Emission and Absorption of Light, Einstein's Relations, Inverted distribution, and Gain Factor, Optical Resonances, Laser Patterns. Laser’s Type: Solid-State Lasers, Semiconductor Lasers, Gas Lasers, Liquid Dye Lasers, Free Electron Laser and Some Modern Lasers. Laser Beam Characteristics: Laser Spectrum Spectroscopy, Beam Diffraction, Beam Interconnection, Luminescence, Laser Beam Synthesis, Q Modulation, Frequency Multiplication, Phase conjugation .Laser Applications: Medical, Industrial, Military, Scientific, Standard, Holographic, and Communication.