A direct solution of the scalar wave equation (SWE) for an elliptical-core weakly guiding fiber is considered. We decompose the SWE into two ordinary differential equations by using the method of separation of variables, demand the periodicity of the solution in terms of the angular coordinate, and, by matching the boundary conditions numerically, obtain the characteristic propagation curves for the two modes. A simple computer program permits the acquisition of two-mode fiber device parameters as functions of the core ellipticity, the core dimensions, and the refractive-index difference.
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http://dx.doi.org/10.1364/ol.16.000135 | DOI Listing |
J Acoust Soc Am
January 2025
Key Laboratory of Modern Acoustics (MOE), School of Physics, Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
In thermal therapies, accurate estimation of in-tissue power deposition density (PDD) is essential for predicting temperature distributions over time or regularizing temperature imaging. Based on our previous work on ultrasound thermometry, namely, multi-thread thermal strain imaging (MT-TSI), this work develops an in vivo PDD estimation method. Specifically, by combining the TSI model infinitesimal echo strain filter with the bio-heat transfer theory (the Pennes equation), a finite-difference time-domain model is established to allow online extraction of the PDD.
View Article and Find Full Text PDFWe propose a scheme to achieve nonreciprocal unconventional magnon blockade (UMB) via the Barnett effect in a spinning ferrimagnetic yttrium-iron-garnet sphere coupled to a microwave cavity that interacts with a parametric amplifier. We show that, with a strong cavity-magnon coupling regime, giant nonreciprocal UMB can emerge by appropriately choosing two sets of parameters in this system, i.e.
View Article and Find Full Text PDFIn this study, a novel precise reconstruction method was proposed for ghost imaging. In traditional ghost imaging (TGI), image quality deteriorates in proportion to the ℓ norm of the observed object. However, the proposed method reduces the effective ℓ norm by filtering an unknown direct current component and an arbitrary alternating current component derived from a pre-measured rough image.
View Article and Find Full Text PDFIn this paper, we study the Schrödinger cat state transfer in a quantum optical version of Newton's cradle in a non-Markovian environment. Based on a non-Markovian master equation, we show that the cat state can be transferred purely through the memory effect of the non-Markovian common environment, even without any direct couplings between neighbor cavities. The mechanism of the environment-induced cat state transfer is analyzed both analytically and numerically to demonstrate that the transfer is a unique phenomenon in a non-Markovian regime.
View Article and Find Full Text PDFOptical neural implants allow neuroscientists to access deep brain regions, enabling to decipher complex patterns of neural activity. In this field, the use of optical fibers is rapidly increasing, and the ability to generate high-quality metal patterns on their non-planar surface would further extend their application. Here, we propose to use alternating metal shielding and dielectric confinement to engineer the mode-division properties of tapered optical fiber neural implants.
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