The first nonlinear effect that appears when an ultrashort laser pulse propagates through an amorphous medium, such as a gas or a glass, is related to an intensity-dependent refractive index: the optical Kerr effect. One of the consequences of the Kerr effect is the self-focusing of the beam, which takes place for input peak powers above a threshold value, the critical power (Pcr) [1,2]. Another consequence of the optical Kerr effect is the spectral broadening related to the self-phase modulation. This spectral broadening is used to generate ultrashort pulses in post-compression schemes, most of them based on the nonlinear propagation of a pulse inside a hollow-core fiber (HCF) .
© 2019 IEEEPDF Article