Conversion of a beam carrying fractionnal angular momentum in High-Harmonics Generation

Abstract

Exotic light fields combining non-trivial spin and angular momentum may not be eigenstates of either the spin or orbital angular momenta operators. For these fields, it is relevant to define a Generalized Angular Momentum operator of which they are eigenvectors. Their associated eigenvalues can take, depending on the case, non-integer values. We report that this new quantity is conserved via non-linear phenomena, such as High Harmonic Generation.