ACS PhotonicsPub Date : 2025-09-25DOI: 10.1021/acsphotonics.5c01334
Aiman Zinaoui, , , Martin Khouri, , , Jean-David Fayssaud, , , Arthur De Sousa Lopes Moreira, , , Miguel Angel Suarez, , , Samuel Queste, , , Laurent Robert, , , Ludovic Gauthier-Manuel, , , Mathieu Chauvet, , and , Nadège Courjal*,
{"title":"A LiNbO3 Platform with Tailored Thickness Bridging Bulk and Thin Film: Application to Broadband Frequency Conversion","authors":"Aiman Zinaoui, , , Martin Khouri, , , Jean-David Fayssaud, , , Arthur De Sousa Lopes Moreira, , , Miguel Angel Suarez, , , Samuel Queste, , , Laurent Robert, , , Ludovic Gauthier-Manuel, , , Mathieu Chauvet, , and , Nadège Courjal*, ","doi":"10.1021/acsphotonics.5c01334","DOIUrl":"10.1021/acsphotonics.5c01334","url":null,"abstract":"<p >We introduce a monolithic LiNbO<sub>3</sub> membrane platform that bridges bulk and thin-film approaches, enabling custom-tailored waveguide cross sections. Using a combination of saw dicing and reactive ion etching (RIE), we fabricate LiNbO<sub>3</sub> structures with adaptable thicknesses ranging from 400 nm to several microns, identifying 2 μm as an optimal value for addressing key challenges in frequency conversion. Our platform demonstrates robust second harmonic generation (SHG) with a broad pump wavelength response of up to 150 nm within the C-band at room temperature, achieved by tuning the waveguide thickness, while maintaining low coupling losses of 0.8 dB/facet. These results represent a significant step toward versatile integrated photonic systems, advancing applications in broadband spectroscopy, quantum information processing, and sensing through efficient and spectrally agile nonlinear frequency conversion.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5614–5622"},"PeriodicalIF":6.7,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145140744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Non-Hermitian Low-Power On-Chip Thermal Modulators Operating Off Exceptional Points","authors":"Youhe Li, , , Zhaoyan Zhou, , , Kaixin Han, , , Wei Xu, , , Jianfa Zhang, , , Jipeng Xu*, , and , Zhihong Zhu*, ","doi":"10.1021/acsphotonics.5c01286","DOIUrl":"10.1021/acsphotonics.5c01286","url":null,"abstract":"<p >As a ubiquitous and economical integrated photonics element, thermal microring resonator (TMRR) modulators play a pivotal role in on-chip communication, computing, and storage. To improve modulation efficiency and reduce power consumption, conventional approaches rely on increasing thermo-optic frequency shifts, which are inherently constrained by material selections and structural designs. Recent advances in non-Hermitian photonics have demonstrated that mode splitting can be boosted at or near the exceptional points (EPs). However, in purely passive structures, the enhanced response is often overwhelmed by the bandwidth broadening and becomes unresolvable. Here, by restricting the heating zone of TMRRs to the nanoscale to magnify the backscattering-induced frequency splitting, we find that the modulation efficiency improves significantly. Furthermore, by introducing another defect-type scatterer to create additional non-Hermiticity, while operating off the EPs, we theoretically and numerically verify an entirely well-resolved 64.2% enhancement in total frequency shift efficiency. Our method synergizes Hermitian and non-Hermitian designs, enriching the functionality of non-Hermitian devices and offering a viable pathway toward high-efficiency, energy-saving integrated optics.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5586–5593"},"PeriodicalIF":6.7,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145140743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
ACS PhotonicsPub Date : 2025-09-25DOI: 10.1021/acsphotonics.5c01192
Shruti Sundar, , , Marakkarakath Vadakkepurayil Jabir, , , Lukas Glandorf, , , Maria Eleni Karakatsani, , , Michael Reiss, , , Ruiqing Ni, , and , Daniel Razansky*,
{"title":"Discerning Amyloid-β and Tau Pathologies with Learning-Based Quantum Sensing","authors":"Shruti Sundar, , , Marakkarakath Vadakkepurayil Jabir, , , Lukas Glandorf, , , Maria Eleni Karakatsani, , , Michael Reiss, , , Ruiqing Ni, , and , Daniel Razansky*, ","doi":"10.1021/acsphotonics.5c01192","DOIUrl":"10.1021/acsphotonics.5c01192","url":null,"abstract":"<p >Photon entanglement, a key feature of quantum correlations, provides a level of coherence absent in classical correlations, potentially offering new information when interacting with biological matter. One promising application is using entanglement decoherence to distinguish between healthy and diseased samples. However, achieving this requires efficient entangled photon sources capable of surviving through biological samples for reliable detection. In this work, we show the applicability of a polarization-entangled photon source as a label-free diagnostic tool for distinguishing between transgenic mouse models of amyloidosis and tauopathy and their respective control strains. We investigated cortical and hippocampal regions of these models, and our findings revealed greater preservation of entanglement in the transgenic samples compared to controls. To further enhance classification accuracy, we employed a supervised machine learning approach, achieving reliable distinctions between disease and control groups in unseen test samples. The quantum-based results were further validated through confocal imaging of the transgenic and control samples. These findings suggest that quantum sensing could serve as a label-free approach for distinguishing biological samples, with potential applications in the study of neurodegenerative disorders.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5510–5521"},"PeriodicalIF":6.7,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acsphotonics.5c01192","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145133875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dislocation-Free InGaN Nanoscale Light-Emitting Diode Pixels on Single-Crystal GaN Substrates","authors":"Nirmal Anand, , , Sadat Tahmeed Azad, , , Christy Giji Jenson, , , Dipon Kumar Ghosh, , , Md. Zunaid Baten, , , Pei-Cheng Ku, , , Grzegorz Muziol, , and , Sharif Md. Sadaf*, ","doi":"10.1021/acsphotonics.5c01349","DOIUrl":"10.1021/acsphotonics.5c01349","url":null,"abstract":"<p >Indium gallium nitride (InGaN) quantum well (QW) micro- and nanoscale light-emitting diodes (LEDs) are promising for next-generation ultrafast optical interconnects and augmented/virtual reality displays. However, scaling to nanoscale dimensions presents significant challenges including enhanced nonradiative surface recombination, defect and/or dislocation-related emission degradation, and nanoscale pixel contact formation. In this work, we demonstrate strain-engineered nanoscale blue LED pixels fabricated via top-down nanostructuring of an all-InGaN quantum well/barrier heterostructure grown by plasma-assisted molecular beam epitaxy (PAMBE) on significantly low dislocation-density single-crystal GaN substrates (in the order of ∼10<sup>5</sup>–10<sup>6</sup> cm<sup>–2</sup>; 2 to 3 orders of magnitude lower than commercial GaN/Sapphire templates). Sidewall passivation using atomic layer deposition (ALD) of Al<sub>2</sub>O<sub>3</sub> enables excellent diode behavior, including a rectification ratio >10<sup>4</sup> between −5 V and +5 V and extremely low reverse leakage (∼0.01 A/cm<sup>2</sup> at −10 V). Monte Carlo analyses suggest almost 100% yield of completely dislocation-free active regions for ∼450 nm nanopixels. Electroluminescence measurements show bright blue emission with a peak external quantum efficiency (EQE) of 0.46% at ∼1.2 kA/cm<sup>2</sup>. Poisson–Schrödinger simulations reveal ∼20% strain relaxation in the QW, effectively mitigating the quantum-confined Stark effect (QCSE). Additionally, finite-difference time-domain (FDTD) simulations confirm that the nanoscale geometry enhances light extraction efficiency by over 40% compared to planar designs, independent of substrate materials. These results establish a scalable pathway for dislocation-free, high-brightness InGaN μLED arrays suitable for advanced display and photonic systems.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5639–5648"},"PeriodicalIF":6.7,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145140829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 Noncooperative Target Ranging at the Single-Photon Level Based on Dual-Comb Asynchronous Optical Sampling","authors":"Qiong Niu, , , Linghui Yang*, , , Youjian Song, , , Shuo Yang, , , Senmiao Han, , , Peipei Tian, , , Jingyi Zhang, , and , Jigui Zhu, ","doi":"10.1021/acsphotonics.5c00452","DOIUrl":"10.1021/acsphotonics.5c00452","url":null,"abstract":"<p >In the field of high-precision, large-scale equipment manufacturing and assembly, it is important to achieve high-precision distance and topography measurements of noncooperative targets with complex topography. However, ensuring a high measurement accuracy under a weak echo remains challenging. Here, a high-precision noncooperative target ranging method based on single-photon frequency up-conversion detection is proposed, which combines time-correlated single-photon counting and dual-comb asynchronous optical sampling. By introducing a silicon-based single-photon avalanche photodetector with photon-level responsivity, the low signal-to-noise ratio problem caused by the low frequency conversion efficiency in the intensity cross-correlation process is overcome, and fast, high-precision absolute ranging is achieved with a large range in ambient illumination conditions and weak echo at the single-photon level. Additionally, it has a high detection sensitivity, precision, and robustness for noncooperative targets with different roughness values at different incidence angles and different acquisition times, as well as the capacity to resolve multiple targets. Specifically, for a positive aluminum oxide plate, the standard deviation of 20 measurements is better than 1.5 μm, and the linearity is within 2 μm. Furthermore, the proposed method has potential application prospects in the fabrication of single-photon LiDAR and three-dimensional profiling measurement with micrometer precision.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5352–5364"},"PeriodicalIF":6.7,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145140741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Spectrally Tunable Reflectance with Invariant Transmittance via Weakly Coupled Dual Cavities","authors":"Cheolhun Kang, , , Seongcheol Ju, , , Incheol Jung, , , Dohyun Kim, , , Donggyu Lim, , , Hui Joon Park*, , , Jaewon Choi*, , and , Kyu-Tae Lee*, ","doi":"10.1021/acsphotonics.5c01767","DOIUrl":"10.1021/acsphotonics.5c01767","url":null,"abstract":"<p >Weakly coupled dual cavities (WCDCs) are demonstrated to enable adjustable reflectance while maintaining invariant transmittance, capabilities that surpass those of conventional thin-film optical coatings. The structure consists of two vertically stacked optical cavities sharing a thin metallic interlayer: the upper cavity comprises a lossy metal, a transparent dielectric, and a reflective metal, while the lower cavity is formed by sandwiching a transparent dielectric between two highly reflective metals. While both cavities influence the reflectance, the transmittance is predominantly governed by the lower cavity. Comprehensive analyses of cavity thicknesses, coupling strength, and interference conditions reveal how spectral reflectance profiles can be tailored without altering the overall transmittance. To the best of our knowledge, this decoupled spectral behavior, tunable reflectance with fixed transmittance, is experimentally demonstrated here for the first time. Experimental demonstrations using three devices with varying upper cavity thicknesses confirm this tunability, showing consistent transmittance and markedly different reflectance spectra. These findings deepen our understanding of optical interference in multilayer structures and highlight the versatility of this design approach for a wide range of applications, including transflective displays, holography, optical isolation, and information encryption.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5799–5805"},"PeriodicalIF":6.7,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145140828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Advances in Fiber Optic Surface-Enhanced Raman Spectroscopy Sensors","authors":"Junyu Wei, , , Yibin Liu, , , Minghui Niu, , , Weihao Lin, , , Chenlong Xue, , , Jiaqi Hu, , , Jinqian Lv, , , Jie Hu, , , Liyang Shao, , , Guanghui Wang, , , Yanan Zhang, , , Shuwen Zeng, , , Georges Humbert, , , Yu Zheng*, , , Gina Jinna Chen*, , and , Perry Ping Shum*, ","doi":"10.1021/acsphotonics.5c00111","DOIUrl":"10.1021/acsphotonics.5c00111","url":null,"abstract":"<p >Surface-enhanced Raman spectroscopy (SERS) is a highly specific and sensitive analytical technique that identifies molecules by amplifying Raman fingerprints through electromagnetic (EM) and chemical (CM) enhancement mechanisms. When SERS is integrated with microstructured optical fibers, the resulting fiber optic SERS sensors extend the applications for in vivo and in situ analysis. This Review discusses recent advancements in fiber optic SERS sensors. It focuses on the additional Raman signal enhancement achieved through specialty optical fibers, their interaction with SERS active materials, and the corresponding sensing systems. We also highlight the unique advantages, such as enhanced sensitivity, remote sensing capability, and challenges including stability, reproducibility, and background noise. Finally, we discuss the technical development trends, provide an overview of fiber optic SERS sensor applications in liquid-, gas-, and solid-phase analytes, and propose future research directions to overcome current limitations.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5312–5344"},"PeriodicalIF":6.7,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145140963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
ACS PhotonicsPub Date : 2025-09-24DOI: 10.1021/acsphotonics.5c01783
Diana Pereira, , , Torsten Wieduwilt, , , Marta S. Ferreira, , and , Markus A. Schmidt*,
{"title":"On-Fiber 3D Nanoprinted Antiresonant Hollow-Core Waveguides for Integrated Optofluidics","authors":"Diana Pereira, , , Torsten Wieduwilt, , , Marta S. Ferreira, , and , Markus A. Schmidt*, ","doi":"10.1021/acsphotonics.5c01783","DOIUrl":"10.1021/acsphotonics.5c01783","url":null,"abstract":"<p >Guiding light in hollow cores represents a major research direction in modern fiber optics, enabling numerous transformative applications. However, structural and fabrication constraints have hindered the implementation of such waveguides in planar platforms, limiting their wide-range application. In this study, we present a new class of high-quality, fiber-integrated hollow-core waveguide that directly adapt the antiresonant guiding mechanism from fiber technology to planar waveguide technology using 3D nanoprinting. By directly fabricating record-high aspect ratio waveguides on fiber end faces, a seamless photonic integration with enhanced optical performance, including polarization-independent transmission and substantially reduced losses is achieved. The approach is supported by strong agreement between experimental results, numerical simulations, and analytical modeling. The relevance of the fiber-inspired platform in the context of optofluidics has been demonstrated by high-precision refractive index sensing and dye-related absorption spectroscopy. These results highlight the potential of the approach to serve as a compact, versatile platform for advanced fiber-based systems in biomedicine, quantum optics, and environmental monitoring.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5788–5798"},"PeriodicalIF":6.7,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145133876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Photon Emission Gain in Er-Doped Si Light-Emitting Diodes by Impact Excitation","authors":"Huayou Liu, , , Jiayuan Zhao, , , Jing Zhang, , , Huan Liu, , , Jiajing He, , , Ulrich Kentsch, , , Shengqiang Zhou, , , Manfred Helm, , and , Yaping Dan*, ","doi":"10.1021/acsphotonics.5c01769","DOIUrl":"10.1021/acsphotonics.5c01769","url":null,"abstract":"<p >This work demonstrates photon emission gain, i.e., emission of multiple photons per injected electron, through impact excitation in Er-doped silicon light-emitting diodes (LEDs). Conventional methods for exciting Er ions in silicon suffer from low efficiency due to mismatched energy transfer between exciton recombination and Er excitation. Here, we propose a reverse-biased Si PN junction diode, where ballistically accelerated electrons induce inelastic collisions with Er ions, enabling tunable excitation via electric field modulation. Theoretical modeling reveals that photon emission gain arises from multiple impact excitations by a single electron traversing the electroluminescence region, with the gain value approximating the ratio of emission region width to electron mean free path, i.e., <i>G</i> = <i>L</i><sub>ex</sub>/<i></i><math><mi>l</mi></math>. Experimental results show an internal quantum efficiency (IQE) of 1.84% at 78 K, representing a 20-fold enhancement over the room-temperature performance. This work provides a critical foundation for on-chip integration of silicon-based communication-band lasers and quantum light sources.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5782–5787"},"PeriodicalIF":6.7,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145116712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
ACS PhotonicsPub Date : 2025-09-22DOI: 10.1021/acsphotonics.5c01464
Yahel Soffer, and , Dan Oron*,
{"title":"Single Pulse Coherent Anti-Stokes Raman Super-Resolved Image Scanning Microscopy","authors":"Yahel Soffer, and , Dan Oron*, ","doi":"10.1021/acsphotonics.5c01464","DOIUrl":"10.1021/acsphotonics.5c01464","url":null,"abstract":"<p >We demonstrate super-resolved coherent vibrational imaging based on single-pulse Coherent Anti-Stokes Raman Scattering (CARS) combined with Image Scanning Microscopy (ISM), enabling label-free vibrational imaging beyond the diffraction limit. As required for coherent imaging, and unlike conventional ISM applied to fluorescence or spontaneous Raman signals, we perform pixel reassignment on the complex optical field rather than the intensity, accounting for the interference-based nature of coherent imaging. In contrast with previous implementations of coherent ISM, here we do not rely on the use of interferometry with an external reference, but rather utilize the intrinsic nonresonant background as reference, while a programmable pulse shaper enables spectral-phase interferometry between the resonant and nonresonant components of the CARS field. After retrieving both the amplitude and the phase of the resonant CARS signal, we apply coherent ISM to achieve resolution enhancement in chemically specific imaging. This technique opens new avenues for high-speed, label-free super-resolved vibrational microscopy and especially for its extension to the low-frequency spectral range and to an implementation in a backscattering geometry.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 10","pages":"5697–5704"},"PeriodicalIF":6.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acsphotonics.5c01464","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145116714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}