Publications de Luis Guillermo Villanueva Torrijo

Hydrodynamic Cavitation-Induced Thrombolysis on a Clot-on-a-Chip Platform

Complications from thrombosis constitute a massive global burden for human health. Current treatment methods have limitations and can cause serious adverse effects. Hydrodynamic cavitation (HC) is a physical phenomenon where bubbles develop and collapse ra ...

2025

Fabrication of fluid-compatible trilayer cantilevers with integrated piezoelectric actuators

Luis Guillermo Villanueva Torrijo, Georg Fantner, Matthias Neuenschwander, Damien Maillard, Nahid Hosseini, Mustafa Kangül

Microcantilevers are popular transducers thanks to their simple design and a high sensitivity. In many applications, the cantilevers need to be actuated, either to induce a controlled deflection or to excite the resonance. This can be achieved with integra ...

2025

Measuring direct flexoelectricity at the nanoscale

Luis Guillermo Villanueva Torrijo, Daniel Moreno Garcia

Flexoelectricity is a property of all dielectric materials, where inhomogeneous strain induces electrical polarization. This effect becomes particularly prominent at the nanoscale where larger strain gradients can be obtained. While flexoelectric charges h ...

Institute of Electrical and Electronics Engineers2025

Suspended lithium niobate acoustic resonators with Damascene electrodes for radiofrequency filtering

Luis Guillermo Villanueva Torrijo, Silvan Stettler

Data rates and volume for mobile communication are ever-increasing with the growing number of users and connected devices. With the deployment of 5G and 6G on the horizon, wireless communication is advancing to higher frequencies and larger bandwidths enab ...

Springer Science and Business Media LLC2025

Fabrication of periodically poled lithium niobate waveguides for broadband nonlinear photonics

Luis Guillermo Villanueva Torrijo, Furkan Ayhan

Nonlinear optics is the precursor for many of the modern-day applications of photonics, including femtosecond pulse synthesis, precision spectroscopy, and metrology. In the last decade, nanophotonic waveguides have not only boosted the efficiencies of nonl ...

2025

Ultraviolet to mid-infrared optical properties of sputtered Al(Sc)N-on-SiO2 thin films and experimental demonstration of AlN integrated photonic devices in the telecom C-band

Luis Guillermo Villanueva Torrijo

Thin film aluminum nitride (AlN) stands out as a promising material for integrated photonics due to its wide bandgap of 6.1 eV, facilitating efficient operation across diverse spectral ranges. Its inherent electro-optic and nonlinear optical properties mak ...

2024

Emulating paper: A review of reflective display technologies

Olivier Martin, Luis Guillermo Villanueva Torrijo, Dorian Giraud Herle

Reflective displays, which harness ambient light, offer energy-efficient alternatives to traditional emissive screens in mobile devices. This review provides an overview of various reflective display technologies and their comparative performance metrics. ...

2024

Ultraviolet astronomical spectrograph calibration with laser frequency combs from nanophotonic lithium niobate waveguides

Luis Guillermo Villanueva Torrijo, Furkan Ayhan

Astronomical precision spectroscopy underpins searches for life beyond Earth, direct observation of the expanding Universe and constraining the potential variability of physical constants on cosmological scales. Laser frequency combs can provide the requir ...

Nature Research2024

Optical Ring Resonators in Sputtered Aluminum Nitride on Insulator for Integrated Photonic MEMS

Luis Guillermo Villanueva Torrijo

This study explores the utilization of sputtered aluminum nitride (AlN) thin film on insulator as a platform for integrated photonic MEMS. We experimentally demonstrate proof-of-concept photonic ring resonators with Q-factors up to 31000 at a resonance wav ...

IEEE Computer Society2024

Effect of annealing on flexoelectricity in hafnium oxide (HfO2)

Luis Guillermo Villanueva Torrijo, Daniel Moreno Garcia

Flexoelectricity is universal in all dielectrics, effective at high temperatures, and a promising transduction technique for nanoelectromechanical systems (NEMS). However, as flexoelectricity is still in its early stages, many aspects require further inves ...

AIP American Institute of Physics2024

Flexoelectricity in amorphous hafnium oxide (HfO2)

Luis Guillermo Villanueva Torrijo, Kaitlin Marie Howell, Daniel Moreno Garcia

Flexoelectricity, inherent in all materials, offers a promising alternative to piezoelectricity for nanoscale actuation and sensing. However, its widespread application faces significant challenges: differentiating flexoelectric effects from those of piezo ...

2024

Silicon microresonator arrays: A comprehensive study on fabrication techniques and pH-controlled stress-induced variations in cantilever stiffness

Luis Guillermo Villanueva Torrijo, Annalisa De Pastina

We introduce a detailed design and fabrication process of Silicon microcantilever arrays for biomolecular detection in liquid environment, utilized with laser readout. We present typical fabrication problems and provide related solutions to obtain high qua ...

Elsevier2024

Piezoelectric and elastic properties of Al0.60Sc0.40N thin films deposited on patterned metal electrodes

Luis Guillermo Villanueva Torrijo, Silvan Stettler, Marco Liffredo, Nan Xu, Federico Peretti

Sc-doped aluminum nitride (AlScN) allows for piezoelectric devices with large electromechanical coupling and the benefits increase with larger Sc doping in the film. However, with a larger Sc concentration, the process window narrows, and it is necessary t ...

2024

New insights on cavitating flows over a microscale backward-facing step

Luis Guillermo Villanueva Torrijo

This study introduces the first experimental analysis of shear cavitation in a microscale backward-facing step (BFS) configuration. It explores shear layer cavitation under various flow conditions in a microfluidic device with a depth of 60 μm and a step h ...

2024

Photostrictive Actuators Based on Freestanding Ferroelectric Membranes

Luis Guillermo Villanueva Torrijo, Daniel Moreno Garcia

Complex oxides offer a wide range of functional properties, and recent advances in the fabrication of freestanding membranes of these oxides are adding new mechanical degrees of freedom to this already rich functional ecosystem. Here, photoactuation is dem ...

Wiley-V C H Verlag Gmbh2024

Periodic Structure of Narrow FBARs Operating on SH1 Mode in LN Membrane Solidly Mounted on SiC Substrate

Luis Guillermo Villanueva Torrijo, Seniz Esra Küçük, Nan Xu

We propose a system of narrow FBARs with alternating voltage polarity on top electrodes on the LN platelet and a common bottom floating electrode positioned on a substrate with high acoustic velocity (SiC). This is a YBAR device that is attached to a SiC s ...

Institute of Electrical and Electronics Engineers Inc.2024

In-Sensor Passive Speech Classification with Phononic Metamaterials

Luis Guillermo Villanueva Torrijo, Daniel Moreno Garcia

Mitigating the energy requirements of artificial intelligence requires novel physical substrates for computation. Phononic metamaterials have vanishingly low power dissipation and hence are a prime candidate for green, always-on computers. However, their u ...

Wiley-V C H Verlag Gmbh2024

Resonant Transducers Consisting of Graphene Ribbons with Attached Proof Masses for NEMS Sensors

Luis Guillermo Villanueva Torrijo, Daniel Moreno Garcia

The unique mechanical and electrical properties of graphene make it an exciting material for nanoelectromechanical systems (NEMS). NEMS resonators with graphene springs facilitate studies of graphene's fundamental material characteristics and thus enable i ...

Amer Chemical Soc2023

Transversal Spurious Mode Suppression in Ultra-Large-Coupling SH0 Acoustic Resonators on YX36 degrees-Cut Lithium Niobate

Luis Guillermo Villanueva Torrijo, Silvan Stettler

This work reports on the design and fabrication of fundamental shear horizontal (SH0) mode acoustic resonators based on a suspended lithium niobate (LNO) film at 1.04 GHz. Due to the large e16 piezoelectric coefficient of YX36 degrees.-cut LNO, fabricated ...

Institute of Electrical and Electronics Engineers2023

Toward Band n78 Shear Bulk Acoustic Resonators Using Crystalline Y-Cut Lithium Niobate Films With Spurious Suppression

Victor Plessky, Luis Guillermo Villanueva Torrijo, Soumya Yandrapalli

This work presents the study of suspended Y-cut Lithium Niobate shear bulk acoustic resonators for wide band filter applications in the frequency range of 3.5-4.5GHz. The resonators consist of a Lithium Niobate film with Aluminum top interdigitated electro ...

Institute of Electrical and Electronics Engineers2023