FIG 4 - uploaded by George Andrew Antonelli
Content may be subject to copyright.
Vibration pattern corresponding to the six normal modes. Regions in which the strain is positive an expansion are shown with lighter shading.
Source publication
We report experiments in which a subpicosecond pump light pulse is used to excite vibrations in a nanostructure consisting of a periodic array of copper wires embedded in a glass matrix on a silicon substrate. The motion of the wires after excitation is detected using a time-delayed probe light pulse. From the measured data, it is possible to deter...
Context in source publication
Context 1
... longitudinal waves c/d is 12.9 GHz, and for transverse waves it is 9.0 GHz. 24 It follows that for the six modes that are shown in Fig. 4, radiation into the substrate can occur only for n0, i.e., all other values of n are beyond cutoff. 25 Thus, in the far field, all radiation propagates away into the substrate at normal incidence. As a result, the rate at which energy is radiated into the substrate as longitudinal waves can be considered to be proportional to the ...
Citations
... 13 The research on acoustic excitations in gratings has been advanced by several groups. Antonelli et al. 7,8 have demonstrated the intrinsic complexity of the acoustics in 1D metallic nonmagnetic gratings, showing that both lateral periodicity Λ and thickness d of metal stripes are important parameters, giving rise to complex spectra of hybridized acoustic eigenmodes for d ≈ Λ. 16 In the present work, we extend these studies to ferromagnetic and magnetostrictive 1D nickel gratings. A recent magnetoacoustic study performed on unstructured ferromagnetic Ni thin films excited in the transient grating (TG) geometry evidenced the generation of surface acoustic modes and their resonant interactions with the FMR precession. ...
Femtosecond (fs) time-resolved magneto-optics is applied to investigate laser-excited ultrafast dynamics of one-dimensional nickel gratings on fused silica and silicon substrates for a wide range of periodicities Λ = 400–1500 nm. Multiple surface acoustic modes with frequencies up to a few tens of GHz are generated. Nanoscale acoustic wavelengths Λ/n have been identified as nth-spatial harmonics of Rayleigh surface acoustic wave (SAW) and surface skimming longitudinal wave (SSLW), with acoustic frequencies and lifetimes being in agreement with theoretical calculations. Resonant magnetoelastic excitation of the ferromagnetic resonance (FMR) by SAW’s third spatial harmonic, and, most interestingly fingerprints of the parametric resonance at 1/2 SAW frequency have been observed. Numerical solutions of Landau–Lifshitz–Gilbert (LLG) equation magnetoelastically driven by complex polychromatic acoustic fields quantitatively reproduce all resonances at once. Thus, our results provide a solid experimental and theoretical base for a quantitative understanding of ultrafast fs-laser-driven magnetoacoustics and tailoring the magnetic-grating-based metasurfaces at the nanoscale.
... For example, the full elastic tensor of cerium dioxide has been characterized by analyzing the Brillouin scattering generated in differently oriented crystals [36] . For opaque materials, as commonly found for nuclear structural and fuel components, a different route can be explored where the elastic properties can be obtained from the velocity of a surface acoustic wave or the damping amplitude of an optically excited transducer vibration [37][38][39] . For example, by measuring the damping of transducer films under different ion doses, Tas et al. utilized picosecond ultrasonics to study the impact of ion implantation on interfacial bonding strength [40] . ...
Picosecond ultrasonics has been demonstrated on a tristructural isotropic (TRISO) fuel compact to measure the elastic properties of each compact layer. This technique utilizes an ultrashort pump laser pulse to excite vibrations in a gold transducer film covering the surface of each component and a second probe laser pulse to record the resulting acoustic strain induced change in optical reflectance. From the damping of this film vibration, the acoustic reflection coefficient, which couples the elastic properties of the transducer film and the sample, can be obtained, enabling a calculation of the sample's acoustic velocity and elastic modulus. Results obtained from this method are consistent with known values of elastic moduli, namely that the SiC coating is the stiffest component of the compact while the carbonaceous matrix is the most compliant. Nanoindentation was conducted as a benchmark technique on the same sample and shows satisfactory agreement with the results of picosecond ultrasonics. Compared to other methods like nanoindentation, picosecond ultrasonics is multimodal with a capability of measuring several key properties simultaneously and has potentials to be coupled into optical fibers for remote sensing. Thus, these demonstration measurements reveal the methodology to be a promising candidate for in-situ and high-throughput optical characterizations of nuclear materials.
... Coherent oscillations in metallic nanostructures are typically driven by ultrafast local heating and impulsive hot electron pressure 17,18 . Vibrational characteristics of gold nanostructures of various shapes and sizes have been intensively studied [19][20][21][22][23][24][25][26] . Strategical positioning of mechanical oscillators in the optical near-field of a plasmonic nanoantenna has been shown to result in antennaenhanced readout effects and amplification of small signal response 20 . ...
... Pulsed excitation does not benefit from enhancement by the mechanical quality factor, as in the case of continuous resonant driving of a single mode, but instead results in a broad spectrum of mechanical modes. [19][20][21][22][23][24][25][26] To reveal the spectrum of modes, a fast Fourier transform (FFT) was carried out on the processed time signals and a >1.5 GHz highpass filter was applied. The results, shown in Figure 2d, reveal distinct modes in the gigahertz range with peak frequencies at 2.33 GHz, 5.33 GHz, 7 GHz, 11 GHz, 11.67 GHz, and 21 GHz. ...
... [73][74][75][76] Additional errors can arise from the interpretation and analysis of the loaddisplacement curve [77][78][79] as well as assumptions regarding Poisson's ratio, where properties such as Young's modulus are of interest. [80][81][82] In contrast, optoacoustic based techniques such as PLA, BLS, and SAW are noncontact and, therefore, intrinsically nondestructive techniques making them suitable for probing a wide range of metallic, [83][84][85] ceramic, 86,87 dielectric, [88][89][90][91][92][93] semiconductor, 94,95 glass, 96,97 polymeric, 98,99 and biological 100,101 materials in bulk, 86 thin film, 88 multilayered, [102][103][104] fiber, 97,100 or nanostructured [105][106][107][108][109][110][111] form. In addition, the full elastic constants for a material can be in many cases derived from such measurements allowing engineering properties such as Young's modulus and Poisson's ratio to be determined independently [112][113][114] with a precision and accuracy approaching 1%. ...
... Still, the mechanical properties of sub-diffraction scale structures have been deduced by these techniques via using arrays of periodic nanostructures. [105][106][107][108][109][110][111] Microfabricated cantilever and resonator structures based on micro/nanoelectromechanical (MEM/NEM) 125,126 approaches allow the mechanical properties of materials to be assessed at the feature size of interest. [127][128][129] Such approaches also allow the influence of microfabrication techniques on the mechanical properties of the material structure of interest to be directly assessed, which is a challenge for indentation and optoacoustic based techniques. ...
Over the past several decades, atomic force microscopy (AFM) has advanced from a technique used primarily for surface topography imaging to one capable of characterizing a range of chemical, mechanical, electrical, and magnetic material properties with subnanometer resolution. In this review, we focus on AFM as a nanoscale mechanical property characterization tool and examine various AFM contact and intermittent contact modes that add mechanical contrast to an imaged surface. Through detailed analysis of the tip-sample contact mechanics, this contrast can be converted into quantitative measurements of various nanomechanical properties including elastic modulus, shear modulus, wear rate, adhesion, and viscoelasticity. Different AFM modes that provide such measurements are compared and contrasted in this work on a wide range of materials including ceramics, metals, semiconductors, polymers, and biomaterials. In the last few years, considerable improvements have been made in terms of fast imaging capabilities, tip preservation, and quantitative mechanics for multifrequency measurements as well as well-known AFM modes like amplitude modulation and peak-force tapping. In line with these developments, a major highlight of this review is the discussion of the operation and capabilities of one such mode, namely, intermittent contact resonance AFM (ICR-AFM). The applications of ICR-AFM to nanoscale surface and subsurface quantitative mechanical characterizations are reviewed with specific examples provided for thin polymeric films and patterned nanostructures of organosilicate dielectric materials. The combination of AFM-based mechanical characterization with AFM-based chemical spectroscopy to allow nanoscale structure-property characterization is also discussed and demonstrated for the analysis of low-k dielectric/copper nanoelectronic interconnect structures and further highlights synergistic advances in the AFM field.
... Des ondes acoustiquesà haute fréquence sontà la fois générées et détectées avec des impulsions laser (durée < 1ps), permettant l'inspection de matériaux submicrométriques [168]. Ce domaine, l'acoustique picoseconde, s'est largement développé ces dernières années et a permis l'étude des propriétésélastiques de films minces, de systèmes multicouches, de nanostructures et de nanoparticules [169,170,171,172]. Cette méthode aégalement eté utilisée pour l'étude des systèmes massifs. ...
Ces travaux de thèse visent à étudier les propriétés élastiques et thermiques des films minces microstructurés par la technique GLAD (GLancing Angle Deposition). Cette technique propose des structurations et des architectures originales favorisant la porosité et les comportements anisotropes. L'accent est mis sur les corrélations entre la forme structurale des films minces en colonnes et leurs propriétés anisotropes. Les mesures de la propagation des ondes acoustiques de surface sont effectuées avec une plateforme pompe sonde hétérodyne femtoseconde. L'influence des différents paramètres et procédés de dépôt à la fois sur l'évolution de la structure des films minces et sur la propagation des ondes élastiques, ont été étudiés. Les paramètres expérimentaux jouent un rôle fondamental sur la forme des colonnes et leur angle de croissance. Un facteur clé jouant sur l’anisotropie des ondes élastiques de surface est la section plus ou moins elliptique des colonnes. Les simulations numériques confirme que la forme de cette section et la porosité jouent un rôle primordial sur la dispersion et la propagation anisotrope des ondes élastiques.Des caractérisations thermiques ont également été effectuées sur les films microstructurés GLAD par la méthode 3 omega et par la technique de thermoréflectance avec le banc de mesure pompe sonde femtoseconde. Des conductivités thermiques considérablement réduites ont été mesurées à température ambiante pour les films GLAD en W. Une anisotropie thermique, plus importantepour les films les plus épais, a été trouvée. Cette caractérisation anisotrope en termes de conductivité thermique a été reliée à la microstructuration anisotrope des films, crée lors de dépôt GLAD.
... Carbon nanotubes are nano materials which have tremendous potential in designs of new sensors, composite materials and gas detection. The superior properties of the carbon nanotubes and its correlates are important instrumental for the improvements in applications (Chong and Lam 1999;Demir et al. 2010;Wagner et al. 1998; Thostenson et al. 2001;Qian et al. 2002;Sirtori 2002;Antonelli et al. 2002;Brauns et al. 2002;Stankovich et al. 2006;Lau et al. 2006;Schedin et al. 2007;Bunch et al. 2007;Chiu et al. 2008;Arash and Wang 2012). Other new fields of application of carbon nanotubes are continuously explored. ...
In this study, free lateral vibration behavior of a functionally graded nanobeam in an elastic matrix with rotationally restrained ends is studied based on the Eringens’ nonlocal theory of elasticity formulated in differential form. Euler–Bernoulli beam theory, Fourier sine series and Stokes’ transformation are used to investigate the vibrational behavior of nanobeams with restrained boundary conditions. Although vibration based dynamical analysis of nanostructures is a widely investigated topic, there are only few studies that exist in the literature pertaining to the analysis of nanobeams with rotationally restrained boundary conditions. To investigate and analyze the effect of deformable boundary conditions on the lateral vibration of nanobeams, the Fourier coefficients obtained by using Stokes’ transformation. Explicit formulas are derived for the elastic nonlocal boundary conditions at the ends. A useful coefficient matrix is derived by using these equations. Moreover, the effects of some parameters such as functional gradient index, nonlocal parameter, and rotational restraints on the natural frequencies are studied and some conclusions are drawn.
... The superior properties of the carbon nanotubes are important instrumental for the improvements in applications. [4][5][6][7][8][9][10][11][12][13][14][15][16] Other new fields of application of carbon nanotubes are continuously explored. These nanosized structures [17][18][19][20][21] show that the superior properties such as physical properties, mechanical properties, chemical properties, etc. ...
Free torsional vibration of cracked carbon nanotubes with elastic torsional boundary conditions is studied. Eringen’s nonlocal elasticity theory is used in the analysis. Two similar rotation functions are represented by two Fourier sine series. A coefficient matrix including torsional springs and crack parameter is derived by using Stokes’ transformation and nonlocal boundary conditions. This useful coefficient matrix can be used to obtain the torsional vibration frequencies of cracked nanotubes with restrained boundary conditions. Free torsional vibration frequencies are calculated by using Fourier sine series and compared with the finite element method and analytical solutions available in the literature. The effects of various parameters such as crack parameter, geometry of nanotubes, and deformable boundary conditions are discussed in detail.
... The thermoreflectance technique was first developed in the 1970s and 1980s, where continuous wave (CW) light sources were used for the heating and sensing. 49,50 With the advancement of pico-and femtosecond pulsed laser in the 1980s, this technique was widely used for studying non-equilibrium electron-phonon interaction, 51-56 coherent phonon transport, 27,[57][58][59][60][61] picosecond acoustics, [62][63][64][65][66][67][68][69][70][71][72] optical properties, [73][74][75] thermal expansion coefficient, 76 and thermal transport properties of thin films 77,78 and interfaces. 40,41,43,44,46,47,[79][80][81][82][83][84][85] Among these, Paddock and Eesley 77 were the first to measure thermal diffusivity of metal films using picosecond transient thermoreflectance, and Humphrey Maris' group have done a series of original research in developing picosecond ultrasonics using picosecond light pulses. ...
... 40,41,43,44,46,47,[79][80][81][82][83][84][85] Among these, Paddock and Eesley 77 were the first to measure thermal diffusivity of metal films using picosecond transient thermoreflectance, and Humphrey Maris' group have done a series of original research in developing picosecond ultrasonics using picosecond light pulses. [62][63][64][65][66][67][68][69][70][71] This technique has been further developed over the last two decades for measuring anisotropic thermal conductivity 24,37,86,87 and probing spectral phonon transport. [88][89][90][91][92] The transient thermoreflectance technique can be implemented as both the TDTR method 22,24,25 and the frequency-domain thermoreflectance (FDTR) method 93,94 (see Sec. III A for more details of FDTR). ...
Measuring thermal properties of materials is not only of fundamental importance in understanding the transport processes of energy carriers (electrons and phonons in solids) but also of practical interest in developing novel materials with desired thermal properties for applications in energy conversion and storage, electronics, and photonic systems. Over the past two decades, ultrafast laser-based time-domain thermoreflectance (TDTR) has emerged and evolved as a reliable, powerful, and versatile technique to measure the thermal properties of a wide range of bulk and thin film materials and their interfaces. This tutorial discusses the basics as well as the recent advances of the TDTR technique and its applications in the thermal characterization of a variety of materials. The tutorial begins with the fundamentals of the TDTR technique, serving as a guideline for understanding the basic principles of this technique. Several variations of the TDTR technique that function similarly as the standard TDTR but with their own unique features are introduced, followed by introducing different advanced TDTR configurations that were developed to meet different measurement conditions. This tutorial closes with a summary that discusses the current limitations and proposes some directions for future development.
... The thermoreflectance technique was first developed in the 1970s and 1980s, where continuous wave (CW) light sources were used for the heating and sensing. 49,50 With the advancement of pico-and femtosecond pulsed laser in the 1980s, this technique was widely used for studying non-equilibrium electron-phonon interaction, 51-56 coherent phonon transport, 27, 57-61 picosecond acoustics, [62][63][64][65][66][67][68][69][70][71][72] optical properties, [73][74][75] thermal expansion coefficient 76 and thermal transport properties of thin films 77,78 and interfaces. 40,41,43,44,46,47,[79][80][81][82][83][84][85] Among these, Paddock and Eesley 77 were the first to measure thermal diffusivity of metal films using picosecond transient thermoreflectance, and Humphrey Maris' group have done a series of original research in developing picosecond ultrasonics using picosecond light pulses. ...
... 40,41,43,44,46,47,[79][80][81][82][83][84][85] Among these, Paddock and Eesley 77 were the first to measure thermal diffusivity of metal films using picosecond transient thermoreflectance, and Humphrey Maris' group have done a series of original research in developing picosecond ultrasonics using picosecond light pulses. [62][63][64][65][66][67][68][69][70][71] This technique has been further developed over the last two decades for measuring anisotropic thermal conductivity 24,37,86,87 and probing spectral phonon transport. [88][89][90][91][92] The transient thermoreflectance technique can be implemented as both the TDTR method 22,24,25 and the frequency-domain thermoreflectance (FDTR) method 93,94 (see Section III(A) for more details of FDTR). ...
Measuring thermal properties of materials is not only of fundamental importance in understanding the transport processes of energy carriers (electrons and phonons) but also of practical interest in developing novel materials with desired thermal conductivity for applications in energy, electronics, and photonic systems. Over the past two decades, ultrafast laser-based time-domain thermoreflectance (TDTR) has emerged and evolved as a reliable, powerful, and versatile technique to measure the thermal properties of a wide range of bulk and thin film materials and their interfaces. This tutorial discusses the basics as well as the recent advances of the TDTR technique and its applications in the thermal characterization of a variety of materials. The tutorial begins with the fundamentals of the TDTR technique, serving as a guideline for understanding the basic principles of this technique. A diverse set of TDTR configurations that have been developed to meet different measurement conditions are then presented, followed by several variations of the TDTR technique that function similarly as the standard TDTR but with their own unique features. This tutorial closes with a summary that discusses the current limitations and proposes some directions for future development.
... However, one major challenge is still the development of a tunable source of high-frequency acoustic phonons capable of replacing the standard metallic thin films. Several approaches have been recently proposed to solve this problem using optimized multilayers [16], optical microcavities [13,17,18], metallic nanoparticles [19,20], and semiconductor nanostructures and quantum dots to name a few [8,[21][22][23]. The use of localized surface plasmons is an alternative to overcome the aforementioned problem that has started to be exploited [24][25][26][27][28][29][30]. ...
Acoustic vibrations at the nanoscale (GHz-THz frequencies) and their interactions with electrons, photons, and other excitations are the heart of an emerging field in physics: nanophononics. The design of ultrahigh frequency acoustic-phonon transducers, with tunable frequency, and easy to integrate in complex systems is still an open and challenging problem for the development of acoustic nanoscopies and phonon lasers. Here we show how an optimized plasmonic metasurface can act as a high-frequency phonon transducer. We report pump-probe experiments in metasurfaces composed of an array of gold nanostructures, revealing that such arrays can act as efficient and tunable photon-phonon transducers, with a strong spectral dependence on the excitation rate and laser polarization. We anticipate our work to be the starting point for the engineering of phononic metasurfaces based on plasmonic nanostructures.
