Applied nonlinear and stochastic dynamics
Natural and technical systems are intrinsically dynamic. They are also frequently composed of
many interacting elements, and are subject to non-negligible amounts of random fluctuations. We
apply a combination of methods originating in disciplines such as statistical physics,
the theory of stochastic processes, and nonlinear dynamics, to different types of problems that
arise in the presence of complex, nonlinear and stochastic interactions. Several of the problems
studied include the dynamics of gene regulation, global brain activity, and
stochastic resonance and signal integration in neuronal models.
Responsible: Jordi Garcia-Ojalvo
Keywords: Nonlinear dynamics, noise, neurodynamics, cell biology, computational neuroscience.
Novel optical devices based on novel photonic materials
We study linear and nonlinear light propagation in periodically and randomly modulated photonic materials (photonic crystals and quasicrystals). Based on the recently discovered fundamental light propagation laws such as self-collimation, subdiffraction, superprisming, spatial filtering, and similar, we engineer new photonic elements and devices, such as subdiffractive resonators, highly angle selective lasers and amplifiers, spatial light filters, nonlinear beam couplers, and others.
Responsible: Kestutis Staliunas
Keywords: Nonlinear optics, photonic materials, light propagation.
Nonlinear dynamics of lasers
Nowadays there is a sizable interest in the unstable behavior of optical systems, in particular
of laser devices. This unstable behavior frequently corresponds to well-structured spatio-temporal
dynamics in the form of periodic or chaotic behavior. We study the spatiotemporal dynamical
behavior of different types of lasers, including gas lasers (atomic or molecular), semiconductor
lasers, solid-state microchip lasers, and optical fiber lasers. The phenomena investigated include
synchronization of coupled lasers, multiphotonic emission, low-frequency fluctuations, multimode
instabilities and polarization dynamics.
Responsible: Jordi Garcia-Ojalvo
Keywords: Nonlinear dynamics, laser instabilities, chaos, synchronization.
Nonlinear photonic crystals
We study light phenomena in nonlinear photonic crystals and photonic crystal devices. In particular,
we are interested in
parametric down-conversion processes and second harmonic generation in photonic crystals in
subdiffractive regimes,
parametric- and second harmonic generation processes in nonlinear quasi-photonic crystals
(systems with random modulation of optical properties),
cubic nonlinear processes in subdiffractive photonic crystals (formation of solitonic beams), and
resonators filled by nonlinear photonic crystals.
Responsible: Kestutis Staliunas
Keywords: Nonlinear optics, photonic crystals, second- and third-order nonlinearities.
Quantum control of ultrafast nonlinear optics
The development of laser systems capable of producing femtosecond laser pulses
has opened the possibility to study chemical reactions in real time and directly
monitor the fundamental step of bond breaking and the formations of new products.
We study quantum control techniques with two-color pulses in two and three level
systems. We model time-resolved non-resonant coherent anti-Stokes Raman scattering
(CARS) processes to probe H2 molecules in the gas phase, and investigate optimal
control of four-wave-mixing processes in β-carotene molecules.
Responsible: Carles Serrat
Keywords: Ultrafast nonlinear optical processes, quantum coherent control,
nonlinear spectroscopy, single-molecule optics, biophotonics.