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Self-diffraction can be induced using a biased photorefractive crystal in the Fourier plane of an imaging system where the light beam intensity is naturally high due to the concentration effect of an optical lens. The spatial frequency spectrum of the output image is proportional to the optical power density distribution in the Fourier plane. A photorefractive crystal with small size can be used and hence an reduced amount of biased voltage is needed to obtain significant diffraction effect in the image plane. When the input image is an overlay of a signal and a noise pattern, theoretic model reveals that the induced diffraction in the Fourier plane may be preferably applied on the noise pattern. In order to illustrate the effect experimentally, a signal from a weakly illuminated object is coupled with an overwhelming noise pattern and then the hidden signal is successfully recovered using a SBN61 crystal with an applied voltage of 800 V in the Fourier plane. Such technology can be employed in encrypted spatial communication systems for security purposes.
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http://dx.doi.org/10.1364/OE.23.002070 | DOI Listing |
J Phys Chem A
September 2025
Department of Inorganic and Physical Chemistry, Indian Institute of Science Bangalore, Bengaluru560012, India.
The microwave spectrum of the complex formed between 1-fluoronaphthalene and HO has been recorded using a chirped pulse Fourier transform microwave spectrometer within the frequency range of 2.0 to 8.0 GHz, with neon as the carrier gas.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Department of Chemistry and Sustainable Technology, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, FI-80100, Joensuu, Finland.
Accurate thermodynamic calculations for aluminum alkyls require proper treatment of low-frequency vibrations poorly described by the harmonic approximation (HA). Here, we present a systematic investigation of hindered rotation and out-of-plane bending in aluminum trichloride (ATC) and its methyl derivatives, employing advanced computational methods to perform anharmonic entropy corrections, such as torsional eigenvalue summation (TES), the extended two-dimensional torsion method (E2DT), the multi-structural approximation with torsional anharmonicity (MS-T), and Fourier grid Hamiltonian (FGH). Our results reveal distinct structure-dependent behaviors: monomers exhibit near-free methyl rotations where the HA overestimates entropy by 20-30 J K mol, while dimers show more hindered rotations adequately described by the HA around room temperature.
View Article and Find Full Text PDFACS Appl Bio Mater
August 2025
Center for Global Health Research, Saveetha Medical College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu 600077, India.
The present study reports an eco-friendly route for the synthesis of chitosan-stabilized gold nanoparticles (Cs@AuNPs) using leaf extract and their dual anticancer and antimicrobial activities. The nanoparticles were comprehensively characterized by ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ζ-potential analysis. Cs@AuNPs exhibited a strong surface plasmon resonance peak at 550 nm, face-centered cubic crystallinity with a predominant (111) plane, spherical morphology, particle size ranging from 5-30 nm, and a positive surface charge.
View Article and Find Full Text PDFACS Nanosci Au
August 2025
Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States.
Plasmonic polarization conversion offers significant advantages over conventional methods, including a smaller device footprint and easier integration into photonic circuits. In this work, we numerically and experimentally investigate the polarization conversion properties of a plasmonic double-hole structure surrounded by circular nanograting, i.e.
View Article and Find Full Text PDFNat Commun
August 2025
Weiyang College, Tsinghua University, Beijing, 100084, China.
Computer-generated holography (CGH) offers a promising method to create true-to-life reconstructions of objects. While recent advances in deep learning-based CGH algorithms have significantly improved the tradeoff between algorithm runtime and image quality, most existing models are restricted to a fixed propagation distance, limiting their adaptability in practical applications. Here, we present a deep learning-based algorithmic CGH solver that achieves propagation-adaptive CGH synthesis using a spatial and Fourier neural operator (SFO-solver).
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