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C. Masoller’s research projects

BE-OPTICAL: Advanced biomedical imaging and data analysis

 

EU-H2020 Marie Skłodowska-Curie Innovative Training Network (2015-2018 H2020-675512) –Principal Investigator and Coordinator: C. Masoller

 

BE-OPTICAL will provide a structured training program to 14 PhD students in a wide range of optical imaging technologies and signal processing tools. The BE-OPTICAL network comprises five academic institutions, two research centers, one company and an ophthalmic clinic.

 

BE-OPTICAL was featured in national and local newspapers (Nov. 2016): La Vanguardia, El Periodico, Diario de Terrassa

 

 

Members of BE-OPTICAL team at UPC (Oct. 2016)

 

Picture taken during the first BE-OPTICAL school (Nov. 2016)

 

Complex physical and biophysical systems: towards a comprehensive view of their dynamics and fluctuations (ComPhysBio)

Ministerio de Economía y Competitividad, Spain (2016 – 2018, FIS2015-66503-C3-2-P) –Principal Investigator at UPC: C. Masoller

 

This coordinated project (which involves three research teams at UPF, UB and UPC) studies nonlinear and stochastic phenomena in a broad class of systems including information processing by optical networks, extreme events in complex systems, neuronal excitability and brain dynamics, among many others.

 

 

  

First workshop of ComPhysBio, Terrassa, June 2016.

ICREA ACADEMIA (2016-2020)

Funded by Institució Catalana de Recerca i Estudis Avançats (ICREA), Generalitat de Catalunya. Principal Investigator: C. Masoller

My research is aimed at i) exploiting nonlinear dynamics for novel applications and ii) developing advanced analysis tools for studying the output signals of complex systems. A first research objective is aimed at exploiting the optical spikes generated by a semiconductor laser with feedback, for implementing photonic neurons that mimic biological ones. I am also interested in exploring the suitability of chaotic semiconductor lasers as light sources for ocular imaging. A second goal is to exploit the analysis tools developed by the LINC project to advance a crucial problem of climate dynamics: predictability in the sub-seasonal time-scale, which lies between the well-established application of weather forecast and that of the seasonal forecast. A third research objective is to provide new quantitative measures for biomedical signals, for reliable classification (healthy vs disease), able to advance the early diagnosis of diseases (cardiac arrhythmias, glaucoma).

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Past projects

LINC: Marie Curie Initial Training Network (ITN) Learning about Interacting Networks in Climate

EU FP7 Marie Curie Initial Training Network (2011-2015) –Principal investigator and Coordinator: C. Masoller

LINC (FP7-289447) main goal was to train 15 researchers (12 PhD students and 3 postdocs) in the complete set of skills required to undertake a successful career in physics and geosciences with expertise in climatology, networks and complex systems. The LINC network comprised six academic partners and three companies. More information about the project can be found in the project web page climatelinc.eu. The results of the LINC project were published in the European Commission web page (Oct. 2016).

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NETT: Neural Engineering Transformative Technologies

EU FP7 Marie Curie Initial Training Network (2012-2016) –Coordinator: Prof. Coombes (Nottingham); PI Prof. García Ojalvo

NETT will provide training to young researchers in Neural Engineering, a new discipline that coalesces engineering, physics and neuroscience for the design and development of brain–computer interface systems, cognitive computers and neural prosthetics. In our lab, the work of the PhD student Carlos Quintero is funded by NETT.

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SILICOS: Stochasticity in Nonlinear Complex Systems (2013-2015)

This project involved the study of a wide range of stochastic and nonlinear phenomena in physical and biological systems, including transport processes, intracellular coupling, bacterial stress, signaling in immune system pathways, pattern formation in biological tissues, neuronal oscillations, visco-elasticity, mixed-mode fracture, symbolic dynamics, polarization dynamics and extreme events in lasers. Funded by the Ministerio de Economía y Competitividad (Spain, FIS2012-37655-C02-01) –PI: J. García Ojalvo

Semiconductor laser complex dynamics: from optical neurons to optical rogue waves (2014-2015)

This project, funded by the European Office of Aerospace Research & Development (EOARD, grant number FA9550-14-1-0359) was aimed at improving our understanding of the complex dynamics in semiconductor lasers induced by external perturbations. A specific goal was to exploit the spiking behavior of semiconductor lasers induced by optical feedback or optical injection for implementing optical neurons which could be building blocks of optical information processing systems. This project was the continuation of previous grants (FA9550-07-1-0238, FA-8655-10-1-3075, FA8655-12-1-2140) which are described below.

ICREA ACADEMIA (2009-2014)

This project was aimed at studying the interplay of noise, delays and nonlinearities in semiconductor lasers, with the ultimate goal of exploiting noise, delays and nonlinearities for novel applications, using them for enhancing the laser performance. In recent years there has been a growing interest in the potential exploitation of noise and delays for controlling the operation of nonlinear devices; from nanoscale systems to opto-electronic devices. In the specific case of vertical-cavity surface-emitting lasers (VCSELs), which are key devices in photonics, nanotechnology, optical signal processing and optical networks, important nonlinear dynamic processes of interaction of light with matter take place, and the unavoidable presence of noise, due to spontaneous emission, and delays, due to finite light propagation time, can significantly degrade the dynamic response of the laser, but on the other hand, these stochastic and nonlinear effects can also be exploited for novel applications.

Funded by Institució Catalana de Recerca i Estudis Avançats (ICREA), Generalitat de Catalunya.

Spiking excitable semiconductor laser as optical neurons: dynamics, clustering and global emerging behaviors (2012-2013)

This project was aimed at exploiting the nonlinear dynamics of semiconductor lasers for novel applications, such as all-optical switching and brain-inspired photonics information processing.

Detailed experimental and numerical studies have been performed, focusing on the interplay of noise and nonlinear dynamics. We used a method of time-series analysis, referred to as symbolic ordinal analysis, to demonstrate that serial correlations present in the output intensity of a semiconductor laser with optical feedback operating in the low-frequency fluctuations regime share common features with serial correlations present in the inter-spike-intervals (ISIs) of biological neuronal systems. The symbolic dynamics underlying the sequence of inter-dropout-intervals in the laser intensity has the same statistical features, in terms of distribution of symbolic patterns, as in ISI sequences of biological neurons. Therefore, semiconductor laser-based optical neurons could provide a novel, inexpensive and controllable experimental set up that could allow for improving our understanding of neuronal activity.

Other topics of research included the analysis of extreme events in the form of ultra-high pulses in the output intensity of semiconductor lasers with continuous-wave (cw) external optical injection or optical feedback. Rogue waves, earthquakes of high magnitude and financial crises are all rare and extreme events corresponding to abrupt changes of environmental or socio-economic conditions with potentially catastrophic consequences. Semiconductor lasers under external perturbations can display a dynamical regime where extreme pulses occasionally occur and thus, they are optimal devices for investigating novel methods for predicting extreme events (revealing early warning signals) and novel methods for controlling these events.

Regarding novel applications, we proposed the implementation of an all-optical stochastic logic gate based in the interplay of polarization bistability and noise in optically injected vertical-cavity surface emitting lasers (VCSELs). We also demonstrated a novel method of sub-wavelength position sensing that exploits the regime of quasiperiodic dynamics of semiconductor lasers with optical feedback from two external cavities.

Funded EOARD, grant number FA8655-12-1-2140.

Stochastic and nonlinear effects in semiconductor lasers (2010-2011)

This project was aimed at contributing to a better understanding of the interplay of noise and nonlinearities in nano-cavity semiconductor lasers, which might result in intrinsic (internal) noise as well as external noise being exploited for novel applications of these devices, and using the potentially beneficial role of noise for optimization of the performance of the next generation of nano-cavity lasers.

In recent years there has been a growing interest in the potential exploitation of noise for controlling the operation of nonlinear devices; from nanoscale systems to opto-electronic devices, noise is gaining a lot of attention for its potentially beneficial role.

In the specific case of vertical cavity semiconductor lasers (VCSELs), which are key devices in photonics, nanotechnology, optical signal processing and optical networks, important nonlinear dynamic processes of interaction of light with matter take place, and the unavoidable presence of noise, due to spontaneous emission, can significantly degrade the dynamic response of the laser, but on the other hand, noise can also be exploited for novel applications.

A first objective of the research project was to study the possibility of controlling the polarization of the optical pulses emitted by a VCSEL by using a properly chosen asymmetric shape for the modulation current and/or by tuning the amount of externally added noise (current or optical noise).

The interplay of nonlinearity and noise can yield logic behavior, and specifically, a noise-controlled logic gate. A second project objective was demonstrating that an optical noise-controlled logic gate can be implemented using a VCSEL, which is naturally a two-state system because the light emitted by a VCSEL can be linearly polarized along two orthogonal directions, usually associated with crystalline orientation or stress.

A third objective of the research project was to investigate the generation of square-wave optical pulses by coupling two VCSELs, such that the mutually injected light has a polarization that is orthogonal to polarization of the natural lasing mode in each VCSEL. The study of the dynamics of such coupled lasers is relevant not only for applications in optical communications but also for analyzing coupling phenomena between nonlinear oscillators.

Funded by EOARD, grant number FA-8655-10-1-3075.

Nonlinear dynamics of novel types of semiconductor lasers (2007-2009)

This project focused on modeling VCSEL nonlinear dynamics, with the objective of improving our understanding of some of nonlinear features. Specific objectives of the project were the study of 1) polarization instabilities due to cavity anisotropies (such as dichroism and birefringence), 2) the interplay of polarization and transverse effects when VCSELs are subjected to external perturbations that induce instabilities (such as current modulation, optical injection, optical feedback) and 3) synchronization phenomena in unidirectional and mutually coupled VCSELs with different types of coupling (through one polarization, both polarizations, and polarization-rotated orthogonal coupling).

Funded by AFOSR, grant number FA9550-07-1-0238.

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