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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.
- Licenciaturas
- M. Sc. Programs
- 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
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- 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.
- Prof. Ewan M. Wright (Optical Sciences Center, University of Arizona, USA)
- Prof. Vladimir Konotop (Physics Dept., Sciences College of University of Lisbon)
- Dr. Nail Akhmediev
(Optical Sciences Centre, RSPhysSE, Australian National University, Australia)
- Dr. Graham Town (School of Electrical and Information Engineering, University of Sydney, Australia)
-
Prof. Rui Almeida (IST at Lisbon University )
- Prof. Mário Ferreira (Physics Dept., University of Aveiro)
- Prof. Panayotis Kevrekidis (Math and Statistics Dept., University of Massachusetts, Amherst, USA)
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
PORTUGAL
Tel.: Int+ 351 - 22 608 26 03
Fax : Int+ 351 - 22 608 26 22
e-mail: asrodrig@fc.up.pt.
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