The Studies Of X-ray Cavity Quantum Optics Based On Resonant Scattering

Quantum optics studies the interaction between light and matter,and nowadays it is one of the most cutting-edge frontiers of physics.With high quality lasers working at the wavelengths from microwave to visible,quantum optics develops rapidly,and has already established some practical applications.With the development of synchrotron radiation and the beamline technology,X-ray quantum optics emerges and has been developed into a new frontier field in the last decade.An important branch of the X-ray quantum optics is the X-ray cavity-QED,in which atoms are embedded in the thin-film planar cavities with different structures,and the interaction between the X-ray and matters can be deeply understood by means of the quantum optics.Up to now,X-ray quantum optics mainly focuses on the nuclear system,and is entering into nonlinear optics from linear optics,and the related theories are still perfected.At the same time,atomic inner-shell system is used for the X-ray quantum optics studies,and the corresponding theoretical and experimental researches are still in infancy.In this thesis,different structures of the thin-film planar cavities are designed and studied respectively for different topics.In the nuclear system,the phenomena of FanoLorentz profile,decoherence and the EIT-ATS crossover are discussed and analyzed using the quantum optics theory.Besides,the Green function method in the nuclear system has been successfully extended to the atomic inner-shell system,which provides a theoretical basis for the future study of quantum optics in the complex cavity structures.In addition,the dynamics parameters of the valence-shell excitations of the CH3C1 are also studied.In detail,the thesis consists of:Ⅰ.In the different types of the thin-film planar cavities with one resonant layer,it is found that their reflectivities are Fano-Lorentz profiles,and the corresponding q factors are the complex number.In the framework of the complex q,a flat Fano profile is predicted under a critical nuclear abundance in the overcritical cavity;Ⅱ.By engineering the different nuclear abundance and incident angles,it is found that there is a clear dependence between the Fano profiles and the decoherence(dissipation and dephasing).With changing the nuclear abundance,the asymmetry factor q of the Fano profile will show a straight line in the complex plane,and the slope of the straight line can be controlled by the phase difference.In this case,the straight line corresponds to the dissipation.With changing the incidence angle of the X-ray,the asymmetry factor q of the Fano profile will show a circular-like trajectory,and the radius of the circular-like trajectory can be modulated by nuclear abundance.In this case,the circular-like trajectory does not correspond to the dephasing;Ⅲ.By reducing the thickness of the top mirror layer,it is found that the reflectivities of the thin-film planar cavities with two nuclear layers change from EIT to EIT-ATS crossover.Using the Green function method to reconstruct the reflectivity,it is found that the flip of the reflectivity is caused by the reflection amplitude of the bare cavity.In addition,through analyzing the equivalent decaying-dressed states formed by the two layers,it is found that the reflectivity can be approximated regarded as the EIT case when the top thickness is thick.When the top thickness is thin,the reflectivity is in the EIT-ATS crossover region;Ⅳ.Theoretical studies of the atomic inner-shell system are still very scarce.In order to explain the experimental phenomena and provide a basic theoretical tool for the future experimental studies,the Green function method used for the nuclear system is extended into the atomic inner-shell system successfully.In the inner-shell Green function method,only the oscillator strength of the electron transition is undetermined.Hence,according to our results,it is found that the oscillator strength of the inner-shell electronic transition can be obtained by fitting the Fano profiles in the thin-film planar cavity,which provides a new experimental method for the measurement of atomic innershell dynamics parameters;Ⅴ.The generalized oscillator strengths,optical oscillator strengths and integral cross sections of the valence-shell excitations of the CH3Cl have been determined at an incident electron energy of 1500 eV and an energy resolution of 70 meV.By comparing the electron energy loss spectra measured at different scattering angles and analyzing the GOSs carefully,it is found that the 1E state has the characteristic of a dipole-forbidden transition.Then the OOSs of the vibronic states of CH3C1 have been obtained by extrapolating the corresponding GOSs to the zero squared momentum transfer K2→0,and the present OOSs are in good agreement with most previous measurements.The Born and BE-scaled ICSs of the valence-shell excitations of CH3Cl have been obtained systematically from the threshold to 5 keV with the aid of the BE-scaling method.The thesis is structured as follows:In chapter 1,it introduces the development of X-ray quantum optics,X-ray film planar cavity,the physical process of cavity-atom interaction and the research status of X-ray cavity quantum optics.Chapter 2 describles theoretical methods and the experimental methods of the X-ray cavity quantum optics.In Chapter 3,it decribles the Fano-Lorentz shape controlled by the collective effect of the nuclear ensemble.Chapter 4 studies the trajectories of the different decoherence channels in the complex q plane.In Chapter 5,the EIT-ATS crossover in the thin-flim planar cavity is studied by adjusting the thickness of the top layer.Apart from these,chapter 6 extends the Green’s function method of the nuclear system to the inner-shell electron transition system,and studies the oscillator strength of the inner-shell electron transition based on the thin film plane cavity.Finally,Chapter 7 introduces the oscillator strength and other dynamic parameters of excited atomic and molecular states.