Summary

Absorption and emission of the light;
Einstein theory of spontaneous and stimulated emission, Einstein coefficients;
Quantum electrodynamics approach to emission and absorption;
Line broadening: natural broadening, pressure broadening, Doppler broadening;
Radiation transfer,
Beer-Lambert law for absorption and absorption coefficient and small signal gain;
Rate equations and conditions for population inversion;
gain saturation;
laser: amplifier and oscillator; Q-switching;
light scattering.