In this paper, we show our preliminary results in the investigation of the nonlinear optical properties of dye sensitized DNA. We are measuring the nonlinear refractive indices of the DNA with cetyltrimethylammonium (CTMA) surfactant, doped with Rhodamine 610 dissolved in butanol. The measurements are made using the Double Z-Scan method using a femtosecond laser at 1030nm as light source working in mode-locked and un-mode-locked regime respectively for discriminating fast nonlinearities from the slow ones.
In this paper we present a series of side-chain polymers bearing original azo-moieties, namely:
poly(methacrylate)s and poly(maleimide-styrene)s; designed for nonlinear optics (NLO). The different classes of azopolymers
are discussed comparatively to one another from the point of view of: solubility, molar weights, glass transition
temperatures & thermal stability, chromophore contents, and as well as from the point of view of their third-nonlinear
response. The third-order nonlinear absorptive and refractive effect of the polymers containing different substituted
azobenzene chromophores were investigated by the Z-scan technique. The effect of substituents on the azobenzene group
and the composition of the polymer chain were investigated by UV-Vis spectroscopy.
In this work, we demonstrate optical functionalities obtained with CdTe nanocrystals embedded in polystyrene.
These functionalities are based on our experimentally observed large, saturable, and controlled nonlinear optical
properties of CdTe nanocrystals, in the case of strong quantum confinement and near resonant interaction with the
excitation light. Our investigation considers the optical limiting functionality, presenting experimental proof of concepts.
These types of functionalities are of special interest for integrated optical quantum dots devices with applications in
imaging and telecommunications.
We have developed a scanning confocal microscopy (SCM) system which can be used to investigate micro-structural
properties of samples with micro-geometry. We present advantages of this imaging technique for visualization and
characterization of some periodic and non-periodic (porous silicon with an alveolar columnar structure (1.5 - 3 μm pores
diameters)) samples. Using the confocal microscopy, we can obtain an enhancement of image resolution and contrast, in
comparison with conventional optical microscopy. Therefore, it has particular advantages for the study of porous silicon.
Confocal imaging method permit the "optical sectioning" of samples and lead to a sub-micron resolution both in lateral
plane and axial plane.
The thermal third order nonlinearity of a neutral density glass is measured using the Z-Scan method. The measurements
are performed using two different laser configurations: a continuous wave laser at 532 nm and a femtosecond laser at
1060 nm. The measurements are used to determine the nonlinear refractive index, n2 and the thermo-optical coefficien dn/dt of the samples. The measurements in the two different laser configurations are in good agreement with the existing
The results obtained using Z-Scan methods (transmission -- TZ-Scan and multiple-pass -- MZ-Scan) for the characterization of the partial transparent nonlinear optical materials (NOM) are presented. For a typical NOM, a monocrystalline Si wafer with thickness 0.4 mm, at λ = 1060 nm, the nonlinear bulk effects are dominant in comparison with the nonlinear effects produced by the entrance interface (due to the sufficient large transmission of Si). In this case, the MZ-Scan at low laser intensity (several MW/cm2) can be analyzed similarly to the TZ-Scan, considering the multiple passes inside the sample and linear Fresnel reflections on both sample faces. Due to these multiple passes inside the sample, the sensitivity of the method is increased. The nonlinear optical susceptibility experimentally determined by multiple-pass Z-Scan is in agreement with a theoretical estimation of this parameter, with the results of other treatments of MZ-Scan and TZ-Scan and with its values obtained by two and four-wave mixing.