Staff directory Omar Enrique Florez Peñaloza

Publications

2022

• Engineering nanoscale hypersonic phonon transport

  Florez O., Arregui G., Albrechtsen M., Ng R.C., Gomis-Bresco J., Stobbe S., Sotomayor-Torres C.M., García P.D. Nature Nanotechnology; 2022. 10.1038/s41565-022-01178-1.

  Controlling vibrations in solids is crucial to tailor their elastic properties and interaction with light. Thermal vibrations represent a source of noise and dephasing for many physical processes at the quantum level. One strategy to avoid these vibrations is to structure a solid such that it possesses a phononic stop band, that is, a frequency range over which there are no available elastic waves. Here we demonstrate the complete absence of thermal vibrations in a nanostructured silicon membrane at room temperature over a broad spectral window, with a 5.3-GHz-wide bandgap centred at 8.4 GHz. By constructing a line-defect waveguide, we directly measure gigahertz guided modes without any external excitation using Brillouin light scattering spectroscopy. Our experimental results show that the shamrock crystal geometry can be used as an efficient platform for phonon manipulation with possible applications in optomechanics and signal processing transduction. © 2022, The Author(s), under exclusive licence to Springer Nature Limited.

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• Excitation and detection of acoustic phonons in nanoscale systems

  Ng R.C., El Sachat A., Cespedes F., Poblet M., Madiot G., Jaramillo-Fernandez J., Florez O., Xiao P., Sledzinska M., Sotomayor-Torres C.M., Chavez-Angel E. Nanoscale; 2022. 10.1039/d2nr04100f.

  Phonons play a key role in the physical properties of materials, and have long been a topic of study in physics. While the effects of phonons had historically been considered to be a hindrance, modern research has shown that phonons can be exploited due to their ability to couple to other excitations and consequently affect the thermal, dielectric, and electronic properties of solid state systems, greatly motivating the engineering of phononic structures. Advances in nanofabrication have allowed for structuring and phonon confinement even down to the nanoscale, drastically changing material properties. Despite developments in fabricating such nanoscale devices, the proper manipulation and characterization of phonons continues to be challenging. However, a fundamental understanding of these processes could enable the realization of key applications in diverse fields such as topological phononics, information technologies, sensing, and quantum electrodynamics, especially when integrated with existing electronic and photonic devices. Here, we highlight seven of the available methods for the excitation and detection of acoustic phonons and vibrations in solid materials, as well as advantages, disadvantages, and additional considerations related to their application. We then provide perspectives towards open challenges in nanophononics and how the additional understanding granted by these techniques could serve to enable the next generation of phononic technological applications. © 2022 The Royal Society of Chemistry.

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