Modes and states in Quantum Optics

Understand

A few decades ago, quantum optics stood out as a new domain of physics by exhibiting states of light with no classical equivalent.

• The first investigations concerned single photons, squeezed states, twin beams and EPR states, that involve only one or two modes of the electromagnetic field.
• The study of the properties of quantum light then evolved in the direction of more and more complex and rich situations, involving many modes, either spatial, temporal, frequency, or polarization modes.
• Actually, each mode of the electromagnetic field can be considered as an individual quantum degree of freedom.