Observation of Phenomena After Pulsed Laser Irradiation of Solid with Optical Wave Microphone

Mitsugi, Fumiaki; Ikegami, Tomoaki; Nakamiya, Toshiyuki; Sonoda, Yoshimi

doi:10.1143/jjap.51.01ac10

Cited by 3 publications

(3 citation statements)

References 30 publications

(29 reference statements)

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“…However, the amplitude distribution obtained from the experiment, shown in Fig. 5, is similar to that obtained by using conventional optical wave microphones that do not use optical fibers [16], [17]. The optimum incident angle was ±2/9 mrad in this setup.…”

Section: A Characteristics Of the Fibered Optical Wave Microphonesupporting

confidence: 74%

“…tomography [15]. Optical wave microphones can also be used to detect pressure waves that originate from ablation plasma [16]- [18] and gliding arc plasma [19]. Recently, we developed a fibered optical wave microphone through which a laser beam penetrates the optical fibers without passing through the detecting region, reducing the interference from electromagnetic noise from the discharges.…”

Section: Introductionmentioning

confidence: 99%

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High-Speed Camera and Fibered Optical Wave Microphone Measurements on Surface-Dielectric-Barrier Discharges

Mitsugi

Nakamiya

Sonoda

et al. 2015

IEEE Trans. Plasma Sci.

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Much focus has been placed on the aerodynamics of surface-dielectric-barrier discharges to control air flow. An important factor to consider to understand the mechanism is pressure waves, which include acoustic waves and shock waves that are emitted from the surface-dielectric-barrier discharges. In this paper, a fibered optical wave microphone, which improves upon a conventional optical wave microphone with regard to signal-to-noise ratio, was developed to detect these pressure waves with high precision. This paper explores the properties of the fibered optical wave microphone. A high-speed camera was used to capture time-resolved microdischarges. After simultaneous observation of the applied voltage, current, pressure waves, and microdischarge images for the surface-dielectric-barrier discharge, the relationships among these factors were analyzed and discussed.Index Terms-Fibered optical wave microphone, high-speed camera, microdischarge plasma, shock waves, surface-dielectricbarrier discharge. Science and Technology, Kumamoto University, since 2014. He has contributed more than 100 papers in international journals and conference proceedings. His current research interests include time-resolved observation of discharge plasmas in atmospheric pressure, pressure waves from discharges, laser-solid processes and thin film fabrication, laser ablation in supercritical fluids, optical wave microphone technique, and the applications of ozone for plants, soil, and water. He has contributed more than 100 papers in international journals and conference proceedings. His current research interests include plasma processes, preparation of functional thin films, discharges in low temperature superfluidity liquid helium, and time-resolved observation of discharge plasmas in low pressure and atmospheric pressure.

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Section: A Characteristics Of the Fibered Optical Wave Microphonesupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

High-Speed Camera and Fibered Optical Wave Microphone Measurements on Surface-Dielectric-Barrier Discharges

Mitsugi

Nakamiya

Sonoda

et al. 2015

IEEE Trans. Plasma Sci.

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“…To similarly monitor processes with higher repetition rates, microphones with frequency ranges of up to at least several hundred kilohertz are necessary, e.g., the optical microphones: they have indeed already been employed to study USP laser ablation 22 , 23 . However, collecting high-frequency acoustic emissions in air has a major disadvantage: the signal amplitude is strongly attenuated with the increasing frequency.…”

Section: Introductionmentioning

confidence: 99%

Real-time defect detection through lateral monitoring of secondary process emissions during ultrashort pulse laser microstructuring

Zuric

Brenner

2022

Opt. Eng.

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Ultrashort pulse (USP) laser machining is characterized both by high spatial precisions as well as rapid changes during the processing. Laser pulses with durations of only a few hundred femtoseconds are deflected over the workpiece surfaces at speeds of up to 10 m/s. Due to the tradeoff between the precision and the productivity, USP laser machining processes can last up to multiple days. Online defect detection and their elimination is therefore essential in order to increase the stability of the established processing as well as accelerate the process development. However, monitoring of USP laser micromachining represents a great challenge because of both the high requirements for the spatial accuracy and the cost-intensive sensor integration. In the scope of this work, this challenge is tackled by laterally collecting the optical process emissions with photodiodes for different wavelength ranges. The monitoring system, which had previously been developed and had undergone initial testing, is further evaluated in this work. These most recent analyses aim to investigate the detection of the surface roughness prior to as well as its evolution during the USP laser machining. In addition, successful localization of defects induced on the workpiece surface by the USP processing is shown. Furthermore, the possibility of online process control was demonstrated by transferring the analysis algorithms to a field programmable gate array (FPGA) and implementing a real-time defect detection and feedback to the user. A decision for each data point is generated within the 10-μs cycle of the data acquisition. Furthermore, the system can be programmed flexibly and thus expanded to include real-time data analyses for further applications as well as process control. In conclusion, the analyses of laterally recorded secondary emissions have shown great potential for differentiating between surface roughness above 1 μm as well as tracking changes for every pass over the surface and localizing defects during the USP-laser machining. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Analysis of Discharge Sound and I-V Characteristic on Gliding Arc Discharge

Mitsugi

Nakamiya

Sonoda

et al. 2016

ELECTROTECHNICAL REVIEW

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Observation of Phenomena After Pulsed Laser Irradiation of Solid with Optical Wave Microphone

Cited by 3 publications

References 30 publications

High-Speed Camera and Fibered Optical Wave Microphone Measurements on Surface-Dielectric-Barrier Discharges

High-Speed Camera and Fibered Optical Wave Microphone Measurements on Surface-Dielectric-Barrier Discharges

Real-time defect detection through lateral monitoring of secondary process emissions during ultrashort pulse laser microstructuring

Analysis of Discharge Sound and I-V Characteristic on Gliding Arc Discharge

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