We study the propagation of the two lowest-order Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Using the Rytov approximation and assuming a slow detector, we calculate the longitudinal and radial components of the scintillation index for a typical free-space laser communication setup. We find the optimal configuration of the two laser beams with respect to the longitudinal scintillation index. We show that the value of the longitudinal scintillation for the optimal two-beam configuration is smaller by more than 50% compared with the value for a single lowest-order Gaussian beam with the same total power. Furthermore, the radial scintillation for the optimal two-beam system is smaller by 35%-40% compared with the radial scintillation in the single-beam case. Further insight into the reduction of intensity fluctuations is gained by analyzing the self- and cross-intensity contributions to the scintillation index.
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http://dx.doi.org/10.1364/josaa.23.003114 | DOI Listing |
Sci Rep
January 2025
Accelerator Operations and Technology Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545, USA.
The pursuit to operate photocathodes at high accelerating gradients to increase brightness of electron beams is gaining interests within the accelerator community, particularly for applications such as free electron lasers (FEL) and compact accelerators. Cesium telluride (CsTe) is a widely used photocathode material and it is presumed to offer resilience to higher gradients because of its wider band gap compared to other semiconductors. Despite its advantages, crucial material properties of CsTe remain largely unknown both in theory and experiments.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
South China Normal University, School of Physics, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangzhou, 510631, CHINA.
With the continuous development of digital information and big data technologies, the ambient temperature and heat generation during the operation of magnetic storage devices play an increasingly crucial role in ensuring data security and device stability. In this study, we examined the lattice thermal conductivity of the van der Waals magnetic semiconductor CrSBr from bulk to monolayer structures using first-principles calculations and the phonon Boltzmann transport equation. Our results indicated that lattice thermal conductivity show anisotropy and CrSBr bilayer exhibits lower thermal conductivity at all temperatures.
View Article and Find Full Text PDFGeroscience
January 2025
National Institute On Aging, Bethesda, MD, USA.
Photobiomodulation (PBM) therapy, a non-thermal light therapy using nonionizing light sources, has shown therapeutic potential across diverse biological processes, including aging and age-associated diseases. In 2023, scientists from the National Institute on Aging (NIA) Intramural and Extramural programs convened a workshop on the topic of PBM to discuss various proposed mechanisms of PBM action, including the stimulation of mitochondrial cytochrome C oxidase, modulation of cell membrane transporters and receptors, and the activation of transforming growth factor-β1. They also reviewed potential therapeutic applications of PBM across a range of conditions, including cardiovascular disease, retinal disease, Parkinson's disease, and cognitive impairment.
View Article and Find Full Text PDFA novel, to the best of our knowledge, approach for the modal decomposition of a fiber laser beam is demonstrated using a spatial mode multiplexer. Since the modal decomposition is carried out optically, this approach is able to obtain the modal content at speeds up to the GHz level. In order to demonstrate such performance, we have applied this approach to the modal analysis of a -switched pulse generated in a multimode fiber with alternating intra-pulse mode content.
View Article and Find Full Text PDFA 1645 nm end-pumped dual-channel Er:YAG vector laser that could generate two cylindrical vector (CV) beams simultaneously with different polarization orders is demonstrated. The laser is designed in a two-arm structure, wherein each arm places a q-plate (QP) to introduce intra-cavity spin-orbital angular momentum conversion, leading to the oscillation of two various CV modes in two arms, and finally output along two directions, respectively. The favorable experimental results illustrate high power stability and polarization mode purity.
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