The development of high-power lasers requires optics with very low absorption to avoid detrimental thermal effects. In this work, we discuss our recent developments on the use of lock-in thermography to measure absorption. We apply this technique in a multipass configuration to increase the effective power on the tested samples. We present a system based on a kW-class ytterbium fiber laser operating at 1.07 µm wavelength, which enables exposing samples to 5 kW effective power and measuring absorption in the ppm range. The implementation, calibration procedure, and obtained performance are discussed with some applications to single-layer coatings of ,,,, and deposited by plasma-assisted electron beam deposition.
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http://dx.doi.org/10.1364/AO.445045 | DOI Listing |
Rev Sci Instrum
January 2025
College of Public Health, Sichuan University, Chengdu 610041, China.
In this paper, a microwave thermal imaging system (MTIS) has been presented for debonding detection of radar absorbing materials (RAMs). First, an overview of the mechanism underlying microwave heating and the fundamental principle of defect detection within RAMs is presented. Then, a multifunctional MTIS capable of performing both microwave lock-in thermography (MLIT) and long-pulse microwave thermography (LPMT) has been introduced, specifically tailored for the in situ inspection of RAMs.
View Article and Find Full Text PDFNatl Sci Rev
June 2024
International Center for Quantum Design of Functional Materials (ICQD), School of Emerging Technology, University of Science and Technology of China, Hefei 230026, China.
Part Fibre Toxicol
May 2024
Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, 1700, Switzerland.
Background: During inhalation, airborne particles such as particulate matter ≤ 2.5 μm (PM), can deposit and accumulate on the alveolar epithelial tissue. In vivo studies have shown that fractions of PM can cross the alveolar epithelium to blood circulation, reaching secondary organs beyond the lungs.
View Article and Find Full Text PDFPhys Rev Lett
November 2023
National Institute for Materials Science, Tsukuba 305-0047, Japan.
We report the observation of the anisotropic magneto-Thomson effect (AMTE), which is one of the higher-order thermoelectric effects in a ferromagnet. Using lock-in thermography, we demonstrated that in a ferromagnetic NiPt alloy, the cooling or heating induced by the Thomson effect depends on the angle between the magnetization direction and the temperature gradient or charge current applied to the alloy. AMTE observed here is the missing ferromagnetic analog of the magneto-Thomson effect in a nonmagnetic conductor, providing the basis for nonlinear spin caloritronics and thermoelectrics.
View Article and Find Full Text PDFSensors (Basel)
October 2023
Henan Key Laboratory of Intelligent Manufacturing of Mechanical Equipment, Zhengzhou University of Light Industry, Zhengzhou 450002, China.
In recent years, infrared thermographic (IRT) technology has experienced notable advancements and found widespread applications in various fields, such as renewable industry, electronic industry, construction, aviation, and healthcare. IRT technology is used for defect detection due to its non-contact, efficient, and high-resolution methods, which enhance product quality and reliability. This review offers an overview of active IRT principles.
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