Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.559616
Xu Yang, Di Wang, He Ren, Shuai Zhou, Zhile Wang, Shouqian Chen
{"title":"Optical analog cross-correlation computing for pattern recognition based on a dielectric metasurface.","authors":"Xu Yang, Di Wang, He Ren, Shuai Zhou, Zhile Wang, Shouqian Chen","doi":"10.1364/OL.559616","DOIUrl":"https://doi.org/10.1364/OL.559616","url":null,"abstract":"<p><p>Optical analog computing has been demonstrated to break the limitations of digital computation and raises a higher level of computational speed, throughput, and efficiency. The employment of optical analog computing for pattern recognition facilitates expeditious segmentation and highlighting of the target pattern from the background, to improve computing efficiency. The scheme of optical analog cross-correlation computing implemented via a dielectric metasurface has been experimentally proven to enable real-time localization and recognition of the specified target pattern at different positions. Specifically, by approximating the Fresnel diffraction process as a Fourier transform, a compact, flexible, and precise optical analog computing kernel is designed, further enhancing system integration. The kernel can be applicable to other functions of optical analog computing as well. The proposed scheme promotes the development and application of optical analog computing in optical information processing and computer vision fields, such as bio-detection and information retrieval.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3736-3739"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187521","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}
Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.559827
Boyong Zhang, Jianyuan Wang
{"title":"Wavelength-dependent tri-state waveform modulation in self-powered n-Si/Au nanoparticles/CdS heterojunction photodetectors.","authors":"Boyong Zhang, Jianyuan Wang","doi":"10.1364/OL.559827","DOIUrl":"https://doi.org/10.1364/OL.559827","url":null,"abstract":"<p><p>Photoresponse waveforms visually describe the charge carrier dynamics in a photodetector (PD) and serve as a means of conveying optical information, analogous to the photoresponse amplitude and polarity. Nevertheless, the waveforms of most photodetectors are frequently neglected due to the difficulty of distinguishing them. Herein, three distinct waveform modes are realized in a self-powered n-Si/Au nanoparticle/CdS heterojunction photodetector, corresponding to different wavelengths from the near-ultraviolet to near-infrared spectrum. This wavelength-dependent tri-state photoresponse is a selective combination of dual-polarity steady-state photocurrents and transient spike currents, which arise from the synergistic effects of several mechanisms, including selective light absorption, opposing built-in electric fields, light-induced pyroelectric effect of wurtzite CdS, and localized surface plasmon resonance of Au nanoparticles. The working principle is systematically verified, and the threshold CdS thickness for tri-state photoresponse is revealed. Notably, the unique property of wavelength-dependent tri-state photoresponse offers a pathway for RGB waveform modulation in visible light communication.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3553-3556"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187547","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}
Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.562200
Zhiyuan Liu, Haicheng Cao, Tingang Liu, Patsy A Miranda Cortez, Zixian Jiang, Kexin Ren, Na Xiao, Yi Lu, Xiao Tang, Zuojian Pan, Xiaohang Li
{"title":"2.3-<b>μ</b>m deep UV micro-LEDs fabricated by self-aligned selective thermal oxidation process.","authors":"Zhiyuan Liu, Haicheng Cao, Tingang Liu, Patsy A Miranda Cortez, Zixian Jiang, Kexin Ren, Na Xiao, Yi Lu, Xiao Tang, Zuojian Pan, Xiaohang Li","doi":"10.1364/OL.562200","DOIUrl":"https://doi.org/10.1364/OL.562200","url":null,"abstract":"<p><p>Recently, techniques for fabricating micro-sized deep ultraviolet light-emitting diodes (DUV LEDs) have been gaining attention. In this work, we propose a selective thermal oxidation (STO) process to fabricate ultra-small DUV micro-LEDs. Annealed in the air at 900°C for 2 h, the p-layers without SiO<sub>2</sub> protection are oxidized into insulating oxides, and oxygen penetrates into parts of the quantum wells. In contrast, the patterned SiO<sub>2</sub> protects the LED structure in the pixel regions. Therefore, micro-LED pixels are formed by the patterned SiO<sub>2</sub> and thermal oxidation process rather than the conventional reactive ion etching. The formed oxide in the unprotected region can function as the insulation layer between p-n electrodes. Meanwhile, the boundary between the pixel and the surrounding oxide is naturally formed during thermal oxidation, which is a \"self-aligned\" process. Dielectric deposition, precise lithography alignment, and aperture etching in the conventional process are no longer required in STO-based micro-LED fabrication, which reduces production complexity and cost. Based on the STO process, we have achieved 2.3-µm DUV micro-LED standalone pixels and arrays with a 270-nm emission wavelength. The standalone DUV micro-LED is possibly the smallest reported in the literature to date, which has a low-operation voltage of 4.9 and 6.75 V at 10 and 1000 A/cm<sup>2</sup>. Meanwhile, the fabricated DUV micro-LED arrays show leakage current density 4 × 10<sup>-7</sup> A/cm<sup>2</sup> at -5 V and a peak EQE of 0.77% under unpackaged conditions. We hope this work provides a new insight into micro-LED fabrication and further promotes future performance growth of DUV LEDs.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3628-3631"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187465","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}
Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.562195
Dongyue Sun, Shi Zhao, Mingyu Zhu, Daoxin Dai, Yaocheng Shi
{"title":"Calibration free broadband polarization-insensitive silicon optical switch.","authors":"Dongyue Sun, Shi Zhao, Mingyu Zhu, Daoxin Dai, Yaocheng Shi","doi":"10.1364/OL.562195","DOIUrl":"https://doi.org/10.1364/OL.562195","url":null,"abstract":"<p><p>We propose and demonstrate a polarization-insensitive optical switch on a 220 nm silicon-on-insulator (SOI) platform. The device utilizes a Mach-Zehnder interferometer (MZI) structure composed of an ultra-wide waveguide with nearly identical effective indices and thermo-optical coefficients for the transverse electric (TE) modes. A mode rotator based on mode hybridization facilitates the conversion between TM<sub>0</sub> and TE<sub>1</sub>. The fabricated device exhibits polarization-insensitive characteristics within the wavelength range of 1500-1600 nm, with an extinction ratio exceeding 18 dB, insertion loss below 1.9 dB, and a switching power consumption of 33.2 mW for the TE mode and 33.8 mW for the TM mode, differing by less than 2%. Additionally, the calibration power for the two polarizations is 1.0 mW and 1.7 mW, both less than 5% <b><i>P</i></b><sub><b><i><i>π</i></i></b></sub>.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3680-3683"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187473","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":"Dispersion-managed all-fiber broadband GHz fs laser at 1.0 <b>μ</b>m.","authors":"Yuke Sheng, Zihan Li, Xiaoyan Zeng, Wei Lin, Lin Ling, Zhaoheng Liang, Xuewen Chen, Yalong Liu, Fei Yang, Xiaoming Wei, Zhongmin Yang","doi":"10.1364/OL.564718","DOIUrl":"https://doi.org/10.1364/OL.564718","url":null,"abstract":"<p><p>We report on a GHz-repetition-rate dispersion-managed all-fiber mode-locked laser by exploring a fiber-type highly dispersive dielectric mirror, which results in soliton broadband mode-locking. The intracavity pulse shaping mechanism is first numerically studied to unravel the origins of the generated spectral sideband and dip-like structures. The soliton pulse generated at a low pump power (i.e., 24 mW) features a fundamental repetition rate of 1.04 GHz and a signal-to-noise ratio of 92 dB. The dispersion-managed broadband soliton pulse is experimentally compressed with a pulse duration of 188 fs. The present setup benefits from the all-polarization-maintaining (PM) fiber scheme that ensures excellent long-term stability. This dispersion-managed all-fiber broadband GHz fs fiber laser is anticipated to be a promising solution for coherent pulse stacking, optical frequency comb spectroscopy, high-speed ablation-cooled material processing, etc.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3644-3647"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187487","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}
Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.559814
Shuaipu Zang, Manman Gong, Qiulei Xu, Jiaojiao Song, Lei Wang, Lin Song Li, Huaibin Shen
{"title":"Facet oriented coupling stabilizes PbS quantum dots for infrared LEDs.","authors":"Shuaipu Zang, Manman Gong, Qiulei Xu, Jiaojiao Song, Lei Wang, Lin Song Li, Huaibin Shen","doi":"10.1364/OL.559814","DOIUrl":"https://doi.org/10.1364/OL.559814","url":null,"abstract":"<p><p>PbS quantum dots (QDs) are excellent infrared semiconductor materials for solution-processed optoelectronic devices. However, poor resistance to moisture, oxygen, and photobleaching cast a shadow over the development of optoelectronic devices based on PbS QDs. Here, we present a strategy for enhancing the stability of PbS QDs through <i>in situ</i> lead halide (PbX<sub>2</sub>, X = Cl, Br, I) induced facet coupling. The addition of PbX<sub>2</sub> ligands has been observed to effectively reduce the Stokes shift of PbS QDs with increasing atomic radius of the halide, suggesting that the PbX<sub>2</sub> ligands effectively passivate the surface of the QDs. Further analysis of the morphology and crystal facets of PbS QDs reveals that PbX<sub>2</sub> ligands can induce coupling of the (200) crystal facet. Consequently, the surface passivation and coupling of non-polar crystal facets result in the demonstration of robust resistance to moisture, oxygen, and photobleaching by PbS-PbI<sub>2</sub> QDs. No notable alterations in the absorption spectrum were discerned following exposure to UV irradiation and prolonged air exposure. Infrared LEDs based on PbS-PbX<sub>2</sub> QDs exhibited enhanced current density and achieved a maximum irradiance of 5.06 W sr<sup>-1</sup> m<sup>-2</sup>.This strategy offers a promising solution to the stability issue of infrared nanomaterials and devices.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3700-3703"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187495","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}
Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.558505
Daozheng Gong, Geneva Anderberg, Chufan Cai, Jing Chen, Patrick J La Rivière, Norbert Scherer
{"title":"Multi-scan structured illumination microscopy for rapid and efficient volumetric super-resolution imaging.","authors":"Daozheng Gong, Geneva Anderberg, Chufan Cai, Jing Chen, Patrick J La Rivière, Norbert Scherer","doi":"10.1364/OL.558505","DOIUrl":"https://doi.org/10.1364/OL.558505","url":null,"abstract":"<p><p>Structured illumination microscopy (SIM) is a widely adopted super-resolution imaging technique. Conventional 3D-SIM requires at least 15 exposures at each z-plane to achieve ∼2 × improved lateral and axial resolution. However, this requirement for a large number of exposures for \"super-resolution\" exacerbates photobleaching and slows imaging speed, thus significantly limiting its application in volumetric biological imaging. Here, we introduce multi-scan SIM (MS-SIM) that integrates a simple beam splitter for simultaneously imaging three different focal planes and a deformable mirror that enables rapid z-scanning over three contiguous sub-volumes. We demonstrate the MS-SIM system through high-quality live whole cell SIM imaging at ∼1 Hz. The high efficiency and flexibility of MS-SIM can significantly impact 3D super-resolution imaging of biological and dense colloidal systems.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3545-3548"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187516","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}
Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.553224
Chunyu Zou, Suhas P Veetil, Na Rong, Zhilong Jiang, Cheng Liu, Jianqiang Zhu
{"title":"Reference-free mode decomposition of few-mode fibers via coherent modulation imaging.","authors":"Chunyu Zou, Suhas P Veetil, Na Rong, Zhilong Jiang, Cheng Liu, Jianqiang Zhu","doi":"10.1364/OL.553224","DOIUrl":"https://doi.org/10.1364/OL.553224","url":null,"abstract":"<p><p>A comprehensive understanding of fiber modes is critical for the practical application of few-mode fibers (FMFs) in areas such as telecommunications, high-power lasers, and optical imaging. This paper introduces a single-exposure, reference-free method for mode decomposition (MD) of FMFs using coherent modulation imaging (CMI). A key advantage of the proposed method is that it requires only one experimentally captured diffraction pattern to reconstruct the complex amplitude of the optical field and perform MD, thereby eliminating the need for multiple measurements, reference beams, or complex preprocessing. To ensure accurate coordinate alignment, the method employs a simulated annealing mode projection (SAMP) algorithm. The approach achieves robust and complete MD with high precision and computational efficiency, requiring less than 2 s per mode projection analysis. Experimental results demonstrate excellent agreement between the retrieved and synthesized optical fields, with intensity correlation coefficients exceeding 0.985 across various mode distributions. This novel technique, to the best of our knowledge, simplifies experimental setups while maintaining exceptional reliability, offering significant potential for industrial and practical applications of FMFs.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3648-3651"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187527","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":"Submilliwatt silicon nitride thermo-optic phase shifter enabled by a dense sinusoidal spiral waveguide.","authors":"Jinjie Zeng, Jiaqi Li, Shuqing Lin, Xiaoqun Yu, Siyuan Yu, Yanfeng Zhang","doi":"10.1364/OL.562570","DOIUrl":"https://doi.org/10.1364/OL.562570","url":null,"abstract":"<p><p>Silicon nitride (SiN<sub><i>x</i></sub>) is an appealing material for large-scale photonic integrated circuits (PICs) due to its large transparency window, low propagation loss, and CMOS compatibility. Specifically, thermo-optic (TO) phase shifters (PSs) are crucial components for programmable circuits. However, conventional phase shifters based on silicon nitride require high power consumption, which limits their scalability. In this Letter, we experimentally demonstrate a submilliwatt phase shifter enabled by a dense sinusoidal spiral waveguide, two orders of magnitude lower than conventional devices. The dense spiral with multiple folding waveguides effectively absorbs the heat generated from the heater, therefore improving thermal efficiency and reducing power consumption. Meanwhile, waveguide cross talk within the dense spiral is suppressed by utilizing sinusoidal modulation. By further suspending the device, we achieve a submilliwatt power consumption of 0.98 mW/<i>π</i> in a 10-fold device. Additionally, the footprint of our device is 300 × 150 <b>μ</b>m<sup>2</sup>, which is more compact in length compared with conventional designs.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3768-3771"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187533","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}
Optics lettersPub Date : 2025-06-01DOI: 10.1364/OL.561464
Hongwei Zou, Shengqiang Zhong, Yili Lu, Kaibin Zeng, Fengzi Ling, Lei Xu, Yuhan Liu, Wenjie Chen, Xiantao Jiang
{"title":"Vortex beam dynamic speckle interference microscopy.","authors":"Hongwei Zou, Shengqiang Zhong, Yili Lu, Kaibin Zeng, Fengzi Ling, Lei Xu, Yuhan Liu, Wenjie Chen, Xiantao Jiang","doi":"10.1364/OL.561464","DOIUrl":"https://doi.org/10.1364/OL.561464","url":null,"abstract":"<p><p>We proposed vortex beam dynamic speckle interference microscopy (VSIM), a novel, to our knowledge, imaging technique that combines dynamic speckle illumination and common-path phase-shifting interferometry for high-resolution quantitative phase imaging. By exploiting the angular properties of perfect optical vortex beams, VSIM generates a refined speckle pattern, providing clear benefits compared to traditional coherent imaging systems. Experimental validation demonstrates that VSIM improves spatial resolution by 1.39-fold and enhances the signal-to-noise ratio (SNR) from 16.4 dB to 34.3 dB. The proposed method achieved phase modulation between the scattered light from the sample and the unscattered reference light in a robust common-path configuration, which circumvents the stringent requirements of spatial correlation in speckle field interference and effectively mitigates the effects of environmental disturbances.This approach enables high-resolution, noninvasive, and label-free phase retrieval, establishing VSIM as a reliable tool for biomedical imaging, as demonstrated with red blood cells (RBCs) and A549 cells in this paper.</p>","PeriodicalId":19540,"journal":{"name":"Optics letters","volume":"50 11","pages":"3676-3679"},"PeriodicalIF":3.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187546","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}