kW-level 1030 nm polarization-maintained fiber laser with narrow linewidth and near-diffraction-limited beam quality is demonstrated. Theoretical simulations based on the power balance equation are first performed to optimize the system parameters of the 1030 nm ytterbium-doped fiber laser for the maximum suppression of amplified spontaneous emission (ASE). With the optimized parameters, both the copumped and counterpumped MOPA lasers are implemented to obtain an output power of >1 kW. In both cases, the ASE suppression ratio reaches 40 dB with a 3 dB linewidth of about 0.14 nm, and the polarization extinction ratio is about 12 dB at 1 kW of output power. The beam quality starts degrading at 900 W of output power in the copumped structure, but maintains nearly single mode (Mx2,My2)=(1.07,1.12) until power is over 1 kW in the counterpumped structure.
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http://dx.doi.org/10.1364/AO.57.002992 | DOI Listing |
Arch Toxicol
January 2025
STARTNETICS - Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy.
Femtosecond lasers represent a novel tool for tattoo removal as sources that can be operated at high power, potentially leading to different removal pathways and products. Consequently, the potential toxicity of its application also needs to be evaluated. In this framework, we present a comparative study of Ti:Sapphire femtosecond laser irradiation, as a function of laser power and exposure time, on water dispersions of Pigment Green 7 (PG7) and the green tattoo ink Green Concentrate (GC), which contains PG7 as its coloring agent.
View Article and Find Full Text PDFBr J Ophthalmol
January 2025
Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Seodaemun-gu, Korea (the Republic of)
Background: The present study aims to identify the relationship between longitudinal changes in corneal hysteresis (CH) and progressive retinal nerve fibre layer (RNFL) thinning in a cohort of medically controlled, early-to-moderate open-angle glaucoma (OAG) patients with a history of laser refractive surgery (LRS).
Methods: A total of 123 consecutive eyes with a diagnosis of medically controlled (peak intraocular pressure (IOP)<18 mm Hg), early-to-moderate OAG with a history of LRS underwent measurements of CH, corneal-compensated intraocular pressure (IOPcc) and RNFL thicknesses every 6 months. Linear models were used to investigate the relationship between CH change and RNFL thickness change over time.
Photodiagnosis Photodyn Ther
January 2025
Department of Oral Maxillofacial Radiologist, Department of OMFS & DOS College of Medicine and Dentistry, Riyadh Elm University, Saudi Arabia.
Sensors (Basel)
January 2025
Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
In the last decade, substantial progress has been made to improve the performance of optical gyroscopes for inertial navigation applications in terms of critical parameters such as bias stability, scale factor stability, and angular random walk (ARW). Specifically, resonant fiber optic gyroscopes (RFOGs) have emerged as a viable alternative to widely popular interferometric fiber optic gyroscopes (IFOGs). In a conventional RFOG, a single-wavelength laser source is used to generate counter-propagating waves in a ring resonator, for which the phase difference is measured in terms of the resonant frequency shift to obtain the rotation rate.
View Article and Find Full Text PDFSensors (Basel)
December 2024
College of Physics and Electronic Engineering, Hainan Normal University, Haikou 571158, China.
Fiber Bragg gratings (FBGs) are widely used in stress and temperature sensing due to their small size, light weight, high resistance to high temperatures, corrosion, electromagnetic interference, and low cost. In recent years, various structural enhancements and sensitization to FBGs have been explored to improve the performance of ocean temperature and depth sensors, thereby enhancing the accuracy and detection range of ocean temperature and depth data. This paper reviews advancements in temperature, pressure, and dual-parameter enhancement techniques for FBG-based sensors.
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