Radiation Emitted from Semiconductor Lasers in Strong Magnetic Fields and under High Hydrostatic Pressures.- I Influence of Magnetic Fields and High Pressures on Energy Spectra of Semiconductors.- §1. Influence of Magnetic Fields on Energy Structure of III–V and IV–VI Semiconductor Compounds.- §2. Influence of Pressure on Energy Structures of III–V and IV–VI Compounds.- §3. Characteristics of Semiconductor Laser Operation Affected by Variation of Temperature, Pressure, and Magnetic Field.- II Experimental Method.- §1. Apparatus for Excitation of Injection Lasers and Recording of Emission Spectra.- §2. Q-Switched CO2 Laser.- §3. Technique Used in Low-Tempe rature Magnetooptic Investigations at Infrared Wavelengths.- §4. Apparatus Used in Optical Measurements at Infrared Wavelengths under High Hydrostatic Pressures at 77°K.- §5. Zinc- and Copper-Doped Germanium Infrared-Radiation Detectors.- §6. Scanning of Infrared Radiation Emitted from InSb Crystals.- §7. Other Measurements.- III Influence of Magnetic Fields on Emission Spectra of p-n Junctions in InAs, InSb, and PbSe.- §1. Spontaneous and Coherent Radiation Emitted from InAs Injection Lasers.- §2. Radiation Emitted from InSb Injection Lasers in Strong Magnetic Fields. Position of Light-Emission Region.- §3. Spontaneous and Coherent Radiation Emitted from p-n Junctions in PbSe,.- IV Magnetically Tuned Stimulated Raman Emission from Indium Antimonide.- §1. Raman Scattering of Light by Plasmons and Landau Levels in Semiconductors.- §2. Stimulated Raman Scattering of Light Accompanied by Spin Flip in Indium Antimonide.- §3. Discussion of Results.- V Influence of Pressure on Radiation Emitted from Lead Selenide and Gallium Arsenide Semiconductor Lasers.- §1. Emission Spectra of PbSe Lasers.- §2. Emission Spectra of GaAs Lasers.- §3. Discussion of Results.- Conclusions.- Literature Cited.- Investigation of the Collective Properties of Excitons in Germanium by Long-Wavelength Infrared Spectroscopy Methods.- I Energy Spectra and Collective Properties of Excitons in Semiconductors.- 1. Energy Spectrum of Excitons.- §1. Theoretical Calculations.- §2. Experimental Results.- 2. Collective Properties of Exciton Systems.- §1. Theoretical Representations.- §2. Discussion of Experimental Results.- II Methods used in Far-Infrared Investigations of Excitons in Semiconductors.- §1. Spectroscopic Measurements.- §2. Apparatus Used in Low-Tempe rature Optical Measurements under Interband Excitation Conditions.- §3. Sources of Exciting Radiation.- §4. Thermal Conditions.- III Far-Infrared Resonance Absorption in Condensed Exciton Phase in Germanium.- §1. Absorption Spectra of Intrinsic Germanium.- §2. Discussion of Parameters of Electron —Hole Drops (n0 and ?).- §3. Temperature Dependence of Resonance Absorption.- §4. Dependence of Resonance Absorption on Excitation Rate.- §5. Resonance Absorption in Doped Germanium.- IV Resonance Luminescence of Condensed Exciton Phase in Germanium.- §1. Experimental Investigation of Resonance Luminescence.- §2. Discussion of Experimental Results. Effective Luminescence Temperature of Drops.- §3. Influence of Inhomogeneous Deformation on Resonance Absorption and Luminescence. Mobility of Electron-Hole Drops.- V Photoionization and Excitation of Free Excitons in Germanium by Submillimeter Radiation.- §1. Photoionization and Excitation Spectra.- §2. Discussion of Experimental Results. Energy Levels of Excitons.- Literature Cited.- Collective Interactions of Excitons and Nonequilibrium Carriers in Gallium Arsenide and Silicon.- I Collective Interactions of Excitons in Semiconductors.- II Measurement Method.- §1. Optical System and Method of Recording Luminescence during Continuous Optical Excitation.- §2. Optical System and Method of Recording Luminescence Due to High-Power Light Pulses.- §3. Temperature Measurement Method.- §4. Determination of Temperature Rise in a Semiconductor during Continuous Optical Excitation.- §5. Determination of Temperature Rise in a Semiconductor during Illumination with High-Power Light Pulses.- III Photoluminescence of Gallium Arsenide.- §1. Excitons in GaAs and Their Role in Radiative Recombination.- §2. Investigation of Luminescence Spectra of GaAs at Different Optical Excitation Rates and Helium Temperatures.- §3. Photoluminescence of GaAs at Temperatures 2–100°K. Investigation of Temperature Dependence of Recombination Radiation Intensity.- §4. Photoluminescence Spectra of GaAs at T = 77°K.- §5. Discussion of Results.- §6. Supplement. Possibility of Existence of Condensate in Pure Epitaxial GaAs Films.- IV Change in Absorption Coefficient of Undoped GaAs Due to Strong Optical Excitation.- V Investigation of Photoluminescence Spectra of Silicon at Different Optical Excitation Rates.- §1. Review of Literature.- §2. Experimental Investigation of the Photoluminescence of Si at Different Optical Excitation Rates.- §3. Photoluminescence Spectra of Si at Different Temperatures. Investigation of the Temperature Dependence of the Luminescence Intensity.- §4. Determination of the Binding Energy of Free Excitons from the Fall of the Luminescence Intensity with Rising Temperature.- §5. Discussion of Experimental Results.- VI Photoelectric Properties of Silicon at High Optical Excitation Rates.- §1. Review of Literature.- §2. Measurement Method.- §3. Photoluminescence Spectra of Si in the Presence of Static Electric Fields. Impact Ionization of Free Excitons.- §4. Kinetics of Recombination Processes in Si.- §5. Investigation of Excitons at High Concentrations in Weak Electric Fields.- Literature Cited.