Science News Everyday 08.06.24

PHYSICS: Rolling Out SinglePhotons

Ian S. Osborne

Carbon nanotubes (CNTs) have been studiedexhaustivelyin terms of electronic and mechanical properties. A large repertoire of potential applications has been demonstrated for these one-dimensional systems ofrolled-upsheetsof carbon.To date, most of the optical studies on CNTs have focused more on characterization.Högeleet al. now show that CNTsexhibitquantum optical behavior. Photons, being bosons, like to bunch together. However, in quantum systems such as atoms and artificial atoms, the confinement of carriers cansplitthe pack behavior, resulting in the photons being emitted one at a time. For applications such asultrasecurecommunication, such antibunching behavior. is desirable. These authors excite a single CNT with a laser pulse and observe that light is emitted as single photonsupon relaxation. The results suggest that CNTs may extend their repertoire beyond logic circuits and other electronic devices, finding application in quantumoptoelectronics.

人们对碳纳米管（CNTs）材料的电子性能和机械性能进行了详尽的研究，这种将碳片层卷曲形成的一维体系被证明具有巨大潜力，可能用于未来的设备制造。迄今为止，CNTs材料的光学研究均是较多地关注其性能表征。现在，Högele 等人研究发现，CNTs材料具有量子光学效应。光子作为玻色子可能会聚集成束。但是，在自然存在的原子和人工原子的量子体系中，载波的限制可以杜绝这种成束行为，从而致使光子一次只释放一个。对于一些用于高度机密通讯的设备来说，这样的反成束行为是非常理想的。笔者利用激光脉冲使一个碳纳米管单位感光，观察到光波在发射时是一个光子一个光子地发射的。这一实验结果表明，CNTs材料不但可以用于逻辑电路和其他电子设备，还可以拓展到其他方面，譬如光电子的应用。