The second-order correlation functions of the stimulated emisson in the case of a three-level cascade atom interacting with radiation fields initially in coherent states or chaotic states are disccused. It is found that there exists photon antibunching.
The time evolution of the antibunching and quantum beat is studied by considering the resonant interaction of two radiation fields with a cascade three-level atom. It is found that different initial atomic states and different ratios of the average photon number of two radiation fields as well as the different coupling coefficients have a remarkable influence on the antibunching and quantum beat of two radiation fields. By numerical summation and a number of figures, it is interesting to note that under certain conditions, some strange behaviour occurs in this cascade three-level atomic system. The explanation of these strange behaviours is given.
Expressions are derived for the intensity correlations or degrees of second-order coherence within and between two light beams of different frequency generated by cascade emission from a three-level atom. The atoms are assumed to be excited by two monochromatic coherent light beams in resonance with the upper and lower pairs of levels that constitute the triplet. The two emitted beams individually show photon antibunching and the correlation between the beams shows another complementary kind of non-classical effect. It is suggested that measurements on the system described here would provide more detailed information on quantum effects in cascade emission than previous observations with direct excitation to the uppermost atomic level by electron bombardment.
Photon statistics are obtained from exact closed-form solutions for both spontaneous and stimulated coherent emissions by a large number of two-level atoms in a Dicke state. Depending on the initial excitation level of the atoms, three types of photon statistics are obtained for the emitted radiation field. Moments of the photon number of the emitted field are calculated in the case of initial atomic coherent states as well as Dicke states, and in the case of n-photon stimulating pulses as well as coherent stimulating pulses. In the particular case of an initial "superradiant" Dicke state stimulated by a coherent-radiation field, the emitted radiation pulse is also fully coherent. In other cases the photon distributions undergo large fluctuations.