top of page

Light-matter interaction in complex media

What we do

Disorder and imperfection are ubiquitous in nature and also have an impact on nanotechnology. Photonic and optomechanical devices are always affected by some degree of disorder that hampers their functionality. At the P2N group, we are exploring novel functionalities induced by disorder particularly related to the photon-phonon interaction. We explore the role of material nonlinearities to modulate the optical modes of these systems. In addition, we do explore the role of disorder in complex optomechanical systems where the mechanical vibrations of matter – phonons - are included as a new degree of freedom in the control of the light-matter interaction.



Finally, we are also interested in the effect of internal light emitters in these structures in the form of quantum wells to implement two-way experiments: the coupling of the emitter to the phononic modes of the system induces a modulation of their emission and the presence of the internal emitter can be used to probe the mechanical modes of the system.

Optomechanical interaction in complex systems

We study complex phononic systems where the modes with frequencies within the GHz range are excited thermally at room temperature so no external excitation scheme is required. Here, we explore disorder to mediate the interaction between GHz vibrations and THz photons. We also exploit silicon material nonlinearities to modulate the optical modes in these systems.

Any photonic or optomechanical nanostructure is affected by some degree of imperfection. This is due to the unavoidable finite tolerance of the fabrication process. In this line of research, we investigate the role and limitations imposed by disorder for the photon-phonon interaction. We also explore novel ways of exploiting disorder as a resource to enhance this coupling in complex systems.


Topological protection for light and sound

We are interested in exploring different topological phases by engineering the unit cell of periodic structures. Band-symmetry inversion trough geometry is the key concept to test in these systems. One of the goals here is to apply topological concepts used in the field of topological insulators in condensed matter Physics and apply them to bosonic systems. One main question we have related to this field is how robust are these analogies taken from solid-sate Physics and applied to the electromagnetic field and the mechanical vibrations. We aim to quantify the robustness of this topological materials against disorder.

We have recently shown how to quantify the robustness of a topological edge state against white noise on its structural parameters. Calculating the backscattering length linked to the group index enables us to do that, as these two parameters are related to each other through the density of optical states. We have made a quantitative analysis of the backscattering mean free path in two waveguides, on topological and one conventional. We conclude that current proposals of topological photonic phases relying on the breaking of different parity symmetries as the valley-Hall effect are quantitatively, by almost  five times, more robust than standard conventional waveguides with small disorder levels, although this protection is lost at higher imperfection amount.


Dr. Ryan




Selected publications

  1. All-optical radio-frequency modulation of Anderson-localized modes. G. Arregui, D. Navarro-Urrios, N. Kehagias, C. M. Sotomayor Torres, and P. D. García Phys. Rev. B 98, 180202(R)  (2018). Link

  2. Anderson Photon-Phonon Colocalization in Certain Random Superlattices. G. Arregui, N. D. Lanzillotti-Kimura, C. M. Sotomayor-Torres, and P. D. García. Phys. Rev. Lett. 122, 043903 (2019). Link

  3. Coherent generation and detection of acoustic phonons in topological nanocavities. G. Arregui, O. Ortíz, M. Esmann, C. M. Sotomayor-Torres, C. Gomez-Carbonell, O. Mauguin, B. Perrin, A. Lemaître, P. D. García, and  N. D. Lanzillotti-Kimura. APL Photonics 4, 030805 (2019). Link

  4. Quantifying the robustness of topological slow light. G. Arregui, J. Gomis-Bresco, C. M. Sotomayor-Torres, P. D. García. Link



  • Dr. Daniel Lanzilotti-Kimura at C2N (France) – Optomechanical interaction in complex low-dimensional systems. Link

  • Prof. Soren Stobbe at DTU (DK) – Optomechanics in low-dimensional silicon structures. link

  • Prof. Matt Doty at University of Delaware (USA) – Emitters in complex photonic media link

  • Dr. Daniel Torrent at UJI (Spain) – Semi-analytical calculation methods to describe complex nanostructures. link



  • TOCHA: TOCHA is a FET-Proactive project funded by the EU toinvestigate topological protection in novel materials and nanoscopic structures to empower electrons, phonons and photons to flow with little or no dissipation and, ultimately, crosslink them within a hybrid platform. This will entail the design of novel topological photonic/phononic waveguides and the engineering of disruptive heterostructures elaborated from the combination of topological insulators and ferromagnetic materials. Link

  • SMOOTH: is  Retos-project funded by the Spanish Governement (2019 - 2021) coodinated with two other research groups.

bottom of page