Quantum And Optical Interaction Between Light And Micro/Nano Structures

The interaction between light and nanostructure has been a greatly popular research field in the world,which provides an important theoretical basis for the development of all-optical networks,quantum information and other emerging technologies.However,the interaction between light and nanostructure involves many complex physical processes,which are much more complex than the surface.Therefore,when we study the interaction between light and matter on the nanometer,sub-nanometer and even atomic scale,we need to treat these problems carefully.Generally speaking,the interaction between light and nanostructure can be classified optical interaction and quantum interaction.Quantum interaction involves energy level splitting at the micro-level,reflecting the change of internal energy state,while the optical interaction involves the coherent interference and coupling between the optical mode elements on the macro-level,which externally reflects the physical changes.Based on the fields and platforms of photonic crystals,surface plasmon,cavity quantum electrodynamics,quantum optics and cavity optomechanical system,this paper has made a careful analysis and understanding of the optical interaction and quantum interaction for the complex systems.In the multimode microcavity,we established the coupled mode theory based on time modulation,and realized the photonic transitions between the two modes.In multimode microcavity of photonic crystals,we have realized the complete energy conversion between a low-Q value microcavity mode and an ultrahigh-Q value microcavity mode based on the photonic transitions,and then developed a new type of dynamic optical memory.This memory can effectively realize the process of capturing signal optical pulse,storing with ultralong time and fast releasing.In addition,we also found that the fundamental link between photon lifetime and operation bandwidth is broken,and a delay-bandwidth product of ?76 is achieved.This approach may pay the way for dynamical control of on-chip all-optical information processing and optical communication.In recent years,there is a controversial problem in the coupling system composed of plasmon cavity and molecules,that is,whether the spectral splitting(scattering spectrum,etc.)is equivalent to the intrinsic energy level splitting of quantum emitter,and truly reflect the energy state evolution and splitting phenomenon of the quantum emitter.In this work,we show that the scattering spectra are very sensitive to the surrounding matter,and the giant spectral splitting stems both from the quantum interaction of a single molecule with plasmons(Rabi splitting)and from the classical optical interaction of multiple molecules with plasmons.To be more quantitative,we use the Lorentz model to approximately describe molecules and plasmons.We found that the collective optical interaction is dominant to generate the giant splitting(in scattering spectra),which is also proportional to ?(N is the number of molecule),over the quantum interaction of single-molecule Rabi splitting.Therefore,the observed giant spectral splitting is not a pure quantum Rabi splitting effect,but rather a mixture contribution from the large spectral modulation by the collective optical interaction of all molecules with plasmons and the modest quantum Rabi splitting of single-molecule strongly coupled with plasmons.Then,based on the above similar coupling system,by placing a point source in the metallic nanogap,i.e.near-field excitation,this excitation mode not only excites the surface plasmon but also excites the near-field near the point source,and these two fields will be a localized field of the metallic nanostructure.It is further found that the localized field can compress the effective mode volume of the microcavity.For the strong coupling system composed of metallic nanocavity and molecule,the molecule can not only interact with the surface plasmons,but also with the near-field.Therefore,we found that both the Rabi splitting in the fluorescence spectrum and the reversible interaction of Rabi oscillations have been enhanced obviously.Furthermore,we found that the coupling strength under the near-field excitation mode is 1.7 times of that under the far-field excitation mode.Therefore,this work can promote the research and development of many quantum technologies and related applications,such as on-chip quantum information processing,quantum logic gates and quantum entanglement.Finally,we extend our research to cavity optomechanical system,and build the quantum interaction system of atom-photon-oscillator.We propose a theoretical model that combines the full quantum method to describe the quantum interaction between atom and photon with the classical method to describe mechanical oscillators,and construct a time-dependent Hamiltonian.With the dressed state approach,we find that the Vacuum Rabi splitting of the system is time-dependent,that is,the splitting of the atomic energy level is always modulated by the mechanical oscillator.We show that even though the atom is not in resonance with photon,it is available to make a phase compensation by mechanical oscillator for the detuning,so that the avoided crossing in the frequency domain can also happen.We extend the theoretical model to the extremely-large-amplitude regime and find that the compensation can readily reach the GHz scale.Finally,our studies show that when the atom is in resonance with the photon,the coupling of the atom-photon-oscillator triple system can reach maximum strength.These results can help to open up a new avenue to explore and harness mechanical oscillators to interfere and manipulate light-matter interaction in optomechanical platform.In general,we have studied the quantum and optical interactions in different systems.In the multi-mode microcavity,we establish the coupled mode theory based on time modulation,and realize the photonic transitions between the two modes.This mechanism of optical interaction has some theoretical significance for the design of new all-optical information processor.Then,in the coupling system of molecules and plasmon,we find that compared with the quantum interaction of single molecule Rabi splitting,the collective optical interaction of molecules and plasmon is the main reason for the giant spectral splitting.This theory can help to figure out the true quantity of the intrinsic energy level splitting of microscopic molecule,answer the question of how large the true Rabi splitting can be,and more importantly find out the true power of human being and the limitation to change the microscopic world.In order to enhance the quantum interaction between the quantum emitter and the metallic nanostructure,we found that the near-field excitation mode can provide two interaction channels for the quantum emitter: the surface plasmon field and the near-field.This discovery will help us to study one cavity with multi-field effects to enhance the quantum interaction and promote the research of novel quantum phenomena on the nanoscale.Finally,we study atom-photonoscillator couplied system.We find that the system is in a state of dynamic energy level splitting under the modulation of mechanical oscillator,and the energy level anticrossing occurs in the time domain.These results are helpful for us to use the mechanical oscillator to interfere the quantum interaction system.At the same time,this modulation can possiblely find new applications in the field of basic science and high technology.