Dontu Ionela Simona

Institute for Research and Development in Optoelectronics | inoe · ITC

In recent years, citizen science has proven to be an effective means of monitoring plastic litter, bring potential benefits to professional researchers and authorities, and create awareness on plastic pollution at a society level. This paper aims to review the advances of employing the citizen science approach for plastic litter evaluation and expl...

Human changes on the Danube River have transformed it into a heavily engineered river, severely threatening its ecological status. The status and management strategies vary significantly between regions of the Danube River Basin. Citizen science approach can be the bridge in harmonizing water management practices across the Danube Basin and in reco...

Urban lakes represent the most extensive water bodies in cities and provide blue ecosystem services, by retaining pollutants, offering cultural services, and mitigating climate change. Human activities threaten to decrease the supply of ecosystem services associated with urban lakes. Exorheic lakes play an essential role in reducing and changing th...

Closed lakes located in urban parks act as sinks of organochlorine pesticides (OCPs), which have been used, for decades, as insecticides, herbicides and fungicides. The closed lakes from Bucharest, Romania, are periodically managed to prevent eutrophication and accumulation of pollutants. However, it is not known if these practices reduce or enhanc...

Water quality is essential for ensuring humane living conditions for inhabitants around the world. In this context, an important aspect that must be taken into consideration is the water quality in rural areas. Special attention must be given in such cases due to a large number of possible pollution sources, from industrial or agricultural, to wast...

In recent years many optoelectronic techniques have been developed for improvement and the development of devices for tissue analysis. Spectral-Domain Optical Coherence Tomography (SD-OCT) is a new medical interferometric imaging modality that provides depth resolved tissue structure information with resolution in the μm range. However, SD-OCT has...

An innovative approach for guiding cancer surgery is proposed in this paper. Spectral-Domain Optical Coherence Tomography (SDOCT) and Hyperspectral Imaging (HSI) are combined with the goal of taking advantage of the complementary capabilities provided by each technique: spatial (3D) information at the micron scale and spectral signatures of the bio...

The river Dambovita, which crosses Bucharest city, is characterized by two superposed artificial riverbeds: the lower part, under Dambovita river floor, which is a channel containing sewage from the city and the upper part, which is cleaner and combines with the lower part when exiting Bucharest. This study aims to evaluate the anthropogenic impact...

The river Dambovita, which crosses Bucharest city, is characterized by two superposed artificial riverbeds: the lower part, under Dambovita river floor, which is a channel containing sewage from the city and the upper part, which is cleaner and combines with the lower part when exiting Bucharest. This study aims to evaluate the anthropogenic impact...

In vivo real-time skin evaluation was performed by fluorescence spectroscopy on three examples of benign lesions: keratoacanthoma, seborrheic keratosis, and dermatofibroma. Spectral domains corresponding to elastin crosslinks, flavins, and porphyrins fluorophores were investigated. For all skin lesions, the total area of the fluorescence spectra wa...

The aim of this paper is to develop an analytical—three-dimensional model for stimulated Brillouin scattering (SBS). The transversal effects on SBS are analyzed with Gauss–Laguerre orthonormale polynomial development. The correlation integrals which contain the information of transversal effects on SBS are described. Using the development of orthon...

Fluorescence spectroscopy and parallel factor (PARAFAC) form a powerful tool in separating different fluorophores and may be useful in detecting the fluorescent signature of dissolved organic matter (DOM). Despite the large number of studies on fluorescence and PARAFAC it is still uncertain if this combination is capable to separate DOM from differ...

Some variable regions of Cryptosporidium gp60 gene may have a potential implication in the pathogenesis of disease caused by this parasite. DNA sequencing provides enough material to specific computational processing methods for the characterization of DNA diversity. A wavelet spectrogram method has been adopted to evaluate the degree of similarity...

The effectiveness of thermal decontamination of a soil sample polluted with crude oil was assessed using optical methods (absorbance and fluorescence spectroscopy) and the standard high performance liquid chromatography method (HPLC). The sample was divided in aliquots and subjected to pyrolysis for 1 h, at three operating temperatures: 300, 400 an...

Molecular investigations of Giardia intestinalis tpi polymorphic gene have facilitated approaching of some mathematical methods to describe the genetic information. In this study, we applied wavelet spectrogram analysis for estimating the degree of similarity and difference between different assemblages and intra-assemblages of infectious parasite...

With the aid of computer simulations we design a tunable 2D photonic crystal with band gaps in microwave range. Results show a simple triangular lattice of air holes in dielectric medium micro-machined on ferroelectrics could have stop bands in the range of approximativelly 10-60 GHz, if the voltage is appropriately triggered. The range is covered...

Purpose: The aim of this paper is to provide an overview of the most investigated optical diagnostic techniques: optical coherence tomography, fluorescence spectrometry, reflectance spectrometry, Raman spectroscopy, and confocal microscopy. Methods: A search of three databases was conducted using specific keywords and explicit inclusion and excl...

In this paper we report a review concerning some experimental results using non-destructive optical methods for the characterization of the thin films of semiconductor chalcogenide glasses and Er3+-doped Ti:LiNbO 3 waveguides, such as: light attenuation in planar, refractive index spatial distribution, dispersion of refractive index, absorption and...

Our knowledge about surroundings can be achieved by observations and measurements but both are influenced by errors (noise). Therefore one of the first tasks is to try to eliminate the noise by constructing instruments with high accuracy. But any real observed and measured system is characterized by natural limits due to the deterministic nature of...

Abstract. The paper contains the description of light propagation in plasmonic structure coupled with planar waveguide. The Fresnel's reflectance is calculated by matrix method and the calculations of the waveguide propagation constants are provided by the solution of the dispersion equation with complex refractive indexes. The result evaluates the...

The surface plasmon resonance calculations were performed for Kretschmann configuration. Two of the layers, gold and chalcogenide films (GaLaS), have finite thickness. The refractive index of coupling prism material is supposed to be lower than the refractive index of amorphous film which composes a plasmonic waveguide. The amorphous film thickness...

The paper contains the description of light propagation in plasmonic structure coupled with planar waveguide. The Fresnel's reflectance is calculated by matrix method and the calculations of the waveguide propagation constants are provided by the solution of the dispersion equation with complex refractive indexes. The result evaluates the condition...

Three dimensional fluorescence spectroscopy, as a spectral fingerprint of dissolved organic matter was used to examine the impact of surrounding areas on groundwater sources (wells) situated in a rural village, Vartoapele de Jos, Teleorman County. Fluorescence indices allowed discriminating between water types in connection with the proximity of di...

In this paper we numerically compute the electric field density in Sal structures, for different distances between the silicon plates and for two wavelengths. Results show light propagation in the SOI structure shows a much higher intensity than that achievable with conventional ways.

We present the propagation of optical beams and the properties of one-dimensional (1D) spatial solitons (“bright” and “dark”) in saturated Kerr-type and quadratic nonlinear media. Special attention is paid to the recent advances of the theory of soliton stability. We show that the stabilization of bright periodic waves occurs above a certain thresh...

In this paper we numerically compute the electric field density in SOI structures, for different distances between the silicon plates. Results show the more distant are the plates, the more is the difference in the electric field density, and the more is the distance between their maxima. Also, we can observe that light propagation in the SOI struc...

Based on the transmission experimental spectra of Er3+ -doped Ti:LiNbO3 optical waveguides in this paper we report some experimental and theoretical results concerning the evaluation of the the radiative lifetime and the real and imaginary parts of the complex atomic susceptibility of the above mentioned waveguides in the visible and near infrared...

In lucrare se realizează o investigare a predictabilităţii folosind algoritmul Grassberger – Proccaccia în cazul laserului ideal cu 4 nivele cu pompaj periodic, continuind astfel o cercetare anterioară. S-au calculat exponenţii Lyapunov maximi, si s-a evidenţiat prezenta haosului la aceeaşi valoare de prag a frecventei de pompaj prin doua metode, ş...

In this paper we present a theoretical analysis of some statistical parameters which characterize the Er3+-doped Ti:LiNbO3 single and M -mode straight and curved waveguides. In the derivation and the evaluation of the spectral optical quality factor, the power spectral density, the Fano factor, the statistical fluctuation and the spontaneous emissi...

The results of an theoretical and experimental study of the properties of a ring resonator used with a Nd:YAG laser operating at 1.06 μm are presented. The rates equations arepresented in a rotative system for an optical field distribution and inversion population obtaining the oscillation conditions of a ring laser resonator. With this model a kin...

Light transport is currently used clinically both as a therapeutic tool and as a diagnostic tool. A concern in all these cases is the difficulty of knowing which regions of the tissues are sufficiently illuminated for therapeutic results, or from which regions the collected fluorescence was emitted. Development of optical models that explain the ob...

This work deals with spatial optical solitons in a ID nonlinear photonic crystal holding a periodical photonic network generated by the Dirac function. We consider a periodic optical structure formed by an area of a nonlinear thin film waveguide. A model for propagation of the optical field in nonlinear photonic crystals is built up using the Lapla...

The study of dynamics of spatial solitons in nonlinear and unidimesional fotonic crystals, with a periodical and nonlinear fotonic network which is generated by Dirac function is presented. Are analysed comparisons and differences which appear in development of periodical models describes by nonlinear Schrödinger equation. Also, is developed theory...

An understanding of light propagation including elastic or inelastic light scattering is mandatory for a successful realization of the potential optical approaches for achieving quality health care. Optical methods are very powerful for living tissue analysis because it is non-invasive, very sensitive and spectroscopic, spatial and temporal selecti...

membran-ectomy, allowing stereoscopic examination of eye's transparent medium and microsurgical procedures in the anterior and posterior chambers using the photodisruptive effect is presented. A circular variable filter and two LED-phototransistor pairs are used to get a precise energy dosing.

This work deals with the spatial optical solitons in a nonlinear photonic crystal holding a periodical photonic network. We consider a periodic optical structure formed by an area of a nonlinear thin film waveguide. A model for propagation of the optical field in nonlinear photonic crystals is built up using the Laplace transform. We describe propa...