Four-wave Mixing Spectroscopy

In this dissertation we conclude the four-wave mixing(FWM)research and ultra－fast modulation spectroscopy(UMS)research which have been developed in the recent years,andstudy theory of the UMS．FWM was applied to the sodiumRydberg-atom system．In the sodium vapor we performed a seriesnon-degenerate four-wave mixing(NDFWM)experiments．We acquired aspectrum of high excited Rydberg－atoms,and also obtained high exciteddressed states of Rydberg-atoms．In addition we have studied onsaturation spectrum of a random Rydberg-atom and studied oninfluence of buffer gas pressure． NDFWM is a non-line optical method which is based on themedium's third-order nonlinear effect,which is usually usedexplore substance's properties,such as resonant and transient,the FWM signal light is a coherent light,which iscompletely Doppler－free spectroscopy,and meet with phasematching conditions,therefore has better direction,highexplore sensitivity,fine Signal-to-Background ratio,which havegood advantage of traditionally Rydberg-atom research methods．NDFWM which is of ten used as research technique can beextended using in other science studies．...