Laser-induced continuum structure

However, we pick out one specific aspect here, because its appreciation does not require a detailed preliminary discussion of the underlying high field interactions the use of a laser to create or embed autoionising structure in an existing continuum is of great significance to the study of how the symmetries of autoionising resonances can be reversed (the so-called q-reversal effect, first discovered in the spectrum of an unperturbed neutral atom [382]). 

If the probing conditions are appropriate (for further discussion, see section 9.12), the induced structure is expected to possess a Beutler-Fano profile, with the specific attraction that both the resonance energy and the width are controllable, which gives some experimental meaning to the otherwise somewhat elusive concept of prediagonalisation in Fano s theory (see chapter 6). 

Unfortunately the detailed situation in LICS experiments is rather complex, and more processes are involved, even in the simplest situation, than in the simple autoionisation problem. To make this clear, consider the LICS and third harmonic generation experiment illustrated in fig. 8.4. We 

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Jian Zhang (1991) Laser-induced Continuum Structure and Third Harmonic Generation in One- and Two-valence Electron Atoms PhD thesis. University of Southern California... 

Coherence Effects in Laser-Induced Continuum Structure... 

Abstract We review recent developments in coherence related phenomena involving metastable states embedded in (multiple) continua via the action of (strong) laser pulses. The role of Laser-Induced Continuum Structure (LICS)... 

Laser-induced continuum structure (LICS) [1, 2] is one such effect. LICS experiments involve using a ("dressing") laser field fo strongly couple an unpopulated bound state to a continuum. A different ("probe") laser field is made to couple a second, populated, bound state to the same continuum. The result is that the transition rate to the continuum acquires a "Fano-resonance" [3]-type shape. 

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