Article
Nanoscience & Nanotechnology
Maria Cristina Larciprete, Daniele Ceneda, Daniele Scire, Mauro Mosca, Dominique Persano Adorno, Sina Abedini Dereshgi, Roberto Macaluso, Roberto Li Voti, Concita Sibilia, Tiziana Cesca, Giovanni Mattei, Koray Aydin, Marco Centini
Summary: The tunability of vanadium dioxide's complex dielectric constants makes it a promising phase-change material for active and dynamic photonics applications. By doping vanadium dioxide with tungsten, the transition temperature of the material can be reduced to room temperature, allowing for further tunability. In this study, we investigated tungsten-doped vanadium dioxide thin films and achieved perfect absorption at different temperatures, demonstrating the potential for thermo-optical devices.
Article
Optics
Wanli Ma, Zhongguo Li, Hongtao Cao, Lingyan Liang, Haishuang Lu, Yushen Liu, Yinglin Song
Summary: This work investigates the modulation of ultrafast nonlinear optical response of SnO2 and SnO thin films by tuning oxygen partial pressure during film sputtering. The results show that intermediate phases have no significant impact on the two-photon absorption (TPA) response, but the effective nonlinear absorption coefficient (beta eff) is enhanced after changing the composition ratio of Sn2+/Sn4+. Furthermore, the intermediate phases accelerate carrier trapping and improve defect-related carrier absorption in SnOx films, while suppressing the TPA response in SnO2-x films.
Article
Optics
Rongyang Xu, Junichi Takahara
Summary: The paper proposes an all-dielectric perfect absorber based on degenerate critical coupling of quadrupole modes to overcome the limitation of maximum absorbance of free-standing ultra-thin films. It is found that perfect absorption can be achieved by spectrally overlapping peaks of electric and magnetic quadrupole modes, extending the degenerate critical coupling method beyond dipole modes. This all-dielectric perfect absorber can be utilized in photodetectors, optical filters, and optical modulators through photothermal effect.
Article
Optics
Dunjian Wang, Jie Luo, Zhouzhou Sun, Yun Lai
Summary: This work demonstrates a unique approach to realize geometry-invariant multi-channel coherent perfect absorbers by embedding ultrathin conductive films in zero-index media, revealing a mechanism to change material responses between zero-index media and coherent perfect absorbers.
Article
Chemistry, Multidisciplinary
Yujie Zhong, Yi Huang, Shuncong Zhong, Tingting Shi, Fuwei Sun, Tingling Lin, Qiuming Zeng, Ligang Yao, Xuefeng Chen
Summary: This study achieves frequency-agile absorption adjustments by utilizing the coupling between total reflection prism and electrically-driven MoS2. The redistribution of electric field and susceptible dielectric response are found to be attributed to limited spatial near-field perturbation. The study also demonstrates that perturbed MoS2 plasmon modes promote the formation of dual-phase singularities to suppress attenuation of absorption amplitude, extending the relative tuning range.
Article
Optics
A. K. M. Naziul Haque, Tashfiq Ahmed, Md Zunaid Baten
Summary: This study proposes and analyzes techniques for controlling the directionality of localized resonant modes of light in random arrays of dielectric scatterers. By gradually increasing randomness along a preferred direction, it is possible to enhance directionality of light emission. The research shows that, even in the absence of periodicity, more than 70% of output power can be emitted along the predefined direction in the disordered regime of the structure.
Article
Physics, Multidisciplinary
I. S. Burmistrov, I. Gornyi, A. D. Mirlin
Summary: This article discusses the formation mechanism of multifractal superconducting state and presents a theory of multifractal superconducting state in thin films. By deriving a modified Usadel equation, the study explores the impact of multifractal-enhanced superconductivity on low-energy physics and reveals strong mesoscopic fluctuations near the spectral gap in the superconducting state.
Article
Chemistry, Multidisciplinary
Andrew L. Bowman, Edwin P. Chan, William B. Lawrimore, John K. Newman
Summary: Through multimillion-atom reactive molecular dynamics simulations, the study predicts the behavior of nanomaterials during supersonic impacts, providing insights into energy absorption mechanisms at the nanoscale for design of materials with superior penetration resistance.
Article
Nanoscience & Nanotechnology
Andrea Ottomaniello, Paolo Vezio, Omar Tricinci, Frank M. Den Hoed, Paul Dean, Alessandro Tredicucci, Virgilio Mattoli
Summary: The continuously increasing interest in flexible and integrated photonics has led to the development of new strategies for manufacturing devices on complex surfaces and with small sizes. Terahertz (THz) technology can greatly benefit from this advancement to create compact systems for emitting, detecting, and manipulating THz radiation. This research presents a novel fabrication method that uses polymeric nanomembranes and direct laser writing to create conformable terahertz metasurfaces. By using new flexible dielectric materials with low absorption and permittivity, this work also enables the realization of ultra-thin, flexible hybrid or all-dielectric devices, expanding the application of THz technologies and flexible photonics.
Article
Energy & Fuels
Rania Afia Nuamah, Saleema Noormohammed, Dilip Kumar Sarkar
Summary: High capacitance Co-Co3O4 nanocomposite thin films were successfully synthesized using different electrodeposition modes, characterized by various techniques to obtain capacitance values and cycling performance, demonstrating their potential as high-performance supercapacitor electrodes.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Review
Chemistry, Multidisciplinary
Zhongkai Cheng, Deirdre M. O'Carroll
Summary: Photon recycling is crucial in the study of semiconductor materials, impacting their optoelectronic applications; however, further in-depth theoretical and experimental studies are needed to demonstrate its advantages and importance rigorously.
Article
Materials Science, Multidisciplinary
Meiling Chen, Jianda Shao, Yuanan Zhao, Guohang Hu, Meiping Zhu, Yingjie Chai, Kaixin Zhang, Hao Ma
Summary: With the development of ultra-short and ultra-intense lasers, the nonlinear response of wide bandgap oxide thin films has gradually emerged and attracted attention. This study proposes a method to suppress the substrate impact and improve the measurement sensitivity of the thin film, enabling effective measurement of the multiphoton absorption coefficient of wide bandgap oxide thin films. Furthermore, the measurements of nonlinear absorption response of wide bandgap oxide thin films can advance the design and fabrication of low-loss photonic devices in ultra-fast lasers.
OPTICAL MATERIALS EXPRESS
(2022)
Article
Optics
Mohammad Ali, A. K. M. Naziul Haque, Nafis Sadik, Tashfiq Ahmed, Md Zunaid Baten
Summary: In this work, a data-driven approach of machine learning is used to predict the most strongly confined resonant mode of light in strongly disordered systems of dielectric scatterers. A dataset of resonant characteristics is generated using finite difference time domain (FDTD) analysis technique, and a regression architecture-based deep neural network (DNN) is trained for prediction. The trained model can accurately predict the Anderson localized resonant wavelength of light in the disordered system, and shows robustness against different particle diameters and fill factors. The proposed model demonstrates the benefits of machine learning in predicting complex behavior of light in strongly disordered systems.
Article
Energy & Fuels
Mengyao Lyu, Jou Lin, Yuxin Wang, Ovais Aulakh, Nathan Ceja, Mary Sheryl Ramesh, Elisabeth Salazar, John Krupczak, Donglu Shi
Summary: A strategy of modulating the solar light spectrum to reduce the temperature dependency of photovoltaic power conversion efficiency (PCE) is developed, using photonic hybrids. Transparent thin films are synthesized with porphyrin compounds and iron oxides to absorb specific wavelengths from the solar spectrum, resulting in a decreased PCE decrease.
Article
Materials Science, Multidisciplinary
Km. Surbhi, Utkalika P. Sahoo, Pratap K. Sahoo, Ritwick Das
Summary: We conducted a detailed investigation on the impact of thermal annealing on the third-order nonlinear optical (NLO) properties of sputtered WSe2 thin films. The annealing process resulted in significant changes in the morphology and texture of the films, as well as a gradual shrinkage of the electronic bandgap. These changes led to enhanced optical limiting behavior in the annealed WSe2 films. The findings suggest that annealing allows for control of the NLO properties and makes the films more suitable candidates for optical limiters in high-power applications.
Article
Physics, Applied
Martin Stiehl, Marius Weber, Christopher Seibel, Jonas Hoefer, Sebastian T. Weber, Dennis M. Nenno, Hans Christian Schneider, Baerbel Rethfeld, Benjamin Stadtmueller, Martin Aeschlimann
Summary: This study investigates the effects of pump photon energy on ultrafast demagnetization dynamics in ferromagnetic nickel, revealing that magnetization dynamics primarily depend on absorbed energy rather than pump photon energy. Stark differences exist between optically excited electronic distributions and demagnetization dynamics, while the measured dynamics can be reproduced using a model based on local temperatures.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Rebecca Renner, Matthias Stolte, Julia Heitmueller, Tobias Brixner, Christoph Lambert, Frank Wuerthner
Summary: The study focused on the functional properties of different PBI anions and dianions with varying bay-substituents, revealing significant changes in their absorption spectra, indicating their potential for optoelectronic device applications.
MATERIALS HORIZONS
(2022)
Article
Optics
Martin Aeschlimann, Tobias Brixner, Felix Fenner, Benjamin Frisch, Patrick Folge, Michael Hartelt, Matthias Hensen, Thomas H. Loeber, Walter Pfeiffer, Sebastian Pres, Bernd Stannowski
Summary: This study demonstrates the imaging of localized modes in golden Vogel spirals using photoemission electron microscopy (PEEM). The ability to visualize these modes offers a means to explore mode dynamics and perform nanospectroscopy.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2023)
Article
Optics
Tobias Brixner, Stefan Mueller, Andreas Mueller, Andreas Knote, Wilhelm Schnepp, Samuel Truman, Anne Vetter, Sebastian von Mammen
Summary: We have developed an interactive simulation software, femtoPro, to efficiently teach the setup process of complex optical experiments. It implements physical models to calculate and visualize the propagation of Gaussian laser beams, ultrashort optical pulses, and their interaction with typical optical elements. The software can simulate various optical arrangements and spectroscopy schemes, allowing users to practice and learn practical skills in the field of (ultrafast) optics.
APPLIED PHYSICS B-LASERS AND OPTICS
(2023)
Article
Chemistry, Physical
Julian Luettig, Peter A. Rose, Pavel Maly, Arthur Turkin, Michael Buehler, Christoph Lambert, Jacob J. Krich, Tobias Brixner
Summary: Time-resolved spectroscopy is widely used to study various phenomena in chemistry, biology, and physics. This study focuses on pump-probe experiments and coherent two-dimensional (2D) spectroscopy, which have been successful in visualizing energy transfer and electronic couplings. The researchers demonstrate that the appearance of a two-quantum (2Q) signal indicates the contamination of a one-quantum (1Q) signal by non-negligible fifth-order interactions. By performing partial integrations, the study shows that clean rQ signals can be obtained in 2D spectra, free from higher-order artifacts.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Daniel Fersch, Pavel Maly, Jessica Ruhe, Victor Lisinetskii, Matthias Hensen, Frank Wurthner, Tobias Brixner
Summary: We introduce fluorescence-detected pump-probe microscopy, which combines a wavelength-tunable ultrafast laser with a confocal scanning fluorescence microscope, allowing access to femtosecond timescales on a micrometer spatial scale. We demonstrate this approach on a model system of a terrylene bisimide dye embedded in a PMMA matrix, obtaining both the linear excitation spectrum and time-dependent pump-probe spectra simultaneously. By analyzing the statistical distribution of excitation spectra from single molecules, we investigate the effect of the molecular environment on excited-state energy.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Pavel Maly, Julian Luettig, Peter A. Rose, Arthur Turkin, Christoph Lambert, Jacob J. Krich, Tobias Brixner
Summary: Quantum states depend on the coordinates of all their constituent particles, with essential multi-particle correlations. Time-resolved laser spectroscopy is widely used to probe the energies and dynamics of excited particles and quasiparticles. However, nonlinear signals from single- and multiple-particle excitations are all present simultaneously and cannot be disentangled without a priori knowledge of the system.
Article
Physics, Multidisciplinary
Sebastian Pres, Bernhard Huber, Matthias Hensen, Daniel Fersch, Enno Schatz, Daniel Friedrich, Victor Lisinetskii, Ruben Pompe, Bert Hecht, Walter Pfeiffer, Tobias Brixner
Summary: In this study, the local detection of nanoscale plasmon quantum wave packets was achieved using plasmon-assisted electron emission as a signal in coherent two-dimensional nanoscopy. The existence of a plasmon quantum wave packet was demonstrated, and an improved model for plasmon-assisted electron emission processes was provided.
Article
Chemistry, Physical
M. Baljozovic, B. Arnoldi, S. Grass, J. Lacour, M. Aeschlimann, B. Stadtmueller, K. -H. Ernst
Summary: It has been shown that electrons interact differently with chiral molecules depending on their polarization. Previous photoemission experiments on enantiomeric pure monolayers of heptahelicene reported opposite asymmetries in spin polarization, attributed to the chirality-induced spin selectivity effect. However, these experiments lack the necessary angular and energy resolution to understand the mechanism of this phenomenon. To fill in the gaps, a detailed spin- and angle-resolved photoemission spectroscopy study of heptahelicene layers on a Cu(111) substrate was conducted, but no chirality-induced spin asymmetry in photoemission was observed. Possible reasons for the absence of spin-dependent electron transmission signatures through the chiral molecular layer are briefly discussed.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Julian Luttig, Stefan Mueller, Pavel Maly, Jacob J. Krich, Tobias Brixner
Summary: Transient absorption and coherent two-dimensional spectroscopy are commonly used methods for studying ultrafast dynamics in quantum systems. This article discusses the potential of higher-order pump-probe and multidimensional spectroscopy in providing insight into excited multiparticle states and their dynamics. The authors demonstrate how phase cycling can be used to isolate higher-order spectra in fluorescence-detected two-dimensional spectroscopy, and discuss the power of coherently detected fifth-order 2D spectroscopy in tracking exciton diffusion. They also show how higher-order signals can be extracted from ordinary pump-probe experiments to study multiexciton interactions and provide annihilation-free signals at high excitation densities.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Correction
Multidisciplinary Sciences
Pavel Maly, Julian Luttig, Peter A. A. Rose, Arthur Turkin, Christoph Lambert, Jacob J. J. Krich, Tobias Brixner
Article
Chemistry, Multidisciplinary
Lea Ress, Pavel Maly, Jann B. Landgraf, Dominik Lindorfer, Michael Hofer, Joshua Selby, Christoph Lambert, Thomas Renger, Tobias Brixner
Summary: This article presents the experimental and theoretical foundations for femtosecond time-resolved circular dichroism (TRCD) spectroscopy of excitonic systems. A new experimental setup, with a polarization grating as the key element, is introduced to generate circularly polarized pulses for TRCD experiments. By applying a specific chopping scheme, left and right circular polarizations can be switched, and transient absorption (TA) and TRCD spectra can be detected simultaneously. Experiments on a squaraine polymer are performed to investigate excitonic dynamics, and a general theory for TRCD experiments of excitonically coupled systems is developed and applied to describe the experimental data.
Article
Chemistry, Physical
Julia Heitmueller, Rebecca Froehlich, Rebecca Renner, Frank Wuerthner, Tobias Brixner
Summary: In this study, ultrafast transient absorption spectroelectrochemistry and coherent two-dimensional electronic spectroelectrochemistry were performed on three different neutral perylene bisimide derivatives and their singly and doubly reduced species. The charged species showed significantly shorter lifetimes compared to the neutral ones. Additionally, Fermi resonance was observed in the flat dianion of parent perylene bisimide, indicating the potential for enhanced charge separation and triplet formation.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Julia Dietzsch, Ajay Jayachandran, Stefan Mueller, Claudia Hoebartner, Tobias Brixner
Summary: We synthesized and analyzed the spectroscopy of RNA with barbituric acid merocyanine rBAM2 as a nucleobase surrogate. Incorporating rBAM2 into RNA by solid-phase synthesis resulted in enhanced fluorescence compared to the free chromophore. Linear absorption studies showed the formation of an excitonically coupled H-type dimer in the hybridized duplex. Ultrafast transient absorption spectroscopy of the non-fluorescent dimer suggested immediate exciton transfer and annihilation within sub-200 fs due to the proximity of rBAM2 units.
CHEMICAL COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Martin Aeschlimann, Tobias Brixner, Mirko Cinchetti, Martin Feidt, Norman Haag, Matthias Hensen, Bernhard Huber, Tristan Kenneweg, Jobynson Kollamana, Christian Kramer, Walter Pfeiffer, Stefano Ponzoni, Benjamin Stadtmuller, Philip Thielen
Summary: This paper demonstrates a surface-sensitive two-dimensional coherent spectroscopy scheme based on photoelectron detection, studying the interface formed between Alq(3) and a ferromagnetic Co surface. Despite inhomogeneous linewidth broadening in the ensemble of disordered molecules, two narrow resonances are resolved, identifying them as LUMO to LUMO + 1 transitions in chemically decoupled second-layer Alq(3) molecules.
