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Photoacoustic Spectroscopy-Based Detection for Identifying the Occurrence and Location of Laser-Induced Damage Using
Katsuhiro Mikami1,2, Ryoichi Akiyoshi2, Yasuhiro Miyasaka3
1Faculty of Biology Oriented Science and Technology, Kindai University, Kinokawa 649-6493, Wakayama, Japan.
Sensors (Basel, Switzerland)
|November 13, 2025
Summary
We developed a new method using photoacoustic spectroscopy and laser Doppler vibrometry for real-time, non-contact detection of laser-induced damage in optical components, achieving high accuracy.
Area of Science:
- Optics and Photonics
- Laser Physics
- Materials Science
Background:
- Laser-induced damage (LID) is a critical issue in high-power laser systems, affecting optical component performance and longevity.
- Current detection methods for LID can be time-consuming, require physical contact, or lack sensitivity for in situ monitoring.
Purpose of the Study:
- To introduce and validate a novel photoacoustic spectroscopy (PAS)-based method utilizing a laser Doppler vibrometer (LDV) for real-time, non-contact detection of LID in optical components.
- To assess the sensitivity, accuracy, and practical applicability of the PAS-LDV method under various experimental conditions.
Main Methods:
- The study employed a PAS-LDV technique to measure audible frequency surface vibrations generated by laser pulses interacting with optical materials.
- Experiments were conducted on dielectric optics (slide glass, single-layer coatings) using an Nd:YAG laser (1064 nm) with different pulse durations (7 ns, 360 ps).
- Finite element modeling (FEM) was used to calculate natural vibration modes for correlation with experimental data.
Main Results:
- The PAS-LDV method demonstrated real-time, remote, and sensitive detection of LID, with accuracy comparable to microscopy.
- Experimental vibration spectra showed good correlation with FEM-calculated natural modes, and location-dependent vibrations were observed.
- The method proved effective even under typical optical component mounting conditions, highlighting its practical utility.
Conclusions:
- The developed PAS-LDV approach provides a promising non-contact, in situ monitoring tool for laser-induced damage in optical components.
- This technique offers a significant advancement for maintaining the integrity and performance of high-power laser systems.
- The correlation between measured vibrations and FEM analysis validates the physical principles underlying the detection method.
