Studies of photon creation and fluctuation emitted from quantum Hall electron systems via on-chip terahertz detection

研究了量子霍尔边缘态注入的电子通过嵌入量子点单太赫兹光子探测器的集成太赫兹光子电路产生回旋辐射的机理。我们发现：（1）THz光子是从边缘态发射的，具有明显的起始电压，其中v=2的外边缘态的电化学势低于v=3的内边缘态的电化学势（其中v是Laudau能级填充因子）和（2）自旋分裂比体GaAs增强约20倍，这是因为自旋极化边缘态中的交换相互作用。这些结果强烈地表明自旋翻转回旋辐射的存在需要自旋-轨道相互作用。这表明了通过相干自旋极化边缘态实现自旋态到光子态的转移的可能性，为量子信息器件提供了一种新的途径。

The purpose of this work is to investigate mechanism of cyclotron emission due to electrons injected by quantum Hall edge states through integrated terahertz photon circuits in which quantum-dot single terahertz photon detectors are embedded. In this work, we found (1) THz photons are emitted from edge states with a clear onset voltage, where the electrochemical potential of the outer v=2 edge states is lower than that of the inner v=3 edge states (where v is Laudau level filling factor) and (2) the spin splitting is enhanced by a factor of about 20, comparing with that in bulk GaAs, because of the exchange interaction in the spin polarized edge states. These results strongly suggest the presence of spin-flip cyclotron emission requiring spin-orbit interaction. This indicates the possibility of transfer from spin states to photon states through coherent spin-polarized edge states, providing a new approach to quantum information devices.