Staff directory Alejandro Martínez Mur

Alejandro Martínez Mur

Visiting Degree Student
Universitat Autònoma de Barcelona (UAB)
alejandro.martinez(ELIMINAR)@icn2.cat
NanoBiosensors and Bioanalytical Applications

Publications

2021

  • Injection locking in an optomechanical coherent phonon source

    Arregui G., Colombano M.F., Maire J., Pitanti A., Capuj N.E., Griol A., Martínez A., Sotomayor-Torres C.M., Navarro-Urrios D. Nanophotonics; 10 (2): 1319 - 1327. 2021. 10.1515/nanoph-2020-0592. IF: 8.449

    Spontaneous locking of the phase of a coherent phonon source to an external reference is demonstrated in a deeply sideband-unresolved optomechanical system. The high-amplitude mechanical oscillations are driven by the anharmonic modulation of the radiation pressure force that result from an absorption-mediated free-carrier/temperature limit cycle, i.e., self-pulsing. Synchronization is observed when the pump laser driving the mechanical oscillator to a self-sustained state is modulated by a radiofrequency tone. We employ a pump-probe phonon detection scheme based on an independent optical cavity to observe only the mechanical oscillator dynamics. The lock range of the oscillation frequency, i.e., the Arnold tongue, is experimentally determined over a range of external reference strengths, evidencing the possibility to tune the oscillator frequency for a range up to 350 kHz. The stability of the coherent phonon source is evaluated via its phase noise, with a maximum achieved suppression of 44 dBc/Hz at 1 kHz offset for a 100 MHz mechanical resonator. Introducing a weak modulation in the excitation laser reveals as a further knob to trigger, control and stabilize the dynamical solutions of self-pulsing based optomechanical oscillators, thus enhancing their potential as acoustic wave sources in a single-layer silicon platform. © 2021 Guillermo Arregui et al., published by De Gruyter.


2020

  • High-Frequency Mechanical Excitation of a Silicon Nanostring with Piezoelectric Aluminum Nitride Layers

    Pitanti A., Makkonen T., Colombano M.F., Zanotto S., Vicarelli L., Cecchini M., Griol A., Navarro-Urrios D., Sotomayor-Torres C., Martinez A., Ahopelto J. Physical Review Applied; 14 (1, 014054) 2020. 10.1103/PhysRevApplied.14.014054. IF: 4.194

    A strong trend for quantum-based technologies and applications follows the avenue of combining different platforms to exploit their complementary technological and functional advantages. Micro and nanomechanical devices are particularly suitable for hybrid integration due to the ease of fabrication at multiscales and their pervasive coupling with electrons and photons. Here, we report on a nanomechanical technological platform where a silicon chip is combined with an aluminum nitride layer. Exploiting the AlN piezoelectricity, surface acoustic waves (SAWs) are injected in the Si layer where the material has been locally patterned and etched to form a suspended nanostring. Characterizing the nanostring vertical displacement induced by the SAW, we find an external excitation peak efficiency in excess of 500 pm/V at 1-GHz mechanical frequency. Exploiting the long-term expertise in silicon photonic and electronic devices as well as the SAW robustness and versatility, our technological platform represents a candidate for hybrid quantum systems. © 2020 American Physical Society.


  • Properties of nanocrystalline silicon probed by optomechanics

    Navarro-Urrios D., Colombano M.F., Maire J., Chávez-Ángel E., Arregui G., Capuj N.E., Devos A., Griol A., Bellieres L., Martínez A., Grigoras K., Häkkinen T., Saarilahti J., Makkonen T., Sotomayor-Torres C.M., Ahopelto J. Nanophotonics; 9 (16): 4819 - 4829. 2020. 10.1515/nanoph-2020-0489. IF: 7.491

    Nanocrystalline materials exhibit properties that can differ substantially from those of their single crystal counterparts. As such, they provide ways to enhance and optimize their functionality for devices and applications. Here, we report on the optical, mechanical and thermal properties of nanocrystalline silicon probed by means of optomechanical nanobeams to extract information of the dynamics of optical absorption, mechanical losses, heat generation and dissipation. The optomechanical nanobeams are fabricated using nanocrystalline films prepared by annealing amorphous silicon layers at different temperatures. The resulting crystallite sizes and the stress in the films can be controlled by the annealing temperature and time and, consequently, the properties of the films can be tuned relatively freely, as demonstrated here by means of electron microscopy and Raman scattering. We show that the nanocrystallite size and the volume fraction of the grain boundaries play a key role in the dissipation rates through nonlinear optical and thermal processes. Promising optical (13,000) and mechanical (1700) quality factors were found in the optomechanical cavity realized in the nanocrystalline Si resulting from annealing at 950°C. The enhanced absorption and recombination rates via the intragap states and the reduced thermal conductivity boost the potential to exploit these nonlinear effects in applications including Nanoelectromechanical systems (NEMS), phonon lasing and chaos-based devices. © 2020 Daniel Navarro-Urrios et al., published by De Gruyter, Berlin/Boston 2020.


2019

  • Synchronization of Optomechanical Nanobeams by Mechanical Interaction

    Colombano M.F., Arregui G., Capuj N.E., Pitanti A., Maire J., Griol A., Garrido B., Martinez A., Sotomayor-Torres C.M., Navarro-Urrios D. Physical Review Letters; 123 (1, 017402) 2019. 10.1103/PhysRevLett.123.017402. IF: 9.227

    The synchronization of coupled oscillators is a phenomenon found throughout nature. Mechanical oscillators are paradigmatic examples, but synchronizing their nanoscaled versions is challenging. We report synchronization of the mechanical dynamics of a pair of optomechanical crystal cavities that, in contrast to previous works performed in similar objects, are intercoupled with a mechanical link and support independent optical modes. In this regime they oscillate in antiphase, which is in agreement with the predictions of our numerical model that considers reactive coupling. We also show how to temporarily disable synchronization of the coupled system by actuating one of the cavities with a heating laser, so that both cavities oscillate independently. Our results can be upscaled to more than two cavities and pave the way towards realizing integrated networks of synchronized mechanical oscillators. © 2019 American Physical Society.


2018

  • Nanocrystalline silicon optomechanical cavities

    Navarro-Urrios D., Capuj N.E., Maire J., Colombano M., Jaramillo-Fernandez J., Chavez-Angel E., Martin L.L., Mercadé L., Griol A., Martínez A., Sotomayor-Torres C.M., Ahopelto J. Optics Express; 26 (8): 9829 - 9839. 2018. 10.1364/OE.26.009829. IF: 3.356

    Silicon on insulator photonics has offered a versatile platform for the recent development of integrated optomechanical circuits. However, there are some constraints such as the high cost of the wafers and limitation to a single physical device level. In the present work we investigate nanocrystalline silicon as an alternative material for optomechanical devices. In particular, we demonstrate that optomechanical crystal cavities fabricated of nanocrystalline silicon have optical and mechanical properties enabling non-linear dynamical behaviour and effects such as thermo-optic/free-carrier-dispersion self-pulsing, phonon lasing and chaos, all at low input laser power and with typical frequencies as high as 0.3 GHz. © 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.


  • Optical modulation of coherent phonon emission in optomechanical cavities

    Maire J., Arregui G., Capuj N.E., Colombano M.F., Griol A., Martinez A., Sotomayor-Torres C.M., Navarro-Urrios D. APL Photonics; 3 (12, 126102) 2018. 10.1063/1.5040061. IF: 0.000

    Optomechanical (OM) structures are well suited to study photon-phonon interactions, and they also turn out to be potential building blocks for phononic circuits and quantum computing. In phononic circuits, in which information is carried and processed by phonons, OM structures could be used as interfaces to photons and electrons thanks to their excellent coupling efficiency. Among the components required for phononic circuits, such structures could be used to create coherent phonon sources and detectors, but more complex functions remain challenging. Here, we propose and demonstrate a way to modulate the coherent phonon emission from OM crystals by a photothermal effect induced by an external laser, effectively creating a phonon switch working at ambient conditions of pressure and temperature and the working speed of which is only limited by the build-up time of the mechanical motion of the OM structure. We additionally demonstrate two other modulation schemes: modulation of harmonics in which the mechanical mode remains active but different harmonics of the optical force are used, and modulation to and from a chaotic regime. Furthermore, due to the local nature of the photothermal effect used here, we expect this method to allow us to selectively modulate the emission of any single cavity on a chip without affecting its surroundings in the absence of mechanical coupling between the structures, which is an important step toward freely controllable networks of OM phonon emitters. © 2018 Author(s).


2017

  • Nonlinear dynamics and chaos in an optomechanical beam

    Navarro-Urrios D., Capuj N.E., Colombano M.F., Garciá P.D., Sledzinska M., Alzina F., Griol A., Martínez A., Sotomayor-Torres C.M. Nature Communications; 8 ( 14965) 2017. 10.1038/ncomms14965. IF: 12.124

    Optical nonlinearities, such as thermo-optic mechanisms and free-carrier dispersion, are often considered unwelcome effects in silicon-based resonators and, more specifically, optomechanical cavities, since they affect, for instance, the relative detuning between an optical resonance and the excitation laser. Here, we exploit these nonlinearities and their intercoupling with the mechanical degrees of freedom of a silicon optomechanical nanobeam to unveil a rich set of fundamentally different complex dynamics. By smoothly changing the parameters of the excitation laser we demonstrate accurate control to activate two- A nd four-dimensional limit cycles, a period-doubling route and a six-dimensional chaos. In addition, by scanning the laser parameters in opposite senses we demonstrate bistability and hysteresis between two- A nd four-dimensional limit cycles, between different coherent mechanical states and between four-dimensional limit cycles and chaos. Our findings open new routes towards exploiting silicon-based optomechanical photonic crystals as a versatile building block to be used in neurocomputational networks and for chaos-based applications. © 2017 The Author(s).


2016

  • Self-pulsing and phonon lasing in optomechanical crystals

    Navarro-Urrios D., Capuj N.E., Gomis-Bresco J., Colombano M.F., García P.D., Sledzinska M., Alzina F., Griol A., Martinez A., Sotomayor-Torres C.M. International Conference on Transparent Optical Networks; 2016-August (7550436) 2016. 10.1109/ICTON.2016.7550436.

    We report on a novel and efficient strategy that can drive a mechanical mode into the lasing regime by exploiting the radiation pressure force in optomechanical (OM) cavities. The pumping mechanism is based on a self-pulsing limit-cycle, which is a spontaneous process that modulates the intracavity radiation pressure force in resonance with a mechanical eigenmode of the OM cavity. © 2016 IEEE.


2015

  • A self-stabilized coherent phonon source driven by optical forces

    Navarro-Urrios D., Capuj N.E., Gomis-Bresco J., Alzina F., Pitanti A., Griol A., Martínez A., Sotomayor Torres C.M. Scientific Reports; 5 ( 15733) 2015. 10.1038/srep15733. IF: 5.578

    We report a novel injection scheme that allows for phonon lasing in a one-dimensional opto-mechanical photonic crystal, in a sideband unresolved regime and with cooperativity values as low as 10'2. It extracts energy from a cw infrared laser source and is based on the triggering of a thermo-optical/free-carrier-dispersion self-pulsing limit-cycle, which anharmonically modulates the radiation pressure force. The large amplitude of the coherent mechanical motion acts as a feedback that stabilizes and entrains the self-pulsing oscillations to simple fractions of the mechanical frequency. A manifold of frequency-entrained regions with two different mechanical modes (at 54 and 122MHz) are observed as a result of the wide tuneability of the natural frequency of the self-pulsing. The system operates at ambient conditions of pressure and temperature in a silicon platform, which enables its exploitation in sensing, intra-chip metrology or time-keeping applications.