{"title":"Digital full-complex hologram compression based on Quad-tree Fresnelet","authors":"Dong-Wook Kim, Young-Ho Seo","doi":"10.1016/j.optcom.2025.132157","DOIUrl":"10.1016/j.optcom.2025.132157","url":null,"abstract":"<div><div>With advancements in 3D technology, digital holography is emerging as a promising next-generation 3D solution. This study presents a compression method that applies quantization to each subband in the frequency domain, derived from Fresnelet-transformed digital holograms, coupled with lossless Huffman coding. Exceptionally high-value, low-frequency coefficients are transmitted unquantized using exception indices, improving image quality by approximately 2 dB despite a slight decrease in compression rate. Experiments with a custom quantizer demonstrate a compression ratio of about 30:1, achieving a PSNR of roughly 35 dB, confirming the method’s effectiveness in balancing compression efficiency and image fidelity.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132157"},"PeriodicalIF":2.2,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Dakshin Tillo, V. Abhijith Tej, Dileep K., J. Solomon Ivan
{"title":"Post processing free random number generation using classical and ambient light sources","authors":"Dakshin Tillo, V. Abhijith Tej, Dileep K., J. Solomon Ivan","doi":"10.1016/j.optcom.2025.132199","DOIUrl":"10.1016/j.optcom.2025.132199","url":null,"abstract":"<div><div>Generation of unbiased random numbers using classical light sources is presented. Bit assignment is based on detecting odd and even number of photons in a time interval, with odd detection assigned bit value ‘0’ and even detection assigned bit value ‘1’. The effect of dead time on the detected number photons for varying incoming photon rates is studied numerically. Random number generation is experimentally demonstrated on the classical sources<!--> <!-->: laser, laser diode, light emitting diode, ambient room light, and ambient sunlight, for varying incoming photon rates, using a single photon avalanche diode. The generated random numbers are shown to successfully pass the NIST statistical suite with a significance level of 0.01, without any requirement for post processing.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132199"},"PeriodicalIF":2.2,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Marko M. Krstić, Stefana D. Bogojević, Jasna V. Crnjanski, Dejan M. Gvozdić
{"title":"Design and spectral shaping of optical frequency combs using gain-switched cascade of a semiconductor laser and optical amplifier","authors":"Marko M. Krstić, Stefana D. Bogojević, Jasna V. Crnjanski, Dejan M. Gvozdić","doi":"10.1016/j.optcom.2025.132194","DOIUrl":"10.1016/j.optcom.2025.132194","url":null,"abstract":"<div><div>In this paper, we present a simple optical frequency comb generation technique based on the optimized structure consisting of a gain-switched DFB laser and reflective semiconductor optical amplifier cascade. Bias currents of the two devices are tailored as multi-harmonic waveforms, using a meta-heuristic algorithm optimization for maximizing the number of comb lines with flatness within 3 dB margin. We report flat-top comb bandwidths in range from 125 to 171 GHz, with up to 29 comb lines and free spectral range tunability from 5 to 12.5 GHz.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132194"},"PeriodicalIF":2.2,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"All-optical switching based on symmetric hybrid microcavities of whispering-gallery and nanobeam modes","authors":"Yanhui Zhao , Can Zhang , Weining Qian , Shuo Cao","doi":"10.1016/j.optcom.2025.132189","DOIUrl":"10.1016/j.optcom.2025.132189","url":null,"abstract":"<div><div>Conventional all-optical switches rely on nonlinear effects that require high pump intensities, limiting their efficiency and integration potential. Here, we propose theoretically and demonstrate numerically a linear all-optical switch utilizing hybrid symmetry in a system with whispering-gallery modes (WGMs) coupled to a nanobeam cavity. Through phase-controlled selective excitation of symmetric or antisymmetric WGMs, we can control the coupling of these modes with the nanobeam cavity, enabling light emission or inhibition. Temporal coupled mode theory and Finite-Difference Time-Domain (FDTD) simulations confirm multifunctional logic gate operations and ultrafast switching with arbitrarily low energy consumption, high contrast, and picosecond switching times. Moreover, the switching time can be dynamically tuned by adjusting the control light’s pulse duration. Interestingly, reducing the mode quality factor accelerates the switching speed, which eases experimental implementation. The proposed architecture offers a simplified, energy-efficient and flexible solution for integrated photonic circuits, combining robust performance with experimental feasibility through relaxed fabrication tolerances.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132189"},"PeriodicalIF":2.2,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144663002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Siyu Bai , Yibin Li , Syed Agha Hassnain Mohsan , Qian Li , H.Y. Fu
{"title":"Receiver-side LSBoost-Aided constellation denoising for energy-efficient VLC systems","authors":"Siyu Bai , Yibin Li , Syed Agha Hassnain Mohsan , Qian Li , H.Y. Fu","doi":"10.1016/j.optcom.2025.132218","DOIUrl":"10.1016/j.optcom.2025.132218","url":null,"abstract":"<div><div>Low-resolution digital-to-analog converters (DACs) have emerged as promising components for visible light communication (VLC) systems, owing to their low power consumption and reduced hardware cost. However, ultra-low-resolution quantization introduces significant signal distortion and limits the achievable modulation formats, particularly in high-speed optical wireless links. In this work, we experimentally demonstrate a receiver-side Least Squares Boosting Constellation Denoiser (LSBCD) designed for asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) VLC systems utilizing low-resolution DACs over a 1-m free-space optical (FSO) link. With standard round-off (RO) quantization, the baseline system supports at most 32-QAM at 4-bit resolution and fails to reach the hard-decision forward error correction (HD-FEC) threshold at 3-bit resolution. While transmitter-side digital resolution enhancer (DRE) techniques can reduce quantization noise and enable higher-order modulation formats (such as 64-QAM at 4-bit), they require additional hardware complexity and transmitter modifications. By contrast, the proposed LSBCD module at the receiver is designed to achieve comparable performance gains with significantly lower computational and implementation complexity. At a symbol rate of 0.75 GBaud, our experimental results show that LSBCD enables reliable 32-QAM transmission using a 3-bit DAC, reducing the bit error rate (BER) from 0.0108 to 0.0033. For 64-QAM with a 4-bit DAC, LSBCD further lowers the BER from 0.0072 to 0.0023, matching or surpassing DRE-based improvements. These findings validate that LSBCD is highly suitable for short-range VLC scenarios. Overall, our research offers a practical and energy-efficient pathway to improve performance in low-resolution OFDM-based VLC systems. The fully receiver-side, modular nature of LSBCD supports flexible integration into future large-scale VLC networks and IoT-oriented optical wireless communication systems, meeting the evolving requirements for cost, scalability, and adaptability in next-generation smart environments.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132218"},"PeriodicalIF":2.2,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144663006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Compact design for robust tip-enhanced nano-spectroscopy in ambient conditions","authors":"Jonggeun Hwang , Yeonjeong Koo , Sehwa Jeong , Yung Doug Suh , Kyoung-Duck Park","doi":"10.1016/j.optcom.2025.132181","DOIUrl":"10.1016/j.optcom.2025.132181","url":null,"abstract":"<div><div>Nano-spectroscopy and -imaging based on scanning probe microscopy, such as tip-enhanced photoluminescence and tip-enhanced Raman spectroscopy, allow us to investigate various quantum materials with a spatial resolution of <span><math><mo><</mo></math></span>10 nm. Although the correlation between topography and nano-spectroscopic response provides distinct material information compared to other optical measurement methods, acquiring high-speed and high-resolution nano-spectroscopic images under ambient conditions remains challenging. One major obstacle is the drift between optical and mechanical components, which causes image distortion and decoupling between the tip and excitation laser, thereby limiting the precision of near-field information. Here, we present a compact design for a homebuilt tip-enhanced nano-spectroscopy system and demonstrate its building with pre-characterization results. The setup is based on an atomic force microscope utilizing a quartz tuning fork as a force sensor. Its compact 6 cm-sized body provides ample space for optical access. This design achieves a low lateral drift rate between the tip and sample, measured at less than 0.65 nm/min, enabling stable nano-spectroscopic measurements of various quantum materials.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132181"},"PeriodicalIF":2.2,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144663001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Xu Geng , Xude Wang , Xu Zhang , Yuexin Li , Zheng Lv , Xiaoping Lou , Lianqing Zhu
{"title":"Dual-mode pulse complexes consisting of dissipative solitons and noise-like pulses in a passively mode-locked fiber laser","authors":"Xu Geng , Xude Wang , Xu Zhang , Yuexin Li , Zheng Lv , Xiaoping Lou , Lianqing Zhu","doi":"10.1016/j.optcom.2025.132212","DOIUrl":"10.1016/j.optcom.2025.132212","url":null,"abstract":"<div><div>In a passively mode-locked Er-doped fiber laser (PMLEDFL) based on nonlinear polarization rotation (NPR), a dual-mode pulse complex (DMPC) is introduced to describe the symbiotic coexistence of dissipative soliton (DS) and noise-like pulse (NLP). The DMPCs exhibiting reversible temporal orderings or containing DS pairs are captured by using the dispersive Fourier transform (DFT) technique. Its physical mechanism is attributed to a delicate balance between repulsive and attractive forces among pulses, resulting from the complex interplay of significant nonlinear effects, dispersion, gain and loss. The experimental results are further verified by the numerical simulations. To the best of our knowledge, this is the first time that DMPC consisting of DS and NLP has been analyzed in detail using DFT technique. This work will help to complement our understanding of multi-pulse dynamics and provide new insights into the dynamic phenomenon of nonlinear optical systems.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132212"},"PeriodicalIF":2.2,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Spin angular momentum of femtosecond striped space-time surface plasmon polaritons","authors":"Kotaro Kihara , Kei Motoi , Naoki Ichiji , Atsushi Kubo","doi":"10.1016/j.optcom.2025.132217","DOIUrl":"10.1016/j.optcom.2025.132217","url":null,"abstract":"<div><div>Surface-bound electromagnetic waves, such as surface plasmon polaritons (SPPs), carry transverse spin angular momentum (SAM) oriented perpendicular to their propagation direction. In ideal monochromatic plane waves, this transverse SAM arises from spatial gradients in the energy flow density and remains confined to the in-plane component. However, when the surface field has a spatial structure, the additional gradient along the in-plane direction gives rise to an out-of-plane SAM component, allowing the spin vector to attain a fully three-dimensional orientation. In this study, we investigate the three-dimensional spin texture of striped space-time SPPs (ST-SPPs)—structured SPP wave packets generated by optical pulses with transverse spatial periodicity and temporal confinement along the propagation axis. Through numerical simulations, we analyze how the SAM texture depends on the transverse periodicity of striped ST-SPPs. Our results reveal that varying the transverse period alters the balance between in-plane and out-of-plane field gradients inherent to SPPs, enabling the emergence of qualitatively distinct spin structures via periodicity control. A comparison between the simulated electric fields and experimentally observed near-field patterns—obtained using two-photon fluorescence microscopy—validates our theoretical model. These findings indicate that striped ST-SPPs offer a versatile platform for robust SAM control on metallic surfaces, with promising applications in chiral-sensitive molecular spectroscopy and surface-bound molecular manipulation.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132217"},"PeriodicalIF":2.2,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144663007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Imperfect preparation and Trojan attack on the phase modulator in the decoy-state BB84 protocol","authors":"Aleksei Reutov","doi":"10.1016/j.optcom.2025.132175","DOIUrl":"10.1016/j.optcom.2025.132175","url":null,"abstract":"<div><div>Quantum key distribution (QKD) provides a theoretically secure method for cryptographic key exchange by leveraging quantum mechanics, but practical implementations face vulnerabilities such as Trojan attack on phase modulators. This work analyzes the security of QKD systems under such attacks, considering both ideal and imperfect state preparation scenarios. The Trojan attack model is generalized to arbitrary states of probing pulses and conservative bounds of information leakage through side-channel of special form are introduced. The quantum coin imbalance, a critical security parameter, remains low (on the order of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>7</mn></mrow></msup></mrow></math></span> for ideal state preparation and <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span> for imperfect preparation) with this new approach and presence additional hardware passive countermeasures. Numerical simulations confirm nonzero secure key rate at distances over 100 km through optical fiber channel.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"593 ","pages":"Article 132175"},"PeriodicalIF":2.2,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144663005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Soukaina Sabsi , Fatima Zohra Harroui , Mohammed Elaouni , Ossama El Abouti , Tarik Mrabti , Madiha Amrani , Soufyane Khattou , Afaf Bouzidi , El Houssaine El Boudouti , Bahram Djafari-Rouhani
{"title":"Temperature sensor based on topological edge states in one-dimensional photonic crystals with a superconductor cavity","authors":"Soukaina Sabsi , Fatima Zohra Harroui , Mohammed Elaouni , Ossama El Abouti , Tarik Mrabti , Madiha Amrani , Soufyane Khattou , Afaf Bouzidi , El Houssaine El Boudouti , Bahram Djafari-Rouhani","doi":"10.1016/j.optcom.2025.132180","DOIUrl":"10.1016/j.optcom.2025.132180","url":null,"abstract":"<div><div>In this study, we investigate topological edge states (TES) arising at the interface of two distinct one-dimensional topological photonic crystals (1D-TPhCs) with a superconducting layer at the interface, designed for high-performance sensing. To investigate the optical properties and topological edge states of the proposed structure, both the transfer matrix method (TMM) and the finite element method (FEM) were used. The TES and the sensitivity induced by the proposed structure strongly depend on the thickness of the superconducting layer, the polarization of the waves, and the number of periods. The proposed structure exhibits exceptional performance, with a sensitivity S <span><math><mrow><mo>=</mo><mn>0</mn><mo>.</mo><mn>55</mn></mrow></math></span> nm/K, a quality factor Q <span><math><mrow><mo>=</mo><mn>1368</mn><mo>.</mo><mn>02</mn></mrow></math></span>, and a figure of merit FOM <span><math><mrow><mo>=</mo><mn>0</mn><mo>.</mo><mn>4074</mn></mrow></math></span>/K, making it a promising candidate for ultra-sensitive temperature detection in photonic sensor applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132180"},"PeriodicalIF":2.2,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}