High sensitive fast gamma radiation sensor based on Yb-doped optical fiber: offline and online detection Esra Kendir Tekgül, Şerafettin Yaltkaya, Timuçin Emre Tabaru, Bülend Ortaç Jphys Photonics, 2026 Radiation science has a wide range of applications, from industrial uses and medical treatments to space research and national defense. Optical fiber technology offers a flexible and sensitive alternative solution for accurate radiation measurements in various applications. This study presents a new sensor design based on Yb-doped optical fibers for gamma radiation detection. The behavior of Yb-doped fibers under gamma irradiation was investigated, and a sensor was developed based on the red (or blue) shift in fluorescence emission. Three homemade and two commercial Yb-doped optical fibers were irradiated to different total doses of gamma radiation, then excited with UV light to record their spectra. A red-shift (or blue-shift in doped with Al and without P) was observed with increasing radiation dose, attributed to the formation of color centers in the fiber. These spectral shifts depend on the fiber composition and radiation dose. The highest sensitivity was observed in Fiber-3HM and Fiber-5HM which are highly radiation-sensitive, and online radiation monitoring has sensitivity as high as 7.56 nm kGy −1 and 3.65 nm kGy −1 . For the first time, we have demonstrated a radiation sensor based on the principle of fluorescence emission shift induced by the applied radiation dose, as described in the existing literature.
Spatiotemporal Confinements of Distance-Dependent Emitters for Enhancing Plasmonic Signals Yusuf Aslan, Esma Derin, Kutay Sagdic, Timuçin Emre Tabaru, Ali Karatutlu, Bülend Ortaç, Fatih Inci ACS Applied Materials and Interfaces, 2026 Surface plasmon resonance (SPR) is a common technique used for the real-time tracing of various analytes through refractive index-dependent resonance shifts. However, many plasmonic biosensors do not meet the clinical detection requirements for ultra-low concentration and low refractive index biomarkers. To address this challenge, researchers have explored unique labeling and interface modification strategies. One common strategy is utilizing fluorescence with plasmonic structures and enhancing the fluorescence intensity. However, these studies primarily focused on plasmon-enhanced fluorescence intensity, leaving the influence of fluorophores on reflection-/absorption-based plasmonic resonance shifts unexplored. Herein, we introduce a technique for amplifying the resonance shift of a plasmonic metasurface by confining the interdistance of fluorescence emitters. By adjusting nanospaces (∼4 to 20 nm), we couple surface plasmons with fluorescence in the near-field, achieving interdistance-dependent resonance shift behavior. This approach results in a 4.5-fold signal enhancement in the resonance shift for detecting conjugated proteins from complex matrices. In this regard, we utilize a plasmonic metasurface and distinct fluorescent emitters (FITC, Texas Red, streptavidin-quantum dot (QD) 525, and streptavidin-QD 625) with diverse excitation and emission assets. We also experimentally demonstrate a spectral blue shift of the plasmonic resonance through resonant coupling between QDs and surface plasmons, in contrast to the conventionally observed red shift. To hurdle the cost- and fabrication-related challenges in metasurfaces, we recycle off-the-shelf digital versatile discs (DVDs) into plasmonic metasurfaces due to their intrinsic nanograting structures, thereby significantly minimizing the cost down to $1.5. Moreover, we collect spatiotemporal signals using a palm-sized platform (5 cm × 10 cm x 1 cm) within 15 min that would be easily adapted into any settings possible. Consequently, this strategy paves the way for creating novel configurations and arrangements on a metasurface sensor to couple with fluorescence molecules while boosting the sensor's analytical performance that would be potentially integrated with biosensing applications in disease diagnostics.
High-Energy Ultrafast Fiber Laser at 2-μm Based on Cb Ni-Metal Organic Framework Harith Ahmad, Muhammad Khairol Annuar Zaini, Zulkifli Mahmoodin, Saliha Mutlu, Volkan Filiz, Sevil Savaskan Yilmaz, Nergis Arsu, Mohamad Akmal Mohamad Lutfi, Kavintheran Thambiratnam, Bülend Ortaç IEEE Journal of Quantum Electronics, 2026 A new carborane-containing metal-organic framework (Cb Ni-MOF) was synthesized using a high-power laser-assisted method. The material was prepared from Nickel(II) chloride hexahydrate (NiCI<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>.6H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O) and m-carborane-1,7-dicarboxylic acid (Cb). FTIR spectroscopy-based structural analysis confirmed successful coordination between the carborane carboxylate groups and Ni(II) ions. SEM-based morphological description revealed 200 nm to 1 μm-sized polyhedral particles, indicating a crystalline and porous nature. TEM images further revealed nanoscale crystallinity with particle diameters around 50 nm, together with single-/polycrystalline structures with identical features. These findings demonstrate that the laser-assisted process is efficient for preparing nano-ordered, highly crystalline Cb-based MOFs. In this work, the generation of a high-performance ultrafast fiber laser system at the 2-μm wavelength region was demonstrated. The system utilized a passively mode-locked oscillator incorporating a Cb Ni-MOF deposited on an arc-shaped fiber, demonstrating exceptional nonlinear optical properties with 14.1% modulation depth and 11.2 MW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> saturation intensity. The laser oscillator generated ultrashort pulses with a duration of 1.2 ps at a center wavelength of 1942.9 nm. Using a chirped pulse amplification (CPA) technique with pre-amplification and main amplification stages, the high-power fiber laser achieves remarkable performance characteristics: 8.4 W average output power, 264 fs pulse duration, 433 nJ pulse energy, and 1.64 MW peak power at 19.4 MHz repetition rate. This high-power ultrafast fiber laser system shows significant potential for applications in invasive medical procedures, advanced material processing, and other fields requiring precise and high-intensity laser-matter interactions.
High-Power Rapid Laser-Induced Synthesis of Multi-functional Cobalt Metal-Organic Framework With an Unprecedented Synthesis Efficiency Saliha Mutlu, Bülend Ortaç, Ali Karatutlu, Taylan Gorkan, Engin Durgun, Dilek Soyler, Saniye Soylemez, Jelena Lillepäg, Volkan Filiz, Nergis Arsu, Sevil Savaskan Yilmaz Advanced Materials Technologies, 2026 A rapid, high‐yield laser‐assisted synthesis route with an exceptional production efficiency (≥90%) is introduced for cobalt‐based metal–organic frameworks (Co‐MOFs), producing ordered hybrid structures within an hour that integrate optical, magnetic, and adsorption functionalities. The Co‐MOFs exhibit tunable properties, including a low‐temperature paramagnetic transition confirmed by magnetic measurements and first‐principles calculations. Gas adsorption studies reveal promising performance for N 2 , CH 4 , and CO 2 , combining low energy consumption with cost‐effective gas separation. Structural analysis indicates mesoporosity with high accessibility, supporting selective uptake under practical conditions. Importantly, Co‐MOF‐modified graphite electrodes demonstrate outstanding electrochemical sensing performance for dopamine, achieving a low detection limit (5.5 µ M ), high sensitivity (121 µA mM − 1 cm − 2 ), and excellent reproducibility in human serum. These results underline the multifunctional potential of laser‐synthesized Co‐MOFs as scalable platforms that couple sustainable gas separation with biomedical diagnostics, advancing the development of framework materials for real‐world applications.
Dissipative Soliton Mode-Locked Yb-Doped Laser Using Cobalt Metal Organic Framework as Nonlinear Optical Material H. Ahmad, M. A. M. Lutfi, S. Mutlu, M. K. A. Zaini, M. Z. H. Mayzan, L. Bayang, K. Thambiratnam, V. Filiz, S. Savaskan Yilmaz, N. Arsu, B. Ortaç, Z. Mahmoodin, M. F. Ismail, Mousa Hussein Journal of Nonlinear Optical Physics and Materials, 2026 This work demonstrates the implementation of a cobalt metal-organic framework (Co-MOF) as a saturable absorber (SA) to achieve dissipative soliton (DS) formation in a ytterbium-doped fiber laser (YDFL). The Co-MOF device exhibits a saturation intensity of 0.7[Formula: see text]MW[Formula: see text]cm[Formula: see text] and a modulation depth of 14.7%. Integrating this nonlinear optical component into the laser cavity facilitates the generation of ultrashort pulses with a duration of 10.6[Formula: see text]ps, centerd at 1,037[Formula: see text]nm. The DS pulses operate at a 32.3[Formula: see text]MHz repetition rate, which is amplified, producing an optical output power of 105[Formula: see text]mW with a pulse energy of 3.3[Formula: see text]nJ.
Gamma Radiation Shielding Efficiency of Cross-Linked Polystyrene-b-Polyethyleneglycol Block Copolymer Nanocomposites Doped Arsenic (III) Oxide and Boron Nitride Nanoparticles Bülend Ortaç, Taylan Baskan, Saliha Mutlu, Sevil Savaskan Yilmaz, Ahmet Hakan Yilmaz Polymers, 2025 In recent years, polymer-based hybrid nanocomposites have emerged as promising alternatives to traditional heavy metal shields due to their low density, flexibility, and environmental safety. In this study, the synthesis of PS-PEG copolymers and the gamma radiation-shielding properties of PS-PEG/As2O3, PS-PEG/BN, and PS-PEG/As2O3/BN nanocomposites with different compositions are investigated. The goal is to find the optimal nanocomposite composition for gamma radiation shielding and dosimetry. Therefore, the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth-value layer (TVL), effective atomic number, mean free path (MFP), radiation shielding efficiency (RPE), electron density, and specific gamma-ray constant were presented. Gamma rays emitted by the Eu source were detected by a high-purity germanium (HPGe) detector device. GammaVision was used to analyze the given data. Photon energy was in the vicinity of 121.8–1408.0 keV. The MAC values in XCOM simulation tools were used to compute. Gamma-shielding efficiency was increased by an increased number of NPs at a smaller photon energy. At 121.8 keV, the HVL of a composite with 70 wt% As2O3 NPs is 2.00 cm, which is comparable to the HVL of lead (0.56 cm) at the same energy level. Due to the increasing need for lightweight, flexible, and lead-free shielding materials, PS-b-PEG copolymer-based nanocomposites reinforced with arsenic oxide and BN NPs will be materials of significant interest for next-generation radiation protection applications.
Cu-MOF as a saturable absorber for mode-locking at 2 µm and beyond Harith Ahmad, Joe Win Chiam, Khalil Kamaruzzaman, Muhamad Zharif Samion, Saliha Mutlu, Volkan Filiz, Nergis Arsu, Sevil Savaskan Yilmaz, Bülend Ortaç, Kavintheran Thambiratnam Scientific Reports, 2025 In this study, a copper-based metal–organic framework (Cu-MOF) was synthesized using terephthalic acid (TPA, H 2 L), 1,2-bis(4-pyridyl)ethene (bpe) as organic binders, and Cu 2+ ions, to act as a saturable absorber (SA) material. The SA was fabricated by depositing Cu-MOF on an arc-shaped fiber, and was then incorporated into a thulium-doped fiber laser (TDFL) and a holmium-doped fiber laser (HDFL), with both achieving stable mode-locking operation. The SA exhibited a modulation depth of 5.7% and a saturation intensity of 13.8 MW/cm 2 , respectively. The maximum average output power of the TDFL was 6.82 mW, while that of the HDFL was 2.64 mW. Pulse widths were measured at 1.08 ps for the TDFL and 1.75 ps for the HDFL respectively. The TDFL achieved a pulse energy of 464 pJ and a peak power of 430 W. The output of the HDFL had a pulse energy of 180 pJ and a peak power of 94.9 W, respectively. Both lasers were monitored for 4 h to ensure their stability.
Synthesis and Characterization of Py(PCL), Py(PLLA) Homopolymers and Py(PCL-b-PLLA) Copolymer via Ring-Opening Polymerization: Determination of Structural, Optical, and Biocompatible Properties Murat Mısır, Saliha Mutlu, Servin Bagheralmoosavi, Bülend Ortaç, Ali Karatutlu, Gurkan Yesilöz, Sevil Savaskan Yılmaz Advanced Materials Interfaces, 2025 Pyrene‐functionalized poly(ɛ‐caprolactone) (Py(PCL)), poly(L‐lactide) (Py(PLLA)) homopolymers, and an AB‐type block copolymer (Py(PCL‐b‐PLLA)) are synthesized via ring‐opening polymerization (ROP) using Sn(Oct)2 catalyst with ɛ‐CL and L‐LA monomers. Structural characterization is confirmed by FTIR, 1H NMR, and XRD analyses, while thermal and optical properties are assessed using TGA, DSC, UV–vis, and photoluminescence spectroscopy. The polymers exhibited strong photoluminescence across 380–700 nm, high thermal stability, and nanostructured surface morphology as revealed by SEM and 3D laser microscopy. Biocompatibility is evaluated by culturing MCF‐7 breast cancer cells on polymer‐coated glass slides. The materials supported uniform cell distribution, robust adhesion, and sustained viability and proliferation. These results highlight the polymers’ suitability for tissue engineering and biomaterials research. The incorporation of pyrene units enabled intrinsic fluorescence tracking, positioning these polymers as multifunctional platforms for applications in cancer research, real‐time bioimaging, and regenerative medicine. By combining fluorescence capability with biodegradability and promotion of cell growth, Py(PCL), Py(PLLA), and Py(PCL‐b‐PLLA) offer a promising, environmentally friendly approach bridging imaging and therapeutic delivery needs in biomedical applications.
100 W all-fiber side-pump combiner on a passive large-pitch photonic crystal fiber European Conference on Lasers and Electro Optics Proceedings Conference on Lasers and Electro Optics Europe CLEO Europe 2025 and European Quantum Electronics Conference Eqec 2025, 2025
In-situ X-ray monitoring using specialty optical fibers and determination of their synchrotron X-ray computed tomography imaging conditions European Conference on Lasers and Electro Optics Proceedings Conference on Lasers and Electro Optics Europe CLEO Europe 2025 and European Quantum Electronics Conference Eqec 2025, 2025
O-band mode-locked femtosecond praseodymium-doped fluoride fiber laser using a nickel metal-organic framework European Conference on Lasers and Electro Optics Proceedings Conference on Lasers and Electro Optics Europe CLEO Europe 2025 and European Quantum Electronics Conference Eqec 2025, 2025
High-Power Laser-Induced Synthesis of Ni-Based Metal-Organic Framework for Electrocatalytic, and Glucose-Sensing Applications European Conference on Lasers and Electro Optics Proceedings Conference on Lasers and Electro Optics Europe CLEO Europe 2025 and European Quantum Electronics Conference Eqec 2025, 2025
Laser-inscribed flexible Bragg gratings containing silicon oxynitride doped silicon thin film for authentication applications and their electronic and structural properties from X-ray absorption Spectroscopy and Ab Initio Calculations European Conference on Lasers and Electro Optics Proceedings Conference on Lasers and Electro Optics Europe CLEO Europe 2025 and European Quantum Electronics Conference Eqec 2025, 2025
Usage of Novel Co-MOF for Mode-Locked Pulse Generation Near 2 μm H. Ahmad, J. W. Chiam, M. Z. Samion, M. F. Ismail, S. Mutlu, V. Filiz, S. Savaskan Yılmaz, N. Arsu, M. K. A. Zaini, K. Thambiratnam, L. Bayang, S. Sun, B. Ortaç IEEE Journal of Quantum Electronics, 2025
High-Power Cladding Light Stripper with Vapor Deposition of Polyethersulfone Bartu Simsek, Ozan Aktas, Ali Karatutlu, Ahmet Basaran, Elif Yapar Yildirim, Yakup Midilli, Bulend Ortac 2021 Conference on Lasers and Electro Optics Europe and European Quantum Electronics Conference CLEO Europe Eqec 2021, 2021
Side pump combiner fabrication on a photonic crystal fiber in (1 + 1) x 1 configuration Optics Infobase Conference Papers, 2021
Demonstration of a novel cladding light stripper fabrication method based on poly (Chloro-P-Xylene) polymer material Optics Infobase Conference Papers, 2021
Production of biaxial polarization-maintaining optical fiber with panda-type and elliptical-core geometry Optics Infobase Conference Papers, 2021
High-power cladding light stripper with vapor deposition of polyethersulfone Optics Infobase Conference Papers, 2021
Properties of a microjoule-class fiber oscillator mode-locked with a SESAM C. Lecaplain, B. Ortac, G. Machinet, J. Boullet, M. Baumgartl, T. Schreiber, E. Cormier, A. Hideur 2011 Conference on Lasers and Electro Optics Europe and 12th European Quantum Electronics Conference CLEO Europe Eqec 2011, 2011
Sub-picosecond microjoule-class fiber lasers C. Lecaplain, B. Ortaç, G. Machinet, J. Boullet, M. Baumgartl, T. Schreiber, E. Cormier, A. Hideur 2011 Conference on Lasers and Electro Optics Laser Science to Photonic Applications CLEO 2011, 2011
130 nJ 77 fs dissipative soliton fiber laser M. Baumgartl, B. Ortaç, C. Lecaplain, A. Hideur, J. Limpert, A. Tünnermann Lasers and Electro Optics Quantum Electronics and Laser Science Conference 2010 Laser Science to Photonic Applications CLEO QELS 2010, 2010
90 nJ energy femtosecond fiber-based chirped-pulse oscillator C. Lecaplain, B. Ortac, A. Hideur, J. Limpert, A. Tunnermann CLEO Europe Eqec 2009 European Conference on Lasers and Electro Optics and the European Quantum Electronics Conference, 2009
Microjoule-level picosecond and femtosecond mode-locked fiber oscillators B. Ortac, M. Baumgartl, O. Schmidt, A. Hideur, I. Sagnes, A. Garnache, J. Limpert, A. Tunnermann CLEO Europe Eqec 2009 European Conference on Lasers and Electro Optics and the European Quantum Electronics Conference, 2009
Femtosecond fiber laser system for medical applications Clemens Hönninger, Marco Plötner, Bülend Ortaç, Roland Ackermann, Robert Kammel, Jens Limpert, Stefan Nolte, Andreas Tünnermann Proceedings of SPIE the International Society for Optical Engineering, 2009
High-energy femtosecond chirped-pulse oscillator C. Lecaplain, B. Ortaç, A. Hideur, J. Limpert, A. Tünnermann 2009 Conference on Lasers and Electro Optics and 2009 Conference on Quantum Electronics and Laser Science Conference CLEO QELS 2009, 2009
Ultra-short pulse mode-locked rod-type fiber laser B. Ortac, O. Schmidt, T. Schreiber, A. Hideur, J. Limpert, A. Tunnermann 2008 Conference on Quantum Electronics and Laser Science Conference on Lasers and Electro Optics CLEO QELS, 2008
