Optics express最新文献

{"title":"Enhancement in terahertz imaging of transparent objects using phase contrast methods in a 4f optical system.","authors":"Adrianna Nieradka, Paweł Komorowski, Mateusz Kaluza, Agnieszka Siemion","doi":"10.1364/OE.565551","DOIUrl":"https://doi.org/10.1364/OE.565551","url":null,"abstract":"<p><p>In this study, the optical system designed to improve the visibility of transparent objects using terahertz radiation at a frequency of 260 GHz is presented. The setup employs the specific lens arrangement known as a 4f system. The imaging was performed using the positive and negative phase contrast methods, where dedicated phase filters introduced a phase delay in the central part of the Fourier plane. A significant improvement in contrast for the transparent samples was achieved, with contrast enhancement of 13.51 and 12.90, respectively.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"38495-38514"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Switchable silica waveguide XOR/XNOR directed logic gate based on E₂₁-E₁₁ mode conversion.","authors":"Tingyu Liu, Weigang Wang, Xinchao Zhang, Manzhuo Wang, Jimin Fang, Xiaoqiang Sun, Yuanda Wu, Daming Zhang","doi":"10.1364/OE.568522","DOIUrl":"https://doi.org/10.1364/OE.568522","url":null,"abstract":"<p><p>Optical directed logic gates are in high demand for artificial intelligence, and optical and quantum computing applications. A silica waveguide XOR/XNOR optical logic gate based on cascaded Mach-Zehnder thermo-optic switches and multimode interference E₂₁-E₁₁ mode converter is demonstrated. When monochromatic light is input into the device, a complementary XOR/XNOR functional output in the form of light can be obtained by controlling the electrical Boolean inputs. The proposed design is fabricated on the CMOS compatible silica planar lightwave circuit platform. The experimental results proved that the signal-to-noise ratio was greater than 10 dB over the entire C band. The proposed device with simple structure, large bandwidth, and versatility would be a promising candidate for information processing in optical wavelength division multiplexing and mode division multiplexing networks. It has good potential in arithmetic operations, parity checks, encryption, and decryption.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"37550-37558"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvements in internal quantum efficiency and wavelength stability of InGaN orange and red MQWs grown on a semi-polar plane.","authors":"Chuanyu Jia, Shihao Wang, Yuan Li, Qi Wang","doi":"10.1364/OE.572328","DOIUrl":"https://doi.org/10.1364/OE.572328","url":null,"abstract":"<p><p>An innovative epitaxial technology was adopted to directly grow semi-polar orange and red InGaN/GaN MQWs on common sapphire substrate. Our research results show that InGaN/GaN MQWs grown on the semipolar surface have significant improvements in internal quantum efficiency (IQE) and color stability compared to those grown on the polar surface. For polar c-plane red MQWs: Strong compressive strain and quantum-confined Stark effect (QCSE) induce pronounced band bending, as evidenced by strain gradients in TEM cross-sections. In-rich clusters form at the QW center due to In migration, causing localized strain concentration and interface blurring. For semi-polar red QWs:reduced polarization fields result in uniform in-plane strain distribution, with significant strain relaxation near QW edges.TEM analysis confirms suppressed QCSE and homogeneous In incorporation, minimizing spectral broadening. As the laser excitation power changes, the peak wavelength blue shift of polar c-plane red MQWs was 63 nm, at peak wavelength of 675 nm and 612.1 nm, the corresponding IQE is 4.4% and 10.8% respectively. While the peak wavelength blue shift of semi-polar plane red MQWs was 19 nm, at peak wavelength of 607 nm and 588 nm, the corresponding IQE is 22.2% and 35.6% respectively.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"38392-38402"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-precision temperature sensor using phase-shifted fiber Bragg grating written directly by femtosecond laser.","authors":"Lijie Wang, Jun He, Runxiao Chen, Hao Luo, Baijie Xu, Xizhen Xu, Zhiyong Bai, Yiping Wang","doi":"10.1364/OE.571136","DOIUrl":"https://doi.org/10.1364/OE.571136","url":null,"abstract":"<p><p>A high-quality π-phase-shifted fiber Bragg grating (PSFBG) was inscribed in conventional single-mode fiber by use of femtosecond laser direct writing technology to demonstrate a high-precision temperature sensor. During grating inscription, the slit beam shaping technique was employed to reduce the 3 dB bandwidth of the grating's phase-shifted peak from 12.0 pm to 4.8 pm, thereby significantly enhancing the wavelength resolution of the fiber Bragg grating. Such a PSFBG exhibited a temperature sensitivity of 10.71 pm/°C, with an average standard deviation range of 0.005-0.016 °C for temperature measurements. This PSFBG represents a highly promising temperature sensor, featuring a minimum temperature resolution of 0.01 °C and a maximum temperature uncertainty of 0.016 °C. This outstanding performance is primarily attributed to the reduction of the PSFBG's birefringence from 5.607 × 10^-5 to 2.247 × 10^-6 using the slit beam shaping technique, which substantially enhances the stability of the resonant wavelength of the grating's phase-shifted peak and the measurement accuracy of the fiber Bragg grating temperature sensor.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"39107-39116"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reversed probabilistic shaping scheme for fiber-visible light communication converged system with Kramers-Kronig receiver.","authors":"Jiabin Ye, Yingjun Zhou, Zengyi Xu, Xianhao Lin, Yunkai Wang, Chao Shen, Ziwei Li, Feng Bao, Junwen Zhang, Nan Chi","doi":"10.1364/OE.570590","DOIUrl":"https://doi.org/10.1364/OE.570590","url":null,"abstract":"<p><p>With the growing demand for high speed, low latency, and flexible access in 6G communication, hybrid fiber-visible light communication (VLC) systems have emerged as a promising solution by combining the capacity of optical fiber with the deployment flexibility of VLC. However, signal distortion and low signal-to-noise ratio (SNR) caused by low received optical power (ROP) in such systems pose some challenges, particularly when using direct detection. To address these issues, we demonstrate a fiber-VLC converged system that integrates a Kramers-Kronig (KK) receiver with a reversed probabilistic shaping (RPS) strategy. The proposed system enables reliable transmission over a 20-km fiber link followed by up to 4 meters of free-space VLC, achieving improved performance in terms of error vector magnitude (EVM), peak-to-average power ratio (PAPR), and normalized generalized mutual information (NGMI) under low-SNR and peak-power-constrained conditions. As the VLC free-space transmission distance increases from 0.5 to 4 meters, the system employing RPS maintains a high-performance net data rate, decreasing from 10.36 Gbps to 8.7 Gbps. To the best of our knowledge, this is the first time that KK detection combined with RPS is experimentally demonstrated in a hybrid fiber-VLC system, which indicates that RPS with a KK receiver is a viable solution for next-generation hybrid optical wireless networks.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"38721-38733"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Localization of macroscopic sources of magnetic field using optical fibers doped with nitrogen-vacancy rich sub-micron diamonds and zero-field resonance.","authors":"Mariusz Mrózek, Adam Filipkowski, Wojciech Gawlik, Ryszard Buczyński, Adam M Wojciechowski, Mariusz Klimczak","doi":"10.1364/OE.567889","DOIUrl":"https://doi.org/10.1364/OE.567889","url":null,"abstract":"<p><p>We employ an optical fiber doped with randomly oriented fluorescent sub-micron diamonds and what we believe to be the novel zero-field resonance protocol to collect information on the localization and orientation of a magnetic-field source and its distribution. Many previous demonstrations of diamond-based magnetic field sensing achieved ultrahigh sensitivities down to the fT range warranted by manipulating spin states of the diamond nitrogen vacancy (NV) centers with externally applied radio or microwaves. The application of such oscillating fields is problematic in distributed magnetic-field measurements and may be incompatible with specific targets. Instead of relying on these approaches, we leveraged cross-relaxations of particular spin-state populations of the NV center under a magnetic field, thus observing zero-field resonances and making external radio frequency fields redundant. Combined with an optical fiber sensitive to the magnetic field along its entire length, remote sensing was realized that returned information on the spatial field distribution without using any moving mechanical elements in the detection system. Variation of the spatial parameters of the investigated field was achieved simply by controlling the current in a pair of induction coils easily integrable with optical fibers without limiting the fiber-specific functionality of the optical readout taking place at a fixed location at the optical fiber output. Lifting of the requirements related to the mechanical scanning of the fiber, the application of external fields, and the orientation of the NV centers against the measured field mark a very practical step forward in optically driven magnetic field sensing, not easily achievable with earlier implementations.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"39036-39044"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-quality polarization 3D reconstruction of weakly textured objects by fusing multi-view images.","authors":"Jintao Zhu, Luoying Peng, Hui Du, Zhiqiang Liu, Yudong Cai, Cunying Pan, Xuan Li, Xiaopeng Shao","doi":"10.1364/OE.570825","DOIUrl":"https://doi.org/10.1364/OE.570825","url":null,"abstract":"<p><p>Multi-view stereo (MVS) estimates depth by matching features across calibrated views. Though highly accurate on textured surfaces, it is prone to holes and coarse geometry in the case of weak textures or limited viewpoints. Shape-from-polarization (SfP) recovers dense normals from polarized reflections regardless of texture but causes ambiguities in angle inversion, demanding additional disambiguation. Based on these complementary strengths, this paper proposes a passive 3D reconstruction framework that fuses coarse but globally consistent depth priors from a self-attention-enhanced PatchMatch network with fine-grained normal gradients recovered from calibrated polarization measurements. These cues are incorporated into a joint optimization that improves linear consistency between depth and polarization-derived normals while applying a robust, graph-based spatial smoothness constraint to address azimuthal ambiguities and suppress outliers. The final surface is acquired by integrating the optimized normal gradient field in the Fourier domain. Experimental results on different weakly textured objects indicate that our method obtains finer details and fewer artifacts than advanced multi-view stereo and deep learning-based methods, with significantly fewer viewpoints and less computational overhead.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"38749-38763"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inverse design of topological valley-locked slow light rainbow trapper based on physics-aware latent diffusion model.","authors":"Hang Liu, Yan Ren, Rui Zhou, Ying Zhang, Hai Lin, Yanwen Wu","doi":"10.1364/OE.573199","DOIUrl":"https://doi.org/10.1364/OE.573199","url":null,"abstract":"<p><p>Valley photonic crystals (VPCs), leveraging topologically protected edge states, provide robust mechanisms for light wave manipulation and propagation. The design of VPCs primarily relies on the configuration and arrangement of the unit cell structures. In conventional structural design, the trial-and-error approach relying on prior structural templates and full-wave simulations leads to significant inefficiencies. In recent years, various inverse design algorithms have been widely adopted for structural generation. However, these methods often fail to meet the demands of multi-objective structural generation under limited physical constraints. We propose a physics-aware latent diffusion model (PALDM). This generative framework enables efficient generation of VPC unit cell structures by embedding physics-aware constraints into the latent diffusion process. Using PALDM, we designed ten different unit cell structures with parametric gradient variations. The topological slow light waveguide composed of these structures achieved slow light rainbow trapping in the topological bandgap, validating the capability of PALDM to generate VPCs with tailored frequency response. The physics-aware approach thus offers a pathway for advanced topological photonic device design.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"38628-38643"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwave pulse generation with independently tunable pulse width and repetition rate in an actively mode-locked optoelectronic oscillator driven by an amplitude-modulated signal.","authors":"Yixuan Liu, Yangxue Ma, Zhuoran Wang, Zhen Zeng, Ziwei Xu, Lingjie Zhang, Yaowen Zhang, Zhiyao Zhang, Heping Li, Yong Liu","doi":"10.1364/OE.569926","DOIUrl":"https://doi.org/10.1364/OE.569926","url":null,"abstract":"<p><p>An approach to generating microwave pulse trains with independently-tunable pulse width and repetition rate is proposed and demonstrated based on an actively mode-locked optoelectronic oscillator (AML-OEO). In this scheme, an external amplitude-modulated signal, consisting of a carrier frequency and an envelope frequency, is injected into a dual-drive Mach-Zehnder modulator (DDMZM) acting as both the modulation device and the mode-locking device in the cavity. Active mode-locking is established by setting the envelope frequency of the amplitude-modulated signal identical to an integer time of the free spectral range (FSR) in the OEO. Microwave pulses are generated at the temporal positions where the amplitude-modulated signal has the maximum absolute amplitudes. In that regard, a higher carrier frequency equal to an integer multiple of the envelope frequency corresponds to a narrower pulse width. Hence, the pulse width and the repetition rate of the microwave pulse train obtained by AML-OEO can be independently tuned through setting the carrier frequency and the envelope frequency of the amplitude-modulated signal. Both numerical simulation and experiment have been accomplished to verify the feasibility of this method. Experimental results show that microwave pulse trains with a fixed repetition rate of 179.61 kHz and tunable pulse widths in the range of 365 ns to 105 ns are generated. In addition, microwave pulse trains with an identical pulse width of 165 ns and tunable repetition rates in the range of 179.61 kHz and 359.22 kHz are generated. Furthermore, an ultra-short microwave pulse train with a pulse width of 15.7 ns and a repetition rate of 475.468 kHz is obtained, where the pulse width is only 3.94% of that from an AML-OEO driven by a sinusoidal signal under an identical repetition rate. The proposed scheme provides a path to independently control the pulse width and the repetition rate of the microwave pulse train and obtain ultra-short microwave pulse trains in an AML-OEO.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"37381-37393"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on the thickness uniformity of TiO₂ and Al₂O₃ coatings on meter-scale surfaces prepared by atomic layer deposition.","authors":"Ziyi Ge, Baoxing Xiong, Bo Zhang, Xiang Zhang, Cunding Liu, Xiao Yuan","doi":"10.1364/OE.568834","DOIUrl":"https://doi.org/10.1364/OE.568834","url":null,"abstract":"<p><p>The feasibility of the atomic layer deposition (ALD) technique for the preparation of optical films on meter-scale full-aperture optical surfaces is demonstrated with a home-built ALD apparatus. Single-layer TiO₂ and Al₂O₃ films are prepared with the apparatus. Influences of precursor dosages and substrate temperature on thickness profiles of the single-layer films are investigated. Based on the study, an area of diameter approximately 700 mm is determined experimentally on the meter-scale substrate, where both the TiO₂ and Al₂O₃ films yield typical ALD characteristics. A two-layer coating with antireflective performance at 633 nm is prepared utilizing TiO₂ and Al₂O₃ as high and low refractive index sublayers, respectively. The nonuniformity in transmittance is 0.5%, as determined from four positions from the center to the rim of the ALD region. This work develops insight into ALD thickness profiles of optical films and, therefore, is helpful for practical applications of ALD on the fabrication of optical interference coatings on large-aperture optical surfaces.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"33 18","pages":"37352-37360"},"PeriodicalIF":3.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}