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Spin angular momentum in extreme nonlinear optics: high harmonic generation with controlled polarization

Event Details

Event Dates: 

Friday, July 26, 2013 - 3:00am

Seminar Location: 

  • JILA X317

Speaker Name(s): 

Oren Cohen

Speaker Affiliation(s): 

Technion/Dept of Physics
Seminar Type/Subject

Scientific Seminar Type: 

  • JILA Public Seminar

Event Details & Abstract: 

High harmonic generation is a unique and highly useful parametric processes in which many infrared or visible pump photons are exchanged into a single short-wavelength photon. Accordingly, the spin angular momentum of the emitted photon should correspond to the total spin of the pump photons. Spin angular momenta of the harmonics are associated with their polarization states. Previous experiments demonstrated very limited control over the polarization of high-order harmonics. I will present high-order harmonics of bi-chromatic counter-rotating elliptically-polarized waves. This system exhibits full control over the harmonics polarization, from circularly through elliptically to linear polarization, without comprising the efficiency of the processes, hence opening the door to new applications. We also observe rich spectral features that qualitatively correspond to, yet quantitatively contradict, conservation of spin angular momentum. This contradiction indicates that a currently unknown quanta participates in the processes.Finally, if time allows, I will also present structure-based super-resolution in optical measurements