Scholarly Publications - Physics
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Item Open Access Multilevel diffraction gratings inside silicon towards spectral filtering(SPIE - International Society for Optical Engineering, 2024-03-12) Bütün, Mehmet; Saylan, Sueda; Sabet, Rana Asgari; Tokel, Onur; Gemini, Laura; Kleinert, Jan; Miyaji, GodaiSilicon-based integrated photonics holds the promise of revolutionizing key technologies, such as telecommunications, computing, and lab-on-chip systems. One can achieve diverse functionalities in two ways: on the wafer surface ("on-chip") or within its bulk ("in-chip"), the latter gaining recognition due to recent advancements in laser lithography. Until recently, 3D in-chip laser writing has only been utilized for single-level devices, leaving a vast potential for monolithic and multilevel functionality within silicon untapped. In our previous research, we successfully designed and fabricated multilevel, high-efficiency diffraction gratings in silicon using nanosecond laser pulses. Their high performance stemmed from effective field enhancement at Talbot self-imaging planes. Our current work takes a theoretical approach, investigating how varying the grating period affects the performance of in-chip multilevel gratings. We demonstrate that the previously achieved 95% diffraction efficiency at a 1550 nm wavelength is also attainable with a reduced period of 3 μm. This smaller period is predicted to allow for spectral filtering, nearly equivalent to commercially available filters in terms of Full Width at Half Maximum (FWHM). Our findings underscore the potential of volumetric Si photonics and mark a significant step towards realizing 3D-integrated monolithic chips.Item Open Access Ultrafast laser system with record GHz repetition rate in burst mode from all single-mode fiber(Optica Publishing Group, 2024) Laçin, Mesut; Repgen, Paul; Maghsoudi, Amirhossein; İlday, Fatih ÖmerWe present a novel laser system integrated within strictly single-mode fibers, capable of generating bursts of 100-fs pulses at a 50 GHz repetition rate with an average power of 100 W. This configuration facilitates highly efficient and precise material processing in the ablation-cooled regime.Item Open Access Uniform 50-fs pulse bursts via gain-managed nonlinear amplification(2024) Maghsoudi, Amirhossein; Repgen, Paul; Laçin, Mesut; Şura, Aladin; İlday, Fatih ÖmerBy studying gain dynamics in burst-mode amplifiers, we report the first gain-managed nonlinear amplifier generating 50 fs, 600 nJ pulses with uniform bursts, resulting in optimal pulse parameters for ultrafast material processing.Item Open Access Ablation efficiency improvement through ultrafast pulse repetition rate scaling(Optica Publishing Group, 2024) Repgen, Paul; Laçin, Mesut; Maghsoudi, Amirhossein; İlday, Fatih ÖmerUltrafast single-pulse material ablation provides supreme precision but suffers severely from low process efficiencies. Increases in the repetition rate with simultaneous reductions of the pulse energy offer significant rises in ablation efficiency as the process is carried on in the ablation-cooled ultrafast removal regime. We present a tenfold gain in ablation efficiency compared to conventional single-pulse processing and a sixfold increase over previously reported results by increasing the repetition rate to 50 GHz.Item Embargo Weakly confined organic-inorganic halide perovskite quantum dots as high-purity room-temperature single photon sources(American Chemical Society, 2024-04-10) Wang, Bo; Lim, Jia Wei Melvin; Loh, Siow Mean; Mayengbam, Rishikanta; Ye, Senyun; Feng, Minjun; He, Huajun; Liang, Xiao; Cai, Rui; Zhang, Qiannan; Kwek, Leong-Chuan; Demir, Hilmi Volkan; Mhaisalkar, Subodh G.; Blundell, Steven A.; Chien Sum, TzeColloidal perovskite quantum dots (PQDs) have emerged as highly promising single photon emitters for quantum information applications. Presently, most strategies have focused on leveraging quantum confinement to increase the nonradiative Auger recombination (AR) rate to enhance single-photon (SP) purity in all-inorganic CsPbBr3 QDs. However, this also increases the fluorescence intermittency. Achieving high SP purity and blinking mitigation simultaneously remains a significant challenge. Here, we transcend this limitation with room-temperature synthesized weakly confined hybrid organic-inorganic perovskite (HOIP) QDs. Superior single photon purity with a low g((2))(0) < 0.07 +/- 0.03 and a nearly blinking-free behavior (ON-state fraction >95%) in 11 nm FAPbBr(3) QDs are achieved at room temperature, attributed to their long exciton lifetimes (tau(X)) and short biexciton lifetimes (tau(XX)). The significance of the organic A-cation is further validated using the mixed-cation FA(x)Cs(1-x)PbBr(3). Theoretical calculations utilizing a combination of the Bethe-Salpeter (BSE) and kp approaches point toward the modulation of the dielectric constants by the organic cations. Importantly, our findings provide valuable insights into an additional lever for engineering facile-synthesized room-temperature PQD single photon sources.Item Embargo Harnessing phonon wave resonance in carbyne-enriched nano-interfaces to enhance energy release in nanoenergetic materials(Begell House, Inc., 2024-07-30) Lukin, Alexander; Gülseren, OğuzThis paper introduces a new nanotechnology-driven approach that provides a transformative pathway to substantially enhance the energy release efficiency of nanoenergetic materials (nEMs) without altering their chemical composition. The groundbreaking concept involves strategically harnessing, self-synchronized collective atomic vibrations and phonon wave resonance phenomena within the transition domain's interconnecting nanocomponents. A key novelty is the incorporation of meticulously engineered two-dimensional-ordered linear-chain carbon-based multilayer nano-enhanced interfaces as programmable nanodevices into these transition domains, facilitated by advanced multistage processing and assembly techniques. These programmable nanodevices enable unprecedented control over the initiation, propagation, and coupling of self-synchronized collective atomic vibrations and phonon waves, unleashing powerful synergistic effects. Central to this approach is the bidirectional, self-reinforcing interaction between precisely tailored nano-architectures and phonon dynamics within the multilayer nano-enhanced interfaces. This synergistic coupling facilitates the rational programming of energy transfer pathways, granting access to previously inaccessible energy reserves inherently locked within the nEM systems. To optimally activate and harness these synergistic mechanisms, a strategic combination of cutting-edge methods is judiciously employed. These include energy-driven stimulation of allotropic phase transformations, surface acoustic wave-assisted manipulation at micro-/nanoscales, heteroatom doping, directed self-assembly driven by high-frequency electromagnetic fields, and a data-driven inverse design framework. Notably, by leveraging a data-driven inverse design strategy rooted in multi-factorial neural network predictive models, we uncover previously hidden structure-property relationships governing the nano-enhanced interfaces. This novel data-driven "nanocarbon genome" approach enables rational maximization of energy release efficiency in nEM systems. Overall, this transformative nanoscale concept not only unlocks unprecedented high-energy functionalities but also ushers in significant improvements in environmental sustainability and operational safety for nEMsItem Open Access Looking for timing variations in the transits of 16 exoplanets(Oxford University Press, 2024-04-05) Yalcinkaya, S.; Esmer, E. M.; Basturk, O.; Muhaymin, A.; Kutluay, A. C.; Silistre, D. I.; Akar, F.; Southworth, J.; Mancini, L.; Davoudi, F.; Karamanli, E.; Tezcan, F.; Demir, E.; Yilmaz, D.; Guleroglu, E.; Tekin, M.; Taskin, I.; Aladag, Y.; Sertkan, E.; Kurt, U. Y.; Fisek, S.; Kaptan, S.; Alis, S.; Aksaker, N.; Yelkenci, F. K.; Tezcan, C. T.; Kaya, A.; Oglakkaya, D.; Aydin, Z. S.; Yesilyaprak, C.We update the ephemerides of 16 transiting exoplanets using our ground-based observations, new Transiting Exoplanet Survey Satellite data, and previously published observations including those of amateur astronomers. All these light curves were modelled by making use of a set of quantitative criteria with the exofast code to obtain mid-transit times. We searched for statistically significant secular and/or periodic trends in the mid-transit times. We found that the timing data are well modelled by a linear ephemeris for all systems except for XO-2 b, for which we detect an orbital decay with the rate of -12.95 +/- 1.85 ms yr(-1) that can be confirmed with future observations. We also detect a hint of potential periodic variations in the transit timing variation data of HAT-P-13 b, which also requires confirmation with further precise observations.Item Open Access Self-consistent electrostatic formalism of bulk electrolytes based on the asymmetric treatment of the short- and long-range ion interactions(Royal Society of Chemistry, 2024-12-07) Büyükdağlı, ŞahinWe predict the thermodynamic behavior of bulk electrolytes from an ionic hard-core (HC) size-augmented self-consistent formalism incorporating asymmetrically the short- and long-range ion interactions via their virial and cumulant treatment, respectively. The characteristic splitting length separating these two ranges is obtained from a variational equation solved together with the Schwinger–Dyson (SD) equations. Via comparison with simulation results from the literature, we show that the asymmetric treatment of the distinct interaction ranges significantly extends the validity regime of our previously developed purely cumulant-level Debye–Hückel (DH) theory. Namely, for monovalent solutions with typical ion sizes, the present formalism can accurately predict up to molar concentrations the liquid pressure dominated by HC interactions, the internal energies driven by charge correlations, and the local ion distributions governed by the competition between HC and electrostatic interactions. We evaluate as well the screening length of the liquid and investigate the deviations of the macromolecular interaction range from the DH length. In fair agreement with simulations and experiments, our theory is shown to reproduce the overscreening and underscreening effects occurring respectively in submolar mono- and multivalent electrolytes.Item Open Access Robustness of GaN on SiC low-noise amplifiers in common source and cascode configurations for X-band applications(John Wiley & Sons Ltd., 2024-08) Nawaz, Muhammad Imran; Zafar, Salahuddin; Gürdal, Armağan; Akoğlu, Büşra ÇankayaCascode HEMTs exhibit high gain and broadband performance. Promising reverse transmission makes matching networks simpler and insensitive to impedance on either side of the HEMT. On the other hand, common source (CS) HEMTs with intentional small inductance at the source provide simultaneous match for optimum noise and input impedance. This paper provides a performance comparison of 4 x 50 mu m cascode HEMTs-based low -noise amplifier and 4 x 50 mu m CS HEMTs-based low -noise amplifiers with specific emphasis on robustness, including survivability and reverse recovery time (RRT). Cascode LNA survives an input power of 33 dBm while CS LNA handles 30 dBm power, each having a 1 k Omega passive limiting resistor on the gate bias line. RRT of cascode LNA is also better. Better survivability and RRT for cascode LNA are attributed to its HEMT's stacked configuration. The designs of LNAs are described, along with their small -signal, noise, and large -signal characteristics in the X -band. Cascode LNA has a better input match, while CS LNA has a better output match. Gains are comparable, while CS LNA has better P1dB at higher band edge frequency. The noise figure for both LNAs is less than 1.9 dB, with CS LNA having a slight edge over cascode. This study benefits RF designers in choosing appropriate HEMT topology as per application for designing robust low -noise amplifiers.Item Open Access Nonlinear optical properties of CVD-synthesized CuS crystals(AIP Publishing LLC, 2024-12-27) Suleiman, Abdulsalam Aji; Rahighi, Reza; Parsi, Amir; Kasırga, Talip SerkanCopper sulfide (CuS) is a material of growing interest due to its distinctive electronic, optical, and catalytic properties. In this study, we successfully synthesized ultrathin CuS crystals, with thicknesses as low as 14 nm and lateral dimensions reaching 60 μm, using a single-step chemical vapor deposition process. Detailed structural, compositional, and morphological analyses revealed intrinsic lattice defects, including stacking faults and domain misorientations. These defects disrupt the centrosymmetry of the CuS lattice and are responsible for an unexpected second harmonic generation response, an uncommon behavior in centrosymmetric materials. In addition, we measured the first-order temperature coefficients of Raman shifts, providing insights into the thermal dynamics of the CuS crystal structure. These findings position CuS as a potential material for nonlinear optical applications, while reinforcing its established roles in catalysis and electronics.Item Open Access Roadmap on computational methods in optical imaging and holography [invited](Springer, 2024-09-10) Rosen, Joseph; Alford, Simon; Allan, Blake; Anand, Vijayakumar; Arnon, Shlomi; Arockiaraj, Francis Gracy; Art, Jonathan; Bai, Bijie; Balasubramaniam, Ganesh M.; Birnbaum, Tobias; Bisht, Nandan S.; Blinder, David; Cao, Liangcai; Chen, Qian; Chen, Ziyang; Dubey, Vishesh; Egiazarian, Karen; Ercan, Mert; Forbes, Andrew; Gopakumar, G.; Gao, Yunhui; Gigan, Sylvain; Goclowski, Pawel; Gopinath, Shivasubramanian; Greenbaum, Alon; Horisaki, Ryoichi; Ierodiaconou, Daniel; Juodkazis, Saulius; Karmakar, Tanushree; Katkovnik, Vladimir; Khonina, Svetlana N.; Kner, Peter; Kravets, Vladislav; Kumar, Ravi; Lai, Yingming; Li, Chen; Li, Jiaji; Li, Shaoheng; Li, Yuzhu; Liang, Jinyang; Manavalan, Gokul; Mandal, Aditya Chandra; Manisha, Manisha; Mann, Christopher; Marzejon, Marcin J.; Moodley, Chane; Morikawa, Junko; Muniraj, Inbarasan; Narbutis, Donatas; Ng, Soon Hock; Nothlawala, Fazilah; Oh, Jeonghun; Özcan, Aydoğan; Park, Yongkeun; Porfirev, Alexey P.; Potcoava, Mariana; Prabhakar, Shashi; Pu, Jixiong; Rai, Mani Ratnam; Rogalski, Mikolaj; Ryu, Meguya; Choudhary, Sakshi; Salla, Gangi Reddy; Schelkens, Peter; Şener, Sarp Feykun; Shevkunov, Igor; Shimobaba, Tomoyoshi; Singh, Rakesh K.; Singh, Ravindra P.; Stern, Adrian; Sun, Jiasong; Zhou, Shun; Zuo, Chao; Zurawski, Zack; Tahara, Tatsuki; Tiwari, Vipin; Trusiak, Maciej; Vinu, R. V.; Volotovskiy, Sergey G.; Yılmaz, Hasan; De Aguiar, Hilton Barbosa; Ahluwalia, Balpreet S.; Ahmad, AzeemComputational methods have been established as cornerstones in optical imaging and holography in recent years. Every year, the dependence of optical imaging and holography on computational methods is increasing significantly to the extent that optical methods and components are being completely and efficiently replaced with computational methods at low cost. This roadmap reviews the current scenario in four major areas namely incoherent digital holography, quantitative phase imaging, imaging through scattering layers, and super-resolution imaging. In addition to registering the perspectives of the modern-day architects of the above research areas, the roadmap also reports some of the latest studies on the topic. Computational codes and pseudocodes are presented for computational methods in a plug-and-play fashion for readers to not only read and understand but also practice the latest algorithms with their data. We believe that this roadmap will be a valuable tool for analyzing the current trends in computational methods to predict and prepare the future of computational methods in optical imaging and holography.Item Embargo “Giant” colloidal quantum well heterostructures of CdSe@CdS Core@Shell nanoplatelets from 9.5 to 17.5 monolayers in thickness enabling ultra-high gain lasing(Wiley-VCH Verlag GmbH & Co. KGaA, 2024-09-19) Işık, Furkan; Delikanlı, Savaş; Durmuşoğlu, Emek G.; Işık, Ahmet Tarık; Shabani, Farzan; Baruj, Hamed Dehghanpour; Demir, Hilmi VolkanSemiconductor colloidal quantum wells (CQWs) have emerged as a promising class of gain materials to be used in colloidal lasers. Although low gain thresholds are achieved, the required high gain coefficient levels are barely met for the applications of electrically-driven lasers which entails a very thin gain matrix to avoid charge injection limitations. Here, “giant” CdSe@CdS colloidal quantum well heterostructures of 9.5 to 17.5 monolayers (ML) in total with corresponding vertical thickness from 3.0 to 5.8 nm that enable record optical gain is shown. These CQWs achieve ultra-high material gain coefficients up to ≈140 000 cm−1, obtained by systematic variable stripe length (VSL) measurements and independently validated by transient absorption (TA) measurements, owing to their high number of states. This exceptional gain capacity is an order of magnitude higher than the best levels reported for the colloidal quantum dots. From the dispersion of these quantum wells, low threshold amplified spontaneous emission in water providing an excellent platform for optofluidic lasers is demonstrated. Also, employing these giant quantum wells, whispering gallery mode (WGM) lasing with an ultra-low threshold of 8 µJ cm−2 is demonstrated. These findings indicate that giant CQWs offer an exceptional platform for colloidal thin-film lasers and in-solution lasing applications.Item Embargo Orientation-dependent photoconductivity of quasi-2D nanocrystal self-assemblies: face-down, edge-up versus randomly oriented quantum wells(Wiley-VCH Verlag GmbH & Co. KGaA, 2024-07-25) Ibrahem, Mohammed A.; Waris, Mohsin; Miah, Md Rumon; Shabani, Farzan; Canımkurbey, Betül; Ünal, Emre; Delikanlı, Savaş; Demir, Hilmi VolkanHere, strongly orientation-dependent lateral photoconductivity of a CdSe monolayer colloidal quantum wells (CQWs) possessing short-chain ligands is reported. A controlled liquid-air self-assembly technique is utilized to deliberately engineer the alignments of CQWs into either face-down (FO) or edge-up (EO) orientation on the substrate as opposed to randomly oriented (RO) CQWs prepared by spin-coating. Adapting planar configuration metal-semiconductor-metal (MSM) photodetectors, it is found that lateral conductivity spans ≈2 orders of magnitude depending on the orientation of CQWs in the film in the case of utilizing short ligands. The long native ligands of oleic acid (OA) are exchanged with short-chain ligands of 2-ethylhexane-1-thiol (EHT) to reduce the inter-platelet distance, which significantly improved the photoresponsivity from 4.16, 0.58, and 4.79 mA W−1 to 528.7, 6.17, and 94.2 mA W−1, for the MSM devices prepared with RO, FO, and EO, before and after ligands exchange, respectively. Such CQW orientation control profoundly impacts the photodetector performance also in terms of the detection speed (0.061 s/0.074 s for the FO, 0.048 s/0.060 s for the EO compared to 0.10 s/0.16 s for the RO, for the rise and decay time constants, respectively) and the detectivity (1.7 × 1010, 2.3 × 1011, and 7.5 × 1011 Jones for the FO, EO, and RO devices, respectively) which can be further tailored for the desired optoelectronic device applications. Attributed to charge transportation in colloidal films being proportional to the number of hopping steps, these findings indicate that the solution-processed orientation of CQWs provides the ability to tune the photoconductivity of CQWs with short ligands as another degree of freedom to exploit and engineer their absorptive devices.Item Open Access Molten glass-mediated conditional CVD growth of MoS2 monolayers and effect of surface treatment on their optical properties(Institute of Physics Publishing Ltd., 2024-05-30) Aras, Fikret Gonca; Suleiman, Abdulsalam Aji; Parsi, Amir; Kasırga, Talip Serkan; Yeltik, AydanIn the rapidly developing field of optoelectronics, the utilization of transition-metal dichalcogenides with adjustable band gaps holds great promise. MoS2, in particular, has garnered considerable attention owing to its versatility. However, a persistent challenge is to establish a simple, reliable and scalable method for large-scale synthesis of continuous monolayer films. In this study, we report the growth of continuous large-area monolayer MoS2 films using a glass-assisted chemical vapor deposition (CVD) process. High-quality monolayer films were achieved by precisely controlling carrier gas flow and sulfur vaporization with a customized CVD system. Additionally, we explored the impact of chemical treatment using lithium bistrifluoromethylsulfonylamine (Li-TFSI) salt on the optical properties of monolayer MoS2 crystals. To investigate the evolution of excitonic characteristics, we conditionally grew monolayer MoS2 flakes by controlling sulfur evaporation. We reported two scenarios on MoS2 films and flakes based on substrate-related strain and defect density. Our findings revealed that high-quality monolayer MoS2 films exhibited lower treatment efficiency due to substrate-induced surface strain. whereas defective monolayer MoS2 flakes demonstrated a higher treatment sensitivity due to the p-doping effect. The Li-TFSI-induced changes in exciton density were elucidated through photoluminescence, Raman, and x-ray photoelectron spectroscopy results. Furthermore, we demonstrated treatment-related healing in flakes under variable laser excitation power. The advancements highlighted in our study carry significant implications for the scalable fabrication of diverse optoelectronic devices, potentially paving the way for widespread real-world applications.Item Open Access Systematic incorporation of ionic hard-core size into the Debye-Huckel theory via the cumulant expansion of the Schwinger-Dyson equations(American Chemical Society, 2024-03-22) Büyükdağlı, ŞahinThe Debye–Hückel (DH) formalism of bulk electrolytes equivalent to the Gaussian-level closure of the electrostatic Schwinger–Dyson identities without the interionic hard-core (HC) coupling is extended via the cumulant treatment of these equations augmented by HC interactions. By comparing the monovalent ion activity and pressure predictions of our cumulant-corrected DH (CCDH) theory with hypernetted-chain results and Monte Carlo simulations from the literature, we show that this rectification extends the accuracy of the DH formalism from submolar to molar salt concentrations. In the case of internal energies or the general case of divalent electrolytes mainly governed by charge correlations, the improved accuracy of the CCDH theory is limited to submolar ion concentrations. Comparison with experimental data from the literature shows that, via the adjustment of the hydrated ion radii, CCDH formalism can equally reproduce the nonuniform effect of salt increment on the ionic activity coefficients up to molar concentrations. The inequality satisfied by these HC sizes coincides with the cationic branch of the Hofmeister series.Item Open Access Steering in the parameter space of a mode-locked laser(EDP Sciences, 2024-10-18) Repgen, Paul; Şura, Aladin; Makey, Ghaith; İlday, Fatih Ömer; Michailovas A.; Mackenzie J.I.; Pirzio F.; Cormier E.The specific control of individual mode-locking states in an ultrafast laser requires knowledge about its phase space. We use a Mamyshev oscillator as a model nonlinear system to present an all-electronic manipulation and steering of nonlinear states. The targeted evolution of the states resembles genetic evolution, illustrated by the Waddington landscape.Item Open Access 50 GHz, 100 fs pulses at 100 W average power from a burst mode, all-single mode, Yb-doped fiber laser system(EDP Sciences, 2024-10-18) Laçin, Mesut; Repgen, Paul; Maghsoudi, Amirhossein; Şura, Aladin; Aydemir, Umut; İlday, Fatih Ömer; Michailovas A.; Mackenzie J.I.; Pirzio F.; Cormier E.We present a uniquely simple laser integrated in strictly single-mode fibers, producing bursts of 100-fs pulses at 50 GHz repetition rate at 100 W average power. This allows material processing with high efficiency and precision in the ablation-cooled regime.Item Open Access A synthetic pulse interaction for modelocking at ~100 GHz(EDP Sciences, 2024-10-18) Şura, Aladin; Maghsoudi, Amirhossein; İlday, Fatih Ömer; Michailovas A.; Mackenzie J.I.; Pirzio F.; Cormier E.Harmonic modelocking allows high repetition rates but has limited controllability and scalability. We propose a synthetic pulse-to-pulse interaction, acting like a saturable absorber, but imparting loss as a function of temporal delay, as a route to ultrahigh frequency fiber lasers.Item Open Access Reprogrammable metasurface design for NIR beam steering and active filtering(Institute of Physics Publishing Ltd., 2024-07-24) Hajian, Hodjat; Proffit, Matthieu; Özbay, Ekmel; Landais, Pascal; Bradley, A. LouiseReprogrammable metasurfaces enable active modulation of light at subwavelength scales. Operating in the microwave, terahertz, and mid-infrared ranges, these metasurfaces find applications in communications, sensing, and imaging. Electrically tunable metasurfaces operating in the near-infrared (NIR) range are crucial for light detection and ranging (LiDAR) applications. Achieving a NIR reprogrammable metasurface requires individual gating of nano-antennas, emphasizing effective heat management to preserve device performance. To this end, here we propose an electrically tunable Au-vanadium dioxide (VO2) metasurface design on top of a one-dimensional Si-Al2O3 photonic crystal (PC), positioned on a SiC substrate. Each individual Au-VO2 nano-antenna is switched from an Off to ON state via Joule heating, enabling the programming of the metasurface using 1-bit (binary) control. While operating as a nearly perfect reflector at lambda(0)=1.55 mu m, the materials, thickness, and number of the layers in the PC are carefully chosen to ensure it acts as a thermal metamaterial. Moreover, with high optical efficiency (R similar to 40% at lambda(0)), appropriate thermal performance, and feasibility, the metasurface also enables broadband programmable beam steering in the 1.4-1.7 mu m range for a wide steering angle range. This metasurface design also offers active control over NIR light transmittance, reflectance and absorptance in the wavelength range of 0.75-3 mu m. These characteristics render the device practical for LiDAR and active filtering.Item Open Access Photoinduced transition from quasi-two-dimensional Ruddlesden-Popper to three-dimensional halide perovskites for the optical writing of multicolor and light-erasable images(American Chemical Society, 2024-01-10) Anoshkin, Sergey S.; Shishkin, Ivan I.; Markina, Daria I.; Logunov, Lev S.; Demir, Hilmi Volkan; Rogach, Andrey L.; Pushkarev, Anatoly P.; (Makarov, Sergey V.Optical data storage, information encryption, and security labeling technologies require materials that exhibit local, pronounced, and diverse modifications of their structure-dependent optical properties under external excitation. Herein, we propose and develop a novel platform relying on lead halide Ruddlesden-Popper phases that undergo a light-induced transition toward bulk perovskite and employ this phenomenon for the direct optical writing of multicolor patterns. This transition causes the weakening of quantum confinement and hence a reduction in the band gap. To extend the color gamut of photoluminescence, we use mixed-halide compositions that exhibit photoinduced halide segregation. The emission of the films can be tuned across the range of 450-600 nm. Laser irradiation provides high-resolution direct writing, whereas continuous-wave ultraviolet exposure is suitable for recording on larger scales. The luminescent images created on such films can be erased during the visualization process. This makes the proposed writing/erasing platform suitable for the manufacturing of optical data storage devices and light-erasable security labels.