Experimental techniques for imaging and measuring transient vapor nanobubbles

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Imaging and measuring transient vapor bubbles at the nanoscale presents significant experimental challenges due to their small size and short lifetimes.
• Quantifying individual photothermally induced vapor nanobubbles (NBs) in single-event experiments requires robust detection methodologies.

Purpose of the Study:

• To analyze and compare three distinct techniques for identifying and quantifying individual photothermally induced vapor nanobubbles (NBs).
• To evaluate the effectiveness of optical scattering and acoustic detection methods across a range of excitation energies.

Main Methods:

• Utilized optical scattering and acoustic detection methods to analyze photothermally induced vapor nanobubbles (NBs).
• Investigated the time-response characteristics (duration and amplitude) of optical scattering and acoustic signals.
• Examined NB detection in both optically transparent and opaque media.

Main Results:

• Optical scattering time-response duration provides the most accurate quantitative detection of NBs in optically transparent media.
• Acoustic time-response amplitude effectively describes NBs in opaque media, particularly when stress waves are absent.
• Both methods allow for the identification and quantification of individual NBs over a wide range of excitation energies.

Conclusions:

• The choice of detection technique for vapor nanobubbles (NBs) is dependent on the optical properties of the surrounding medium.
• Optical scattering and acoustic detection offer viable, distinct approaches for characterizing nanoscale NBs in single-event experiments.