Glossary

Laser: acronym of : « light amplification by stimulated emission of radiation » ; device emitting spatially and temporally coherent light radiation based on the stimulated emission
Optical length of a cavity: optical length corresponding to a single round trip in the cavity
Longitudinal mode: resonnant wavelength or frequency of a laser or a Fabry Perot interferometer
Wavelength ( of a light wave ): distance between two consecutive identical states of the electric ( or magnetic ) field
Frequency: reverse value of the period
Free spectral range ( Fabry Perot ): distance between two consecutive longitudinal modes