Hai-Chao Li

Coherent competition and control between three-wave mixing and four-wave mixing in superconducting circuits

  1. Miao-Xiang Liang,
  2. Yu-Xiang Qiu,
  3. Hai-Chao Li,
  4. and Wei Xiong
Exploring intermixing and interplay between different frequency-mixing processes has always been one of the interesting subjects at the interface of nonlinear optics with quantum optics.
Here we investigate coherent competition and control between three-wave mixing (TWM) and four-wave mixing (FWM) in a cyclic three-level superconducting quantum system. In the weak control-field regime, strong competition leads to an alternating oscillation between TWM and FWM signals and this oscillation is a signature of strong energy exchange between these two nonlinear processes. In particular, such oscillation is absent from conventional multi-wave mixing in atomic systems. Surprisingly, synchronous TWM and FWM processes are demonstrated in the strong control-field regime and, at the same time, their efficiencies can be as high as 40% and 45%, respectively. Our study shows that these competitive behaviors between TWM and FWM can be manipulated by tuning the control-field intensity.
arxiv pdf

Phase- and frequency-controlled interference nonlinear optics in superconducting circuits

  1. Hai-Chao Li,
  2. Hai-Yang Zhang,
  3. Qing He,
  4. and Guo-Qin Ge
We present a new type of phase- and frequency-sensitive amplification and attenuation in a cyclically driven three-level superconducting Josephson system. Different from the previous
linear theory of pure phase-sensitive amplification, a new physical mechanism−combined action of nonlinear wave mixing and wave interference−is developed and leads to not only amplification but also attenuation. This is referred to as interference nonlinear optics. Our results show the sudden output signal transition from large gain to deep suppression by tuning the relative phase and in this case the system can act as a phase-controlled amplitude modulator. We also show the continuous change from output enhancement to attenuation by adjusting the driving-field frequency and in this situation the system behaves as a frequency-controlled amplitude modulator. Our study opens up a new perspective for its widespread applications in quantum information science.
arxiv pdf