Femtosecond spectroscopy of acoustic frequency combs in the 100-GHz frequency range in Al/Si membranes

Großmann, Martin; Klingele, Matthias; Scheel, Patricia; Ristow, Oliver; Hettich, Mike; He, Chuan; Waitz, Reimar; Schubert, M.; Bruchhausen, A. E.; Gusev, Vitalyi; Scheer, Elke; Dekorsy, Thomas

doi:10.1103/physrevb.88.205202

Cited by 25 publications

(27 citation statements)

References 28 publications

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“…6), the dip around 25 GHz in the frequency spectrum on the right side of Fig. 7 is not due to the acousto-optic detection, which takes place mostly in Al layer, but due to a specific competition of the thermoelastic and deformation potential mechanisms of the phonons photo-excitation [12]. The deformation potential in the Si is the dominant contribution to the spectral weight of the induced stress at low frequencies.…”

Section: Al/si Double Layer Membrane Systemmentioning

confidence: 95%

“…Hence it appears first after 83 ps. Details regarding the generation and detection of the pulses as well as the origin of the different strain fronts are described in detail elsewhere [12].…”

Section: Al/si Double Layer Membrane Systemmentioning

confidence: 99%

“…That pulse can be measured using a probe beam with an equally short absorption length which will then result in a frequency comb in the Fourier domain. Details regarding the simulation of the stress distribution and associated transient reflectivity changes in the membranes are described elsewhere [12].…”

Section: Longitudinal Acoustic Mode Spectrum Of a Membranementioning

confidence: 99%

“…superlattices, to study phonon properties [1][2][3][4][5] and to generate new coherent sources [6][7][8][9]. In recent years also membranes have proven to be an excellent model system to investigate high frequency phonon in the GHz to THz frequency range [10][11][12]. The main focus of this article is to summarize our recent results and elucidate acoustic phonon dynamics in single-crystalline membranes generated by ultrashort light pulses.…”

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Generation and detection of gigahertz acoustic oscillations in thin membranes

Schubert

Großmann

et al. 2015

Ultrasonics

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Section: Al/si Double Layer Membrane Systemmentioning

confidence: 95%

Section: Al/si Double Layer Membrane Systemmentioning

confidence: 99%

Section: Longitudinal Acoustic Mode Spectrum Of a Membranementioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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Generation and detection of gigahertz acoustic oscillations in thin membranes

Schubert

Großmann

et al. 2015

Ultrasonics

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“…Details regarding the fabrication of the membranes and the gratings are discussed in the previous publications. 12,17 The method and setup used are similar to the one previously employed for the generation and detection of Rayleigh waves. 12 We excite and detect the Lamb waves with an optical pump-probe technique based on high-speed asynchronous optical sampling (ASOPS) with femtosecond lasers at GHz repetition rate.…”

mentioning

confidence: 99%

Time-resolved detection of propagating Lamb waves in thin silicon membranes with frequencies up to 197 GHz

Großmann

Ristow

Hettich

et al. 2015

Applied Physics Letters

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Guided acoustic waves are generated in nanopatterned silicon membranes with aluminum gratings by optical excitation with a femtosecond laser. The spatial modulation of the photoacoustic excitation leads to Lamb waves with wavelengths determined by the grating period. The excited Lamb waves are optically detected for different grating periods and at distances up to several lm between pump and probe spot. The measured frequencies are compared to the theoretical dispersion relation for Lamb waves in thin silicon membranes. Compared to surface acoustic waves in bulk silicon twice higher frequencies for Lamb waves (197 GHz with a 100 nm grating) are generated in a membrane at equal grating periods. 4,5 Continuous progress in the development of methods for the fabrication of membranes with a thickness in the nm range for a variety of applications 6 requires the evaluation of their parameters and quality, e.g., their dispersion relation and damping, the development of methods for both the generation and detection of acoustic waves at GHz frequencies.Standing waves in free-standing films of lm thickness have been first detected by Brillouin scattering. 7 Recently, femtosecond lasers have been successfully applied to generate and detect longitudinal acoustic modes in free-standing silicon (Si) membranes with frequencies up to 500 GHz corresponding to 20 nm wavelengths. [8][9][10] As the dispersion relations of propagating Lamb waves are emerging from standing wave resonances, 11 these experiments indicate that propagating Lamb waves in membranes at similarly high frequencies could be monitored all-optically as well, if the conditions for their effective generation and detection are achieved. Recently, Rayleigh waves with wavelengths down to 45 nm (Refs. 12 and 13) and frequencies up to 90 GHz (Ref. 12) have been generated and detected based on the deposition of a metallic grating of nanometer periodicity on the substrate surface. Rayleigh waves are surface acoustic waves on a semi-infinite substrate. 14 Here, we combine the femtosecond pump-probe technique applied earlier to the monitoring of standing wave resonances 8-10 and of Rayleigh waves 12 with nanostructuring of the surface 12,13,15 in order to achieve the generation and detection of propagating Lamb waves at frequencies up to 197 GHz and wavelengths down to 50 nm in thin semiconductor membranes. Those high frequencies can be generated because for the same wave vectors the dispersion relations of Lamb waves contain modes of much higher frequencies than those of Rayleigh waves. The highest frequencies of the detected coherent Lamb modes are nearly three times higher than the highest frequencies of thermal Lamb modes detected by classical Brillouin scattering. 16 Different samples with aluminum (Al) gratings from 100 nm to 500 nm period are prepared on crystalline Si membranes (326 nm thickness). The grating stripes are oriented perpendicular to the [110]-direction on the (001)-surface of Si with a filling factor of 50%. The thickness of the Al is 17 nm and the st...

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Femtosecond laser-acoustic modeling and simulation for AlCu nanofilm nondestructive testing

Wang,

Min,

et al. 2024

Front. Mech. Eng.

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Femtosecond spectroscopy of acoustic frequency combs in the 100-GHz frequency range in Al/Si membranes

Cited by 25 publications

References 28 publications

Generation and detection of gigahertz acoustic oscillations in thin membranes

Generation and detection of gigahertz acoustic oscillations in thin membranes

Time-resolved detection of propagating Lamb waves in thin silicon membranes with frequencies up to 197 GHz

Femtosecond laser-acoustic modeling and simulation for AlCu nanofilm nondestructive testing

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