Adiabatic processes in frequency conversion

Adiabatic evolution, an important dynamical process in a variety of classical and quantum systems providing a robust way of steering a system into a desired state 1-5, was introduced only recently to frequency conversion 6-9. Adiabatic frequency conversion allowed the achievement of efficient scalable broadband frequency conversion 8, 9 and was applied successfully to the conversion of ultrashort pulses, demonstrating near-100% efficiency for ultrabroadband spectrum 10-16. The underlying analogy between undepleted pump nonlinear processes and coherently excited quantum systems was extended in the past few years to multi-level quantum systems, demonstrating new concepts in frequency conversion, such as complete frequency conversion through an absorption band 17-20. Additionally, the undepleted pump restriction was removed, enabling the exploration of adiabatic processes in the fully nonlinear dynamics regime of nonlinear optics 21-26. In this article, the basic concept of adiabatic frequency conversion is introduced, and recent advances in ultrashort physics, multi-process systems, and the fully nonlinear dynamics regime are reviewed.