Abstract
The theory of light emission due to the decay of a coherent superposition of states to some lower state is outlined with special emphasis on a coherently excited two level system. With foil excitation several types of coherence have to be considered. The effects of these are demonstrated with quantum beat measurements in the electromagnetic and zero fields in H and He emission: (a) foil-, (b) electric field-, and (c) magnetic field-induced coherence. The information carried about the initial wavefunctions by the beat amplitudes and phases is discussed for each case, with main interest in the production of alignment of M L states. Based on these considerations, the determination of fs and hfs separations with quantum beat, magnetic resonance and level- crossing measurements is possible. With the derivation of the formula for the level-crossing signal, it is shown that this observation method is not sensitive to beam velocity uncertainties and is therefore well suited for precision measurements on ions after beam-foil excitation. The observation of level-crossing and Hanle effect in He emission is presented.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
