Prof. Marta Castillejo

Instituto de Química Física Rocasolano, CSIC, Madrid, Spain

Non-linear optics in laser ablation plasmas



Laser ablation plasmas constitute an example of complex environments populated by different species ranging from neutral and ionized atoms to nanoparticles. Characterization of the composition and dynamics of ablation plasmas is crucial in pulsed laser deposition, a technique that allows the generation of functional, nanostructured films of different materials, and is the basis for analysis of solids via laser induced breakdown spectroscopy. Particularly, for ultrashort laser pulses the derived ablation plasmas are also being studied as sources of short wavelength coherent light by high harmonic generation (HHG).
In this talk I will present measurements of the nonlinear response of nanosecond and femtosecond laser ablation plasmas of solid targets in both the perturbative (low-order harmonics) and non-perturbative (HHG) regimes. The dependence of harmonic intensity with laser ablation spot size and position across the plasma plume, pulse energy and ablation-driving delay display distinct characteristics for each studied material. Different temporal components of the harmonic signal are attributed to the various plume populations propagating with decreasing velocity as their size increases, thus providing a way to assess the presence of nanoparticles in these plasmas. I will also show that nanoparticle-containing ablation plasmas lead to efficient conversion towards the short-wavelength range through HHG and display superior performance to those corresponding to bulk targets of the same metallic element.
Marta Castillejo obtained her PhD degree in Physics from Complutense University of Madrid in 1984. She worked as postdoctoral fellow at the Institute of Environmental Studies, Tsukuba Japan, and at the Physics Department of Imperial College London (UK). In 1987 she became member of staff of IQFR-CSIC, where she coordinates the Group "Lasers, Nanostructures and Materials Processing". Her scientific interests are focused on the laser processing and fabrication of nanomaterials and applications in Nanoscience and conservation of Cultural Heritage.
She has authored about 200 refereed publications in peer reviewed journals, has given about 270 presentations in Conferences and has delivered more than 45 invited talks at national and international level. She has coordinated numerous national projects and a number of bilateral program exchanges with academic European institutions and has participated in various projects funded by the framework programs of the EU. As Academic Visitor, she stayed at University Cergy-Pontoise and Observatoire de Paris Meudon, at Department of Chemistry and Chemical Biology of Harvard University and at Imperial College London. She has lectured in various Doctorate and Master courses and has supervised 8 PhD Thesis. Marta Castillejo has acted as Management Committee member and as Chair of the Board of User Representatives of LASERLAB EUROPE. She and sits in scientific committees of various international conference series in the fields of laser materials processing and conservation of Cultural Heritage (COLA, CLEO-Europe, LACONA, TECHNART, OA3).

Date: 6/4/2016
Time:11:00 (coffee & cookies will be served at 10:45)
Place:FORTH Seminar Room 1