Introduction to coherent multidimensional spectroscopy

Coherent multidimensional spectroscopy is a state-of-the-art technique with applications in a variety of subjects, such as chemistry, molecular physics, biochemistry, biophysics, and materials science. Due to dramatic advances in ultrafast laser technologies, a diverse range of coherent multidimensional spectroscopic methods utilizing combinations of THz, infrared, visible, UV, and X-ray radiation sources have been developed and used to study the real-time dynamics of small molecules in solutions, proteins and nucleic acids in condensed phases and membranes, single and multiple exciton states in functional materials like semiconductors, quantum dots, and solar cells, photo-excited states in light-harvesting complexes, ions in battery electrolytes, electronic and conformational changes in charge or proton transfer systems, and excess electrons and protons in water and biological systems. In this chapter, we introduce the theory behind coherent multidimensional spectroscopy and a summary of recent experiments.