The spectrum of a two-level atom in the presence of a multimode laser pulse is calculated. The field is allowed to fluctuate in amplitude or in phase; the emitted spectrum has richer emission lines than in the case of the nonfluctuating field and shows peaks shifted toward the blue with respect to the traditional harmonic peaks. The position of the lines is predicted by the formula ω<sub>2<i>n</i>+1</sub> = (2<i>n</i> + 1)(1 + Δ)ω<sub><i>L</i></sub> with Δ being a parameter that can be found numerically. In this way the fluctuations seem to result in an effective increase of the laser frequency.
© 1998 Optical Society of America
Emilio Fiordilino, Francesca Morales, and Rosalba Daniele, "Fluctuating laser field that induces a blueshift in harmonic generation," J. Opt. Soc. Am. B 15, 118-121 (1998)