Atomic Microwave Magnetic Field Detection And Its Application To Resonance Characteristics Measurement Of Microwave Cavity

Recently,atom-based microwave(MW)measurement has also inspired great interest because of its potential ability to link the MW quantities with SI units.As a result,relying on various physical principles,many atom-based MW detectors have been developed,such as the MW electrometry,MW magnetometry,and MW power standard.As compared to traditional measurement,atom-based measurement is intrinsically calibrated where field strength is translated into Rabi frequency ? via well-known atomic constants.This dissertation reports on the development of a MW measuring technique via atomic Rabi resonances,also detailedly investigatesthe working principle and detection capacity of the proposed detector and its application to MW broadband characteristics measurement.The main contents are divided into four parts shown as follows.Firstly,the theoretical model of field measurement is developed based on atomic Rabi resonance theory.The development of an atomic MW field detector involves the interactions of atoms with a static magnetic field,a MW field,and an optical field.Therefore,the effects of the magnetic fields(including static and MW fields)on the atoms are analyzed,and the relationship between atomic Rabi frequency and the measured MW magnetic field is constructed in this dissertation.In particular,the Rabi resonance theory and the field measurement model based on it,are thoroughly studied here.In this field dectection technique,a phase-modulated field drives atomic Rabi resonance,which is a function of the modulation frequency ? and reaches its peak when ? = ??2.By scanning ? for a given input power,the resonance lineshape is obtained;then,?is determined by fitting the measured data to the theoretical model of field measurement.Then,a proof-of-principle experimental setup is constructed to validate the proposed Rabi resonance-based field detection technique.By using this detector,the field strength inside an X-band cavity is determined for applied power in the range of-21 dBm to 20 dBm.The comparison between the results measured by our approach and those calculated by simulationsshows a good agreement.Moreover,free space frequency transfer with passive phase conjunction correction is demonstrated to provide a possible basis for electromagnetic quantities transfer.The field detection technique via Rabi resonances on magnetic-insensitive transition states provides an alternate,direct means for accurate measurement of magnetic field strength inside a cell in gas-type atomic clocks.After that,a free space,low Q-factor cavity is designed to create a similar MW environment for different vapor cells that allows for comparison measurements.With this specially designed cavity,the dissertation investigates the resonance lineshapes for field detection under various measurement settings including cell temperature,laser intensities,and vapor pressures,to show how to optimize the present field detection technique.Finally,an approach for continuously frequency-tunable MW magnetic field detection using atomic Rabi resonances of different magnetic-sensitive hyperfine transitions,including ?transitions and?transition is presented in this dissertation.Over the past several years,atom-based MW detections were demonstrated only at discrete frequencies.Until the last two years,Dr.P.Treutlein group in Switzerland and Prof.G.Raithel group in Unite States reported on their works on MW magnetometry via Rabi oscillations and MW electrometry via electromagnetically induced transparency and Autler-Townes effects,respectively,both with the frequency-tunable abilities to detect MW field.In this dissertation,by exploring Rabi resonances' capacity for using magneticsensitive states,broadband field detection is also realized.And the MW field frequency to be detected can be tuned by adjusting the static field.To demonstrate the potential to evaluate the MW broadband characteristics,Rabi resonances on ? transitions,? |3,3 ? |4,4 transition,and ? |3,3 ? |4,4 transition are used to character the cavity resonating at 9.2 GHz,8.3 GHz,and 9.8 GHz,respectively.The obtained response curves show good agreements with those measured via vector network analyzer.To sum up,a new atomic MW magnetic field detection technique is developed in the dissertation,and a proof-of-principle experimental setup is constructed to validate the proposed Rabi resonance-based field detection technique.As a first application,the MW field strength inside an X-band cavity is determined with the field detector.Furthermore,as an additional innovative application,the response curves of cavities resonating at different frequencies are successfully measured with the developed broadband atombased technique,meaning that the atomic field detector functions partially as a networker analyzer.More importantly,thismeans that the MW cavity response can be linked directly to Rabi frequency,indicating thepossibility of evaluating the broadband MW characteristics with an atom-based,self-calibrated,SI-traceable means.