Laser induced short plane acoustic wave focusing in water

Ko, Seung Hwan; Ryu, Sang Gil; Misra, Nipun; Pan, Heng; Grigoropoulos, Costas P.; Kladias, Nick; Panides, Elias; Domoto, G. A.

doi:10.1063/1.2768192

Cited by 22 publications

(11 citation statements)

References 17 publications

(6 reference statements)

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“…Moreover, thin films are optimal for generating sound waves perpendicular to the target surface. Propagation of sound waves in the direction perpendicular to the surface of chromium film from laser irradiation was extensively studied by Ko et al 13 Sound waves with different parameters (amplitude, frequency, etc.) can be formed by different generation mechanisms; however, the strongest ultrasound signal is generated from a surface vibration in the direction perpendicular to the surface.…”

Section: Introductionmentioning

confidence: 99%

Comparison between optical-resolution photoacoustic microscopy and confocal laser scanning microscopy for turbid sample imaging

U-Thainual

Kim

2015

J. Biomed. Opt

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Optical-resolution photoacoustic microscopy (ORPAM) in theory provides lateral resolution equivalent to the optical diffraction limit. Scattering media, such as biological turbid media, attenuates the optical signal and also alters the diffraction-limited spot size of the focused beam. The ORPAM signal is generated only from a small voxel in scattering media with dimensions equivalent to the laser spot size after passing through scattering layers and is detected by an acoustic transducer, which is not affected by optical scattering. Thus, both ORPAM and confocal laser scanning microscopy (CLSM) reject scattered light. A multimodal optical microscopy platform that includes ORPAM and CLSM was constructed, and the lateral resolution of both modes was measured using patterned thin metal film with and without a scattering barrier. The effect of scattering media on the lateral resolution was studied using different scattering coefficients and was compared to computational results based on Monte Carlo simulations. It was found that degradation of lateral resolution due to optical scattering was not significant for either ORPAM or CLSM. The depth discrimination capability of ORPAM and CLSM was measured using microfiber embedded in a light scattering phantom material. ORPAM images demonstrated higher contrast compared to CLSM images partly due to reduced acoustic signal scattering.

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Section: Introductionmentioning

confidence: 99%

Comparison between optical-resolution photoacoustic microscopy and confocal laser scanning microscopy for turbid sample imaging

U-Thainual

Kim

2015

J. Biomed. Opt

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“…A calculation has shown that the penetration depth for a 4 MHz acoustic wave traveling in glycerin is about 8 mm. 24,25 The high attenuation may also cause a decrease in the contribution of the waves generated from the outer electrodes to the interference, making the axial pressure distributions of the three FZPs become similar ͑Fig. 5͒.…”

Section: ͑4͒mentioning

confidence: 99%

Self-focused acoustic ejectors for viscous liquids

Hon

Kwok

Li³

et al. 2010

Review of Scientific Instruments

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Self-focused acoustic ejectors using the Fresnel zone plate ͑FZP͒ have been developed for ejecting viscous liquids, without nozzle, in the drop-on-demand mode. The FZP is composed of a lead zirconate titanate piezoelectric plate patterned with a series of annular electrodes, with the unelectroded region of the plate removed. Our results show that the acoustic waves are effectively self-focused by constructive interference in glycerin ͑with a viscosity of 1400 mPa s͒, giving small focal points with a high pressure. Due to the high attenuation, the wave pressure decreases significantly with the distance from the FZP. Nevertheless, the pressure at the focal points 2.5 and 6.5 mm from the FZP is high enough to eject glycerin droplets in the drop-on-demand mode. Driven by a simple wave train comprising a series of sinusoidal voltages with an amplitude of 35 V, a frequency of 4.28 MHz, and a duration of 2 ms, the ejector can eject fine glycerin droplets with a diameter of 0.4 mm at a repetition frequency of 120 Hz in a downward direction. Droplets of other viscous liquids, such as the prepolymer of an epoxy with a viscosity of 2000 mPa s, can also be ejected in the drop-on-demand mode under similar conditions.

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“…The momentum of the plasma plume becomes the impulse or the excitation force for the irradiated material. LA has various applications, including plasma growth, 23 LA shockwave in air, 24 LA in water, 25 cavitation bubble, 26 laser propulsion, 27,28 laser micromachining, 29 laser deposition, 30 laser peening, 31 and vibration tests and acoustic tests using LA or laser-induced breakdown (LIB). [32][33][34][35][36][37][38][39][40][41] Although multiple stress waves in silica glass generated by femtosecond LA 20 have been visualized using the shadowgraph technique, using LA as an excitation force for gels has yet to be investigated.…”

Section: Introductionmentioning

confidence: 99%

High spatial and temporal resolution measurement of mechanical properties in hydrogels by non-contact laser excitation

et al. 2016

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Gels have received increased attention as potential materials for biological materials because they can exhibit similar mechanical properties. One obstacle for using gels is that their mechanical properties are significantly altered by defects, such as an inhomogeneous crosslink density distribution. If these defects could be detected and the values and spatial distributions of mechanical properties in the gel could be determined, it would be possible to apply gels for several fields. To achieve the high spatial and temporal resolution measurement of mechanical properties in hydrogels, in our method, a conventional contact excitation device is replaced with a non-contact excitation using laser ablation for the input and magnetic resonance elastography to measure stress waves is replaced with the Schlieren method with a high-speed camera. Magnetic resonance elastography is a local measurement technique, and consequently, requires a lot of time to characterize a sample, as well as does not have sufficient spatial resolution to obtain a broad range of elasticity coefficients of gels. We use laser ablation to apply non-contact impulse excitations to gels to generate stress waves inside them. We can determine mechanical properties of gels using the stress waves’ propagation velocity.

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Laser induced short plane acoustic wave focusing in water

Cited by 22 publications

References 17 publications

Comparison between optical-resolution photoacoustic microscopy and confocal laser scanning microscopy for turbid sample imaging

Comparison between optical-resolution photoacoustic microscopy and confocal laser scanning microscopy for turbid sample imaging

Self-focused acoustic ejectors for viscous liquids

High spatial and temporal resolution measurement of mechanical properties in hydrogels by non-contact laser excitation

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