Atoms in Strong Light Fields

The monograph is devoted to phenomena of nonlinear optics appearing on a macro scopic level in the interaction of intense light with an isolated atom. It is a first attempt to summarize the elementary phenomena of nonlinear optics and present the various methods used in experiment and theory. In essence, this book can be considered an expanded version of the new aspect of quantum mechanics and atomic physics that in time will be incorporated into te- books on this subject. By the middle of this century the interaction of light with atoms had become one of the most investigated branches of physics. However, in the mid-sixties the development of high-power lasers changed this situation completely. It is a well-known fact that lasers are essentially new sources of light with high intensity, sharp directivity, and practically ideal monochromaticity. Entirely new phenomena came up in the studies of the interaction of light with atoms. In an intense light field, multiphoton transitions become important. The field disturbs the atomic levels, shifting, broadening, and mixing them. In an extremely strong field the atom ceases to be a bound system. These and similar phenomena on the atomic (microscopic) level determine the variations in the averaged, macroscopic properties of the medium, variations that cause nonlinear-optics phenomena, which radically change the fundamental classical laws of the interaction of light with matter.

Contenu
1.1 The Strong Light Field.- 1.2 The Atom.- 1.3 Interaction of an Atom and a Light Field.- 2. Time-Dependent Perturbation Theory.- 2.1 First-Order Perturbation Theory.- 2.2 Second-Order Perturbation Theory.- 2.3 The Diagrammatic Technique for Monochromatic Perturbations...- 2.4 Perturbation Theory of Arbitrary Order.- 2.5 Monochromatic Perturbation and Degenerate States.- 2.6 The Green's Function in Time-Dependent Perturbation Theory.- 3. The Resonance Approximation.- 3.1 A Two-Level System in a Resonance Field.- 3.2 Multi-Photon Resonance.- 3.3 Degeneracy in a Resonance Field.- 3.4 A Two-Level System in a Circularly Polarized Electromagnetic Field.- 3.5 A Two-Level System in a Resonance Field: Time-Dependent Parameters.- 3.6 A Three-Level System in Two Fields.- 4. The Adiabatic Approximation.- 4.1 General Theory.- 4.2 Bound-Bound Resonance Transitions.- 4.3 A Two-Level System in a Strong Field of Arbitrary Frequency.- 4.4 Transitions Between Degenerate States.- 4.5 Bound-Free Transitions.- 5. Laser Radiation.- 5.1 Intensity of Radiation.- 5.2 Frequency of the Radiation.- 5.3 The Polarization of the Radiation.- 5.4 The Monochromaticity of Laser Radiation.- 6. Experimental Aspects.- 6.1 Atomic Target.- 6.2 Competing Processes.- 6.3 The Self-Induced Distortion of Intense Light in Atomic Targets.- 6.4 Experimental Methods for Studying the Phenomena Produced by Strong Electromagnetic Fields Interacting with Atoms.- 6.5 The Measurement of the Main Parameters that Characterize the Interaction Between Intense Electromagnetic Radiation and an Atom.- 7. Nonresonant Phenomena.- 7.1 Nonlinear Atomic Susceptibilities.- 7.2 Perturbation of Isolated Atomic States.- 7.2.1 Dynamic Polarizability of an Isolated Nondegenerate Atomic State.- 7.2.2 Dynamic Hyper-Polarizability.- 7.2.3Criteria for Applying Perturbation Theory.- 7.2.4 The Dynamic Polarizability as a Function of the Perturbing Field.- 7.2.5 Experimental Data.- 7.3 Perturbation of Degenerate States.- 7.4 Nonlinear Scattering of Light.- 7.5 Nonresonant, Nonlinear Ionization.- 7.6 Ionization in a Short-Range Potential.- 7.7 The Ionization of Atoms.- 8. Resonance Phenomena.- 8.1 Spontaneous Emission of Light by an Atom in a Resonance Field.- 8.2 Resonance Fluorescence.- 8.3 Multi-Photon Excitation and Emission.- 8.4 Spontaneous Raman Scattering.- 8.5 A Three-Level System in Two Resonance Fields.- 8.6 Resonance Ionization of Atoms.- 9. Conclusion.- 9.1 The Role of the Non-monochromaticity of Laser Radiation.- 9.2 Many-Electron Approximation.- 9.3 Ultrahigh Fields.- 9.4 Highly Excited Atomic States in a Strong Electromagnetic Field.- Notation Index.- References.