Laser interferometers in physical acoustics

Kokkonen, Kimmo

doi:10.1109/ultsym.2009.5441587

Cited by 11 publications

(2 citation statements)

References 47 publications

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“…As a practical example, the technique was utilized to lower the noise floor in our first measurement results regarding BAW transmission properties of an acoustic mirror presented in our conference paper [85] and as a part of data presented in an invited paper [86]. The filtering was [92].…”

Section: Filtering Of Wave Field Data In Wave-vector Domainmentioning

confidence: 99%

Measurement of evanescent wave properties of a bulk acoustic wave resonator [Letters]

Kokkonen

Meltaus

Pensala

et al. 2012

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Aalto University publication series DOCTORAL DISSERTATIONS 112/2014 © Kimmo Kokkonen AbstractThe research summarized in this dissertation focuses on the development of a heterodyne scanning laser interferometer and of data-analysis techniques for the characterization and analysis of the surface vibration fields in microacoustic devices and test structures.The heterodyne laser interferometer enables a phase-sensitive, absolute-amplitude detection of the out-of-plane component of a surface vibration field, with a minimum detectable amplitude of less than a picometer, while the lateral resolution is better than 1 micrometer. The instrument features a flat frequency response up to 6 GHz.The phase-sensitive absolute-amplitude data enables the visualization of the actual wave behavior in electromechanical components and test structures, but more importantly, it is the basis for further analysis. The research instrument is applied to the study of electroacoustic devices based on surface acoustic wave (SAW) and bulk acoustic wave (BAW) technologies. Two novel SAW devices are studied in detail: a phononic crystal (PnC) structure and a scattering structure resulting in a random wave field. PnCs are acoustic metamaterials that can provide engineered material properties. The laser interferometric measurements were amongst the first to directly characterize the wave interaction with the PnC. SAW slowness curves of an anisotropic substrate material are extracted by measuring and analyzing the scattered random wave field. Data analysis methods are developed further in the context of BAW research by experimentally addressing two important aspects of device design: the correct operation of the acoustic reflector used to confine the energy in the resonator, and investigation of the role of the dispersion and standing wave resonances to the spurious responses often observed in high-Q resonators. Fourier transform techniques are used for selective visualization of wave fields and for the extraction of the dispersion characteristics of the plate-waves. The dispersion data are then further used to analyze the transfer characteristics of an acoustic reflector and to study the properties of lateral eigenresonances and the lateral energy confinement in detail.The research described in this thesis provides a detailed characterization of the operation of SAW and BAW devices and effects within, highlighting and further developing the experimental characterization capabilities and data-analysis methods.Keywords laser interferometry, microacoustics, surface acoustic waves, bulk acoustic waves Tiivistelmä Väitöskirjatyö käsittelee heterodyne-tyyppisen laserinterferometrin sekä interferometrin tuottaman datan analyysitekniikoiden kehittämistä pintavärähtelykenttien karakterisoimiseksi ja analysoimiseksi mikroakustisissa komponenteissa ja testirakenteissa.Työssä rakennettu heterodynelaserinterferometri mahdollistaa pintavärähtelyiden vaiheherkät absoluuttiamplitudimittaukset aina 6 GHz taajuuteen asti. Laitteisto kykenee värähtely-kenttien k...

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Section: Filtering Of Wave Field Data In Wave-vector Domainmentioning

confidence: 99%

Measurement of evanescent wave properties of a bulk acoustic wave resonator [Letters]

Kokkonen

Meltaus

Pensala

et al. 2012

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…Non-contact optical probing techniques are widely utilized to directly measure surface vibration fields in a wide variety of electromechanical devices [1][2][3][4][5]. Scanning laser interferometry [6][7][8][9], capable of detecting (sub)picometer vibration amplitudes, has dominated the characterization of high-frequency electromechanical devices, for which the typical maximum amplitudes are below 1 nm and the operation frequencies can extend up to several GHz.…”

Section: Introductionmentioning

confidence: 99%

Characterization of surface acoustic waves by stroboscopic white-light interferometry

Kokkonen¹,

Lipiäinen²,

Shavrin³

et al. 2015

Opt. Express

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We present phase-sensitive absolute amplitude measurements of surface acoustic wave fields obtained using a stroboscopic white-light interferometer. The data analysis makes use of the high resolution available in the measured interferometric phase data, enabling the characterization of the out-of-plane surface vibration fields in electrically excited microstructures with better than 100 pm amplitude resolution. The setup uses a supercontinuum light source with tailored spectral properties for obtaining the high amplitude resolution. The duration of the light pulses is less than 300 ps to allow the detection of high frequencies. These capabilities enabled a detailed measurement of the focusing of surface acoustic waves by an annular interdigital transducer structure operating at 74 MHz, featuring a maximum vibration amplitude of 3 nm.

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Homodyne full-field interferometer for measuring dynamic surface phenomena in microstructures

Lipiäinen

Kokkonen

Kaivola

2017

Optics and Lasers in Engineering

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Laser interferometers in physical acoustics

Cited by 11 publications

References 47 publications

Measurement of evanescent wave properties of a bulk acoustic wave resonator [Letters]

Measurement of evanescent wave properties of a bulk acoustic wave resonator [Letters]

Characterization of surface acoustic waves by stroboscopic white-light interferometry

Homodyne full-field interferometer for measuring dynamic surface phenomena in microstructures

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