Title: Attosecond goes Quantum in Solids
Dr. Michael Krueger
Assistant Professor / Senior Lecturer
Department of Physics and Solid State Institute Technion – Israel Institute of Technology
Time: Tuesday, October 15 2024 at 2PM
Location: Physics Research Building 1080, Smith Seminar Room and online
ABSTRACT: Strong-field physics looks into the ultrafast interaction of intense laser pulses with matter, with high-harmonic generation (HHG) as its hallmark effect. While light and matter are quantum, a semiclassical perspective is sufficient to describe this interaction. In my talk, we will discuss two works that break this perspective, each in a different way. In the first work, we successfully replace the classical (coherent-state) laser pulses by intense non-classical light – bright squeezed vacuum (BSV) – to drive HHG in solids. We show how the BSV’s extremely noisy photon statistics is transferred to its harmonics, leading to a strong enhancement of the harmonic yield and enabling studies of electron-hole dynamics at extreme intensities. In the second work, we study HHG from GaN, a semiconductor with strong excitonic emission. While one would assume that an increase of the laser intensity leads to ever increasing harmonic yield, here we observe resonant enhancement of the yield at specific intensities. We identify the underlying mechanism as ponderomotive detuning, measure the corresponding attosecond time delays and find signatures that cannot be explained with the picture of semiclassical electron-hole trajectories. In the future, ponderomotive detuning may open the door to create entanglement between harmonic photons, extending quantum optics to the extreme ultraviolet.
This event is open to the public.
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