This course is an introductory lecture about light and lasers, providing comprehensive description of the physics underlying the operation of lasers.
After introducing the main physical processes responsible for light emission, this lecture develops a comprehensive treatment for the fundamental concepts of lasers physics and the basic operation principles. Spatial, temporal and coherence properties of laser light are also explored. Detailed example and tutorials are included.
1. Light emission
Historical context, thermal and blackbody emission, spontaneous and stimulated emission, spatial and temporal coherence.
2. Photon-atom interaction.
Energy levels, radiative and non-radiative transitions, Einstein coefficients, levels populations, rate equations.
3. Light amplification
Conditions for amplification, pumping and population inversion, 2-level, 3-level and 4-level systems, gain and saturation.
4. The laser oscillator
Conditions for laser starting, resonant oscillation, steady-state regime, output intensity.
5. Laser cavities and laser beams
Longitudinal modes, cavity stability, transverses modes and Gaussian beams.
6. Pulsed regimes
Spiking, Q-switch, Modelock