Delayed Transition to Coherent Emission in Nanolasers with Extended Gain Media
Delayed Transition to Coherent Emission in Nanolasers with Extended Gain Media
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DOI：
10.1103/physrevapplied.10.054055
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发表时间：
2018-09
影响因子：
4.6
通讯作者：
F. Lohof;R. Barzel;P. Gartner;C. Gies
中科院分区：
文献类型：
--
作者：
F. Lohof;R. Barzel;P. Gartner;C. Gies
高β激光器的实现是腔QED的主要应用之一，有望在绿色光子学领域实现超低阈值、可集成性和降低功耗。在这种纳米激光器中，自发发射甚至可以在阈值以上发挥核心作用。通过超越速率方程方法，我们根据输入输出特性和发射的相干程度重新审视激光阈值的定义。我们证明了腔 QED 激光的新机制，例如已实现。在具有扩展增益材料的高 Q$ 纳米激光器中，两者可以显着不同，从而在比观察阈值强度跳跃所需的泵浦功率高得多的泵浦功率下达到相干性。与普遍看法相反，此类设备在功耗降低方面并没有受益于高 $\beta$ 因素，因为需要大量的受激发射来消除自发发射噪声。
The realization of high-$\beta$ lasers is one of the prime applications of cavity-QED promising ultra-low thresholds, integrability and reduced power consumption in the field of \textit{green photonics}. In such nanolasers spontaneous emission can play a central role even above the threshold. By going beyond rate-equation approaches, we revisit the definition of a laser threshold in terms of the input-output characteristics and the degree of coherence of the emission. We demonstrate that there are new regimes of cavity-QED lasing, realized e.g. in high-$Q$ nanolasers with extended gain material, for which the two can differ significantly such that coherence is reached at much higher pump powers than required to observe the thresholdlike intensity jump. Against the common perception, such devices do not benefit from high-$\beta$ factors in terms of power reduction, as a significant amount of stimulated emission is required to quieten the spontaneous emission noise.