
Introduction.- Background.- Nonlinear Optical Signals.- Excited State Distributions and Fluorescence Signals.- Pump-Probe Measurements with Entangled Photons.- Interferometric Setups.- Frequency Conversion.- Trapped Ion Spectroscopy.- Conclusions and Outlook.

Introduction.- Background.- Nonlinear Optical Signals.- Excited State Distributions and Fluorescence Signals.- Pump-Probe Measurements with Entangled Photons.- Interferometric Setups.- Frequency Conversion.- Trapped Ion Spectroscopy.- Conclusions and Outlook.