。这一结果表明，尽管任一激光场位相起伏较大，但两场的位相是匹配的。与基于原子吸收的相位匹配效应不同，这里的两个激光场之间的最终相干性不受饱和展宽的限制，并且激光强度越高，相干性越高。此外，基于线性稳定性分析，我们发现场稳态的不稳定性可以在很大程度上限制这种相位匹配效应在高泵浦速率的坏腔极限内的出现。我们还讨论了输出场的幅度涨落频谱，结果表明，在两场振荡的情况下，腔内振荡的单场的低频幅度涨落的压缩受到破坏。
The theory of a quantum-limited phase-matching effect in a $\ensuremath{\Lambda}$-type lasing system is studied in detail based on the quantum Langevin approach. Two quasimonochromatic fields are directly generated based on two lasing transitions. We find that the coherence between two lasers can well exceed the linewidth of either laser field. This result denotes that two field phases match each other although either laser field has a high phase fluctuation. Unlike the phase-matching effect based on atomic absorption, the final coherence between two laser fields here is not limited by saturation broadening, and the higher laser intensities lead to a higher coherence. Additionally, based on a linear stability analysis, we find that the instability of the field steady state can substantially restrict the occurrence of this phase-matching effect in the bad-cavity limit for a high pump rate. We also discuss the spectrum of amplitude fluctuations of output fields, and the result shows that the squeezing of amplitude fluctuations at low frequencies for a single field oscillating inside the cavity is damaged in the case of two fields oscillating.