Article
Optics
Stephen W. Grib, Hans U. Stauffer, Sukesh Roy, S. Alexander Schumaker
Summary: This study demonstrates the multiphoton-resonance enhancement of a rare-gas-assisted nitrogen femtosecond-laser electronic-excitation-tagging (FLEET) signal, showing an order of magnitude increase compared to previous near-resonance excitation methods. By tuning to three-photon-resonant transitions of argon, energy can be more efficiently deposited into the mixture, resulting in a stronger and longer-lived FLEET signal.
Article
Materials Science, Multidisciplinary
Hanbing Song, Peng Lang, Boyu Ji, Xiaowei Song, Jingquan Lin
Summary: The research focuses on actively controlling the localized plasmonic field in the femto-nano scale using chirped femtosecond laser pulses. The study reveals the influence of laser chirp on the transferring of the plasmonic field between poles of a nanocross system, as well as the temporal distribution of resonant frequencies in the chirped pulse.
OPTICAL MATERIALS EXPRESS
(2021)
Article
Energy & Fuels
Tianfeng Liang, Hongwei Zang, Wei Zhang, Liansheng Zheng, Danwen Yao, Helong Li, Huailiang Xu, Ruxin Li
Summary: This study utilizes femtosecond filamentating laser to ignite a premixed methane-air mixture over long distance and with ultra-low energy. The technique is insensitive to the position of the ablator and can operate sustainably with minimal sample removal.
Article
Optics
Zixin Wang, Xiaowei Ji, Ningning Dong, Chenduan Chen, Zhouyuan Yan, Xun Cao, Jun Wang
Summary: In this study, the changes in the optical properties of VO2 films induced by fs laser were investigated using a variable-temperature Z-scan. The results showed that high-repetition-frequency laser can induce phase transition in VO2, which is reversible and leads to significant changes in the optical properties of the film.
Article
Multidisciplinary Sciences
S. Jaiswal, E. M. Aguirre, G. Veda Prakash
Summary: The study demonstrates the strong emission of the auroral green line in an atmospheric pressure plasma jet system using pure argon gas, with potential applications in various fields such as blood coagulation and waste treatment. The research also provides insights on the chemical reactions involved in the production of O(1S) and the characterization of the O(1S) emission by changing different parameters.
SCIENTIFIC REPORTS
(2021)
Article
Materials Science, Multidisciplinary
Jean-Luc Deziel, Louis J. Dube, Charles Varin
Summary: The study examines the controversy over the possibility of triggering ionization avalanche in dielectrics with laser-induced breakdown on a subpicosecond time scale, and the relative importance of carrier-impact ionization versus field ionization. By proposing a rate-equation model that tracks the gradual heating of charge carriers and dynamically defines collisional impact rate, the research demonstrates computational simplicity and the ability to extract effective values from experimental data. The model matches experimental scaling trends for laser-induced damage threshold of various dielectric materials for pulse durations ranging from a few femtoseconds to a few picoseconds, indicating potential advantages for large-scale, three-dimensional electromagnetic modeling of laser-induced breakdown in transparent media.
Article
Optics
Zhen Pan, Lianzhong Deng, Long Cheng, Yunhua Yao, Dalong Qi, Wenjing Cheng, Zhenrong Sun, Shian Zhang
Summary: We experimentally demonstrate that trivalent samarium ions in BaFCl nanocrystals can be efficiently converted into divalent ions under the influence of an 800 nm fs laser field. We investigate the dependence of the luminescence intensity of the photoinduced divalent ions on the femtosecond laser power, central wavelength, and polarization. Theoretical fits suggest that a resonance-mediated (2 + 2) four-photon absorption is most likely involved in the multiphoton induced photoreduction process.
JOURNAL OF LUMINESCENCE
(2023)
Article
Optics
Xuehao Hu, Zhen Chen, Xin Cheng, Rui Min, Hang Qu, Christophe Caucheteur, Hwa-Yaw Tam
Summary: This study reports the inscription of 2-mm-long fiber Bragg gratings (FBGs) on BDK-doped PMMA optical fibers using a femtosecond laser and point-by-point FBG inscription technique. The highest reflectivity of approximately 99% was achieved with a pulse energy of 68.5 nJ, indicating a large refractive index modulation amplitude of 7.2 x 10(-4). The stability of the gratings at temperatures up to 80 degrees C was also investigated.
Article
Chemistry, Physical
L. Museur, A. Manousaki, D. Anglos, G. D. Tsibidis, A. Kanaev
Summary: The study investigates the reaction control by laser light on TiO2 monocrystals, showing different surface morphologies and the crucial role of the critical temporal delay in the formation of grooves and periodic structures.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Analytical
Hao Wu, Xiaobin Zhang, Weina Han
Summary: This paper investigated the properties of nitrogen-doped Ge2Sb2Te5 (GST) using a femtosecond laser and proposed a bond effect. The results showed that element doping could change photon absorption, increase the rate of reflectivity change, and improve thermal stability.
Article
Optics
Fengqin Huang, Jinhai Si, Tao Chen, Tianlun Shen, Mengjie Shi, Xun Hou
Summary: This study investigated the transient temporal-spatial evolution of femtosecond laser pulse-induced filaments and electronic plasma in fused silica using fs time-resolved pump-probe shadowgraphy. It was found that the material damage threshold occurred at 8 μJ pump energy, beyond which laser-induced damage occurred. These results suggest that fs time-resolved pump-probe shadowgraphy is a meaningful tool for predicting the distribution of laser-induced microstructures in ultrafast laser micromachining.
Article
Optics
Chen Jiang, Kaiming Zhou, Bing Sun, Zhiqiang Wang, Ying Wan, Yuehui Ma, Chengbo Mou, Lei Shen, Lei Zhang, Jie Luo, Yunqi Liu
Summary: In this paper, the authors propose and demonstrate the inscription of parallel long-period gratings (LPGs) in a few-mode fiber (FMF) using femtosecond lasers. They achieve mode conversion and multi-channel core mode conversion in a single FMF, offering a highly integrated option for multi-wavelength laser systems and wavelength/mode division multiplex communication systems.
Article
Multidisciplinary Sciences
Maria Ruchkina, Dina Hot, Pengji Ding, Ali Hosseinnia, Per-Erik Bengtsson, Zhongshan Li, Joakim Bood, Anna-Lena Sahlberg
Summary: Laser-induced grating spectroscopy (LIGS) was explored for the first time in a configuration based on the crossing of two focused femtosecond laser pulses and a focused continuous-wave laser beam. The study demonstrated the feasibility of using this configuration for thermometry in heated nitrogen gas flows. Additionally, the research revealed the multi-photon absorption pathways for N2 and N2+ ion, as well as the impact of plasma generation on the LIGS signal at higher pulse energies.
SCIENTIFIC REPORTS
(2021)
Article
Engineering, Chemical
A. E. Zarvin, V. Zh Madirbaev, K. A. Dubrovin, V. V. Kalyada
Summary: This paper experimentally studied the features of argon radiation mixed with molecular and atomic impurities in condensing supersonic jets, and identified the anomalous increase in radiation intensity on individual lines of atomic argon in a certain pressure range, caused by the highly efficient molecular cluster mechanism.
PLASMA CHEMISTRY AND PLASMA PROCESSING
(2022)
Article
Optics
Rong Zhao, Xuewen Shu
Summary: This paper presents an ingenious method for exciting higher-order modes in few-mode fiber (FMF) using a femtosecond laser, and proposes a new type of in-fiber Mach-Zehnder interferometer (MZI) for bending sensing. The device has a wide curvature measurement range, high curvature sensitivity, low temperature sensitivity, and advantages of small size, simple manufacturing, high reproducibility, low insertion loss, and high spectral contrast.
OPTICS AND LASER TECHNOLOGY
(2022)