Nonlinear Optics

In this paper we investigated the dynamics of the processes occurring in a Q-switched laser. This work was stimulated by the lack of data on the spatial and temporal development of generation, despite the obvious importance of such data in the use of giant light pulses in in­ vestigations of the nonlinear interaction of radiation and matter. From a systematic con­ sideration of a relatively simple model of a Q-switched laser we analytically investigated two main phases of development of the giant pulse - the phase of linear development of generation, which begins with amplification of the spontaneous emission in the modes, and the phase of nonlinear transverse development, during which the giant light pulse proper is emitted. In ad­ dition, fo r a thorough inve stigation of the picture of development of the pulse as a whole the equations were numerically integrated. ' Subsequent experiments [26, 27] confirmed the occurrence of transverse development of the giant pulse, while recent experiments on nonlinear amplification [28] have shown the sig­ nificance of this effect in the propagation of the giant pulse in a nonlinear medium. A know­ ledge of the transverse development of the giant pulse would appear to be essential for the exact determination of the true strength of the light field in experiments on multi photon pro­ cesses [29]. The developed theory also leads to recommendations for the design of lasers to generate giant light pulses of minimum length and minimum divergence of emission.

Inhalt

Some Questions of Gas Laser Theory.- § 1. Optical Masers (Lasers).- § 2. Content, of Work.- I: Interaction of a Quantum System and an Electromagnetic Field.- 1. Induced Emission in a Strong Monochromatic Field.- § 3. Basic Equations.- § 4. Kinetics of Induced Transitions.- § 5. Induced Emission of Moving Atoms.- § 6. Spatial Inhomogeneity of Medium Due to Saturation Effect.- 2. Spontaneous Emission with Induced Transitions Taken into Account.- § 7. General Theory.- § 8. Spontaneous Emission of Stationary Atoms in an External Field.- § 9. Spontaneous Emission of Moving Atoms.- 3. Induced Emission and Absorption of a "Weak" Field in the Presence of a "Strong" Field.- § 10. Formulation of Problem.- § 11. Forced Emission and Absorption of Weak Field by Stationary Atoms in a Strong Monochromatic Field.- § 12. Induced Emission and Absorption of Weak Field by Moving Atoms.- 4. Effect of Atomic Collisions.- § 13. Classical Theory of Doppler Broadening of Spectral Lines with Collisions Taken into Account. General Theory.- § 14. Doppler Broadening.- § 15. Broadening Due to Interactions and Doppler Effect.- § 16. On the Relaxation Terms in the Equation for the Density Matrix.- § 17. The Saturation Effect with Collisions Taken into Account.- II. Application to Laser Theory.- 5. Monochromatic Generation.- § 18. Self-Consistent Problem.- § 19. One-Dimensional Laser Model.- § 20. Stationary Atoms.- § 21. Moving Atoms.- 6. Stability of Monochromatic Generation.- § 22. Formulation of Problem.- § 23. General Formulas.- § 24. Stationary Atoms.- § 25. Moving Atoms. Gas Losers.- Appendix. Spectroscopic Applications of Gas Lasers.- Literature Cited.- Interaction of Electromagnetic Fields with Active Media.- 1. Calculation of Polarization of Medium.- 2. One-Dimensional Laser Model. Monochromatic Generation.- 3. Some Properties of Two-Dimensional Active Resonators.- 4. Weak Fields in a Resonator Generating Monochromatic Radiation.- 5. Nonlinear Interaction of Weak Fields in the Presence of a Strong Monochromatic Field in a Traveling-Wave Amplifier.- Summary.- Literature Cited.- Electrodynamics of Lasers with an Open Resonator and Inhomogeneous Filling.- Literature Cited.- Dynamics of a Q-Switched Laser.- § 1. Formulation of the Problem. Basic Equations.- § 2. Initial Conditions.- § 3. Linear Development of Generation. Solution of Equations.- § 4. Field Distribution and Dependence on Initial Conditions.- § 5. Nonlinear Transverse Development of Generation.- § 6. Numerical Integration of Equations.- Summary.- Literature Cited.- Nonlinear Interactions of Electromagnetic Waves in an Active Medium and Their Possible Application to the Development of New Types of Lasers.- § 1. Derivation of Equations of Fields in "Resonance Parametic" and "Two-Photon" Lasers. Calculation of Nonlinear.- Polarization with Saturation Taken into Account.- § 2. Two-Photon Laser.- § 3. Generation of Submillimeter Waves by Two-Quantum Luminescence 183 § 4. Theory of the "Resonance Parametric" Laser in the Stable Phase Case.- § 5. Theory of the "Resonance Parametric" Laser at the Random-Phase Limit.- § 6. Discussion of Results and Experimental Approach To Their Realization.- Appendix 1. Quantum-Electrodynamic Description of Multiphoton Processes.- Appendix 2. Nonlinear Interactions with Random Phase. Comparison of Quantum and Semiclassical Descriptions of Nonlinear Interactions.- Literature Cited.