Generation of sub-microsecond quasi-unipolar pressure pulses

Area of Science:

• Physics
• Materials Science
• Acoustics

Background:

• Generating controlled, high-frequency acoustic pulses is crucial for advanced material characterization.
• Existing methods may lack precision, repeatability, or a suitable frequency bandwidth.

Purpose of the Study:

• To present a novel method for generating sub-microsecond quasi-unipolar pressure pulses.
• To characterize the acoustic properties of the generated pulses.
• To explore potential applications in ultrasonic characterization.

Main Methods:

• Laser irradiation of a thin copper wire submerged in water.
• Recording acoustic waveforms using piezoelectric and optical interferometry detection techniques.
• Analyzing the relationship between laser fluence, source size, and peak pulse pressure.

Main Results:

• The irradiated copper wire acts as an omnidirectional acoustic source.
• Peak pulse pressure shows a linear dependence on laser fluence and source size.
• An empirical equation was proposed for the spatial and temporal profile of the pressure pulse.
• The generated pulses exhibit a quasi-unipolar time profile and wide ultrasonic bandwidth.

Conclusions:

• The developed method provides an easy-to-implement, repeatable way to generate high-quality ultrasonic pressure pulses.
• The source's characteristics are suitable for various ultrasonic characterization tasks, including transducer and material analysis.
• This technique holds promise for advancing non-destructive testing and material science research.