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About

About


Maria Inês Carvalho graduated in Electrical and Computer Engineering from the University of Porto in 1990 and received her M.S. and Ph.D. degrees in Electrical Engineering from Lehigh University, USA, in 1994 and 1996, respectively. She joined the Electrical and Computer Engineering Department at the University of Porto in 1996 as an assistant professor, where she is presently an associate professor. In 2009 she joined INESC TEC as a researcher. Her main research area has been the propagation of light in nonlinear media. Her work includes both the theoretical modeling of these phenomena and their numerical simulation and has addressed, among others, soliton beams in photorefractive media, incoherent solitons and microstructured optical fibers. She is a member of the Optical Society of America.

Interest
Topics
Details

Details

  • Name

    Maria Inês Carvalho
  • Role

    Senior Researcher
  • Since

    22nd May 2009
006
Publications

2025

Dissipative pulses stabilized by nonlinear gradient terms: A review of their dynamics and their interaction

Authors
Descalzi, O; Facao, M; Carvalho, MI; Cartes, C; Brand, HR;

Publication
PHYSICA D-NONLINEAR PHENOMENA

Abstract
We study the dynamics as well as the interaction of stable dissipative solitons (DSs) of the cubic complex Ginzburg-Landau equation which are stabilized only by nonlinear gradient (NLG) terms. First we review stationary, periodic, quasi-periodic, and chaotic solutions. Then we investigate sudden transitions to chaotic from periodic and vice versa as a function of one parameter, as well as different outcomes, for fixed parameters, when varying the initial condition. In addition, we present a quasi-analytic approach to evaluate the separation of nearby trajectories for the case of stationary DSs as well as for periodic DSs, both stabilized by nonlinear gradient terms. In a separate section collisions between different types of DSs are reviewed. First we present a concise review of collisions of DSs without NLG terms and then the results of collisions between stationary DSs stabilized by NLG terms are summarized focusing on the influence of the nonlinear gradient term associated with the Raman effect. We point out that both, meandering oscillatory bound states as well as bound states with large amplitude oscillations appear to be specific for coupled cubic complex Ginzburg-Landau equations with a stabilizing cubic nonlinear gradient term.

2024

Tutorial on the Use of the Photon Diffusion Approximation for Fast Calculation of Tissue Optical Properties

Authors
Pinheiro, MR; Carvalho, MI; Oliveira, LM;

Publication
JOURNAL OF BIOPHOTONICS

Abstract
Computer simulations, which are performed at a single wavelength at a time, have been traditionally used to estimate the optical properties of tissues. The results of these simulations need to be interpolated. For a broadband estimation of tissue optical properties, the use of computer simulations becomes time consuming and computer demanding. When spectral measurements are available for a tissue, the use of the photon diffusion approximation can be done to perform simple and direct calculations to obtain the broadband spectra of some optical properties. The additional estimation of the reduced scattering coefficient at a small number of discrete wavelengths allows to perform further calculations to obtain the spectra of other optical properties. This study used spectral measurements from the heart muscle to explain the calculation pipeline to obtain a complete set of the spectral optical properties and to show its versatility for use with other tissues for various biophotonics applications.

2024

Determination of the spectral dispersion for the heart muscle - A Kramers-Kronig approach

Authors
Oliveira L.M.; Pinheiro M.R.; Oliveira H.P.; Carvalho M.I.; Tuchin V.V.;

Publication
2024 International Conference Laser Optics Iclo 2024 Proceedings

Abstract
The refractive index of the pigs heart was measured at wavelengths between 255 and 850 nm to calculate the dispersion. The total transmittance and total reflectance spectra of the pig heart were measured between 200 and 1000 nm to calculate the spectral absorption coefficient. Using Kramers-Kronig relations, the dispersion of the heart was matched to experimental refractive index values.

2023

Characterization of time-dependence for dissipative solitons stabilized by nonlinear gradient terms: Periodic and quasiperiodic vs chaotic behavior

Authors
Descalzi, O; Facao, M; Cartes, C; Carvalho, MI; Brand, HR;

Publication
CHAOS

Abstract
We investigate the properties of time-dependent dissipative solitons for a cubic complex Ginzburg-Landau equation stabilized by nonlinear gradient terms. The separation of initially nearby trajectories in the asymptotic limit is predominantly used to distinguish qualitatively between time-periodic behavior and chaotic localized states. These results are further corroborated by Fourier transforms and time series. Quasiperiodic behavior is obtained as well, but typically over a fairly narrow range of parameter values. For illustration, two examples of nonlinear gradient terms are examined: the Raman term and combinations of the Raman term with dispersion of the nonlinear gain. For small quintic perturbations, it turns out that the chaotic localized states are showing a transition to periodic states, stationary states, or collapse already for a small magnitude of the quintic perturbations. This result indicates that the basin of attraction for chaotic localized states is rather shallow.

2023

Quartic solitons of a mode-locked laser distributed model

Authors
Malheiro, D; Facao, M; Carvalho, MI;

Publication
OPTICS LETTERS

Abstract
Dissipative quartic solitons have gained interest in the field of mode-locked lasers for their energy-width scaling which allows the generation of ultrashort pulses with high energies. Pursuing the characterization of such pulses, here we found soliton solutions of a distributed model for mode locked lasers in the presence of either positive or negative fourth-order dispersion (4OD). We studied the impact the laser parameters may have on the profiles, range of existence, and energy-width relation of the output pulses. The most energetic and narrowest solutions occur for negative 4OD, with the energy having an inverse cubic dependence with the width in most cases. Our simulations showed that the spectral filtering has the biggest contribution in the generation of short (widths as low as 39 fs) and very energetic (391 nJ) optical pulses.(c) 2023 Optica Publishing Group

Supervised
thesis

2023

Optical characterization of atmospheric turbulence

Author
Paulo Alexandre Paiva de Andrade

Institution
UP-FEUP

2023

Light localization in two-dimensional moiré lattices

Author
José Pedro Afonso Gomes Luís

Institution
UP-FEUP

2023

Light localization in two-dimensional moiré lattices

Author
José Pedro Afonso Gomes Luís

Institution
UP-FEUP

2023

Light localization in two-dimensional moiré lattices

Author
José Pedro Afonso Gomes Luís

Institution
UP-FEUP

2023

Caracterização dos mecanismos de transparência em tecidos cardíacos

Author
Inês Soraia Dias Martins

Institution
UP-FEUP