X-Ray Quantum Optics Studies Based On Thin-Film Planar Cavity

Quantum Optics is a powerful tool to study the fundamental interaction between photons and matters,and now it is an essential subfield of physics after half a century of development.Over a hundred of years,the brilliance of x-ray sources has grown by over ten orders of magnitude.Especially in recent years,the new generation of high-energy synchrotron radiation and hard x-ray free electron laser have greatly improved the brightness and coherence of x-ray.Based on the achievement of high quality of x-ray source,quantum optics has been extended to the x-ray region,which gradually forms the emerging area of x-ray quantum optics.Benefit from the mature technologies of sample preparation and detection,the using of x-ray cavity for coherent control has became an important branch of x-ray quantum optics.The x-ray cavity is made by the multilayer films,so it is also called thin-film planar cavity.The atoms are embedded in the x-ray thin-film planar cavity in the form of an ultrathin layer and interact with the x-ray pho-tons inside the cavity.According to the type of excitation processes of the matters,the x-ray thin-film planar cavity can realize the controlling for different systems such like the nuclear transition and inner-shell transition of atoms.Specifically,the researches on the nuclear transition system has been expanded from single collective excitation to the interaction between multiple nuclear ensembles which is more complex,and up to now the interaction mechanism is still unclear.On the other hand,atomic inner shell system has complex energy level structures and has rarely been studied.In this thesis,a series of x-ray quantum optics studies are carried out with the x-ray thin-film planar cavity combining with the nuclear ensembles or the atomic inner-shell systems.The main purpose of this thesis is to broaden the research scopes of x-ray quantum optics and promote the control method of x-ray thin-film planar cavity into a more practical regime.The content of this thesis includes:(1)Using the basic single nuclear ensemble structure as a paradigm,the theoretical tools such as Parratt formalism,transfer matrix and the quantum optics model are intro-duced,and a concise transfer matrix is developed by our group which can quickly solve the multiple nuclear ensembles structure.Using these theoretical tools,the coupling between the two nuclear ensembles is studied,and the exchange interaction between the two nuclear ensembles is found to have a periodic relationship with the spacing be-tween them.Based on the periodic behavior,a spacing-controlling electromagnetically induced transparency(EIT)is realized by the double nuclear ensembles configuration.On the other hand,the antinode-node-antinode(101)configuration composing of three nuclear ensembles is designed,it can be used to achieve a novel collective dark state.The dark state is similar to a cavity of superior quality,which can achieve Rabi split of the nuclei;(2)By applying the x-ray thin-film planar cavity to the atomic inner shell system,research scopes are extended.Firstly,atom W is selected because it has a strong resonant fluorescence channel.The emission rate of the resonant channel can be adjusted directly by choosing different orders of cavity mode,and a indirectly controlling of core-hole lifetime is realized.Secondly,inelastic fluorescence line is chosen which exists more widely.Using the ability to select vacuum mode of the thin-film planar cavity,the directional fluorescence emission effect is supposed;(3)The experimental platform for nuclear quantum optics at beamline station ID33 in Beijing High Energy Photon Source(HEPS)was designed.ID33 includes the nuclear resonant scattering technique,which provide possibility for the experimental x-ray nu-clear quantum optics research in China.This designing also solves the problem of in-sufficient bunch interval in ID33 for 57Fe isotope.This thesis designs an energy-domain nuclear resonant scattering spectrometer:Synchrotron Mossbauer Source(SMS).The thesis is structured as follows:In chapter 1,the brief history of x-ray quan-tum optics is outlined.The x-ray thin-film planar cavity is introduced,and the control method of thin-film cavity can be applied to two different systems of nuclear ensembles or atomic inner-shell transitions.Chapter 2 describes the theoretical methods in detail,including classical Parratt formulism,semi-classical transfer matrix method,quantum optics model,and the semi-classical concise transfer matrix method developed by our group.Chapter 2 also introduces the experimental methods,including nuclear resonant scattering technique for detecting the nuclear ensembles system which has two different modes in time-domain or energy-domain,the x-ray grazing fluorescence and resonant inelastic x-ray scattering(RIXS)techniques for detecting the atomic inner-shell.In chapter 3,the system of nuclear ensembles is studied.Firstly,field redistribution in-side the cavity induced by the resonant single nuclear ensemble is studied.Secondly,spacing-dependent EIT is realized by two nuclear ensembles.Lastly,a novel system of quantum dark state constructing nuclear cavity is constructed by three nuclear ensem-bles.In chapter 4,the system of the atomic inner-shell is studied.Firstly,core-hole lifetime controlling for L? shell of W atom is realized.Secondly,x-ray inelastic fluo-rescence directional emission is supposed based on the ability of selecting vacuum mode by thin-film planar cavity.Chapter 5 designs a spectrometer of SMS and describes the scheme for setup installation and commissioning in forthcoming NRS beamline ID33 in HEPS.