Applied Physics BPub Date : 2026-04-11DOI: 10.1007/s00340-026-08671-8
Ludovica Appignani, Peter Tidemand-Lichtenberg, Lasse Høgstedt, Søren Michael Mørk Friis, Christian Pedersen
{"title":"CW and self-pulsating operation of a Tm:YLF 1.91 μm hemispherical laser","authors":"Ludovica Appignani, Peter Tidemand-Lichtenberg, Lasse Høgstedt, Søren Michael Mørk Friis, Christian Pedersen","doi":"10.1007/s00340-026-08671-8","DOIUrl":"10.1007/s00340-026-08671-8","url":null,"abstract":"<div><p>2 μm lasers are widely employed in LIDAR systems, photomedicine, and as pump sources for OPOs and mid-IR lasers. Tm:YLF is an optimal laser crystal for a 2 μm laser owing to its good mechanical properties, a negative thermo-optic coefficient, and intrinsic birefringence supporting polarized emission. However, many 2 μm lasers have been reported to exhibit unstable operation with a tendency towards self-pulsation (SP). In this paper, we investigate design parameters influencing the temporal output of a compact diode-laser pumped Tm:YLF 1.91 μm laser for stable continuous-wave (CW) and self-pulsating operation. Different sources of perturbation are discussed as main causes for SP. We introduce a novel pulse attenuation parameter, <span>(delta )</span>, to assess laser stability. We report optical-to-optical slope efficiencies of 35% and 41.5% in stable CW and SP operation, respectively.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08671-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-04-09DOI: 10.1007/s00340-026-08669-2
Lyubomir I. Stoyanov, Maria Mincheva, Aleksander Stefanov, Ivan Stefanov, Alexander Dreischuh
{"title":"Single-shot polarization mapping of optical elements introducing spatially varying birefringence","authors":"Lyubomir I. Stoyanov, Maria Mincheva, Aleksander Stefanov, Ivan Stefanov, Alexander Dreischuh","doi":"10.1007/s00340-026-08669-2","DOIUrl":"10.1007/s00340-026-08669-2","url":null,"abstract":"<div>\u0000 \u0000 <p>Polarization mapping plays a key role in modern photonics, as many advanced optical applications, ranging from vector beam engineering to optical communication and material characterization, rely on precise knowledge of spatial polarization distributions. However, conventional mapping techniques often suffer from limitations such as multi-step measurements, sensitivity to misalignment, or the need for bulky setups, making single-shot and high-resolution polarization mapping particularly challenging. Here, we report a single-shot polarization mapping technique for parallel determination of the polarization change introduced by an unknown optical birefringent element or even device (e.g. <i>q</i>-plates, spatial light modulators). To achieve this, we used a 9<span>(times )</span>9 array of linearly polarized probe sub-beams to capture spatially resolved polarization information in a single measurement, allowing the two-dimensional polarization distribution to be reconstructed from just one data acquisition step. In this way, the measurement time is reduced while high spatial resolution is preserved. To demonstrate the robustness of the technique, we present a measurement with commercially available polarizing vortex plates, which convert linearly polarized light into radially or azimuthally polarized light, and the determination of the polarization response of a commercially available spatial light modulator. The main advantage of the method is its simplicity, achieved without sacrificing efficiency, which makes it readily accessible to any laboratory.</p>\u0000 </div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08669-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-04-08DOI: 10.1007/s00340-026-08645-w
Ganesh M. Balasubramaniam, Srinivasa Rao Allam, Vijayakumar Anand, Md. Haider Ansari, Francis Gracy Arockiaraj, Shlomi Arnon, Purnesh Singh Badavath, Mansi Baliyan, Petr Bouchal, Zdeněk Bouchal, Sakshi Choudhary, Ahmed H. Dorrah, Yuxiang Duan, Kelsey Everts, Andrew Forbes, Matthew R. Foreman, Darius Gailevičius, Akanksha Gautam, Greg Gbur, Shivasubramanian Gopinath, Narmada Joshi, Saulius Juodkazis, Olga Korotkova, Kaupo Kukli, Judy Kupferman, Praveen Kumar, Ravi Kumar, Vijay Kumar, Gokul Manavalan, Ayush Mehra, Naveen K. Nishchal, Takashige Omatsu, Cade Peters, Andra Naresh Kumar Reddy, Salla Gangi Reddy, Valeria Rodríguez-Fajardo, Carmelo Rosales-Guzmán, Joseph Rosen, Sarita, Allarakha Shikder, Rakesh Kumar Singh, Xinzhou Su, Aile Tamm, Ganesh Velagala, Petr Viewegh, Eulàlia Puig Vilardell, Alan E. Willner, Agnes Pristy Ignatius Xavier, Amit Yadav, Huibin Zhou
{"title":"Roadmap on singular optics and its applications","authors":"Ganesh M. Balasubramaniam, Srinivasa Rao Allam, Vijayakumar Anand, Md. Haider Ansari, Francis Gracy Arockiaraj, Shlomi Arnon, Purnesh Singh Badavath, Mansi Baliyan, Petr Bouchal, Zdeněk Bouchal, Sakshi Choudhary, Ahmed H. Dorrah, Yuxiang Duan, Kelsey Everts, Andrew Forbes, Matthew R. Foreman, Darius Gailevičius, Akanksha Gautam, Greg Gbur, Shivasubramanian Gopinath, Narmada Joshi, Saulius Juodkazis, Olga Korotkova, Kaupo Kukli, Judy Kupferman, Praveen Kumar, Ravi Kumar, Vijay Kumar, Gokul Manavalan, Ayush Mehra, Naveen K. Nishchal, Takashige Omatsu, Cade Peters, Andra Naresh Kumar Reddy, Salla Gangi Reddy, Valeria Rodríguez-Fajardo, Carmelo Rosales-Guzmán, Joseph Rosen, Sarita, Allarakha Shikder, Rakesh Kumar Singh, Xinzhou Su, Aile Tamm, Ganesh Velagala, Petr Viewegh, Eulàlia Puig Vilardell, Alan E. Willner, Agnes Pristy Ignatius Xavier, Amit Yadav, Huibin Zhou","doi":"10.1007/s00340-026-08645-w","DOIUrl":"10.1007/s00340-026-08645-w","url":null,"abstract":"<div>\u0000 \u0000 <p>Singular optics is a branch of modern electromagnetics and optics that investigates solutions to Maxwell’s equations that exhibit nontrivial topological features under various boundary conditions. These solutions give rise to light fields containing singularities, points or regions at which certain optical properties, such as phase or polarization, become undefined. Over time, singular optics has evolved into a unifying framework for understanding and engineering optical fields that possess phase, polarization, coherence, and spatiotemporal singularities, each characterized by quantized topological properties. Such structured light fields enable high-dimensional information encoding, robust light–matter interactions, and sensitive probing of complex media, thereby impacting optical communication, imaging, sensing, and materials processing. Parallel advances in theory, fabrication techniques, detection hardware, and computational methods have created a diverse and rapidly expanding landscape, underscoring the need for an integrated and forward-looking perspective. This roadmap synthesizes emerging applications of singular optics across multiple platforms, offering a concise overview of current developments and highlighting key physical concepts, new architectures, and transformative technologies that bridge subfields. In addition to reflecting the insights of leading contributors to these research directions, it also surveys selected recent advances, providing a concise overview of current trends and a foundation for shaping the future of singular optics and its applications.</p>\u0000 </div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08645-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-04-07DOI: 10.1007/s00340-026-08660-x
Kristin Wallmeier, Nick S. Lemberger, Carsten Fallnich
{"title":"Two- and three-beam photothermal vs. conventional stimulated Raman scattering","authors":"Kristin Wallmeier, Nick S. Lemberger, Carsten Fallnich","doi":"10.1007/s00340-026-08660-x","DOIUrl":"10.1007/s00340-026-08660-x","url":null,"abstract":"<div>\u0000 \u0000 <p>Photothermal stimulated Raman scattering (PT-SRS) was investigated without a probe beam in addition to the pump and Stokes beams, demonstrating that the thermal lens generated within stimulated Raman scattering (SRS) can be detected on one of the intrinsically involved beams as well. The additional signal contribution led to a twofold enhancement of the resonant SRS signal and allowed for a comparison between SRS and PT-SRS signal contributions when an iris aperture with appropriate size was implemented in front of the detector. Additionally, detailed investigations on the signal-to-noise ratio of both PT-SRS and SRS signals demonstrated that the experimental conditions and requirements predefine which technique is more sensitive and provide a decision-making aid based on available laser parameters and detection schemes.</p>\u0000 </div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08660-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-04-06DOI: 10.1007/s00340-026-08666-5
Sarka Nemcova, Uliana Finaeva, Martin Zmeskal
{"title":"Near-infrared diffuse transmittance imaging for localization of pulmonary nodules","authors":"Sarka Nemcova, Uliana Finaeva, Martin Zmeskal","doi":"10.1007/s00340-026-08666-5","DOIUrl":"10.1007/s00340-026-08666-5","url":null,"abstract":"<div>\u0000 \u0000 <p>Near-infrared diffuse transmittance imaging was investigated as a non-radiative real-time imaging technique for localizing solitary pulmonary nodules during pulmonary endoscopy and thoracoscopy combined. Ex vivo experiments on porcine lungs tissue were performed to examine near-infrared light propagation and to assess detectability of embedded optical phantoms. Transmittance measurements at 632.5 nm and 850 nm showed markedly higher signal levels and improved spatial information at 850 nm, consistent with the first NIR window. Tissue optical clearing with commercially available e-cigarettes liquids was used to increase transmitted signal levels and its applicability for the diagnostic method was examined. NIR imaging of tissue samples showed that the bronchial wall causes strong scattering and broadens the illumination spot. Nevertheless, small artificial nodules placed beneath the bronchial wall still produce detectable changes in the recorded images. The results confirm the feasibility of the method for detecting scattering local structures within heterogenous lung tissue. This study’s findings provide a technical basis for further optimization of near-infrared diffuse transmittance imaging as a minimally invasive, radiation-free real-time diagnostic imaging method for solitary pulmonary nodules localization.</p>\u0000 </div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08666-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-04-04DOI: 10.1007/s00340-026-08665-6
Yasemin Demirhan, Sinan Eroglu, Necip Ayhan Tertemiz, Sinan Balci, Hakan Altan, Lutfi Ozyuzer
{"title":"Graphene based mesa metamaterials for detection of terahertz waves","authors":"Yasemin Demirhan, Sinan Eroglu, Necip Ayhan Tertemiz, Sinan Balci, Hakan Altan, Lutfi Ozyuzer","doi":"10.1007/s00340-026-08665-6","DOIUrl":"10.1007/s00340-026-08665-6","url":null,"abstract":"<div>\u0000 \u0000 <p>A high performance terahertz (THz) metamaterial structure based on graphene is presented, exploiting hybrid dielectric graphene resonances to achieve tunable resonance frequencies. Graphene coated mesa metamaterial structures were designed and fabricated on a single chip, enabling strong electromagnetic field confinement and tunable response without the need for additional metamaterial layers. The proposed architecture provides a compact and efficient platform for tunable THz photodetection and opens new possibilities for next generation graphene based plasmonic devices. The metamaterial unit cells were optimized using CST Microwave Studio simulations to operate at target frequencies of 1.1, 0.9, and 0.8 THz, respectively. Device fabrication was performed on high resistivity silicon substrates via UV lithography and reactive ion beam etching, followed by graphene deposition using chemical vapor deposition (CVD). The electromagnetic responses of the fabricated devices were characterized using a continuous-wave THz imaging system. The effects of graphene thickness and Fermi level on the reflection spectra were investigated, and the hybrid dielectric graphene resonance modes were qualitatively analysed and compared with the experimental results. By integrating graphene conformally onto three dimensional dielectric mesa resonators, enhanced light–matter interaction and tunable hybrid resonances can be achieved. The proposed plasmonic enhanced metamaterial detector provides a promising platform for future bio-THz sensing applications.</p>\u0000 </div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08665-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-03-27DOI: 10.1007/s00340-026-08661-w
Wei He, Shaode Li, Zhehai Zhou, Qiongyue Zhang
{"title":"Large-range strain measurement and elastic-plastic loading analysis in liquid helium environments based on metallized fiber Bragg grating sensor","authors":"Wei He, Shaode Li, Zhehai Zhou, Qiongyue Zhang","doi":"10.1007/s00340-026-08661-w","DOIUrl":"10.1007/s00340-026-08661-w","url":null,"abstract":"<div><p>Propellant tanks typically operate under low-temperature and high-pressure conditions. However, existing fiber optic sensors often fail to meet the comprehensive and reliable assessment requirements for large-range strain measurements and mechanical performance in such extreme environments. To address this challenge, two types of metallized-packaged fiber Bragg gratings (FBGs) strain sensors were designed and fabricated, demonstrating exceptional suitability for high-precision localized and long-term strain monitoring at ultra-low temperatures. The FBGs were inscribed using a femtosecond laser line-by-line method and securely bonded to a metallic substrate with tin (Sn) solder, ensuring robust strain transfer and enhanced mechanical stability during cryogenic testing. Experimental results demonstrated that the FBG temperature sensors effectively performed temperature sensing in the ultra-low temperature liquid helium (LH) environment (5 K). To evaluate the mechanical performance of the FBG strain sensors in the LH environment, a cyclic load test of 1000 N was first conducted, followed by four overload tests with maximum loads reaching 3000 N. Experimental results demonstrated that the metallized FBG strain sensors exhibited a well-defined elastic region under loads up to 2500 N, characterized by a strain sensitivity of over 1.26 pm/N, and a hysteresis error less than 0.1 nm. Beyond 2500 N, the sensors transitioned into a plastic deformation regime, with the hysteresis error increasing to more than 1.47 nm.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08661-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-03-27DOI: 10.1007/s00340-026-08658-5
B. Hadzic, M. Curcic, I. Kuryliszyn-Kudelska, M. Romcevic, W. D. Dobrowolski, N. Romcevic
{"title":"Laser-driven phase transformations and surface phonon dynamics in ZnO/MnO nanocomposites","authors":"B. Hadzic, M. Curcic, I. Kuryliszyn-Kudelska, M. Romcevic, W. D. Dobrowolski, N. Romcevic","doi":"10.1007/s00340-026-08658-5","DOIUrl":"10.1007/s00340-026-08658-5","url":null,"abstract":"<div><p>Raman spectroscopy, widely applied to probe phonon dynamics in nanomaterials, is often considered non-destructive; however, localized laser-driven heating may significantly affect vibrational and structural responses in thermally sensitive systems. We present a systematic Raman spectroscopic study of laser-driven nanostructuring, phase evolution, and surface optical-phonon behavior in ZnO/MnO nanocomposites over a broad range of MnO concentrations (5–95%). Laser power density was varied, from 159 to 955 kW/cm<sup>2</sup>, during Raman measurements to evaluate its influence on phonon behavior and phase stability. A critical laser power threshold of 40 mW (637 kW/cm<sup>2</sup>) was identified at 30% MnO concentration, where a Raman mode near 258 cm<sup>−1</sup> splits into two components, providing direct spectroscopic evidence of this phase transition involving MnO-related intermediate phases. At higher manganese concentrations, the Raman response reveals a complex coexistence and evolution of manganese-related phases, including MnO, Mn<sub>2</sub>O<sub>3</sub>, MnO<sub>2</sub>, MnOOH, Mn<sub>3</sub>O<sub>4</sub>, ZnMn<sub>2</sub>O<sub>4</sub>, and ZnMnO<sub>3</sub>. Surface-related vibrational modes progressively weaken and disappear with increasing manganese content and laser power, indicating a transition from zinc oxide to manganese oxide-dominated structures. These findings highlight the decisive role of laser excitation conditions in Raman spectroscopy and provide practical guidance for interpreting measurements of thermally sensitive mixed-oxide nanomaterials. </p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08658-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Applied Physics BPub Date : 2026-03-27DOI: 10.1007/s00340-026-08664-7
Patnala Vanitha, Seonghu Jung, Do-Kyeong Ko
{"title":"Evolution of topological charge in a triangular interference lattice","authors":"Patnala Vanitha, Seonghu Jung, Do-Kyeong Ko","doi":"10.1007/s00340-026-08664-7","DOIUrl":"10.1007/s00340-026-08664-7","url":null,"abstract":"<div><p>Optical vortices can be generated periodically across an interference region when three or more coherent waves interact, forming an optical vortex array (OVA). In this work, we investigate how the initial topological charge (TC) of the incident beam is redistributed among the phase singularities formed in the interference field by interfering a Laguerre-Gaussian beam carrying orbital angular momentum (OAM) of ± <i>l</i> with two Gaussian beams, while the total TC remains constant. We demonstrate that, for a zero-order vortex beam (<i>l</i> = 0), the interference results in paired vortices carrying opposite unit TCs of ± 1, whereas for nonzero TCs (<i>l</i> > 0), the original TC does not remain localized in a single higher-order vortex but instead undergoes a systematic splitting into <i>l</i> individual unpaired vortices, each carrying a unit TC of + 1. For fractional TC, the number of unpaired vortices follows a nearest integer rule of the imposed TC, exhibiting <i>n</i> unpaired vortices for fractional charges closer to the integer <i>n</i> and <i>n +</i> 1 unpaired vortices as the charge approaches the next higher integer. The reported results are supported by numerical simulations and experimental verification, providing new insight into optical vortex formation and enabling controlled vortex engineering with potential applications in optical trapping and manipulation, high-dimensional optical communication, and structured-light-based information encoding.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08664-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Thin film filter design and fabrication for human safe far-UVC lamp with excimer light sources","authors":"Nurcin Karadeniz, Merve Ekmekcioglu, Serap Yigen, Polatkan Ozcan, Hatice Eker, Metin Kaya, Mehtap Ozdemir, Lutfi Ozyuzer","doi":"10.1007/s00340-026-08662-9","DOIUrl":"10.1007/s00340-026-08662-9","url":null,"abstract":"<div>\u0000 \u0000 <p>Dielectric Barrier Discharge (DBD) excimer lamps emitting at 222 nm are promising for sterilization due to strong antimicrobial activity and reduced risks to human health. Unlike conventional 254 nm mercury lamps, Far-UVC at 222 nm penetrates microorganisms but not living human cells, enabling safe use in occupied spaces. This study reports the design and fabrication of optical thin-film filters that selectively transmit 222 nm radiation while blocking harmful 254 nm light. Filters were designed with OpenFilters software and deposited on quartz substrates using 2-inch magnetron sputtering. The multilayer structure of Si<sub>3</sub>N<sub>4</sub>, Al, and SiO<sub>2</sub> showed ~ 7% transmittance at 222 nm with complete blocking at 254 nm. Microbiological experiments were performed using a KrCl<sub>2</sub> excimer lamp operated with and without the filter. For <i>Escherichia coli</i>, the filtered lamp achieved log reductions of up to 1.47 after 45 min, while the unfiltered lamp produced reductions exceeding 4 log under identical conditions. Similar trends were observed for <i>Staphylococcus aureus</i>. Although reduced microbial inactivation was observed with the filtered system, the effective suppression of hazardous wavelengths demonstrates its potential for safer Far-UVC disinfection. These results highlight the role of 222 nm band-pass filters in improving the safety and applicability of DBD excimer lamps for UV sterilization.</p>\u0000 </div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"132 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-026-08662-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}