Nanoscopy
Optics
Laser Microfabrication
Materials Characterization
Some topics that fascinate us are listed here
GON develops research lines at the frontier of knowledge in physics, in the areas of Optics and Nanoscopy. Our research environment is coupled with UFAL's postgraduate programs in PHYSICS (masters and doctorate) and MATERIALS (doctorate). We have frequent visits from foreign researchers and from other research centers of the country, as well as postdoctoral and postgraduate students doing medium and short-term internships. The main lines of research developed in GON are described below:
A very important technique in material characterization is Scanning Probe Microscopy (SPM) and its variants, with which is possible to observe, manipulate and explore the various physical effects of nanostructures and biological samples with nanometric precision.
In our lab, an SPM platform allows fully-integrated use of confocal Raman microscopy and AFM (Atomic Force Microscope). The myriad of SPM techniques allows the study of topographical, electrical, and mechanical properties can be performed with any laser source available in Raman spectrometer, or with other external illumination.
Raman and AFM (Atomic Force Microscope) analysis are combined on a single microscope system, opening interesting new capabilities and providing enhanced information on sample composition and structure by collecting physical and chemical information on the same sample area. Co-localized AFM/Raman measurement is the sequential or simultaneous acquisition of overlapped SPM and Raman maps with pixel-to-pixel correspondence in the images.
On one hand, AFM and other SPM techniques provide topographic, mechanical, thermal, electrical, and magnetic properties down to the molecular resolution (~ nm, over μm2 area), on the other hand, confocal Raman spectroscopy and imaging provides specific chemical information about the material, with diffraction-limited spatial resolution (sub-micron).
Our group has two major topics concerning light manipulation: Classical Optics, Microfabrication and Quantum Optics.
By making use of Spatial Light Modulator (SLM), we have achieved a great position in terms of beam-shaping techniques. This allows us to control the transverse field distribution as wish, generating complex structured beams such as Laguerre-Gaussian, Hermite-Gaussian, Ince-Gaussian, Bessel, Mathieu and controlled speckles, to cite a few. Studies involving self-reconfiguration and statistical control of speckle beams, leading to applications like multi-layered microscopy and image reconstruction after highly diffusive media, compose our linear optics interests. Concerning nonlinear optics, fundamental analysis of two- and four-wave mixing processes have been in development in the past few years. Besides wave mixtures, we are also interested in the interaction of structured light with photorefractive crystals and engineered nanometric media.
We recently build a very new laboratory for quantum optics experiments. Here, we aim to study quantum protocols such as quantum teleportation, quantum entanglement, quantum communication, for example. Together with the µFab laboratory, we are also interested in photon propagation in coupled wave-guides using doped glasses. In this context, the wave-guides act as gain and loss coupled media, where the study of non-Hermitian systems possessing PT symmetry is possible.
As a recent feature, fabrication of microstructures is performed by using a Newport µFab System and ultrashort lasers sources. Through two-photon polymerization technique in specific photoresists, it is possible to construct biomaterials (cellular scaffolds using biocompatible resins). In addition, the nonlinear interaction between the fs-laser and the transparent materials can be used to modify optical properties of the material making possible construct micro-optical devices (microlenses, lenses matrix, diffractive optical elements) and waveguides possessing novel properties depending on the material used.
The physical and chemical properties of materials depend intrinsically on the atomic arrangement. Therefore, knowing their structural characteristics and their spatial arrangement, shape, defects andinclusions allows us to understand properties, propose modifications and/or new production processes. Furthermore, that knowledge also facilitates the modeling of functions and the design ofsimilar structures with distinct properties. Hence, the structural characterization of a material is a basic step for any study, whether for fundamental research or for application purposes. Because of that, the characterizations are performed in the multi-user laboratory, serving 10 research groups from the Federal University.
We are always interested in hearing from fellow scientists wishing to work with us.