| The strong coupling between photon and exciton and their quantum state manipulations are important for realizing the quantum optoelectronic devices and solid quantum chips.Researchers have achieved strong coupling between photon and exciton,as well as their quantum state manipulation under low temperature and high vacuum conditions based on various solid-state optical microcavities.However,to achieve the strong coupling between photon and exciton under ambient conditions has become an important goal that people are pursuing.In the past two decades,researchers have designed and prepared a variety of plasmon metal nanostructures based on the light confining effect of the plasmon resonance,and they gradually realized the strong coupling between plasmon and exciton at room temperature.Especially in recent years,breakthroughs have been made in demonstrating the strong coupling of room-temperature plasmon-exciton strong coupling at the single exciton level,providing experimental foundation for developing and applying room-temperature quantum optoelectronic devices.However,most of recent plasmon-exciton strong coupling system is based on a single type of exciton state,and there are only two hybrid states(qubit states)generated by strong coupling,which is obviously not enough for complex quantum information processing where multiple qubits are required.Therefore,further research and development of theoretical models and experimental platforms for strong coupling between plasmon and multiple different exciton states are highly desired in the field of strong coupling between light-matter room temperature quantum.In this thesis,based on previous studies,a quantum mechanics model of the strong coupling between plasmon and multiple different exciton states has been constructed,by comprehensively using Green’s function,Heisenberg’s equation of motion and numerical calculation.This approach provides an accurate description of the absorption spectrum response,energy dispersion and other basic properties of the strong coupling system between plasmons and multiple different excitons states.Meanwhile,the Au@Ag NR/S0041@S2165@S2278 J-aggregates hybrid system is prepared by electrostatic assembly technology,and the strong coupling between plasmons and three different exciton states is realized at room temperature.In addition,the transient absorption characteristics of the coupled system are studied by femtosecond laser ultrafast pump-probe detection technology.It is found that the hybrid states generated by the strong coupling of plasmon-exciton and the acoustic phonon oscillations of metal nano resonant cavity have a mutual regulation effect.The research of this topic not only provides a powerful theoretical analysis tool for the research of multi-mode hybridization and multi-qubit control based on plasmon resonance,but also provides a good platform for the research of ultrafast energy transfer dynamics and the development of ultrafast plasmon and phonon devices based on the strong coupling of plasmon and multiple different exciton states.The main innovations of this thesis are as follows:(1)A quantum mechanical model of strong coupling between plasmon and multiple different exciton states was developed,which can accurately describe the spectral response characteristics,energy dispersion relation of hybrid states and the proportion of each component in hybrid states.(2)The strong coupling between the plasmon and two and three different exciton states was successfully demonstrated by the hybridization of Au@Ag NRs with three different J-aggregate.(3)The transient absorption process of the plasmon-multiexciton strongly coupled system was measured.It was found that the strong electronic interactions between the plasmons and excitons can effectively modulate the coherent acoustic phonon vibrations in the plasmonic nanocavities via the mixed generation states.Accordingly,the coherent acoustic phonon vibrations can also modulate the dynamics damping of these newly formed mixed plexciton states. |
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