Li Yue-Ke’s scientific contributions

The emission spectrum of a two-level atom interacting with a single mode radiation field in the case of periodic oscillation coupling coefficient is investigated. A general expression for the emission spectrum is derived. The numerical results for the initial field in pure number stare are calculated. It is found that the effect of the coupling coefficient modulation on the spectral structure is very obvious in the case of a low modulation frequency and larger amplitude when the initial field is vacuum, which is potentially useful for exploring a modulated light source.

The cavity field spectra of two modes field both in the binomial state interacting with a two-level atom in an ideal cavity is investigated. The results for the weak initial fields are calculated. The influence of the quantum interference on the cavity field spectra is discussed. It’s shown that the quantum interference term performs periodical damped oscillation with the changing of the difference of the two field frequencies. The periodicity is about 016 g（g is the coupling coefficient between the atom and the fields）. When the difference of the two field frequencies is larger than 16 g, the quantum interference term can be ignored. Otherwise, the quantum interference term is related to photon number of initial field. The quantum interference term strengthens gradually with the photon number increasing, but weakens abruptly when the maximal photon number becomes greater than 4 The quantum interference phenomenon almost vanishes when the photon number is greater than 6.

The cavity field spectrum of the nondegenerate two-photon Jayners-Cummings model with an additional Kerr medium is investigated. The results for the initial fields in binomial states are presented. The influence of the Kerr effect on the quantum interference of the two mode cavity field spectra is discussed. It is found that the quantum interference item shows a periodical damped oscillation irregularly when the Kerr effect is increased. The amplitude of the oscillation relate to the difference of the two field frequencies intimately. When the Kerr coefficient χg (g is coupling coefficient between atom and the fields), the change of the quantum interference item is strong with χ. And when χ>g, it is weakly. The cavity field spectra usually take on a complex asymmetric structure with many peaks when Kerr coefficient is large.

The cavity field spectra of two different atoms interacting with two-mode field s through Raman process are studied.The effects of relative coupling constant R=g2/g1 on the spectrum structure are discussed.It is found thatR pla ys a different role in the syectrum for vacuum,weak or strong initial field.Dege nerate spectrum structure appears usually forR=1 orR=0.A complicated a symmetric multipeak structure appears when R is between 0 and 1.When the f ield of upper frequency mode is vacuum,its spectrum is influenced sensitively by the field intensity of the other mode for fixed R.