A waveguide-QED with giant atoms,which is capable of accessing various limits of a small one,provides a new paradigm to study photon scatterings.Thus,how to achieve nonreciprocal photon transmissions via such a giant ...A waveguide-QED with giant atoms,which is capable of accessing various limits of a small one,provides a new paradigm to study photon scatterings.Thus,how to achieve nonreciprocal photon transmissions via such a giant atom setup is highly desirable.In this study,the nonreciprocal single-photon scattering characteristics of a double-drivenΛ-type three-level giant atom,where one of the transition couples to a 1D waveguide at two separate points,and the other is driven by two coherent driving fields,are investigated.It is found that a frequency-tunable single-photon diode with an ideal contrast ratio can be achieved by properly manipulating the local coupling phases between the giant atom and the waveguide,the accumulation phase between the two waveguide coupling points,the Rabi frequencies and phase difference of the two driven fields.Compared to the previous single driving schemes,on the one hand,the presence of the second driving field can provide more tunable parameters to manipulate the nonreciprocal single-photon scattering behavior.On the other hand,here perfect nonreciprocal transmission for photons with arbitrary frequencies is achievable by tuning the driving phases while the two driving fields keep on turning,which provides an alternative way to control the nonreciprocal single-photon scattering.Furthermore,the results reveal that both the location and width of each optimal nonreciprocal transmission window is also sensitive to the driving detuning,and a single-photon diode with wide or narrow bandwidth can be realized based on demand.These results may be beneficial for designing nonreciprocal single-photon devices based on a double-driven giant atom setup.展开更多
基金supported by the China Postdoctoral Science Foundation (Grant No.2023M732028)the Zhejiang Province Key Laboratory of Quantum Technology and Device (Grant No.20230201)+2 种基金the Zhejiang Provincial Natural Science Foundation of China (Grant No.LY21A040003)the National Key Research and Development Program of China (Grant No.2021YFA1400602)the National Natural Science Foundation of China (Grant Nos.11864018,12164022,12174288 and 12274326)。
文摘A waveguide-QED with giant atoms,which is capable of accessing various limits of a small one,provides a new paradigm to study photon scatterings.Thus,how to achieve nonreciprocal photon transmissions via such a giant atom setup is highly desirable.In this study,the nonreciprocal single-photon scattering characteristics of a double-drivenΛ-type three-level giant atom,where one of the transition couples to a 1D waveguide at two separate points,and the other is driven by two coherent driving fields,are investigated.It is found that a frequency-tunable single-photon diode with an ideal contrast ratio can be achieved by properly manipulating the local coupling phases between the giant atom and the waveguide,the accumulation phase between the two waveguide coupling points,the Rabi frequencies and phase difference of the two driven fields.Compared to the previous single driving schemes,on the one hand,the presence of the second driving field can provide more tunable parameters to manipulate the nonreciprocal single-photon scattering behavior.On the other hand,here perfect nonreciprocal transmission for photons with arbitrary frequencies is achievable by tuning the driving phases while the two driving fields keep on turning,which provides an alternative way to control the nonreciprocal single-photon scattering.Furthermore,the results reveal that both the location and width of each optimal nonreciprocal transmission window is also sensitive to the driving detuning,and a single-photon diode with wide or narrow bandwidth can be realized based on demand.These results may be beneficial for designing nonreciprocal single-photon devices based on a double-driven giant atom setup.
