scholarly journals Thin-film lithium niobate modulators for non-invasive sensing of high-frequency electric fields

2021 ◽  
Vol 38 (2) ◽  
pp. 336
Author(s):  
John Rollinson ◽  
Mona Hella ◽  
Seyfollah Toroghi ◽  
Payam Rabiei ◽  
Ingrid Wilke
Keyword(s):  
Thin Film ◽  
Lithium Niobate ◽  
Electric Fields ◽  
High Frequency ◽  
Non Invasive

scholarly journals Magnetic Temporal Interference for Noninvasive Focal Brain Stimulation

2022 ◽  
Author(s):  
Adam Khalifa ◽  
Seyed Mahdi Abrishami ◽  
Mohsen Zaeimbashi ◽  
Alexander D. Tang ◽  
Brian Coughlin ◽  
...  
Keyword(s):  
Electric Fields ◽  
Brain Stimulation ◽  
High Frequency ◽  
Low Frequency ◽  
Brain Regions ◽  
Strong Increase ◽  
Non Invasive ◽  
Frequency Magnetic Field ◽  
Fos Expression ◽  
The Brain

Non-invasive stimulation of deep brain regions has been a major goal for neuroscience and neuromodulation in the past three decades. Transcranial magnetic stimulation (TMS), for instance, cannot target deep regions in the brain without activating the overlying tissues and has a poor spatial resolution. In this manuscript, we propose a new concept that relies on the temporal interference of two high-frequency magnetic fields generated by two electromagnetic solenoids. To illustrate the concept, custom solenoids were fabricated and optimized to generate temporal interfering electric fields for rodent brain stimulation. C-Fos expression was used to track neuronal activation. C-Fos expression was not present in regions impacted by only one high-frequency magnetic field indicating ineffective recruitment of neural activity in non-target regions. In contrast, regions impacted by two fields that interfere to create a low-frequency envelope display a strong increase in c-Fos expression. Therefore, this magnetic temporal interference solenoid-based system provides a framework to perform further stimulation studies that would investigate the advantages it could bring over conventional TMS systems.

scholarly journals Recent Progress in Devices Based on Magnetoelectric Composite Thin Films

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8012
Author(s):  
Deepak Rajaram Patil ◽  
Ajeet Kumar ◽  
Jungho Ryu
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Electric Fields ◽  
High Frequency ◽  
Frequency Conversion ◽  
Limit Of Detection ◽  
Very High Frequency ◽  
Magnetic Field Sensors ◽  
Magnetoelectric Composite ◽  
Band Pass

The strain-driven interfacial coupling between the ferromagnetic and ferroelectric constituents of magnetoelectric (ME) composites makes them potential candidates for novel multifunctional devices. ME composites in the form of thin-film heterostructures show promising applications in miniaturized ME devices. This article reports the recent advancement in ME thin-film devices, such as highly sensitive magnetic field sensors, ME antennas, integrated tunable ME inductors, and ME band-pass filters, is discussed. (Pb1−xZrx)TiO3 (PZT), Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), Aluminium nitride (AlN), and Al1−xScxN are the most commonly used piezoelectric constituents, whereas FeGa, FeGaB, FeCo, FeCoB, and Metglas (FeCoSiB alloy) are the most commonly used magnetostrictive constituents in the thin film ME devices. The ME field sensors offer a limit of detection in the fT/Hz1/2 range at the mechanical resonance frequency. However, below resonance, different frequency conversion techniques with AC magnetic or electric fields or the delta-E effect are used. Noise floors of 1–100 pT/Hz1/2 at 1 Hz were obtained. Acoustically actuated nanomechanical ME antennas operating at a very-high frequency as well as ultra-high frequency (0.1–3 GHz) range, were introduced. The ME antennas were successfully miniaturized by a few orders smaller in size compared to the state-of-the-art conventional antennas. The designed antennas exhibit potential application in biomedical devices and wearable antennas. Integrated tunable inductors and band-pass filters tuned by electric and magnetic field with a wide operating frequency range are also discussed along with miniaturized ME energy harvesters.

Formation of Regular Domain Structures in Quenched Ferroelectrics Under the Influence of an External High-frequency Electric Field

2019 ◽  
Vol 9 (3) ◽  
pp. 344-352 ◽  
Author(s):  
L.I. Stefanovich ◽  
O.Y. Mazur ◽  
V.V. Sobolev
Keyword(s):  
Lithium Niobate ◽  
Electric Field ◽  
Domain Structure ◽  
High Frequency ◽  
Evolution Equations ◽  
Regular Domain ◽  
Field Frequency ◽  
Domain Structures ◽  
Alternating Electric Field ◽  
Lithium Niobate Crystals

Introduction: Within the framework of the phenomenological theory of phase transitions of the second kind of Ginzburg-Landau, the kinetics of ordering of a rapidly quenched highly nonequilibrium domain structure is considered using the lithium tantalate and lithium niobate crystals as an example. Experimental: Using the statistical approach, evolution equations describing the formation of the domain structure under the influence of a high-frequency alternating electric field in the form of a standing wave were obtained. Numerical analysis has shown the possibility of forming thermodynamically stable mono- and polydomain structures. It turned out that the process of relaxation of the system to the state of thermodynamic equilibrium can proceed directly or with the formation of intermediate quasi-stationary polydomain asymmetric phases. Results: It is shown that the formation of Regular Domain Structures (RDS) is of a threshold character and occurs under the influence of an alternating electric field with an amplitude less than the critical value, whose value depends on the field frequency. The conditions for the formation of RDSs with a micrometer spatial scale were determined. Conclusion: As shown by numerical studies, the RDSs obtained retain their stability, i.e. do not disappear even after turning off the external electric field. Qualitative analysis using lithium niobate crystals as an example has shown the possibility of RDSs formation in high-frequency fields with small amplitude under resonance conditions

scholarly journals Electro-Optic Control of Lithium Niobate Bulk Whispering Gallery Resonators: Analysis of the Distribution of Externally Applied Electric Fields

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 298
Author(s):  
Yannick Minet ◽  
Hans Zappe ◽  
Ingo Breunig ◽  
Karsten Buse
Keyword(s):  
Lithium Niobate ◽  
Electric Field ◽  
Electric Fields ◽  
Frequency Comb ◽  
Parametric Oscillation ◽  
Pockels Effect ◽  
Optical Mode ◽  
Cylindrical Resonator ◽  
Whispering Gallery ◽  
Electro Optic

Whispering gallery resonators made out of lithium niobate allow for optical parametric oscillation and frequency comb generation employing the outstanding second-order nonlinear-optical properties of this material. An important knob to tune and control these processes is, e.g., the linear electro-optic effect, the Pockels effect via externally applied electric fields. Due to the shape of the resonators a precise prediction of the electric field strength that affects the optical mode is non-trivial. Here, we study the average strength of the electric field in z-direction in the region of the optical mode for different configurations and geometries of lithium niobate whispering gallery resonators with the help of the finite element method. We find that in some configurations almost 100% is present in the cavity compared to the ideal case of a cylindrical resonator. Even in the case of a few-mode resonator with a very thin rim we find a strength of 90%. Our results give useful design considerations for future arrangements that may benefit from the strong electro-optic effect in bulk whispering gallery resonators made out of lithium niobate.

scholarly journals Non-invasive high-frequency oscillatory ventilation in preterm infants after extubation: a randomized, controlled trial

2021 ◽  
Vol 49 (2) ◽  
pp. 030006052098491
Author(s):  
Yan Li ◽  
Qiufen Wei ◽  
Dan Zhao ◽  
Yan Mo ◽  
Liping Yao ◽  
...  
Keyword(s):  
Randomized Controlled Trial ◽  
Preterm Infants ◽  
High Frequency ◽  
Controlled Trial ◽  
High Frequency Oscillatory Ventilation ◽  
Positive Pressure ◽  
Non Invasive ◽  
Randomized Controlled ◽  
Oscillatory Ventilation ◽  
High Frequency Oscillatory

Objective To investigate the effectiveness and safety of non-invasive high-frequency oscillatory ventilation (NHFOV) in post-extubation preterm infants. Methods This was a randomized, controlled trial. A total of 149 preterm infants aged between 25 to 34 weeks’ gestational age with a birth weight of <1500 g who required invasive mechanical ventilation on admission were included. After extubation, they were randomized to the NHFOV group (n = 47), nasal intermittent positive pressure ventilation (NIPPV) group (n = 51), or nasal continuous positive airway pressure (NCPAP) group (n = 51). We compared the effectiveness and safety among these three groups. Results A total of 139 preterm infants finally completed the study. The reintubation rate was significantly lower in the NHFOV group than in the other groups. The duration of non-invasive ventilation and the length of hospital stay in the NHFOV and NIPPV groups were significantly shorter than those in the NCPAP group. The incidence of bronchopulmonary dysplasia in the NHFOV and NIPPV groups was significantly lower than that in the NCPAP group. The NHFOV group had significantly less nasal injury than the NCPAP group. Conclusion As post-extubation respiratory support in preterm infants, NHFOV has a lower reintubation rate compared with NCPAP and NIPPV, without increasing the rate of complications.

scholarly journals Advanced Electrode Design for Low-Voltage High-Speed Thin-Film Lithium Niobate Modulators

2021 ◽  
Vol 13 (2) ◽  
pp. 1-9
Author(s):  
Xingrui Huang ◽  
Yang Liu ◽  
Zezheng Li ◽  
Huan Guan ◽  
Qingquan Wei ◽  
...  
Keyword(s):  
Thin Film ◽  
Lithium Niobate ◽  
High Speed ◽  
Low Voltage ◽  
Electrode Design

scholarly journals The thin film bulk acoustic wave resonator based on single-crystalline 43○Y-cut lithium niobate thin films

AIP Advances ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 075002
Author(s):  
Xiaoyuan Bai ◽  
Yao Shuai ◽  
Lu Lv ◽  
Ying Xing ◽  
Jiaoling Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Lithium Niobate ◽  
Acoustic Wave ◽  
Bulk Acoustic Wave ◽  
Single Crystalline ◽  
Bulk Acoustic Wave Resonator ◽  
Wave Resonator ◽  
Film Bulk
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