Research lines

Our research in this field is centered on the generation of low and high-order harmonics in laser-induced ablation plasmas. These plasmas show interesting properties as nonlinear media, due both to their often complex composition (radicals, clusters, nanoparticles, etc.) and to the possibility of controlling their macroscopic behavior, and thus the phase matching. 

 

Experiments on harmonic generation contain a twofold approach: on one hand they can be understood as a diagnostic of composition and dynamics of the species of the plasma, through their nonlinear optical response; on the other hand, control of the plasma properties can globally tune the efficiency of such response, and it is possible to search for efficient ablation plasmas that show a high harmonic yield.

In our labs at IQFR, we can measure harmonics up to the 9th order of the fundamental Nd:YAG IR laser operating at 1.064 μm. It is important to note that the 9th harmonic is at 118 nm, well in the VUV spectral region. In these experiments, since two different laser sources are employed for laser ablation and for harmonic generation, complete freedom of the spatiotemporal exploration of the plasma allows the search for a broad range of particle emitters.

Through our collaborations with Prof. J.P. Marangos and Prof. R.A. Ganeev (Imperial College London, UK) we have also studied high-order harmonic generation of a fundamental ultrashort laser. Resonance effects and the presence of nanoparticles have been successfully explored as means to enhance harmonic generation.

Setup for the generation of low-order harmonics in a laser ablation plasma.

 

Some publications in this field:

M. Oujja et al., Appl. Surf. Sci. 392, 372 (2017).

M. Oujja et al., Surf. Sci. 336, 53 (2015).

R.A. Ganeev et al., Phys. Rev. A 88, 033803 (2013).

C. Hutchinson et al., Phys. Chem. Chem. Phys. 15, 12308 (2013).

I. Lopez-Quintas et al., Appl. Surf. Sci. 278, 33 (2013).

M. López-Arias et al., Molecular Physics 110, 1651 (2012).

R. de Nalda et al., Phys. Chem. Chem. Phys. 13, 10755 (2011).

M. Oujja et al., Phys. Rev. A. 81, 043841 (2010).

   

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