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Vortex Beam Source Synthesis Method Based on Finite Difference Time Domain Method

A time-domain finite difference, synthesis method technology, applied in instruments, design optimization/simulation, measurement devices, etc., can solve the problems of long calculation time, low accuracy of calculation results, and low calculation efficiency

Active Publication Date: 2022-06-21
HARBIN INST OF TECH
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Problems solved by technology

[0004] The purpose of the present invention is to solve the limitations of hardware and frequency band caused by the existing method of studying particle scattering, as well as the problems of low calculation efficiency, long calculation time, and low accuracy of calculation results, and propose a vortex based on the time-domain finite difference method. Combination method of beam source

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  • Vortex Beam Source Synthesis Method Based on Finite Difference Time Domain Method
  • Vortex Beam Source Synthesis Method Based on Finite Difference Time Domain Method
  • Vortex Beam Source Synthesis Method Based on Finite Difference Time Domain Method

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specific Embodiment approach 1

[0050] Embodiment 1: The specific process of the vortex beam source synthesis method based on the finite difference time domain method in this embodiment is as follows:

[0051] Step 1. Obtain a simple harmonic plane wave in the frequency domain;

[0052] Step 2: According to the simple harmonic plane wave in the frequency domain, the time-domain Gaussian pulse is obtained;

[0053] Step 3: The present invention first uses the pulse to study the scattering of the plane wave by the dielectric sphere, and verifies the correctness of the algorithm by comparing it with the analytical solution of the scattering of the dielectric sphere (simulation verification);

[0054] Based on the time-domain Gaussian pulse function, the required pulse of the vortex electromagnetic field in the time domain is obtained.

specific Embodiment approach 2

[0055] Embodiment 2: The difference between this embodiment and Embodiment 1 is that in the step 1, a simple harmonic plane wave in the frequency domain is obtained; the specific process is:

[0056] The expression for a simple harmonic plane wave in the frequency domain is:

[0057]

[0058] In the formula, is the exponential term of the simple harmonic plane wave; E m1 is the amplitude value of the simple harmonic plane wave in the frequency domain; ω is the angular frequency; t is the time; is the wave vector of the simple harmonic plane wave in the frequency domain; is the vector radius of any point in space; exp is the base of natural logarithm; j is the imaginary unit, j 2 =-1.

[0059] Other steps and parameters are the same as in the first embodiment.

specific Embodiment approach 3

[0060] Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that in the second step, the time-domain Gaussian pulse is obtained according to the simple harmonic plane wave in the frequency domain; the specific process is:

[0061] Since for time domain simulation, the harmonic plane wave form in frequency domain can be directly replaced by a broadband time domain incident pulse, and time domain and frequency domain are connected by Fourier transform; since Gaussian pulse has rich frequency domain Therefore, the Gaussian pulse is used as the incident pulse to generate the frequency domain plane wave, and the replaced form is:

[0062]

[0063] where E(t) is the time-domain Gaussian pulse function, t 0 is the abscissa corresponding to the maximum value of the Gaussian pulse, the dimension is time, and the unit is seconds; ω is the angular frequency; E m2 is the amplitude value of the time-domain Gaussian pulse;

[0064] Using the expression (2) with...

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Abstract

A vortex beam source synthesis method based on a time domain finite difference method, the invention relates to a vortex beam source synthesis method. The purpose of the present invention is to solve the problems of hardware and frequency band limitation, low calculation efficiency, long calculation time and low calculation result accuracy caused by existing methods for studying particle scattering. The specific process of the vortex beam source synthesis method based on the time domain finite difference method is as follows: step 1, obtain the simple harmonic plane wave in the frequency domain; step 2, obtain the Gaussian pulse in the time domain according to the simple harmonic plane wave in the frequency domain; step 3, based on Time-domain Gaussian pulse function, to obtain the pulse required by the vortex electromagnetic field in the time domain. The invention belongs to the technical field of microwave engineering and the field of computational electromagnetics algorithm.

Description

technical field [0001] The invention relates to a method for synthesizing a vortex beam source, belonging to the technical field of microwave engineering and the field of computational electromagnetic algorithms. Background technique [0002] With the development of science and technology, modern research has shown that electromagnetic waves can carry not only energy but also momentum. Besides linear momentum based on Poynting vector, they can also carry angular momentum, including spin angular momentum (SAM for short). ) and orbital angular momentum (Orbital Anglar Momentum, OAM). At present, there are mainly antennas, array antennas, metasurfaces, etc. for the synthesis of electromagnetic waves carrying OAM. However, when using electromagnetic waves carrying OAM to study particle scattering characteristics, these methods appear to be inadequate. First, these methods are all frequency domain solution methods. When you want to observe the scattering characteristics of parti...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/23G01R29/08
CPCG01R29/0892
Inventor 张狂马嘉禹袁乐眙王禹翔丁旭旻吴群
Owner HARBIN INST OF TECH