Transfer of orbital angular momentum in high harmonic generation using two driving beams

Thierry Ruchon (1, 2) , Celine Chappuis (1) , Romain Geneaux (1, 3, 4) , David Bresteau (1, 2) , Olivier Gobert (1, 5) , Giovanni de Ninno (6, 7) , David Gauthier (1, 3) , Thierry Auguste (1, 2)

1 LIDYL - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
2 ATTO - Attophysique
3 DICO - Dynamique et Interactions en phase Condensée
4 UC Berkeley - University of California [Berkeley]
5 PHI - Physique à Haute Intensité
6 Elettra Sincrotrone Trieste
7 University of Nova Gorica

Light beams may carry both a spin and an orbital angular momentum (OAM). While the former is associated to their polarization state, the latter stems from the geometrical properties of their wavefront. In their prototypical form, beams with OAM have "donuts-like" intensity profile and helicoidal wavefront, carrying integral multiples of h as angular momenta. Since their "rediscovery" in the late 90's, beams with OAM of visible wavelengths have found innumerable applications in quantum optics, microscopy or information transfer. A major recent development was the generation of such beams with much smaller wavelengths - in the extreme ultraviolet (XUV) - using synchrotron sources, free electron lasers as well as high harmonic sources (HHG). In this latter case, it creates ultrashort XUV sources of beams with OAM, suited for time-resolved applications at femtosecond and attosecond time scales. Remarkably, we showed that even though HHG is a non-perturbative process, the OAM transfer from the driving beam to the harmonics was purely parametric; i.e., the q-th harmonic - which can be thought as the upconversion of q infrared photons - carries q times the OAM of the driver [3, 4]. However, this rule limits severely the flexibility in choosing the OAM of the XUV emission.

Domaines: Physique [physics]

Thierry Ruchon, Celine Chappuis, Romain Geneaux, David Bresteau, Olivier Gobert, et al.. Transfer of orbital angular momentum in high harmonic generation using two driving beams. CLEO/Europe-EQEC 2019 - 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference, Jun 2019, Munich, Germany. ⟨10.1109/cleoe-eqec.2019.8873108⟩. ⟨cea-04445886⟩