Ultra-high power (exceeding the self-focusing threshold by more than three orders of magnitude) light beams from ground-based laser systems may find applications in space-debris cleaning. The propagation of such powerful laser beams through the atmosphere reveals many novel interesting features compared to traditional light self-focusing. It is demonstrated here that for the relevant laser parameters, when the thickness of the atmosphere is much shorter than the focusing length (that is, of the orbit scale), the beam transit through the atmosphere in lowest order produces phase distortion only. This means that by using adaptive optics it may be possible to eliminate the impact of self-focusing in the atmosphere on the laser beam. The area of applicability of the proposed "thin window" model is broader than the specific physical problem considered here. For instance, it might find applications in femtosecond laser material processing.
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http://dx.doi.org/10.1038/srep30697 | DOI Listing |
Light Sci Appl
January 2025
Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, and Center for Light-Matter Interaction, Tel Aviv University, Tel Aviv, Israel.
This item from the News and Views (N&V) category aims to provide a summary of theoretical and experimental results recently published in ref. , which demonstrates the creation of corner modes in nonlinear optical waveguides of the higher-order topological insulator (HOTI) type. Actually, these are second-order HOTIs, in which the transverse dimension of the topologically protected edge modes is smaller than the bulk dimension (it is 2, in the case of optical waveguide) by 2, implying zero dimension of the protected modes, which are actually realized as corner or defect ones.
View Article and Find Full Text PDFNanoscale
December 2024
Department of Engineering and Materials Physics, Institute of Chemical Technology-Indian Oil Odisha Campus, Bhubaneswar, 751013, India.
In the present study, lanthanum oxytellurate (LOT) samples with varying La : Te ratios are successfully synthesized using a simple hydrothermal method that has enormous advantages. The prepared samples crystallize in a LaOTe composite phase with an orthorhombic crystal system. A nanorod-like morphology is observed for each sample, and the presence of constituent elements is verified from EDX results.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Laboratory for Chemistry and Life Science, Institute of Integrated Research, Institute of Science Tokyo, R1-12, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
The photoinduced molecular reorientation of liquid crystals (LCs) caused by their nonlinear optical responses has attracted much attention due to their large refractive index change, leading to promising applications in optical devices. This reorientation is typically induced by light irradiation above a threshold intensity and is temporary, with the initial orientation recovering unless the LCs are polymerized and cross-linked. Our report highlights the memory effect of molecular reorientation in LCs.
View Article and Find Full Text PDFBased on a split-step Fourier algorithm, the transmission of circular Airy beams with quadratic phase modulation (QPM) is investigated in the fractional Schrödinger equation (FSE) under diffraction modulations (periodic modulation, linear modulation and power function modulation) and external potentials (parabolic potential and linear potential). The results show that QPM is able to change the focusing position and intensity, as well as the transmission trajectory of the beam. In a periodic modulation, the circular Airy beam (CAB) exhibits periodic variation characteristics, and the beam splitting is retarded under the action of the QPM.
View Article and Find Full Text PDFDouble line self-focusing characteristics of elliptical Airyprime beams (EAPBs) with different elliptical vertical-axis factor β are investigated by varying the main ring radius r. Overly large or small r results in the inhomogeneous distribution of light intensity at one linear focus of the double line self-focusing. Only when r is appropriate and β is within a certain range, can double uniform line self-focusing happen to the EAPB.
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