We experimentally demonstrate that Kerr spatial self-cleaning of a pulsed beam can be obtained in an amplifying multimode optical fiber. An input peak power of 500 W only was sufficient to produce a quasi-single-mode emission from the double-clad ytterbium doped multimode fiber (YMMF) with non-parabolic refractive index profile. We compare the self-cleaning behavior observed in the same fiber with loss and with gain. Laser gain introduces new opportunities to achieve spatial self-cleaning of light in multimode fibers at a relatively low power threshold.
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http://dx.doi.org/10.1364/OE.25.004783 | DOI Listing |
Nanoscale
December 2024
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, P. R. China.
We experimentally study the spatial beam profile and the spectral broadening at the output of a multimode air-silica microstructure fiber taper, used along the direction of an increasing fiber diameter. By using a laser pump at 1064 nm emitting 60 ps Gaussian beam pulses, we observed a competition between Raman beam cleanup and Kerr beam self-cleaning: the multimode frequency conversion process permits to generate spectral sidebands with frequency detuning from the pump that are difficult to obtain in standard graded-index multimode fibers. The generated supercontinuum spans from 500 nm up to 2.
View Article and Find Full Text PDFWe report on a comprehensive experimental investigation into the spatial-spectral complexity of the laser beam during Kerr-induced beam self-cleaning in graded-index multimode fibers. We demonstrate the self-cleaning of beams using both transform-limited and chirped femtosecond pulses. By utilizing the spectrally resolved imaging technique, we examine variations in beam homogeneity during the beam cleanup process and reveal correlations observed among spatial beam profiles at different wavelengths for the various cleaned pulses.
View Article and Find Full Text PDFMicromachines (Basel)
May 2024
Department of Electrical Electronic and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
In this article, we demonstrate a high-energy, wide-spectrum, spatiotemporal mode-locked (STML) fiber laser. Unlike traditional single-mode fiber lasers, STML fiber lasers theoretically enable mode-locking with various combinations of transverse modes. The laser can deliver two different STML pulse sequences with different pulse widths, spectra and beam profiles, due to the different compositions of transverse modes in the output pulses.
View Article and Find Full Text PDFNanomaterials (Basel)
September 2023
Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, Wuhan 430074, China.
The water pollution caused by the release of organic pollutants has attracted remarkable attention, and solutions for wastewater treatment are being developed. In particular, the photocatalytic removal of organic pollutants in water systems is a promising strategy to realize the self-cleaning of ecosystems under solar light irradiation. However, at present the semiconductor-based nanocatalysts can barely satisfy the industrial requirements because their wide bandgaps restrict the effective absorption of solar light, which needs an energy band modification to boost the visible light harvesting via surface engineering.
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