We discuss two ways to use femtosecond pulsed lasers as a new interferometric light source for enhanced precision surface-profile metrology. First, a train of ultrafast laser pulses yields repeated low temporal coherence, which allows unequal-path scanning interferometry, which is not feasible with white light, to be performed. Second, the high spatial coherence of femtosecond pulsed lasers enables large-sized optics to be tested in nonsymmetric configurations with relatively small-sized reference surfaces. These two advantages are verified experimentally with Fizeau and Twyman-Green type scanning interferometers.
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http://dx.doi.org/10.1364/ol.30.002650 | DOI Listing |
Phys Chem Chem Phys
January 2025
Theoretical Physics Section, Bhabha Atomic Research Centre, Mumbai-400085, India.
Extensive research on ultrashort laser-induced melting of noble metals like Au, Ag and Cu is available. However, studies on laser energy deposition and thermal damage of their alloys, which are currently attracting interest for energy harvesting and storage devices, are limited. This study investigates the melting damage threshold (DT) of three intermetallic alloys of Au and Cu (AuCu, AuCu and AuCu) subjected to single-pulse femtosecond laser irradiation, comparing them with their constituent metals.
View Article and Find Full Text PDFSci Rep
January 2025
Udmurt Federal Research Center of the Ural Branch of RAS, Baramzina str. 34, Izhevsk, 426067, Russia.
Ultrasound can improve the quality of finished products by reducing porosity and enhancing microstructure in selective laser melting, directed energy deposition, and laser beam welding. This study evaluates the efficiency of ultrasound produced by a pulsed laser via the optoacoustic effect. A quantitative model of collapse of vapor-gas bubbles has been developed under the conditions of ultrasonic treatment at near resonance frequencies.
View Article and Find Full Text PDFNeurosci Lett
January 2025
Department of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, 268 Chungwon-daero, Chungju-si, Chungcheongbuk-do, 27478, Republic of Korea. Electronic address:
Laser-induced plasma technology provides a novel method for generating tactile sensations without physical contact, offering precise and controlled stimulation. However, the impact of varying energy levels on human cognitive and perceptual responses is not yet fully understood. This study aimed to present tactile sensations using laser-induced plasma in a non-contact manner and investigate the cognitive characteristics linked to changes in the plasma's energy parameters, specifically Pulse Width (PW) and Set Current (SC).
View Article and Find Full Text PDFNano Lett
January 2025
Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720, United States.
Ultrafast near-field optical nanoscopy has emerged as a powerful platform to characterize low-dimensional materials. While analytical and numerical models have been established to account for photoexcited carrier dynamics, quantitative evaluation of the associated pulsed laser heating remains elusive. Here, we decouple the photocarrier density and temperature increase in near-field nanoscopy by integrating the two-temperature model (TTM) with finite-difference time-domain (FDTD) simulations.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
School of Physics, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China.
Ultrashort laser pulses are extensively used for efficient manipulation of interfacial spin injection in two-dimensional van der Waals (vdW) heterostructures. However, physical processes accompanying the photoinduced spin transfer dynamics on the all-semiconductor ferromagnetic vdW heterostructure remain largely unexplored. Here, we present a computational investigation of the femtosecond laser pulse induced purely electron-mediated spin transfer dynamics at a time scale of less than 50 fs in a vdW heterostructure.
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