Spectral, Spatial, and Temporal Properties of Lasers

During the decade there were many developments in laser research and numerous applications of the laser were made in fields of science and engineering. Many theoretical and experimental ad­ vances were made in the Soviet Union; often they paralleled those taking place in the United States and elsewhere but started from different points, proceeded along different paths, and yielded dif­ ferent insights into the physical processes taking place in the la­ ser. The present book offers a unified theory of lasers by which the operating characteristics of the laser are described and re­ lated to the details of the radiation emitted. Extensive emenda­ tions to the original, Soviet edition were supplied by the author and incorporated into the text, and references to the English literature were added to the translation to permit the reader to readily ex­ plore topics in greater detail. Since the Soviet edition's appearance in 1968 one very impor­ tant area has developed-that of mode locking and picosecond pulse production. This area is so important that no comprehensive work on the laser published in 1972 could neglect it. Accordingly, Chap­ ter XII was added to round off the treatment. I am indebted to my colleague, Professor A. J. Carruthers of the University of Min­ nesota for many illuminating discussions on mode locking.

Basic Notation.- I. Certain Information from Luminescence Theory.- § 1. Absorption and Luminescence Spectra of Impurity Luminophors.- § 2. Nonradiative Transitions Between Electronic Levels of an Impurity Atom.- § 3. Nonradiative Energy Transfer Between Impurity Atoms.- Conclusions.- II. The Threshold and Output Power of a Laser.- § 4. The Effective Absorption Coefficient.- § 5. The Threshold Pumping Power.- § 6. The Output Radiation Power of a Laser.- Conclusions.- III. The Natural Oscillations of an Ideal Resonator (Linear Theory).- § 7. The Oscillation Modes of a Closed Resonator.- § 8. The Modes of an Open Resonator.- Conclusions.- IV. The Transverse Structure of the Electromagnetic Field in a Plane-Parallel Resonator.- § 9. The Equation for the Electromagnetic Field.- §10. The Field Distribution over a Cross Section Having the Shape of a Half-Plane.- § 11. The Intensity Distribution over a Cross Section Having Finite Dimensions.- § 12. The Diffraction Losses.- § 13. The Range of Application of the Treatment. Comparison with Experiment.- Conclusions.- V. Longitudinal Structure of the Electromagnetic Field in a Plane-Parallel Resonator.- § 14. The Longitudinal Mode of a Resonator Having an Infinite Cross Section.- § 15. The Number of Simultaneously Generated Longitudinal Modes.- § 16. The Electromagnetic Field in a Resonator Having a Finite Cross Section.- §17. The Effective Absorption Coefficient.- Conclusions.- VI. A Laser with Concave Reflectors.- §18. The Equivalent Mechanical System.- § 19. Taking Account of the Active Medium.- §20. Cylindrical Mirrors.- §21. Reflectors in the Shape of a Surface of Rotation.- § 22. The Spectral Composition of the Radiation.- § 23. The Transition to a Resonator with Plane Mirrors.- § 24. An Optical Resonator with Lenses.- Conclusions.- VII. Relaxational Intensity Oscillations.- §25. The Kinetic Equations.- §26. The General Picture of Oscillations of Stimulated Emission.- §27. Oscillations Having a Large Amplitude.- §28. Damping of Oscillations and Their Amplitudes.- §29. Range of Applicability and Experimental Data.- §30. Self Oscillations.- Conclusions.- VIII. The Spectral Width of the Radiation.- § 31. The Spectral Composition of the Radiation.- § 32. The Effect of Kinetic Operation on the Spectral Width of the Generation.- Conclusions.- IX. The Threshold Phenomena Related to Microinhomogeneity of the Active Medium.- § 33. Spectral Width of Radition from a Laser with an Inhomogeneously Broadened Luminescence Line. The Basic Equations.- § 34. The Spectral-Broadening Threshold.- § 35. The Equation for the Intensity of the Polarization Components.- § 36. The Second Generation Threshold.- § 37. The Intensity of the Fundamental Component under Conditions when the Second Component Cannot Be Generated.- § 38. The Degree of Polarization of the Radiation.- § 39. Comparison with Experimental Data.- Conclusions.- X. Active Q-Modulation.- § 40. Obtaining a Single Pulse by Means of Rapid Q-Switching.- § 41. Equations for Light Energy in a Resonator with Modulated Q.- § 42. Shape of the Intensity Peak.- § 43. Effect of a Finite Q-Switching Rate and Pump Nonuniformity on the Shape of the Peak.- § 44. Stimulated Intensity Oscillations.- Conclusions.- XI. Passive Q-Modulation.- § 45. The Mechanism of Passive Q-Modulation.- § 46. The Equation for a Passive Optical Shutter.- § 47. A Passive Shutter Open Either Negligibly or Completely.- § 48. Various Operating Modes of a Laser with a Passive Shutter.- Conclusions.- XII. Mode Locking and Ultrashort Pulses.- § 49. The Electric Field of a Multimode Laser.- § 50. Forced Mode Locking.- § 51. Self Mode Locking.- § 52. Pulse Velocity Inside the Cavity.- Conclusions.- References.