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(n.1966) Assistant Professor at University of Porto since 1996 ; "Licenciatura" in Physics, University of Porto, 1987; M. Sc. in Solid State Physics, University of Porto, 1990; M. Sc. in Optics, University of Arizona (USA), 1994; Ph. D. in Optics, University of Arizona (USA), 1996.


Ultra-short pulse propagation
The propagation of short pulses of light in nonlinear media has in general to take into account the dispersion of the group velocity (GVD) and the nonlinearity of the material. In one-dimensional media (e.g. slab waveguide or optical fiber) this leads to the Non-Linear Schrödinger (NLS) equation.
As other effects become important due to non-instantaneous non-linear response (e.g. Raman effect), shorter pulses (e.g. third order dispersion) or higher order nonlinear effects, other terms must be added to this equation, leading to a variety of forms generally refered to as Modified NonLinear Schröedinger equation (MNLS).
One effect that arises close to the half-band gap in semiconductors is nonlinear dispersion, which can be seen as an intensity-dependent group velocity. By itself leads to optical shock but dispersion is in general able to (eventually) balance it, leading to the propagation of stable, asymmetric pulses. The discovery of these solutions was the main result of my Ph. D. thesis.
One of my students (Ricardo Morla) extended these results to the situation where we have a coupler made of two guides each having nonlinear dispersion.
Nonlinear chains
Solid state and fibre lasers
These systems have group velocity dispersion (GVD), net linear gain, spectral filtering, nonlinear gain or loss (e.g. a saturable absorber). They can be modeled through the cubic-quintic Complex Ginzburg-Landau (CGL) equation, in which the quintic terms represent saturation of the nonlinear gain and of the (phase) nonlinearity.
Photonic band-gap crystals
It is known from several areas of Physics that a wave impinging on a (spatially) periodic structure will not be allowed to propagate if its frequency falls within certain bands. Examples are Bragg reflection and electrons propagating in semiconductors.



Supervised Masters and Ph. D. Students

Manuel A.V. Baptista Masters (1999) Numerical solution of Poisson's equation applied to the calculation of the demagnetization field.
Ricardo S. Morla Masters (2001) Soliton switching in non-linear optical fibers.
Jaime R. Viegas Masters (2003) Photonic bandgap crystals with nonlinearity.

  • A. S. Rodrigues, M. Santagiustina, E. M. Wright, ``Nonlinear Pulse Propagation in the Vicinity of a Two-photon Resonance'', Phys. Rev. A, 52,4, 3231 (1995)
  • P.T.Guerreiro,S.G.Lee, A.S.Rodrigues,Y.Z.Hu, E.M.Wright, S.I.Najafi, J. Mackenzie,N.Peyghambarian, ``Femtosecond pulse propagation near a two-photon transition in a semiconductor quantum dot waveguide'', Opt. Letts., 21, 9, 659 (1996)
  • A. S. Rodrigues, M. Santagiustina, E. M. Wright, ``Femtosecond pulse propagation and optical solitons in semiconductor-doped glass waveguides in the vicinity of a two-photon resonance'', Opt. Quant. Elect., 29, 10, 961 (1997)
  • N. Akhmediev, A.S. Rodrigues and G. Town, ``Interaction of dual-frequency pulses in passively mode-locked lasers'', Opt. Comm., 187, 4-6, 419 (2001)
  • R.M. Almeida, A.S. Rodrigues, ``Photonic bandgap materials and structures by sol-gel processing'', J. Non-Crystalline Solids 326&327, 405 (2003)
  • P G Kevrekidis, V V Konotop, A Rodrigues and D J Frantzeskakis, ``Dynamic generation of matter solitons from linear states via time-dependent scattering lengths'', J. Phys. B: At. Mol. Opt. Phys., 38, No 8, 1173-1188 (2005)
  • Sofia C.V. Latas, Mário F.S. Ferreira and Augusto S. Rodrigues, ``Bound states of plain and composite pulses: Multi-soliton solutions'' Opt. Fiber Tech, 11, 292-305 (2005)
  • A. S. Rodrigues, P. G. Kevrekidis, Mason A. Porter, D. J. Frantzeskakis, P. Schmelcher, and A. R. Bishop, ``Matter-wave solitons with a periodic, piecewise-constant scattering length'', Phys. Rev. A, 78, 1, 013611 (2008)
  • A. S. Rodrigues, P. G. Kevrekidis, R. Carretero-González, D. J. Frantzeskakis, P. Schmelcher, T.J. Alexander and Yu.S. Kivshar, ``Spinor Bose-Einstein condensate flow past an obstacle'', Phys. Rev. A, 79,4, 043603 (2009)




Dive Shop , in Tucson, Arizona, PADI's Open Water and Advanced Open Water Certificates


Sunrise ski area, White Mountains, Arizona: where it all began, courtesy of Maria João Simas, José "Doc" Simas, Tiago Guerreiro and Leo Caiaffa.
Snowbowl ski area, near Flagstaff, Arizona
Purgatory resort, near Durango, Colorado
Tourmalet ski area, includes Barèges and La Mongie, Pyrenees, France
Perisher Blue Resort in the Blue Mountains, Australia
Font-Romeu ski area, Pyrenees, France
El Formigal ski area, Pyrenees, Spain
Soldeu el Tarter ski area, Pyrenees, Andorra
Pal Arinsal ski area, Pyrenees, Andorra

Augusto da Silveira Rodrigues
Professor Auxiliar
Centro de Física do Porto
Departamento de Física
Faculdade de Ciências da Universidade do Porto
R. Campo Alegre, 687
4169-007 Porto
Tel.: Int+ 351 - 22 608 26 03
Fax : Int+ 351 - 22 608 26 22

This page is maintained by Augusto Rodrigues and was last updated on Dec 18, 2002