§04§1. Coherent Nonlinear Optics.- 1.1 Introductory Comments.- References.- 2. Superradiance.- 2.1 Background Material.- 2.2 Physical Principles.- 2.3 Theoretical Treatments.- 2.4 Results of the Theory.- 2.5 Relation to Other Coherent Phenomena.- 2.6 Experiments.- 2.7 Concluding Remarks.- References.- 3. Coherence in High Resolution Spectroscopy.- 3.1 Coherent Phenomena in Resonant Processes.- 3.2 Coherent Phenomena in Saturated Absorption Spectroscopy.- 3.3 Coherent Phenomena in Multilevel Systems.- 3.4 Method of Separated Optical Fields.- References.- 4. Multiphoton Resonant Processes in Atoms.- 4.1 Various Experimental Aspects of Resonant Multiphoton Transitions in Atoms.- 4.2 Doppler-Free Two-Photon Experiments.- 4.3 Theory of Two-Photon Transitions in Atoms.- 4.4 Multiphoton Transitions.- 4.5 Dispersion Near a Two-Photon Resonance.- 4.6 Transient Processes Involving Doppler-Free Two-Photon Excitation.- References.- 5. Coherent Excitation of Multilevel Systems by Laser Light.- 5.1 §04§ Multilevel Molecular Systems.- 5.2 Interaction of Equidistant Nondegenerate Multilevel Systems with a Quasi-Resonant Field.- 5.3 Interaction of Nonequidistant Multilevel Systems with a Quasi-Resonant Field.- 5.4 Excitation of Triply-Degenerate Vibrational Modes of Spherical-Top Molecules.- References.- 6. Coherent Picosecond Interactions.- 6.1 Overview.- 6.2 Theory of Investigations.- 6.3 Experimental.- 6.4 Experimental Results and Discussion.- 6.5 Interaction Processes.- References.- 7. Coherent Raman Spectroscopy.- 7.1 Historical Background.- 7.2 Theory.- 7.3 Experimental Techniques.- 7.4 Applications.- 7.5 Conclusions.- References.- Additional References with Titles. §04§enomena.- 3.4 Method of Separated Optical Fields.- 3.4.1 Two-Photon Resonance in Separated Fields.- Narrow Two-Photon Absorption Resonances of the Sequence of Supershort Pulses in a Gas.- 3.4.2 Resonance in Separated Fields for Two-Level Atoms.- 3.4.3 Coherent Radiation and Macroscopic Polarization Transfer in Separated Fields.- 3.4.4 Properties of Coherent Radiation in Separated Fields.- Destruction of an Interference Structure and Attainment of Resonances with a Radiative Width.- Particle Scattering.- 3.4.5 Coherent Raman Scattering in Separated Fields.- 3.4.6 Transient Resonant Coherent Effects.- References.- 4. Multiphoton Resonant Processes in Atoms.- 4.1 Various Experimental Aspects of Resonant Multiphoton Transitions in Atoms.- 4.1.1 Selective Pumping of an Excited Level with Multiphoton Transition.- 4.1.2 Intermediate Step in Other Processes.- 4.1.3 Spectroscopy Using Broadband Lasers.- 4.2 Doppler-Free Two-Photon Experiments.- 4.2.1 Principle of Doppler-Free Multiphoton T §04§ransitions.- 4.2.2 Experimental Observation of Doppler-Free Two-Photon Transitions.- Typical Experiment in Sodium.- Thermoionic Detection.- 4.2.3 Doppler-Free Two-Photon Transitions in Hydrogen.- 4.2.4 Other Possibilities of Doppler-Free Two-Photon Transitions.- 4.2.5 Experiments with Two Different Light Sources.- 4.3 Theory of Two-Photon Transitions in Atoms.- 4.3.1 The Effective Hamiltonian.- 4.3.2 Solution of the Density Matrix Equation.- 4.3.3 Case of Two Waves with Complex Polarizations.- 4.3.4 Two-Photon Line Shape in Vapors.- 4.3.5 Light Shifts.- Comparison with Experiments.- 4.3.6 Selection Rules for Two-Photon Transitions.- 4.4 Multiphoton Transitions.- 4.4.1 Generalization of the Effective Hamiltonian.- 4.4.2 Discussion of the Light Shifts.- Case of a Standing Wave.- 4.4.3 Application to Multiphoton Ionization.- 4.4.4 Doppler-Free Three-Photon Transition.- 4.4.5 Three-Photon Selection Rules.- 4.5 Dispersion Near a Two-Photon Resonance.- 4.5.1 Refractive Index for a Trave §04§lling Wave.- 4.5.2 Refractive Indices for Two Waves of Different Frequencies.- 4.5.3 Refractive Index for a Standing Wave.- 4.6 Transient Processes Involving Doppler-Free Two-Photon Excitation.- 4.6.1 Free Induction Transients.- 4.6.2 Transients in the Driven Regime.- References.- 5. Coherent Excitation of Multilevel Systems by Laser Light.- 5.1 Multilevel Molecular Systems.- 5.1.1 The Schrödinger Equation for Multilevel Systems in the Rotating-Wave Approximation.- 5.1.2 "Quasi-Energy" or "Dressed-States" Approach for Multilevel Systems.- Constant Optical Electric Field.- Adiabatic Switching on of the Field.- 5.2 Interaction of Equidistant Nondegenerate Multilevel Systems with a Quasi-Resonant Field.- 5.2.1 Analytical Solutions for an Exactly Resonant Field.- Harmonic Oscillator.- Infinite System with Equal Dipole Moments.- A System with Decreasing Dipole Moments.- N-Level System with Equal Dipole Moments.- 5.2.2 Does Resonance Always Result in Effective Excitation?.- 5.2.3 Nonexa
