SPECTRAL FEATURES OF FM SPECTROSCOPY OF 2-PHOTON INTERACTIONS

The spectral features of FM two-photon resonant interaction processes have been calculated for five different frequency modulation versions of counter-propagating incident fields. It is found that the proposed new modulation version (case b in the text) provides novel spectral fe atures for a completely canceled absorption and a sharp dispersion sha pe at the fundamental beat note. Moreover, its absorption feature appe ars at the second harmonic of the RF modulation frequency generated by the joint modes via six interaction pathways without mutual phase shi ft. Such features persist even when the effects of the second-order si debands of the incident fields are taken into account. Application pot entials are emphasized,