The analogy is a fundamental tool for understanding Mother Nature since it associates various phenomena related by common properties or comparable behavior. In particular, the analogies between classical physics and the quantum world show the fact that similar scientific formalisms apply to phenomena that are completely different. The role of mathematics is essential because the analogy principle exists in the fact that totally different systems can be modeled by similar mathematical equations. Specifically, analogies between quantum mechanics and wave optics have been emphasized since the beginning of quantum mechanics: wave effects like interference and diffraction were taken from optics and applied to exhibit the wavy idea of quantum particles, such as electrons, neutrons, and atoms. After the complete development of quantum theory, the exchange of ideas in the opposite way started to happen. In the recent decade quantum-classical analogies have seen a great revival thanks to quantum control schemes for the transfer of populations, such as excitation with the rapid adiabatic passage, stimulated Raman adiabatic passage, and composite pulses.
Adiabatic processes in a dynamical system occur when an external perturbation of the system varies very slowly compared to its internal dynamics, allowing the system the time to adapt to the external changes. Mathematically, it means that for the entire dynamical evolution, the system remains at one of the eigenmodes of the system.
Composite pulses are solutions to arbitrary optimization problems in a quantum system, driven by an external radiation field. The basic idea is to improve the performance of single-pulse excitation processes by applying multi-pulse (i.e. composite pulse) processes. The phases of the pulses in the composite sequence are appropriately chosen to yield a better performance of the composite excitation process compared to the single-pulse excitation.
Now in this book, we will use the concepts of composite pulses and adiabatic evolution, from the realm of coherent quantum control, to demonstrate: (a) novel robust polarization manipulation devices, (b) efficient broadband and scalable
frequency conversion schemes as well as optical parametric amplification schemes, (c) several new optical isolators, (d) several control schemes in waveguide arrays.
All of this research is done by making the analogy between quantum mechanics and classical optics.