Results in Optics最新文献

{"title":"Optical audio signal hiding algorithm based on fractional Fourier transform domain and Gerchberg Saxton phase recovery","authors":"Hang Chen ,&nbsp;Zhenduo Ma ,&nbsp;Ziyi Zhang ,&nbsp;Zhengjun Liu","doi":"10.1016/j.rio.2025.100898","DOIUrl":"10.1016/j.rio.2025.100898","url":null,"abstract":"<div><div>This article proposes an audio signal encryption method based on the Gerchberg-Saxton (G-S) phase recovery algorithm in the fractional Fourier transform domain. The algorithm first encodes the original audio signal into an image format and encrypts it. Subsequently, the G-S phase recovery algorithm is used in the fractional Fourier domain to extract the phase information of the audio signal. On this basis, the original audio phase is replaced with a reference phase representing the secret information to achieve information embedding. This technology can select two different types of keys according to encryption requirements, further increasing the difficulty of decryption and ensuring information security. Ultimately, the encrypted image can be decrypted and restored to the original audio signal. This scheme achieves effective embedding and extraction of secret information in audio signals through the replacement and recovery of phase information.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100898"},"PeriodicalIF":3.0,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature distribution simulation and laser performance of Nd:YAG composite laser crystals","authors":"Zhao Chen ,&nbsp;Fei Li ,&nbsp;Wenpeng Liu ,&nbsp;Yufa Zhang ,&nbsp;Qingli Zhang","doi":"10.1016/j.rio.2025.100899","DOIUrl":"10.1016/j.rio.2025.100899","url":null,"abstract":"<div><div>YAG/Nd:YAG and YAG/Nd:YAG/YAG composite laser crystals were fabricated through thermal bonding method. The temperature distribution and laser properties of Nd:YAG, YAG/Nd:YAG and YAG/Nd:YAG/YAG crystals under LD end-pumping conditions were studied. Laser outputs with wavelengths of 1064 nm and 946 nm have been achieved. Temperature simulation results revealed that at 20 W pump power, the YAG/Nd:YAG/YAG crystal exhibited 15 K lower temperature compared to Nd:YAG crystal, with a 33 K reduction in end-face temperature. Under 20 W pumping, the maximum continuous-wave output powers of YAG/Nd:YAG/YAG crystal reached 4.412 W at 1064 nm and 668 mW at 946 nm, corresponding to slope efficiencies of 34.66 % and 6.68 %, and optical-to-optical conversion efficiencies of 34.77 % and 5.99 %, respectively. These values represent 1.6-fold and 1.8-fold improvements in output power, 13.4 % and 4.33 % enhancements in slope efficiency, as well as 9.31 % and 3.92 % increases in conversion efficiency compared to Nd:YAG crystal. Moreover, the YAG/Nd:YAG/YAG crystal demonstrated superior beam quality with lower M² factors than both Nd:YAG/YAG composite crystal and Nd:YAG crystal. It is shown that the composite YAG/Nd:YAG/YAG crystal has better cooling efficiency, which is beneficial to reduce the thermal lens effect and improve the laser efficiency.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100899"},"PeriodicalIF":3.0,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature-dependent phase evolution of the Gd3+ doped strontium compounds: Structural and optical properties","authors":"C. Dlamini ,&nbsp;M.R. Mhlongo ,&nbsp;V.M. Maphiri ,&nbsp;T.D. Malevu ,&nbsp;L.F. Koao ,&nbsp;T.E. Motaung ,&nbsp;T.T. Hlatshwayo ,&nbsp;S.V. Motloung","doi":"10.1016/j.rio.2025.100895","DOIUrl":"10.1016/j.rio.2025.100895","url":null,"abstract":"<div><div>Mixed-phases of the SrCO₃/Sr₃Al₂O₆/SrAl₂O₄/SrAl₄O₇/SrAl₁₂O₁₉ (hereafter called SSSSS) doped with Gd³⁺ (SSSSS: 0.05 % Gd³⁺) nanopowders were prepared using the citrate sol–gel method. The effect of annealing temperature (T_a) on the structure, morphology, and photoluminescence (PL) properties was investigated. The T_a was varied in a range of 600–1300 °C, while the dopant concentration was kept constant at 0.05 % Gd³⁺. X-ray diffraction (XRD) results revealed that the prepared nanopowders consist of a mixture of orthorhombic (SrCO₃), cubic (Sr₃Al₂O₆), monoclinic (SrAl₂O₄ and SrAl₄O₇), and hexagonal SrAl₁₂O₁₉ structures. It was noted that increasing the phase composition depends on the T_a. The Fourier-transform infrared spectroscopy (FTIR) shows several peaks at around 529, 874, 1181, 1442, 2947, and 3421 cm⁻¹. The Energy dispersive spectroscopy (EDS) confirmed the elementary composition of the Sr, C, O, and Al. The scanning electron microscope (SEM) images showed that the phase composition highly depends on the T_a. Transmission electron microscope (TEM) showed that the particle sizes are in the nanoscale. The ultraviolet–visible (UV–vis) diffuse reflection spectroscopy results showed that the absorption peaks below 300 nm are influenced by the T_a. The PL results showed three emission peaks located around 431, 541, and 657 nm when excited at 272 nm. These emission peaks were attributed to SrCO₃, SrAl₂O₄, and Sr₃Al₂O₆ crystal lattice, respectively. The results showed that the luminescence intensity and lifetime of the prepared samples depends on the T_a. The chromaticiy coordinate showed that all samples emit in a blue region and the color purity was influenced by the T_a.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100895"},"PeriodicalIF":3.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel quad-port configuration CPW-fed MIMO antenna design with triangular PBG structures for 6G communications in the sub-terahertz band","authors":"Nasredine Boujmil ,&nbsp;Mohammed Fattah ,&nbsp;Mohammed Mahfoudi ,&nbsp;Wafae El Hamdani ,&nbsp;Said Mazer ,&nbsp;Moulhime El Bekkali","doi":"10.1016/j.rio.2025.100896","DOIUrl":"10.1016/j.rio.2025.100896","url":null,"abstract":"<div><div>The race toward 6G networks necessitates innovative antenna designs to exploit the sub-terahertz (sub-THz) band’s extensive bandwidth. However, conventional antenna designs usually suffer from poor bandwidth, low gain, and insufficient power efficiency, which are required for emerging 6G applications needing ultra-high data rates, low latency, and massive connectivity. To address this problem in this paper, a compact coplanar waveguide (CPW) MIMO antenna with periodic PBG structures is proposed. Our approach incorporates a rectangular patch radiator that has been strategically modified with diagonal and U-shaped slots, further enhanced by triangular air holes in the polyimide substrate to achieve optimal impedance characteristics. The resulting quad-port configuration (2000 μm × 2000 μm × 75 μm) demonstrates exceptional performance across 0.1–1 THz. Its 776.73 GHz bandwidth qualifies its wideband capability to support ultra-fast 6G data rates, while an ECC of less than 0.006 and diversity gain approaching 10 dB ensure robust MIMO performance. With a peak gain of 9.04 dBi and 97 % radiation efficiency, the design supports efficient sub-THz operation, making it a strong candidate for 6G wireless communications, and advanced security sensing applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100896"},"PeriodicalIF":3.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact analysis of optical filter parameters on the flatness of optical frequency comb lines","authors":"Azza Abdulla Ali,&nbsp;Ibrahim Khider Eltahir,&nbsp;Elmustafa Sayed Ali","doi":"10.1016/j.rio.2025.100897","DOIUrl":"10.1016/j.rio.2025.100897","url":null,"abstract":"<div><div>This paper introduces an innovative approach for generating flat optical frequency combs (OFCs) through the use of M-ary quadrature amplitude modulation (M-QAM) combined with Mach-Zehnder modulation (MZM). Unlike traditional methods that rely on a conventional radio frequency (RF) signal, our technique employs a digital signal (DS) to activate electro-optic modulators (EOMs). The study meticulously examines the influence of various parameters of optical filters on their output characteristics. We conducted evaluations using two distinct types of filters: the Gaussian filter (GF) and the Butterworth filter (BWF). This work not only delves into the mathematical modeling of the OFC generator system but also provides a comprehensive simulation using OptiSystem software, showcasing the sophisticated setup involved. Our findings reveal that each parameter distinctly shapes the spectral output, with specific operational ranges identified as optimal for achieving peak performance, favorable outcomes, and enhanced flatness. Both types of filters contribute effectively to flattening the comb lines (CLs); however, the GF demonstrates slightly superior results compared to its BWF counterpart. Additionally, the convenience of adjusting the comb spacing of the OFCs by simply manipulating the bit rate of the DS streamlines operational efficiency.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100897"},"PeriodicalIF":3.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-loss and broadband 1 × 8 thermo-optic selective switch using bent directional couplers","authors":"Cheng Ji ,&nbsp;Daming Zhang ,&nbsp;Guoyan Zeng ,&nbsp;Minghui Zhou ,&nbsp;Yingzhi Ding ,&nbsp;Yuexin Yin","doi":"10.1016/j.rio.2025.100891","DOIUrl":"10.1016/j.rio.2025.100891","url":null,"abstract":"<div><div>Low-loss and broadband optical switches are essential components for all optical networks. In this paper, we experimentally demonstrate a 1 × 8 thermo-optic switch that exhibits broadband property with the worst crosstalk of −17.20 dB and the maximum fiber-to-fiber loss of 5.56 dB over the wavelength range from 1500 to 1630 nm. The elementary unit, which is based on 2 × 2 Mach-Zehnder interferometers utilizing bent directional couplers, demonstrates a crosstalk less than −19.08 dB and the extinction ratio larger than 18.92 dB, from 1500 nm to 1630 nm. For 1 × 8 switch, the power consumption of channel switching is lower than 1.204 W. The measured rise (10 %–90 %) and fall (90 %–10 %) time of the switch unit are 1.04 ms and 600 μs, respectively. These favorable performances promise the demonstrated switch potential in all optical network applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100891"},"PeriodicalIF":3.0,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stable and channel spacing tunable of SOA-based multiwavelength fiber laser utilizing parallel Lyot filter","authors":"Norasmahan Muridan ,&nbsp;Abdul Hadi Sulaiman ,&nbsp;Siti Fatimah Norizan ,&nbsp;Siti Azlida Ibrahim ,&nbsp;Nelidya Md Yusoff","doi":"10.1016/j.rio.2025.100890","DOIUrl":"10.1016/j.rio.2025.100890","url":null,"abstract":"<div><div>We proposed the generation of a tunable channel-spacing in a multiwavelength fiber laser that incorporates a semiconductor optical amplifier (SOA) and a parallel Lyot filter. Previously, only a few works demonstrated channel spacing tunability using parallel Lyot filter, with none of them utilizing SOA. A stable and tunable multiwavelength spectrum with up to three distinct channel spacings is demonstrated using three different sets of parallel Lyot filter either Short, Long, and Mixed based on varying lengths of polarization-maintaining fiber (PMF). Channel spacing tunability is achieved by selecting different PMF length combinations. Experimental results show that two channel spacing modes, either single or multiple, can be selected for each configuration. Additionally, increasing the SOA drive current results in a greater number of lasing lines with higher intensity within the cavity. The system demonstrates good stability, with peak power differences of 1.46 dB, 0.65 dB, and 2.61 dB for the Short, Long, and Mixed sets, respectively, during a 60-minute observation period.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100890"},"PeriodicalIF":3.0,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methodology of teaching the topic of “electromagnetic waves” in a systematized and integrated way","authors":"Yunusali Xolboyev ,&nbsp;Kamiljan Tursunmetov ,&nbsp;Xolidaxon Tajiboyeva ,&nbsp;Dilfuza Begmatova ,&nbsp;Nuraddin Abdullayev ,&nbsp;Shohida Sodiqova ,&nbsp;Dilnoza Nomozova","doi":"10.1016/j.rio.2025.100889","DOIUrl":"10.1016/j.rio.2025.100889","url":null,"abstract":"<div><div>The topic of electromagnetic waves is considered one of the most multifaceted, complex, and information-rich areas of physics. Therefore, it is essential to study this topic in a systematized and integrated manner within a limited time. This article presents a systematized and integrated teaching methodology designed to facilitate the effective and in-depth understanding of the topic “Electromagnetic Waves,” which is one of the key sections of physics taught in higher education institutions. The methodology incorporates modern pedagogical technologies such as clustering, block diagram creation, brainstorming, and step-by-step analytical approaches. Particular emphasis is placed on the advantages of using artificial intelligence tools to explain complex concepts in a visual and interactive format. The article also utilizes case study methods related to the physical properties and practical applications of electromagnetic waves in everyday life, which foster student interest in the subject and help develop the ability to apply theoretical knowledge in practice. Furthermore, this approach contributes to the development of students’ independent thinking, analytical reasoning, and interdisciplinary integration competencies. The research results offer valuable insights into increasing the effectiveness of teaching this topic and provide broad opportunities for delivering physics education through modern and innovative methods.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100889"},"PeriodicalIF":3.0,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum-optical photonic analogies as a tool for free-space propagation of a Pearcey beam","authors":"M.P. Chavez-Flores ,&nbsp;J.A. Anaya-Contreras ,&nbsp;A. Zúñiga-Segundo ,&nbsp;H.M. Moya-Cessa","doi":"10.1016/j.rio.2025.100885","DOIUrl":"10.1016/j.rio.2025.100885","url":null,"abstract":"<div><div>The theoretical and experimental generation of the Pearcey–Gaussian beam has inspired the study of a broader family of related beams, such as the circular Pearcey beam and, more recently, the abruptly dual auto-focusing circular Pearcey edge dislocation beam, which exhibits both abrupt dual auto-focusing and enhanced self-healing capabilities, paving the way for various applications such as optical communication, optical metrology, and optical tweezers. In this context, we present the analytical solution for the paraxial propagation of a finite-energy Pearcey beam using the <span><math><mrow><mi>S</mi><mi>U</mi><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow></math></span> Lie group. This group-theoretical approach provides a robust and general framework for addressing propagation problems in optics and photonics. Although the Pearcey beam is a well-known example, this is, to our knowledge, the first time it has been analytically treated through this method.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100885"},"PeriodicalIF":3.0,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wideband GeTe-based near-perfect THz metamaterial absorber for 6G applications","authors":"Md. Saffat Gohor ,&nbsp;Mehedi Hasan Tonmoy ,&nbsp;Md. Islahur Rahman Ebon ,&nbsp;Foez Ahmed ,&nbsp;Jaker Hossain","doi":"10.1016/j.rio.2025.100886","DOIUrl":"10.1016/j.rio.2025.100886","url":null,"abstract":"<div><div>Germanium Telluride (GeTe) metamaterial absorber of its first kind is comprehensively studied and demonstrated. The proposed design features a multilayered configuration comprising a geometrically optimized, symmetrical GeTe-driven square split-ring resonator (SSRR) with an auxetic structure in the center and a metallic gold (Au) ground plane, separated by an MF₂ (M = Mg, Ca, Sr, Ba) dielectric substrate. Under normal incidence, the structure exhibits excellent absorption performance at THz waves, maintaining an absorption efficiency above 90 % over a wide frequency ranging from 2.26 THz to 7.32 THz, corresponding to a relative absorption bandwidth (RAB) of 105.6 %. Two prominent absorbing crests are observed at 2.72 THz as well as 6.49 THz, with a central frequency of 4.79 THz. The findings confirm that strategic structural design and optimization play a pivotal role in enhancing the absorber’s performance. Furthermore, by tuning the conductivity of GeTe, the absorber demonstrates dynamically adjustable absorption capabilities, which offer versatile and tunable functionality. In addition, the structure retains stable absorption characteristics across various polarization states and angles which are incidental for both transverse electric (TE) and transverse magnetic (TM) modes, confirming its polarization insensitivity and angular stability. With its wideband response, tunability, and robust absorption behavior, the proposed GeTe-based absorber opens a new dimension for a wide range of THz applications, including 6G communications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100886"},"PeriodicalIF":3.0,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144925610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}