[1] [1] For resonant two-photon transition, see N. Bloembergen. Proposal for a new type solid state maser. Phys. Rev., 1956, 104(2): 324～327

[2] [2] P. T. Greenl, D. N. Travis, D. J. H. Wort. Resonant ionization polarization spectroscopy in uranium. J. Phys. (B): At. Mol. Opt. Phys., 1990, 23(17): 2945～2956

[3] [3] L. R. Wilcox, W. E. Lamb Jr.. Rate equations versus Bloche quations in multiphoton ionization. Phys. Rev., 1960, 119(6): 1915～1933

[4] [4] J. R. Ackerhalt, B. W. Shore. Rate equation versus Bloche quations in multiphoton ionization. Phys. Rev. (A), 1977, 16(1): 277～282

[5] [5] J. A. Paisner, R. W. Solarz. Resonance photoionization spectroscopy. in L. J. Redziemski et al. ed. Laser spectroscopy and its application. Optical Engineeringseries, New York: Marcel Dekker Inc., 1987. 175～260

[6] [6] J. E. Bjorkholm, P. F. Liao. Resonant enhancement of two-photon absorption in sodium vapor. Phys. Rev. Lett., 1974, 33(3): 128～131