10 results on '"Jinyun, Zhou"'
Search Results
2. Ultra-broadband THz absorber with doped silicon based on periodic T-shaped arrays
- Author
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Jimin Fang, Kunhua Wen, Jinyun Zhou, Fangteng Zhang, Li Chen, Liang Lei, Zhaogang Nie, Bo Wang, Xiangjun Xing, and Ziming Meng
- Subjects
Electromagnetic field ,Materials science ,Silicon ,Terahertz radiation ,business.industry ,Impedance matching ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,010309 optics ,chemistry ,0103 physical sciences ,Optoelectronics ,Electrical and Electronic Engineering ,Center frequency ,Wideband ,0210 nano-technology ,Absorption (electromagnetic radiation) ,business ,Electrical impedance - Abstract
A polarization-independent ultra-broadband T-type absorber with doped silicon in the terahertz band is proposed, which consists of T-shaped Si/SiO2 arrays. The results show that the absorption is more than 95% at 1.0–5.3 THz. Such an absorber can have a center frequency and relative bandwidth ratio of 3.15 THz and 137%. In addition, the absorption of 90% can be achieved at 1.0–5.3 THz with the incident angle of 0–44°. The energy distribution of the electromagnetic field at the peak of the ultra-broadband absorber is clearly explained by finite element method. Furthermore, compared with the proposed reference planar absorber and the reported broadband absorber, the T-type absorber in this work has better absorption bandwidth, center frequency, and relative bandwidth ratio. The impedance of T-type terahertz absorber is demonstrated well by impedance matching theory. It is believed that the ultra-wideband terahertz absorber with silicon doped based on periodic T-shaped arrays has great potential in the wideband terahertz absorber field and can be applied in the biomedical field.
- Published
- 2021
3. Newly reflective bi-function beam splitter by SiO2 pencil-like arrays on silver plate
- Author
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Zefan Lin, Xiangjun Xing, Zhisen Huang, Bo Wang, Zhaogang Nie, Kunhua Wen, Ziming Meng, Liang Lei, Jinyun Zhou, Li Chen, and Fangteng Zhang
- Subjects
Diffraction ,Materials science ,business.industry ,Bandwidth (signal processing) ,Physics::Optics ,02 engineering and technology ,Function (mathematics) ,Grating ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Finite element method ,Electronic, Optical and Magnetic Materials ,law.invention ,Pencil (optics) ,010309 optics ,Optics ,law ,0103 physical sciences ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Computer Science::Databases ,Beam splitter - Abstract
An enhanced newly high-efficiency dual-function beam splitter of the grating is described in this paper. The proposed grating can realize newly dual-function at infrared wavelength under second Bragg incidence, which can function as high-efficiency component for TE polarization. Moreover, under TM polarization, the grating is different from the other traditional dual-function grating, which can achieve a three-port output with high efficiency and good uniformity. By using the finite element method, an optimum grating structure can be presented with the efficiency of three diffraction orders (0th, −1st, −2nd) for TM polarization greater than 30%. As for TE polarization, the efficiency of −2nd order will be better than 95% with a wide bandwidth. Therefore, the proposed grating can be well applied in variety optical fields.
- Published
- 2021
4. Theory research of glare reduction based on the Fresnel principle
- Author
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Jinyun Zhou, Tan Ji, Lai Jinxiang, Li Chen, Qi Wang, Liang Lei, and Miao He
- Subjects
Physics ,business.industry ,Optical engineering ,02 engineering and technology ,Elimination method ,Image detection ,Fresnel equations ,Polarization (waves) ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Displacement factor ,010309 optics ,Optics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Image acquisition ,020201 artificial intelligence & image processing ,Electrical and Electronic Engineering ,business - Abstract
Glare reduction is the focus of much attention in the field of optical engineering owing to its vital role in high-quality image acquisition in photoelectric visual inspection technology. Based on Fresnel reflection theory, we have derived a polarization factor related to the glare intensity distribution and have obtained theoretical results showing that the factor plays a leading role in reducing glare. Based on the image detection model, we have derived a displacement factor which determines the position and the size of the glare area, and have obtained theoretical results showing that the factor plays a supporting role in reducing glare. The image gray-scale transformation curve is obtained by sampling image data under the different polarization and positions. And these image data are measured from certain object in the equivalent environment while the different conditions. Then the theories above have been justified and the whole theory of the polarization-based glare elimination method has been interpreted completely via actual experiments in glare elimination. As a result, reducing the intensity contrast between the glare area and its neighboring area is proved to be the essence of glare elimination. Furthermore, the glare can be nearly eliminated perfectly by adjusting the polarization factor and the displacement factor.
- Published
- 2017
5. Ultrabroadband two-layer dielectric/metal on a silica substrate hybrid grating polarizer
- Author
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Li Chen, Bo Wang, Xiangjun Xing, Zhaogang Nie, Chen Fu, Liang Lei, Ziming Meng, Hao Pei, Jimin Fang, Jinyun Zhou, and Kunhua Wen
- Subjects
Diffraction ,Materials science ,Extinction ratio ,business.industry ,Physics::Optics ,Dielectric ,Grating ,Polarizer ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Wavelength ,Optics ,Extinction (optical mineralogy) ,law ,Reflection (physics) ,Electrical and Electronic Engineering ,business - Abstract
We developed an ultrabroadband two-layer hybrid grating for polarizer. The efficiencies and extinction ratios of the two-layer polarizer were characterized for different grating geometrical parameters including periods, duty cycles and dielectric layer thicknesses. In order to obtain the suitable grating geometric parameters, the diffraction was numerically simulated by using rigorous coupled-wave approach in the near infrared incident regions. Based on the simulation results, reflection efficiency of TE-polarized light and transmission efficiency of TM-polarized light more than 96 % can be obtained within the incident wavelength rang of 1220−1940 nm and incident angle range of 4.2–58.8°. Furthermore, the extinction ratio of the grating can reach 28.09 dB for the polarizer.
- Published
- 2020
6. Characteristics of dual-function splitting by embedded three-layer grating
- Author
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Bo Wang, Wenhua Zhu, Ziming Meng, Li Chen, Xiangjun Xing, Liang Lei, Jinyun Zhou, Zhaogang Nie, and Kunhua Wen
- Subjects
Diffraction ,Materials science ,business.industry ,02 engineering and technology ,Grating ,021001 nanoscience & nanotechnology ,Polarization (waves) ,Diffraction efficiency ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,010309 optics ,Wavelength ,Optics ,0103 physical sciences ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Dual function - Abstract
The subwavelength three-layer embedded grating is described under Littrow mounting for dual-function splitting. At the incident 800 nm wavelength, diffraction efficiency of TE polarization is 97.04 % for the optimized profiles. For TM polarization, diffraction efficiencies corresponding to 49.64 % and 49.80 % are obtained in two ports. The diffraction efficiency of the new embedded grating is higher than that of the previously reported surface-relief three-layer grating-based dual-function splitting. Moreover, the new grating can exhibit large deviation using angle.
- Published
- 2020
7. Linear exchanging operation and random phase encoding in gyrator transform domain for double image encryption
- Author
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Qu Wang, Liang Lei, Qing Guo, and Jinyun Zhou
- Subjects
Transformation matrix ,Amplitude ,Gyrator transform ,business.industry ,Computer science ,Robustness (computer science) ,Top-hat transform ,Electrical and Electronic Engineering ,Encryption ,business ,Algorithm ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Abstract
We present an optical method for double image encryption by using linear exchanging operation and double random phase encoding (DRPE) in the gyrator transform (GT) domain. In the linear exchanging operation, two primitive images are linearly recombined via a random orthogonal transform matrix. The resultant blended images are employed to constitute a complex-valued image, which is then encoded into a noise-like encrypted image by a DRPE structure in the GT domain. One can recover the primitive images exactly with all decryption keys correctly applied, including the transform orders, the random phase masks and random angle function used for linear exchanging operation. Computer simulations have been given to demonstrate that the proposed scheme eliminates the difference in key spaces between the phase-based image and the amplitude-based image encountered in the previous schemes. Moreover, our scheme has considerably high security level and certain robustness against data loss and noise disturbance.
- Published
- 2013
8. Color image hiding based on phase-truncation and phase retrieval technique in the fractional Fourier domain
- Author
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Qing Guo, Qu Wang, and Jinyun Zhou
- Subjects
Channel (digital image) ,Color image ,Computer science ,Iterative method ,business.industry ,Phase (waves) ,Data_CODINGANDINFORMATIONTHEORY ,Encryption ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,Fourier transform ,Phase correlation ,Computer Science::Multimedia ,symbols ,Cryptosystem ,Electrical and Electronic Engineering ,business ,Phase retrieval ,Algorithm ,Computer Science::Cryptography and Security - Abstract
An asymmetric cryptosystem is proposed in this paper for color image hiding and extracting using phase truncated fractional Fourier transforms (FrFTs) and phase retrieval iterative algorithm. The secret image are decomposed into R , G and B channels, and permuted by Arnold transforms (ARTs). The R channel is self-encoded in the manner that the other two channels are separated into three phase masks (PMs) as encryption keys in the following three phase truncated FrFT operations while phase keys for decryption are generated and retained. A phase retrieval iterative algorithm in fractional Fourier domain is employed to hide the self-encoded result in one color channel of host image. The phase keys for decryption are different from those for encryption, which indicates the asymmetry of the proposed method and higher security. Numerical simulations are given to show the validity and robustness of our system.
- Published
- 2013
9. Composite wavelet based morphological correlation for continuous-scale-invariant pattern recognition
- Author
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Jinyun Zhou, Li Chen, Qinghua Lin, and Qu Wang
- Subjects
Discrete wavelet transform ,Sparse image ,business.industry ,Computer science ,Matched filter ,Stationary wavelet transform ,Second-generation wavelet transform ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Pattern recognition ,Cascade algorithm ,Composite image filter ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Wavelet packet decomposition ,Adaptive filter ,Wavelet ,Kernel adaptive filter ,Artificial intelligence ,Electrical and Electronic Engineering ,business - Abstract
A composite nonlinear correlation is proposed to perform invariant recognition for the input image with continuous-scale distortions. The proposed correlation can be considered as a summation of many composite wavelet matched filters. Every matched filter consists of a linear combination of binary slices that are generated from threshold decomposition of the training images, and an adaptive wavelet filter. The adaptive wavelet is optimized to produce the sparse image features. Computer simulations are carried out to prove the scale-invariance and noise robustness of the new scheme.
- Published
- 2012
10. A reflective surface-relief two-layer grating for splitting beams with the polarization-selective property
- Author
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Liang Lei, Jinyun Zhou, Bo Wang, Li Chen, and Wenhao Shu
- Subjects
Diffraction ,Materials science ,Holographic grating ,business.industry ,Physics::Optics ,Bragg's law ,Grating ,Polarization (waves) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Ultrasonic grating ,Optics ,law ,Blazed grating ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Beam splitter - Abstract
A polarization-selective beam splitter is presented based on a reflective surface-relief two-layer grating with a metal slab. The grating is composed of two dielectric layers and a metal slab on the substrate. For TE polarization, efficiencies of 97.58% can be diffracted into the reflective −1st order. For TM polarization, two-port output of 47.55% and 47.11% can be split into the 0th order and the −1st order, respectively. Such a polarization-selective beam splitter can be fulfilled by one grating in reflection. The grating depths of two layers are optimized by using rigorous coupled-wave analysis with the given duty cycle of 0.6 and period of 1100 nm. The performance for different incident conditions is investigated when the incident wavelength and angle deviate from the central wavelength and the Bragg angle, respectively. For TM polarization, good uniformity can still be achieved within the given incident wavelength and angle regions. For TE polarization, the reflective polarization-selective beam splitter can have merits of wideband for different incident wavelengths.
- Published
- 2014
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