Journal Description
Photonics
Photonics
is an international, scientific, peer-reviewed, open access journal on the science and technology of optics and photonics, published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 15.5 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journal: Optics.
Impact Factor:
2.4 (2022);
5-Year Impact Factor:
2.4 (2022)
Latest Articles
Polarization Strips in the Focus of a Generalized Poincaré Beam
Photonics 2024, 11(5), 430; https://doi.org/10.3390/photonics11050430 (registering DOI) - 04 May 2024
Abstract
We analyze the tight focusing of a generalized Poincaré beam using a Richards–Wolf formalism. Conventional Poincaré beams are superpositions of two Laguerre–Gaussian beams with orthogonal polarization, while the generalized Poincaré beams are composed of two arbitrary optical vortices with rotationally symmetric amplitudes. Analytical
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We analyze the tight focusing of a generalized Poincaré beam using a Richards–Wolf formalism. Conventional Poincaré beams are superpositions of two Laguerre–Gaussian beams with orthogonal polarization, while the generalized Poincaré beams are composed of two arbitrary optical vortices with rotationally symmetric amplitudes. Analytical relationships for projections of the electric field in the focal plane are derived. Using the superposition of a right-handed circularly polarized plane wave and an optical vortex with a topological charge of −1 as an example, relationships for the intensity distribution and the longitudinal projection of the spin angular momentum vector are deduced. It is theoretically and numerically shown that the original beam has a topological charge of –1/2 and a C-point of circular polarization, and it is generated at the focal plane center, producing an on-axis C-line with a singularity index of –1/2 (a star). Furthermore, when making a full circle of some radius around the optical axis, the major axis vector of polarization ellipse is theoretically and numerically shown to form a one-sided polarization (Möbius) strip of order −3/2, which has three half-twists and a single ‘patching’ in which two oppositely directed vectors of the major axis of polarization ellipse occur close to each other.
Full article
(This article belongs to the Special Issue Recent Advances in Diffractive Optics)
Open AccessArticle
Efficient Pipeline Conflict Resolution for Layered QC-LDPC Decoders in OFDM-PON
by
Zhijie Wang, Zhengjun Xu, Kun Chen, Yuanzhe Qu, Xiaoqun Liu, Yingchun Li and Junjie Zhang
Photonics 2024, 11(5), 429; https://doi.org/10.3390/photonics11050429 (registering DOI) - 04 May 2024
Abstract
The high standard of communication quality in optical access networks makes forward error correction (FEC) schemes, such as LDPC, an integral part of the system. However, pipeline conflict arising from data dependencies is a common issue encountered in the hardware implementation of
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The high standard of communication quality in optical access networks makes forward error correction (FEC) schemes, such as LDPC, an integral part of the system. However, pipeline conflict arising from data dependencies is a common issue encountered in the hardware implementation of layered QC-LDPC decoders. This paper proposes an efficient layered decoding architecture to reduce pipeline conflicts without introducing stall cycles. It can solve some of the pipeline conflicts by flexibly reordering the processing order of inter-layer and intra-layer submatrices offline. In addition, the patch method, based on variable-to-check messages, allows for the delayed use of gains between layer iterations, which can further minimize the performance loss caused by the remaining pipeline conflicts. The experimental results on the LDPC code of the IEEE802.16 standard in the OFDM-PON system demonstrate that the proposed architecture has sensitivity improvements of 0.125 dBm and 0.375 dBm, respectively, compared with our previous work and the method described in the other work. The optimized architecture improves the reliability of the decoder and can also make a contribution to efficient PON systems.
Full article
(This article belongs to the Section Optical Communication and Network)
Open AccessArticle
Tightly Trapped Atom Interferometer inside a Hollow-Core Fiber
by
Yitong Song, Wei Li, Xiaobin Xu, Rui Han, Chengchun Gao, Cheng Dai and Ningfang Song
Photonics 2024, 11(5), 428; https://doi.org/10.3390/photonics11050428 - 03 May 2024
Abstract
We demonstrate a fiber-guided atom interferometer in a far-off-resonant trap (FORT) of 100 μK. The differential light shift (DLS) introduced by the FORT leads to the inhomogeneous dephasing of the tightly trapped atoms inside a hollow-core fiber. The DLS-induced dephasing is greatly suppressed
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We demonstrate a fiber-guided atom interferometer in a far-off-resonant trap (FORT) of 100 μK. The differential light shift (DLS) introduced by the FORT leads to the inhomogeneous dephasing of the tightly trapped atoms inside a hollow-core fiber. The DLS-induced dephasing is greatly suppressed in Doppler-insensitive interferometry. The spin coherence time is extended to 13.4 ms by optimizing the coupling of the trapping laser beam into a quasi-single-mode hollow-core anti-resonant fiber. The Doppler-sensitive interferometry shows a much shorter coherence time, indicating that the main limits to our fiber-guided atom interferometer are the wide axial velocity distribution and the irregular modes of the Raman laser beams inside the fiber. This work paves the way for portable and miniaturized quantum devices, which have advantages for inertial sensing at arbitrary orientations and in dynamic environments.
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(This article belongs to the Special Issue The Integration of Quantum Communication and Quantum Sensors)
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Improved Optics for Super-Resolution Time-Lapse Observations of Biological Phenomenon Using Speckle Interferometry
by
Yasuhiko Arai
Photonics 2024, 11(5), 427; https://doi.org/10.3390/photonics11050427 - 03 May 2024
Abstract
This study proposes a new optical system with the potential for time-lapse observation of living cellular tissue beyond the diffraction limit through speckle interferometry to facilitate biological research. The spatial resolution of this optical system was investigated and improved upon. This study also
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This study proposes a new optical system with the potential for time-lapse observation of living cellular tissue beyond the diffraction limit through speckle interferometry to facilitate biological research. The spatial resolution of this optical system was investigated and improved upon. This study also experimentally verified a finding from an earlier simulation study that the new super-resolution technology could be realised by analysing the phase distribution related to the shape of the measured object, preserved in the light reflected from the object. Additionally, a method was presented to confirm the positions of microstructures, based on the extracted characteristics of the structure.
Full article
(This article belongs to the Special Issue Coherence Properties of Light: From Theory to Applications)
Open AccessArticle
An Empirical Approach to Rerouting Visible Light Pathways Using an Adjustable-Angle Mirror to Sustain Communication between Vehicles on Curvy Roads
by
Ahmet Deniz, Burak Aydın and Heba Yuksel
Photonics 2024, 11(5), 426; https://doi.org/10.3390/photonics11050426 - 03 May 2024
Abstract
In this paper, a novel method is demonstrated to sustain vehicle-to-vehicle (V2V) communication on curvy roads via the arrangement of the lateral position of a self-angle-adjustable mirror–reflective road sign (SAAMRS) and light-direction-sensing wide-angle complementary photodiodes (CPDs). Visible light communication (VLC) between vehicles attracts
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In this paper, a novel method is demonstrated to sustain vehicle-to-vehicle (V2V) communication on curvy roads via the arrangement of the lateral position of a self-angle-adjustable mirror–reflective road sign (SAAMRS) and light-direction-sensing wide-angle complementary photodiodes (CPDs). Visible light communication (VLC) between vehicles attracts attention as a complementary technology to radio-frequency-based (RF-based) communication technologies due to its wide, license-free spectrum and immunity to interferences. However, V2V VLC may be interrupted on curvy roads due to the limited field of view (FOV) of the receiver or the line of sight (LOS) being interrupted. To solve this problem, an experiment was developed using an SAAMRS along with wide-angle light-direction-sensing CPDs that used a precise peak detection (PPD) method to sustain communication between vehicles in dynamic environments by rerouting the incident light with the highest signal intensity level to the receiver vehicle on curvy roads. We also used real images of curvy roads simulated as polynomials to calculate the necessary rotation angles for the SAAMRS and regions where communication exist. Our experimental results overlapped almost completely with our simulations, with small errors of approximately 4.8% and 4.4% for the SAAMRS angle and communication region, respectively.
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(This article belongs to the Special Issue Visible Light Communications)
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Open AccessArticle
Polarization Diffraction Gratings in PAZO Polymer Thin Films Recorded with Digital Polarization Holography: Polarization Properties and Surface Relief Formation
by
Nataliya Berberova-Buhova, Lian Nedelchev, Georgi Mateev, Ludmila Nikolova, Elena Stoykova, Branimir Ivanov, Velichka Strijkova, Keehoon Hong and Dimana Nazarova
Photonics 2024, 11(5), 425; https://doi.org/10.3390/photonics11050425 - 03 May 2024
Abstract
In this work, we study the polarization properties of diffraction gratings recorded in thin films of the azopolymer PAZO (poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt]) using digital polarization holography. Using two quarter-wave plates, the phase retardation of each pixel of the SLM is converted into
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In this work, we study the polarization properties of diffraction gratings recorded in thin films of the azopolymer PAZO (poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt]) using digital polarization holography. Using two quarter-wave plates, the phase retardation of each pixel of the SLM is converted into the azimuth rotation of linearly polarized light. When recording from the azopolymer side of the sample, significant surface relief amplitude is observed with atomic force microscopy. In contrast, recording from the substrate side of the sample allows the reduction of the surface relief modulation and the obtaining of polarization gratings with characteristics close to an ideal grating, recorded with two orthogonal circular polarizations. This can be achieved even with a four-pixel period of grating, as demonstrated by our results.
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(This article belongs to the Special Issue Technologies and Applications of Digital Holography)
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Open AccessArticle
Deep Learning-Enhanced Inverse Modeling of Terahertz Metasurface Based on a Convolutional Neural Network Technique
by
Muzhi Gao, Dawei Jiang, Gaoyang Zhu and Bin Wang
Photonics 2024, 11(5), 424; https://doi.org/10.3390/photonics11050424 - 03 May 2024
Abstract
The traditional design method for terahertz metasurface biosensors is cumbersome and time-consuming, requires expertise, and often leads to significant discrepancies between expected and actual values. This paper presents a novel approach for the fast, efficient, and convenient inverse design of THz metasurface sensors,
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The traditional design method for terahertz metasurface biosensors is cumbersome and time-consuming, requires expertise, and often leads to significant discrepancies between expected and actual values. This paper presents a novel approach for the fast, efficient, and convenient inverse design of THz metasurface sensors, leveraging convolutional neural network techniques based on deep learning. During the model training process, the magnitude data of the scattering parameters collected from the numerical simulation of the THz metasurface served as features, paired with corresponding surface structure matrices as labels to form the training dataset. During the validation process, the thoroughly trained model precisely predicted the expected surface structure matrix of a THz metasurface. The results demonstrate that the proposed algorithm realizes time-saving, high-efficiency, and high-precision inversion methods without complicated data preprocessing and additional optimization algorithms. Therefore, deep learning algorithms offer a novel approach for swiftly designing and optimizing THz metasurface sensors in biomedical detection, bypassing the complex and specialized design process of electromagnetic devices, and promising extensive prospects for their application in the biomedical field.
Full article
(This article belongs to the Special Issue Fiber Optic Sensors: Science and Applications)
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Open AccessArticle
Intermodal Fiber Interferometer with Spectral Interrogation and Fourier Analysis of Output Signals for Sensor Application
by
Aleksandr Petrov, Andrey Golovchenko, Mikhail Bisyarin, Nikolai Ushakov and Oleg Kotov
Photonics 2024, 11(5), 423; https://doi.org/10.3390/photonics11050423 - 02 May 2024
Abstract
Interferometric fiber-optic sensors provide very high measurement accuracy and come with many other benefits. As such, the study of signal processing techniques for fiber-optic interferometers in order to extract information about external perturbation is an important area of research. In this work, the
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Interferometric fiber-optic sensors provide very high measurement accuracy and come with many other benefits. As such, the study of signal processing techniques for fiber-optic interferometers in order to extract information about external perturbation is an important area of research. In this work, the method of Fourier analysis was applied to extract information from the output signals of an intermodal fiber interferometer with spectral interrogation. It is shown that the external perturbation can be measured by obtaining the phase spectrum of the spectral transfer function of an intermodal fiber interferometer and determining the phase difference of a certain pair of mode groups. A mathematical model of this approach was developed, taking into account the parameters of the laser and the optical fiber, the number of excited mode groups, and the parameters of external perturbation. The theoretically considered method of Fourier analysis was experimentally verified, and it was proved to provide a linear response to external perturbation in a wide dynamic range.
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(This article belongs to the Special Issue Fiber Optic Sensors: Science and Applications)
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Open AccessArticle
High-Precision Semiconductor Substrate Thickness Gauge Based on Spectral-Domain Interferometry
by
Shuncong Zhong, Renyu He, Yaosen Deng, Jiewen Lin and Qiukun Zhang
Photonics 2024, 11(5), 422; https://doi.org/10.3390/photonics11050422 - 01 May 2024
Abstract
The flatness of semiconductor substrates is an important parameter for evaluating the surface quality of semiconductor substrates. However, existing technology cannot simultaneously achieve high measurement efficiency, large-range thickness measurement, and nanometer-level measurement accuracy in the thickness measurement of semiconductor substrates. To solve the
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The flatness of semiconductor substrates is an important parameter for evaluating the surface quality of semiconductor substrates. However, existing technology cannot simultaneously achieve high measurement efficiency, large-range thickness measurement, and nanometer-level measurement accuracy in the thickness measurement of semiconductor substrates. To solve the problems, we propose to apply the method that combines spectral-domain optical coherence tomography (SD-OCT) with the Hanning-windowed energy centrobaric method (HnWECM) to measure the thickness of semiconductor substrates. The method can be employed in the full-chip thickness measurement of a sapphire substrate, which has a millimeter measuring range, nanometer-level precision, and a sampling rate that can reach up to 80 kHz. In this contribution, we measured the full-chip thickness map of a sapphire substrate by using this method and analyzed the machining characteristics. The measurement results of a high-precision mechanical thickness gauge, which is widely used for thickness measurement in the wafer fabrication process, were compared with the proposed method. The difference between these two methods is 0.373%, which explains the accuracy of the applied method to some extent. The results of 10 sets of repeatability experiments on 250 measurement points show that the maximum relative standard deviation (RSD) at this point is 0.0061%, and the maximum fluctuation is 71.0 nm. The above experimental results prove that this method can achieve the high-precision thickness measurement of the sapphire substrate and is of great significance for improving the surface quality detection level of semiconductor substrates.
Full article
(This article belongs to the Topic Advance and Applications of Fiber Optic Measurement: 2nd Edition)
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Open AccessArticle
Group Control of Photo-Responsive Colloidal Motors with a Structured Light Field
by
Dianyang Li, Huan Wei, Hui Fang and Yongxiang Gao
Photonics 2024, 11(5), 421; https://doi.org/10.3390/photonics11050421 - 01 May 2024
Abstract
Using structured light to drive colloidal motors, due to its advantages of remote manipulation, energy tunability, programmability, and the controllability of spatiotemporal distribution, has been attracting much attention in the fields of targeted drug delivery, environmental control, chemical agent detection, and smart device
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Using structured light to drive colloidal motors, due to its advantages of remote manipulation, energy tunability, programmability, and the controllability of spatiotemporal distribution, has been attracting much attention in the fields of targeted drug delivery, environmental control, chemical agent detection, and smart device design. Here, we focus on studying the group control of colloidal motors made from a photo-responsive organic polymer molecule NO-COP (N,O-Covalent organic polymer). These colloidal motors mainly respond to light intensity patterns. Considering its merits of fast refreshing speed, good programmability, and high-power threshold, we chose a digital micromirror device (DMD) to modulate the structured light field shining on the sample. It was found that under ultraviolet or green light modulation, such colloidal motors exhibit various group behaviors including group spreading, group patterning, and group migration. A qualitative interpretation is also provided for these observations.
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(This article belongs to the Special Issue Emerging Topics in Structured Light)
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Functional Optical Coherence Tomography of Rat Cortical Neurovascular Activation during Monopulse Electrical Stimulation with the Microelectrode Array
by
Lin Yao, Jin Huang, Taixiang Liu, Han Gu, Changpeng Li, Ke Yang, Hongwei Yan, Lin Huang, Xiaodong Jiang, Chengcheng Wang and Qihua Zhu
Photonics 2024, 11(5), 420; https://doi.org/10.3390/photonics11050420 - 30 Apr 2024
Abstract
This paper presents a study to evoke rat cortical functional activities, including hemodynamic and neural tissue signal changes, by monopulse electrical stimulation with a microelectrode array using functional optical coherence tomography (fOCT). Based on the principal component analysis and fuzzy clustering method (PCA-FCM),
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This paper presents a study to evoke rat cortical functional activities, including hemodynamic and neural tissue signal changes, by monopulse electrical stimulation with a microelectrode array using functional optical coherence tomography (fOCT). Based on the principal component analysis and fuzzy clustering method (PCA-FCM), the hemodynamic response of different size blood vessels in rat cortex are analyzed, showing that the hemodynamic response of the superficial large blood vessels is more concentrated. In the regions of neural tissue where blood vessels are removed, positive significant pixels (the intensity of the pixel for five consecutive frames is greater than the average value plus triple standard deviation) and negative significant pixels (the intensity of the pixel for five consecutive frames is less than the average value minus triple standard deviation) exist, and the averaged intensity signal responds rapidly with an onset time of ~20.8 ms. Furthermore, the hemodynamic response was delayed by ~3.5 s from the neural tissue response. fOCT can provide a label-free, large-scale and depth-resolved map of cortical neurovascular activation, which is a promising technology to monitor cortical small-scale neurovascular activities.
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(This article belongs to the Section Biophotonics and Biomedical Optics)
Open AccessArticle
Direct Numerical Modeling as a Tool for Optical Coherence Tomography Development: SNR (Sensitivity) and Lateral Resolution Test Target Interpretation
by
Samuel Lawman and Yao-Chun Shen
Photonics 2024, 11(5), 419; https://doi.org/10.3390/photonics11050419 - 30 Apr 2024
Abstract
Optical Coherence Tomography (OCT) is a growing family of biophotonic imaging techniques, but in the literature there is a lack of easy-to-use tools to universally directly evaluate a device’s theoretical performance for a given metric. Modern computing tools mean that direct numerical modeling
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Optical Coherence Tomography (OCT) is a growing family of biophotonic imaging techniques, but in the literature there is a lack of easy-to-use tools to universally directly evaluate a device’s theoretical performance for a given metric. Modern computing tools mean that direct numerical modeling can, from first principles, simulate the performance metrics of a specific device directly without relying on analytical approximations and/or complexities. Here, we present two different direct numerical models, along with the example MATLAB code for the reader to adapt to their own systems. The first model is of photo-electron shot noise at the detector, the primary noise source for OCT. We use this firstly to evaluate the amount of additional noise present (1.5 dB) for an experimental setup. Secondly, we demonstrate how to use it to precisely quantify the expected shot noise SNR limit difference between time-domain and Fourier-domain OCT systems in a given hypothetical experiment. The second model is used to demonstrate how USAF 1951 test chart images should be interpreted for a given lateral PSF shape. Direct numerical modeling is an easy and powerful basic tool for researchers and developers, the wider use of which may improve the rigor of the OCT literature.
Full article
(This article belongs to the Special Issue Recent Progress in Biophotonics)
Open AccessReview
Hybrid Integrated Silicon Photonics Based on Nanomaterials
by
Domenic Prete, Francesco Amanti, Greta Andrini, Fabrizio Armani, Vittorio Bellani, Vincenzo Bonaiuto, Simone Cammarata, Matteo Campostrini, Samuele Cornia, Thu Ha Dao, Fabio De Matteis, Valeria Demontis, Giovanni Di Giuseppe, Sviatoslav Ditalia Tchernij, Simone Donati, Andrea Fontana, Jacopo Forneris, Roberto Francini, Luca Frontini, Gian Carlo Gazzadi, Roberto Gunnella, Simone Iadanza, Ali Emre Kaplan, Cosimo Lacava, Valentino Liberali, Leonardo Martini, Francesco Marzioni, Claudia Menozzi, Elena Nieto Hernández, Elena Pedreschi, Paolo Piergentili, Paolo Prosposito, Valentino Rigato, Carlo Roncolato, Francesco Rossella, Andrea Salamon, Matteo Salvato, Fausto Sargeni, Jafar Shojaii, Franco Spinella, Alberto Stabile, Alessandra Toncelli, Gabriella Trucco and Valerio Vitaliadd
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Photonics 2024, 11(5), 418; https://doi.org/10.3390/photonics11050418 - 30 Apr 2024
Abstract
Integrated photonic platforms have rapidly emerged as highly promising and extensively investigated systems for advancing classical and quantum information technologies, since their ability to seamlessly integrate photonic components within the telecommunication band with existing silicon-based industrial processes offers significant advantages. However, despite this
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Integrated photonic platforms have rapidly emerged as highly promising and extensively investigated systems for advancing classical and quantum information technologies, since their ability to seamlessly integrate photonic components within the telecommunication band with existing silicon-based industrial processes offers significant advantages. However, despite this integration facilitating the development of novel devices, fostering fast and reliable communication protocols and the manipulation of quantum information, traditional integrated silicon photonics faces inherent physical limitations that necessitate a challenging trade-off between device efficiency and spatial footprint. To address this issue, researchers are focusing on the integration of nanoscale materials into photonic platforms, offering a novel approach to enhance device performance while reducing spatial requirements. These developments are of paramount importance in both classical and quantum information technologies, potentially revolutionizing the industry. In this review, we explore the latest endeavors in hybrid photonic platforms leveraging the combination of integrated silicon photonic platforms and nanoscale materials, allowing for the unlocking of increased device efficiency and compact form factors. Finally, we provide insights into future developments and the evolving landscape of hybrid integrated photonic nanomaterial platforms.
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(This article belongs to the Special Issue Photonic Integrated Circuits for Information, Computing and Sensing)
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Simulation Method for the Impact of Atmospheric Wind Speed on Optical Signals in Satellite–Ground Laser Communication Links
by
Wujisiguleng Zhao and Chunyi Chen
Photonics 2024, 11(5), 417; https://doi.org/10.3390/photonics11050417 - 30 Apr 2024
Abstract
To analyze the intensity of atmospheric turbulence in a satellite–ground laser communication link, it is important to consider the effect of increased atmospheric turbulence caused by wind speed. Atmospheric turbulence causes a change in the refractive index, which negatively impacts the quality and
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To analyze the intensity of atmospheric turbulence in a satellite–ground laser communication link, it is important to consider the effect of increased atmospheric turbulence caused by wind speed. Atmospheric turbulence causes a change in the refractive index, which negatively impacts the quality and focusing ability of the laser beam by altering its phase front. To simulate the changes in amplitude and phase characteristics of laser beam propagation in atmospheric turbulence caused by wind speed, a transverse translation phase screen is used. To better understand and address the influence of atmospheric wind speed on the phase of optical signals in satellite–ground laser communication links, this paper proposes a Monte Carlo simulation method. This method utilizes the spatial and temporal variations in the refractive index in the atmosphere and integrates the principles of optical signal propagation in the atmosphere to simulate changes in the phase of optical signals under different wind speed conditions. By analyzing the variations in the received optical signal’s power, the Monte Carlo method is employed to simulate phase screens and logarithmic amplitude screens. Additionally, it models the probability density of the statistical behavior of received optical signal’s fluctuations, as well as the time autocorrelation coefficient of optical signals. This paper, under the coupling condition in satellite–ground laser communication links, conducted a Monte Carlo simulation experiment to analyze the characteristics of the optical signal’s fluctuations in the link and discovered that atmospheric wind speed affects the shape of the power spectral density model of the received optical signal. Increasing wind speed leads to a decrease in the time autocorrelation coefficient of the received optical signal and affects the coupling efficiency. The paper then used a cubic spline interpolation fitting method to verify the models of the power spectral density and the autocorrelation time coefficient of the optical signal. This provides a theoretical foundation and practical guidance for the optimization of satellite–ground laser communication systems.
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(This article belongs to the Section Optical Communication and Network)
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Modulation of Second-Order Sideband Efficiency in an Atom-Assisted Optomechanical System
by
Liang-Xuan Fan, Tao Shui, Ling Li and Wen-Xing Yang
Photonics 2024, 11(5), 416; https://doi.org/10.3390/photonics11050416 - 30 Apr 2024
Abstract
We propose an efficient scheme to enhance the generation of optical second-order sidebands (OSSs) in an atom-assisted optomechanical system. The cavity field is coupled with a strong driving field and a weak probe field, and a control field is applied to the atom.
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We propose an efficient scheme to enhance the generation of optical second-order sidebands (OSSs) in an atom-assisted optomechanical system. The cavity field is coupled with a strong driving field and a weak probe field, and a control field is applied to the atom. We use the steady-state method to analyze the nonlinear interaction in the system, which is different from the traditional linear analysis method. The existence of an auxiliary three-level atom driven by the control field significantly enhances the generation of an OSS. It is found that the efficiency of the OSS can be effectively modulated by adjusting the Rabi frequency of the control field, optomechanical cooperativity and atomic coupling strength. Our scheme provides a promising solution for controlling light propagation and has potential application in quantum optical devices and quantum information networks.
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(This article belongs to the Special Issue Optics and Laser: Light Field Manipulation)
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A Novel 4 × 1 MISO-VLC System with FBMC-OQAM Downlink Signals
by
Yufeng Shao, Yanlin Li, Anrong Wang, Yaodong Zhu, Chong Li, Peng Chen, Renjie Zuo, Jie Yuan and Shuanfan Liu
Photonics 2024, 11(5), 415; https://doi.org/10.3390/photonics11050415 - 30 Apr 2024
Abstract
A novel visible-light communication (VLC) system with 4 × 1 multi-input–single-output (MISO) channels is designed. In the system, the filter bank multicarrier (FBMC) and offset quadrature amplitude modulation (OQAM) techniques are used to generate downlink signals. The principles and implementation methods are proposed
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A novel visible-light communication (VLC) system with 4 × 1 multi-input–single-output (MISO) channels is designed. In the system, the filter bank multicarrier (FBMC) and offset quadrature amplitude modulation (OQAM) techniques are used to generate downlink signals. The principles and implementation methods are proposed and analyzed, and the light intensity and received light power distribution of four LED emitters are discussed. The results demonstrate that it not only satisfies the requirements of indoor information access but also provides daily lighting. The used FBMC-OQAM signals exhibit better reception performance than orthogonal frequency division multiplexing (OFDM) signals. The system used has a lower bit error rate (BER) and larger access bandwidth compared to a 1 × 1 single-input–single-output (SISO) system. It has the potential for application advantages in future indoor VLC system applications.
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(This article belongs to the Special Issue Visible Light Communications)
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Open AccessReview
The Structure and Applications of Fused Tapered Fiber Optic Sensing: A Review
by
Siqi Ban and Yudong Lian
Photonics 2024, 11(5), 414; https://doi.org/10.3390/photonics11050414 - 30 Apr 2024
Abstract
Tapered optical fibers have continuously evolved in areas such as distributed sensing and laser generation in recent years. Their high sensitivity, ease of integration, and real-time monitoring capabilities have positioned them as a focal point in optical fiber sensing. This paper systematically introduces
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Tapered optical fibers have continuously evolved in areas such as distributed sensing and laser generation in recent years. Their high sensitivity, ease of integration, and real-time monitoring capabilities have positioned them as a focal point in optical fiber sensing. This paper systematically introduces the structures and characteristics of various tapered optical fiber sensors, providing a comprehensive overview of their applications in biosensing, environmental monitoring, and industrial surveillance. Furthermore, it offers insights into the developmental trends of tapered optical fiber sensing, providing valuable references for future related research and suggesting potential directions for the further advancement of optical fiber sensing.
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(This article belongs to the Special Issue Fabrication of Optical Fiber and Fiber Amplifiers: From Design to Applications)
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Open AccessTechnical Note
Design and Test of a Klystron Intra-Pulse Phase Feedback System for Electron Linear Accelerators
by
Luca Piersanti, Marco Bellaveglia, Fabio Cardelli, Alessandro Gallo, Riccardo Magnanimi, Sergio Quaglia, Michele Scampati, Giorgio Scarselletta, Beatrice Serenellini and Simone Tocci
Photonics 2024, 11(5), 413; https://doi.org/10.3390/photonics11050413 - 29 Apr 2024
Abstract
Beam stability and timing jitter in modern linear accelerators are becoming increasingly important. In particular, if a magnetic or radio-frequency (RF) compression regime is employed, the beam time of arrival jitter at the end of the linac can be strictly correlated with the
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Beam stability and timing jitter in modern linear accelerators are becoming increasingly important. In particular, if a magnetic or radio-frequency (RF) compression regime is employed, the beam time of arrival jitter at the end of the linac can be strictly correlated with the phase noise of the accelerating fields of the RF structure working off-crest. For this reason, since 2008, an RF fast-feedback technique, which acts within each RF pulse, has been successfully employed at LNF-INFN (Laboratori Nazionali di Frascati dell’Istituto Nazionale di Fisica Nucleare) in the SPARC_LAB (Sources for Plasma Accelerators and Radiation Compton with Laser And Beam) facility on S-band ( 2856 MHz) klystrons powered by pulse-forming network (PFN) modulators, as reported in this paper. However, in order to meet the more stringent requirements of plasma wakefield acceleration schemes, some upgrades to this feedback system have been recently carried out. The first prototype has been experimentally tested on a C-band ( 5712 MHz) klystron, driven by a solid-state modulator, in order to investigate the possibility for additional improvement resulting from the inherently more stable power source. In this paper, the design, realization and the preliminary measurement results obtained at SPARC_LAB after such upgrades will be reviewed.
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(This article belongs to the Special Issue Recent Advances in Free Electron Laser Accelerators)
Open AccessArticle
Design and Analysis of a Narrow Linewidth Laser Based on a Triple Euler Gradient Resonant Ring
by
Yikai Wang, Boxia Yan, Mi Zhou, Chenxi Sun, Yan Qi, Yanwei Wang, Yuanyuan Fan and Qian Wang
Photonics 2024, 11(5), 412; https://doi.org/10.3390/photonics11050412 - 29 Apr 2024
Abstract
We designed a narrow-linewidth external-cavity hybrid laser leveraging a silicon-on-insulator triple Euler gradient resonant ring. The laser’s outer cavity incorporates a compact, high-Q resonant ring with low loss. The straight waveguide part of the resonant ring adopts a width of 1.6 μm to
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We designed a narrow-linewidth external-cavity hybrid laser leveraging a silicon-on-insulator triple Euler gradient resonant ring. The laser’s outer cavity incorporates a compact, high-Q resonant ring with low loss. The straight waveguide part of the resonant ring adopts a width of 1.6 μm to ensure low loss transmission. The curved section is designed as an Euler gradient curved waveguide, which is beneficial for low loss and stable single-mode transmission. The design features an effective bending radius of only 26.35 μm, which significantly improves the compactness of the resonant ring and, in turn, reduces the overall footprint of the outer cavity chip. To bolster the laser power and cater to the varying shapes of semiconductor optical amplifier (SOA) spots, we designed a multi-tip edge coupler. Theoretical analysis indicates that this edge coupler can achieve an optical coupling efficiency of 85%. It also reveals that the edge coupler provides 3 dB vertical and horizontal alignment tolerances of 0.76 μm and 2.4 μm, respectively, for a spot with a beam waist radius of 1.98 μm × 0.99 μm. The outer cavity, designed with an Euler gradient micro-ring, can achieve a side-mode suppression ratio (SMSR) of 30 dB within a tuning range of 100 nm, with a round-trip loss of the entire cavity at 1.12 dB, and an expected theoretical laser linewidth of 300 Hz.
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(This article belongs to the Special Issue Narrow Linewidth Laser Sources and Their Applications)
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Open AccessCommunication
Mueller Matrix Polarizing Power
by
José J. Gil
Photonics 2024, 11(5), 411; https://doi.org/10.3390/photonics11050411 - 29 Apr 2024
Abstract
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The transformation of the states of polarization of electromagnetic waves through their interaction with polarimetrically linear media can be represented by the associated Mueller matrices. A global measure of the ability of a linear medium to modify the states of polarization of incident
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The transformation of the states of polarization of electromagnetic waves through their interaction with polarimetrically linear media can be represented by the associated Mueller matrices. A global measure of the ability of a linear medium to modify the states of polarization of incident waves, due to any combination of enpolarizing, depolarizing and retarding properties, is introduced as the distance from the Mueller matrix to the identity matrix. This new descriptor, called the polarizing power, is applicable to any Mueller matrix and can be expressed as a function of the degree of polarimetric purity and the trace of the Mueller matrix. The graphical representation of the feasible values of the polarizing power provides a general view of its main peculiarities and features. The values of the polarizing power for several typical devices are analyzed.
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