Article
Spectroscopy
Konstantin A. Vereshchagin, Alexey K. Vereshchagin, Vyacheslav B. Morozov, Vladimir G. Tunkin
Summary: A cascade mechanism of radiation emerging in blue and red spectral ranges in the KTP crystal was discovered through non-collinear parametric down- and up-conversion. Injection seeding amplifies the radiation and leads to the appearance of specific radiation patterns corresponding to phase-matched processes between signal and idler waves in the crystal.
JOURNAL OF RAMAN SPECTROSCOPY
(2021)
Article
Optics
Feng Zhou, Xiyuan Lu, Ashutosh Rao, Jordan Stone, Gregory Moille, Edgar Perez, Daron Westly, Kartik Srinivasan
Summary: A novel scheme, called hybrid-mode-family OPO (hOPO), is proposed in this study, which uses different families of transverse spatial modes for optical parametric oscillation. Compared to traditional single-mode-family OPO, hOPO shows better robustness in dispersion, device geometry, pump frequency, and temperature, and is capable of generating coherent visible and infrared light sources efficiently.
LASER & PHOTONICS REVIEWS
(2022)
Article
Nanoscience & Nanotechnology
Agostino Di Francescantonio, Attilio Zilli, Davide Rocco, Laure Coudrat, Fabrizio Conti, Paolo Biagioni, Lamberto Duo, Aristide Lemaitre, Costantino De Angelis, Giuseppe Leo, Marco Finazzi, Michele Celebrano
Summary: By utilizing a nonlinear periodic metasurface, we have demonstrated all-optical routing of telecom photons upconverted to the visible range. This was achieved through the interference between two frequency-degenerate upconversion processes, namely third-harmonic and sum-frequency generation, controlled by tuning the relative phase and polarization between the pump beams. This technique allows for the modulation of the upconverted signal among the diffraction orders of the metasurface with high efficiency.
NATURE NANOTECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Gregoire Saerens, Thomas Dursap, Ian Hesner, Ngoc M. H. Duong, Alexander S. Solntsev, Andrea Morandi, Andreas Maeder, Artemios Karvounis, Philippe Regreny, Robert J. Chapman, Alexandre Danescu, Nicolas Chauvin, Jose Penuelas, Rachel Grange
Summary: The generation of high-rate photon pairs from nanoscale structures remains a challenge due to parasitic signals from the substrate. In this study, we achieved type-0 spontaneous parametric down-conversion at 1550 nm from individual bottom-up grown zinc-blende GaAs nanowires. The biphoton generation rate of 60 GHz/Wm achieved in this research is at least 3 times higher than that of previously reported single nonlinear micro-and nanostructures.
Article
Chemistry, Analytical
Qian Zhang, Cong Su, Xiaorui Tian, Chun-yang Zhang
Summary: In this study, a fluorescent biosensor with a low background was developed for label-free detection of long noncoding RNAs (lncRNAs). The biosensor utilized duplex-specific nuclease (DSN)-assisted target recycling amplification and transcription-driven synthesis of fluorogenic RNA aptamer-Corns. The biosensor demonstrated high sensitivity for quantifying lncRNA, capable of detecting as low as 31.98 aM. It could also accurately quantify lncRNA at the single-cell level and distinguish tumor cells from normal cells, offering potential for molecular diagnosis.
ANALYTICAL CHEMISTRY
(2023)
Article
Optics
Lars Behnke, Edcel J. Salumbides, Guido Goeritz, Yahia Mostafa, Dion Engels, Wim Ubachs, Oscar Versolato
Summary: This article describes a laser system that generates high-energy pulses at a wavelength of 2 μm with tunable pulse widths from 10-24 ns. It consists of an optical parametric oscillator that generates mJ-level signal seed radiation and an optical parametric amplifier that boosts the output to 800 mJ of combined signal and idler when pumped with 2 J pulses of 1064-nm laser light. The system is characterized in the spatial, temporal, and spectral domains while operating at a 10 Hz repetition rate with KTP crystals. The output pulses approach flat-top spatial and box-shaped temporal profiles due to the saturation effect, making it suitable for various applications. The amplified pulses can be imaged down to sub-100 μm diameters, making this laser system a suitable driver for plasma sources of extreme ultraviolet light.
Article
Engineering, Multidisciplinary
Hong Zhang, Jingye Yan, Xu Qian, Songhe Song
Summary: In this study, a new high-order unconditionally structure-preserving single-step method is proposed for solving Allen-Cahn-type parabolic equations. The method can unconditionally preserve the maximum principle and conserve mass, and it does not require limiters or cutoff post-processing. It offers a simple, practical, and effective approach to developing high-order unconditionally structure-preserving algorithms.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Optics
Xiaolu Hu, Quanlong Yang, Lingli Ba, Junliang Yang
Summary: Near-perfect light harvesting can be achieved with a metasurface-based absorber, which has numerous potential applications in sensing, cloaking, and photovoltaics. In this study, a reconfigurable perfect absorber based on a MoTe2 hybrid metasurface at terahertz frequency is presented. The optical response of the metasurface-based absorber shows a reconfigurable switching from dual-frequency perfect absorption to a new single-frequency absorption when illuminated by light. The absorption mechanism of the hybrid metasurface is well demonstrated with the analytical coupled-dipole model and impedance analysis. The proposed reconfigurable THz meta-absorber provides a new route for active radar stealth, frequency-selective detection, and next-generation wireless communication.
Article
Engineering, Electrical & Electronic
Liangliang Chen, Lin Guo, Deqiang Cheng, Qiqi Kou
Summary: This study proposes a structure-preserving and color-restoring up-sampling method for single low-light image super-resolution. By distinguishing reflectance and illumination, the limitations of existing methods on low-light images are addressed, and the quality of super-resolution texture is further improved through the reconstruction of gradient information.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY
(2022)
Article
Optics
A. Rasputnyi, D. A. Kopylov
Summary: Theoretical study of quantum cascaded up-conversion (CUpC) of parametric down conversion (PDC) in a finite nonlinear crystal is conducted within parametric approximation, highlighting the exact solutions in high-gain regime and the analysis of parametric amplification and oscillating regions for different mode cases. The influence of CUpC on quadrature squeezing of degenerate PDC is also estimated.
Article
Optics
Noah Flemens, Nicolas Swenson, Jeffrey Moses
Summary: The concept of efficient optical parametric amplification (OPA) based on simultaneously phase-matched idler second harmonic generation (SHG) is introduced, which allows for amplification efficiency exceeding that of conventional OPA. A Duffing oscillator model is developed to unify the description of conventional OPA and amplification accompanied by idler photon displacement. A spatiotemporal analysis predicts energy conversion up to 55% in devices based on birefringent or superlattice quasi-phase matching in common bulk media.
Article
Chemistry, Physical
Jie Zhang, Huizhong Ma, Xiao Zhang, Yuchen Ma
Summary: Metal-free perovskites have gained significant attention in optoelectronics and photonics due to their lack of toxic metal elements and chemical diversity. First-principles calculations reveal that the photoluminescence emission in metal-free perovskites originates from halogen vacancies rather than self-trapped excitons. Optical excitation near a halogen vacancy can lead to the release of H2 and NH3 molecules, causing degradation and quenching of the photoluminescence.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Haiming Wu, Ye-Guang Fang, Rajini Anumula, Gaya N. Andrew, Ganglong Cui, Weihai Fang, Zhixun Luo, Jiannian Yao
Summary: A highly stable Cu-doped undeca-gold cluster with a unique coordination structure was synthesized in this study. The nanocluster exhibits superatom stability and interesting optical properties, showing emissions in both ultraviolet-visible and near infrared regions with novel anti-Stokes up-conversion lasing characteristics.
Article
Polymer Science
Qiang Fu, Jiaqiang Rui, Jiaojiao Fang, Yaru Ni, Liang Fang, Chunhua Lu, Zhongzi Xu
Summary: This study utilizes TTA-UCL chromophores to achieve polymerization and photo curing reactions under visible light, and investigates the effects of chromophore concentration and incident light power on the reaction efficiency. The results demonstrate that an appropriate concentration of TTA-UCL chromophores is beneficial for various engineering applications including polymerization and adhesive bonding.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2022)
Article
Materials Science, Ceramics
Xiaoni Wang, Ting Li, Wenchao Liang, Chunchun Zhu, Liandong Guo
Summary: This study investigates the UCL properties of lanthanide ions doped BaTiO3 particles and demonstrates that Er3+ single doping can produce emission colors from green to yellow and orange depending on concentration and excitation wavelength. Additionally, introducing a small amount of Ho3+ can achieve pure red emission under 1550nm excitation, while Yb3+-Tm3+ co-doping results in intense blue emission under 980nm excitation.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
