Strong-field approximations Ionization 12 Intracycle interferences 8 Photons 8 Atoms 6 Electron emission 6 Laser pulses 6 Photoionization 6 Polarization 6 Trajectories 6 Atom lasers 4 Coarse-grained structure 4 Coherent superpositions 4 Color 4 Continuum distorted waves 4 Distortion (waves) 4 Interference patterns 4 Interference structures 4 Kinetic energy 4 Kinetics 4 Multiphoton ionization 4 Photo-electron emission 4 Photoelectron spectroscopy 4 Photoelectrons 4 Time delay 4 Above-threshold ionization 2 Absorption and emissions 2 Analytic expressions 2 Angle-resolved photoelectron spectra 2 Angular distribution 2