Time‐Resolved Second‐Order Coherence Characterization of Broadband Metallic Nanolasers
Time‐Resolved Second‐Order Coherence Characterization of Broadband Metallic Nanolasers
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DOI：
10.1002/lpor.202000593
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发表时间：
2021-10
影响因子：
11
通讯作者：
Agnes George;A. Bruhacs;A. Aadhi;W. Hayenga;Rachel Ostic;Erin Whitby;M. Kues;Zhiming Wang;C. Reimer;M. Khajavikhan;R. Morandotti
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作者：
Agnes George;A. Bruhacs;A. Aadhi;W. Hayenga;Rachel Ostic;Erin Whitby;M. Kues;Zhiming Wang;C. Reimer;M. Khajavikhan;R. Morandotti
高带宽金属同轴纳米激光器对于研究激光物理（例如无阈值相干跃迁）具有很高的兴趣，并且由于其超小尺寸和大光谱带宽而具有各种有前途的应用。光学相干特性通常在Hanbury-Brown和Twiss实验中表征。然而，当相干时间比单光子探测器的时间分辨率短一个数量级时，这些很难在宽带激光器中执行，因此需要显著的光谱滤波。本文展示了一种新的方法，在调查的时间动态的光子统计与纳米激光发射，而无需光谱滤波的要求。当用纳秒脉冲光学泵浦纳米激光器时，在泵浦脉冲的持续时间内评估时间分辨的二阶相干特性。在收集的时间分辨光子统计数据中观察到从热发射到激光发射的相干跃迁，这与纳秒泵浦脉冲的光功率的时间变化有关。由于纳米激光器对于脉冲泵浦方案显示出更好的性能，这些脉冲的时间包络调制导致纳米激光器脉冲包络内的不同程度的相干性。这种方法也可以很容易地应用于表征各种宽带激光器。
High‐bandwidth metallic coaxial nanolasers are of high interest to investigate laser physics such as thresholdless coherence transitions, and have a large variety of promising applications enabled by their ultrasmall size and large spectral bandwidth. Optical coherence properties are commonly characterized in Hanbury‐Brown and Twiss experiments. However, those are difficult to perform in broadband lasers when the coherence time is an order of magnitude shorter than the temporal resolution of the single‐photon detectors, thus requiring significant spectral filtering. This paper demonstrates a new approach in investigating the temporal dynamics of the photon statistics associated with the nanolaser emission, obtained without the requirement of spectral filtering. While optically pumping the nanolasers with nanosecond pulses, time‐resolved second‐order coherence properties are evaluated over the time duration of the pump pulse. Coherence transitions from thermal emission to lasing are observed in the gathered time‐resolved photon statistics, linked to the temporal change in optical power of the nanosecond pump pulses. As nanolasers show better performance for the pulsed pumping scheme, the temporal envelope modulation of these pulses results in varying degrees of coherence within the nanolaser pulse envelope. This approach can also be readily applied to characterize a large variety of broadband lasers.