Exploring multi-photon dressed states and microwave amplification with a strongly driven multi-level single artificial atom in front of a mirror

Fahad Aziz^1*, Kuan Ting Lin², Ping Yi Wen³, Samina¹, Yu-Chen Lin², Emely Wiegand⁴, Ching-Ping Lee¹, Yu-Ting Cheng¹, Ching-Yeh Chen¹, Chin-Hsun Chien¹, Kai-Min Hsieh¹, Yu-Huan Huang¹, Haw-Tyng Huang⁵, Hou Ian^6,7, Jeng-Chung Chen^1,8, Yen-Hsiang Lin^1,8, Anton Frisk Kockum⁴, Guin-Dar Lin^1,9,10, Io-Chun Hoi^11,1

¹Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
²Department of Physics and CQSE, National Taiwan University, Taipei 10617, Taiwan
³Department of Physics, National Chung Cheng University, Chiayi 621301, Taiwan
⁴Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
⁵Department of Geoscience, Mineral Physics Institute, Stony Brook University, 167 Earth and Space Sciences Building, Stony Brook, NY 11794-2100, USA
⁶Institute of Applied Physics and Materials Engineering, University of Macau, Macau
⁷UMacau Zhuhai Research Institute, Zhuhai, Guangdong, China
⁸Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
⁹Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
¹⁰Trapped-Ion Quantum Computing Laboratory, Hon Hai Research Institute, Taipei 11492, Taiwan
¹¹Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR 999077, China

* Presenter:Fahad Aziz, email:sm108022858@gapp.nthu.edu.tw

Our study investigates the probe response of a superconducting artificial atom, a transmon, coupled to a one-dimensional semi-infinite waveguide under a strong pumping field. The microwave field is reflected at the end of the transmission line, which acts as a mirror. The strong pump field creates multi-photon excitations in the dressed states due to the weak anharmonicity of the artificial atom. The weak probe either amplifies or attenuates the multiple Rabi sidebands. We observe a significant enhancement in amplification, due to the quantum coherence between the two amplified Rabi sidebands. As a result, we achieved a power amplification of 1.402±0.025, surpassing the results of previous experiments with a single artificial atom. Furthermore, we investigate the amplification properties by measuring the saturation power and spectrum of spontaneous emission.

Keywords: Population inversion, multi-photon, quantum coherence, amplification, superconducting artificial atom