1) Details and dates of previous employment.
From May – 2002 to June – 2006 I’ve worked on my PhD. thesis at the Physics
Institute of the University of Rio Grande do Sul, conducted at the Laser and Optics Group.
In the following a present the abstract of the thesis.
PhD Thesis Abstract
The main subject of the thesis work dealed with the investigation of the
intermolecular dynamics in pure liquids, liquid mixtures and polymeric mixtures through
the technique of time-resolved heterodyne detected optical Kerr effect. In summary, this is
a nonresonant pump-probe technique and we worked with a Ti:Sapphire laser system that
emited 170-fs pulses centered at 800 nm. The molecules studied were carbon disulfide
(CS2), benzene (C6H6), allylbenzene (C9H10), and polystyrene (PS). The theory necessary to
describe the results was developed in the time regime. The Debye model for the diffusive
relaxation of the orientational anisotropy describes the slow time component of the
measured signal above one picosecond. Departing from the interaction Hamiltonian, we
developed the linear response function theory, arriving at an expression for the relaxation of
the anisotropic polarizability, necessary to describe the fast subpicosecond time component
of the measured signal. We also have discussed the passage to the spectral regime using
only experimental data and without the need of models. The results show that the diffusive
times for the pure liquids and the mixtures follow the Debye-Stokes-Einstein equation,
which implies that an increase in the material's viscosity generates an increase of the
diffusive times. The fast times were analyzed in terms of the non-diffusive component of
the spectral response that is associated with the molecular dynamics. The variations of the
spectrum were quantified and the explanation of the observed changes was given in terms
of the structural interaction configurations that produced changes in the intermolecular
potential within which the molecules execute librational motions.
Beyond the intermolecular dynamics investigation, we have studied in detail a
ultrashort pulse characterization technique (GRENOUILLE) and proposed a modification
which allowed for lowering the costs of the setup. Moreover, this modification introduced
new characteristics which solved some problems that the original setup presented and also
made possible a better characterization of the technique itself. The conditions that have to
be satisfied by the beam's geometry and by the experimental components to obtain a correct
characterization of the ultrashort pulses and, also, the system calibration procedure was
discussed in detail. Pulses with different durations and phase functions have been
characterized and the results have been validated by tests of confiability of the recovered
information.
As a test of principles problem we investigated the shaping of incoherent light
pulses. To do this, we worked with a large spectral bandwidth dye laser, obtained from a
laser cavity without spectral selection element. The experimental setup that we used was
the forced light scattering technique coupled to a phase shaper. This shaper was composed
of a diffraction grating, a lens and a mask that changed the relative phase function of the
pulses that formed the transient grating in the material under investigation. We realized a
detailed analysis of this experimental setup and derived expressions to fit to the
experimental data. The results show that the correlation function can be modified in a
specific form by adjusting the spectral phase function.
For further details, results and discussions that originated from the PhD. work, I
attached the papers published until now and also the manuscripts that were sent for
publication.
2) Details and dates of current employer/employment.
Since late July, I am working as a postdoctoral researcher at the Photonics Group at
the Physics Institute of São Carlos – USP (University of São Paulo). The main objective of
the project is the implementation of coherent control techniques that use high energy
ultrashort pulses, a topic that is totally incipient in our country (Brazil) and is at the frontier
of chemical physics knowledge. This work consists of the application of techniques that
allow the manipulation of the amplitude and/or phase of the ultrashort pulse’s spectral
composition, shaping these, with the objective to control, effectively, nonlinear processes in
many different materials. Our interest is mainly in organic molecules, focusing on a kind of
molecules named Y-shaped chromophores and also on another class of molecules known as
diazocompounds. Presently, the group is beginning the work with coherent control using a
deformable mirror and a Ti:Sapphire oscillator. However, the energy of the pulses
generated by the oscillator is in the nJ/ pulse range, which is insufficient for most of the
frontier applications, especially on the control of chemical reactions. To improve our
possibilities, we have to implement an amplification system to increase the pulse energy to
the mJ/pulse level. Depending on the control form to be implemented, we will use the
deformable mirror, which has already been used in the results presented by the IFSC
photonics group, or a liquid crystal shaper, that will expand considerably the experimental
possibilities.
3) Relevant information, experiences and interests.
The Brazilian scientists are always faced with the little financial support problem. In
virtue of this, the experimental problems that appear during the execution of a PhD thesis
work, for example, have to be resolved by the own student. So I’ve learned to work with:

electronic problems: construction of circuits to amplify photodiodes; in
dealing with weak signals, design and construction of electronic filters to
enhance the signal/noise relation; implement the interface of the computer
with oscilloscopes / lock-in amplifiers / boxcar integrators through serial
ports, USB ports and GPIB; control step-motor through the computer
parallel port;

construction of ultrashort pulse characterization setup’s, as second-order
autocorrelator and the modified GRENOUILLE setup;
dye laser
construction and alignment;

all measurements automation where realized through the LabView
language. To analyze the results we also worked with the LabView
language, Matlab, Mathcad and Maple;

during my PhD work, I was also responsible to orient undergrad students
that realized experiments a variety of different experiments.
4) Supplementary statement about interest in, suitability for,
the post.
When I was close to finish my PhD work, the only Ti:Sapphire laser system that we
access to was broken and, as a consequence of reduced financial budget, the continuity of
the work that dealed with the investigation of the intermolecular dynamics in liquids was
interrupted. So, a moved to another university to begin to work on a different subject (as
described in topic 2 above) that appeared to me as a new motivating challenge. But as I was
informed about the possibility to participate in a post-doctoral program to study the
ultrafast dynamics in a range of complex fluids, including polymer solutions,
microemulsions and proteins, I envisioned a chance to apply and really improve my
knowledge in this area. A feel that my experimental ant theoretical skills experiences
suitable to execute this work, and above all, I am are very much motivated to participate in
this postdoctoral work.