Describing Spatiotemporal Couplings in Ultrashort Pulses Using Amplitude Coupling Coefficients

An amplitude coupling coefficient has been defined to quantify spatiotemporal couplings in ultrashort pulses, which is dimensionless and normalized. The amplitude couplings in ultrashort pulses, such as first-order spatial chirp and angular dispersion caused by angular dispersion elements have been studied by using the defined amplitude coupling coefficient, and corresponding amplitude coupling coefficients have been given analytically. Furthermore, the second-order spatial chirp caused by angular dispersion elements have been studied.