Coherent Nonlinear Optics

1. Coherent Nonlinear Optics.- 1.1 Introductory Comments.- References.- 2. Superradiance.- 2.1 Background Material.- 2.2 Physical Principles.- 2.3 Theoretical Treatments.- 2.3.1 Initiation of Superradiance: Quantized Field Treatment.- 2.3.2 Semiclassical Theory.- 2.4 Results of the Theory.- 2.4.1 Superradiance in the Ideal Limit.- 2.4.2 Influence of Quantum Fluctuations.- 2.4.3 Deviations from Ideal Behavior.- Finite Inversion Time.- Uniform Inversion: Cooperation Length.- Decay and Dephasing Times.- Feedback Initial Polarization.- Initial Polarization.- 2.4.4 Further Discussion of the Basic Assumptions.- Neglect of Interaction of Forward and Backward Waves.- Limitations of the Plane Wave Approximation.- 2.4.5 Point Sample Superradiance.- 2.5 Relation to Other Coherent Phenomena.- 2.5.1 Limited Superradiance.- 2.5.2 Transient Phenomena in Optically Thick Media.- 2.5.3 Stimulated and Superradiant Emission.- 2.6 Experiments.- 2.6.1 Experimental Observation of Superradiance.- 2.6.2 Recent Experimental Results.- 2.6.3 Comparison with Theory.- 2.7 Concluding Remarks.- 2.7.1 Applications.- 2.7.2 Summary.- References.- 3. Coherence in High Resolution Spectroscopy.- 3.1 Coherent Phenomena in Resonant Processes.- 3.2 Coherent Phenomena in Saturated Absorption Spectroscopy.- 3.2.1 Standing Wave.- 3.2.2 Probe Wave Resonances.- Oppositely Traveling Waves.- Unidirectional Waves.- High-Frequency Stark Effect on Doppler Broadened Transitions.- Spectroscopic Applications. Measurement of Relaxation Constants.- Study of Level Structures and Separation of Weak Lines.- Optical Instability. Generation Stability.- Recoil Effect.- 3.2.3 Influence of Collisions on Coherent Processes.- Study of Relaxation Processes.- Dipole Scattering.- Influence of the Elastic Scattering Without Phase Randomization on Resonance Characteristics.- 3.3 Coherent Phenomena in Multilevel Systems.- 3.3.1 Resonant Processes in Three-Level Systems.- 3.3.2 Two-Photon Resonances.- 3.3.3 Relation to Other Phenomena.- 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 Transitions.- 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 Travelling 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 Nonexact Resonance and Its Compensation by Power Broadening.- Step-Function Laser Pulse.- Adiabatically Switched-On Pulse.- General Estimates for Maximum Detuning.- 5.3 Interaction of Nonequidistant Multilevel Systems with a Quasi-Resonant Field.- 5.3.1 Multiphoton Resonances.- Rabi Frequency for Multiphoton Transitions.- 5.3.2 Numerical Calculations for Multilevel Systems.- 5.3.3 Dynamic Stark Effect and Frequency Shifts.- An Analytically Solvable Example.- General Approach to an Approximate Description of the Dynamics of Oscillator-Type Systems.- Upper Subsystem - Harmonic Oscillator.- Upper Subsystem with Equal Dipole Moments.- 5.3.4 "Leakage" from the Lower Quantum States into the Upper Levels.- 5.3.5 Excitation of Multiplet Systems with a Quasi-Continuous Structure of Transitions.- 5.4 Excitation of Triply-Degenerate Vibrational Modes of Spherical-Top Molecules.- 5.4.1 Vibrational States and Vibrational Hamiltonian.- Expression of the Hamiltonian in Terms of Cartesian Creation and Annihilation Operators.- Orders of Magnitude of Anharmonic Operators.- Final Form of the Vibrational Hamiltonian.- Comparison with Hecht's Hamiltonian.- The Spherical Vibrational Basis.- Eigenvalues of the Vibrational Hamiltonian.- 5.4.2 Physical Significance of Vibrational Anharmonic Parameters.- 5.4.3 Rotational States and Vibration-Rotation Bases.- Rigid-Rotor Wave Functions.- Coupled Vibration-Rotation Basis.- Symmetry-Adapted Vibration-Rotation Basis.- 5.4.4 Vibration-Rotation Hamiltonian.- 5.4.5 Dipole Transition Moments in Spherical-Top Molecules.- 5.4.6 Experimental Determination of the Anharmonic Parameters of the v3 Mode of SF6.- Effective-State Models for Molecular Multiphoton Calculations.- Absorption Strength of an Ensemble of Two-Level Systems.- Effective-State Equations of Motion.- Dipole Transition Moments Between Effective States.- Calculation of Degeneracies and Transition Strengths.- 5.4.8 Calculation of Multiphoton Excitation Including a Thermal Distribution of Initial State.- 5.4.9 Numerical Calculations of Multiphoton Excitation of SF6.- References.- 6. Coherent Picosecond Interactions.- 6.1 Overview.- 6.2 Theory of Investigations.- 6.2.1 Excitation Process.- 6.2.2 Coherent Probing.- 6.3 Experimental.- 6.3.1 Generation of Ultrashort Laser Pulses.- 6.3.2 Coherent Excitation and Probing Techniques.- 6.4 Experimental Results and Discussion.- 6.4.1 Modes with Homogeneous Line Broadening.- 6.4.2 Modes with Discrete Substructure.- 6.4.3 Modes with Inhomogeneous Line Broadening.- 6.4.4 Vibrational Modes in Solids.- 6.5 Interaction Processes.- References.- 7. Coherent Raman Spectroscopy.- 7.1 Historical Background.- 7.1.1 Prehistory.- 7.1.2 The Tunable Laser Era.- 7.2 Theory.- 7.2.1 Extended Two-Level Model for Coherent Raman Spectroscopy.- 7.2.2 The Nonlinear Polarization.- Stimulated Raman Gain and Loss Spectroscopy, and the Raman Induced Kerr Effect.- Coherent Anti-Stokes and Coherent Stokes Raman Spectroscopy.- Four-Wave Mixing.- Photoacoustic Raman Spectroscopy.- 7.2.3 The Nonlinear Susceptibility Tensor.- 7.2.4 Doppler Broadening.- 7.2.5 Symmetry Considerations.- 7.2.6 Relationship Between xR and the Spontaneous Cross Section.- 7.2.7 The Coherent Raman Signal.- 7.2.8 Focusing Considerations.- 7.2.9 Accentric Crystals and Polaritons.- 7.2.10 Resonant Effects and Absorbing Samples.- 7.3 Experimental Techniques.- 7.3.1 CARS in Liquids and Solids.- 7.3.2 CARS in Gases: Pulsed Laser Techniques.- 7.3.3 Multiplex CARS.- 7.3.4 CW CARS.- 7.3.5 Nonlinear Ellipsometry.- 7.3.6 Raman Induced Kerr Effect Spectroscopy (RIKES).- 7.3.7 Optical Heterodyne Detected RIKES.- 7.3.8 Stimulated Raman Gain and Loss Spectroscopy.- 7.3.9 Four-Wave Mixing.- 7.3.10 Signals, Noise and Sensitivity.- 7.3.11 Signal Enhancement with Interferometers, Intra-Cavity Techniques and Multipass Cells.- 7.4 Applications.- 7.4.1 Combustion Diagnostics: Concentration and Temperature Measurement.- 7.4.2 Raman Cross Section and Nonlinear Susceptibility Measurements.- 7.4.3 High-Resolution Molecular Spectroscopy.- 7.4.4 Raman Spectra of Fluorescent and Resonant Samples.- 7.4.5 Polariton Dispersion: Spectroscopy in Momentum Space.- 7.4.6 Low Frequency Modes.- 7.4.7 Vibrational and Rotational Relaxation Measurements.- 7.5 Conclusions.- References.- Additional References with Titles.