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Wednesday, 17 March 2021

Injection locking process observed in optomechanical systems

A new research published in ‘Nanophotonics’ reports the observation of injection locking of self-pulsing-driven oscillations of optomechanical systems. This collaborative study, to which ICN2 group leader ICREA Prof. Clivia Sotomayor-Torres participated, shines more light into the use of these systems.

A paper recently published in Nanophotonics presents a study on optomechanical systems in which injection locking of frequency oscillations was observed. This is a phenomenon by which an oscillating system picks up the frequency of another one, resulting in two coupled systems oscillating at the same frequency. In particular, the authors of this study found spontaneous frequency locking of the mechanical motion of an optomechanical crystal that had been brought to a self-sustained state.

Researchers employed coherent self-sustained acoustic sources (specifically, phonon lasers), based on optomechanical crystal cavities (OMCs) that use the inherent material non-linearities of silicon. Taking advantage of this physical mechanism, they showed that these phonon sources can be locked to the frequency of an external source which modulates the laser light. In addition, the mechanical signal inherits the noise characteristics of the external modulation, which can be produced with very high purity. The ability to process information using mechanical waves (phonons) relies on the use of phonon sources over which the frequency and noise level can be controlled.

These results provide relevant information for further investigations on optoelectronical oscillators or neuromorphic computing, using distributed arrays of oscillators based on a single small-footprint chip.

This research was developed in collaboration by various institutions, among which is the ICN2. In particular, ICREA Prof. Clivia Sotomayor-Torres and her group of Phononic and Photonic Nanostructures, conceived the device layout as well as the methodology and carried out the experimental characterization. The study was led by Prof. Daniel Navarro-Urrios from the MIND-IN2UB of the Department of Electronic and Biomedic Engineering of the Universitat de Barcelona. The samples were fabricated at the Polytechnic University of Valencia (Spain).

 

Reference article:

Arregui, M. F. Colombano, J. Maire, A. Pitanti, N. E. Capuj, A. Griol, A. Martínez, C. M. Sotomayor-Torres, D. Navarro-Uríos, Injection locking in an optomechanical coherent phonon source. Nanophotonics, Volume 10, pp 1319-1327; DOI: 10.1515/nanoph-2020-0592