Article
Optics
Jian Huang, Lianqun Yao, Shuyun Wu, Gongchang Wang
Summary: The Shack-Hartmann wavefront sensor is crucial in adaptive optics systems for detecting aberrant wavefronts. However, under-sampling due to imperfect micro-lenslets or pupil shift can lead to degraded wavefront reconstruction. This study evaluates the impact of under-sampling on wavefront reconstruction using an AO system simulation.
Article
Materials Science, Multidisciplinary
Yan Liang, Tianfei Zhu, Xinling Du, Jinliang Xu, Shuwei Fan, Hongxing Wang
Summary: A microlens array on a diamond for Shack Hartmann sensor was successfully fabricated using thermal reflow and dry etch technique. The diamond microlens array exhibited good uniformity, surface smoothness, and had the potential to work under harsh conditions.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Optics
Mingze Liu, Wenqi Zhu, Pengcheng Huo, Lei Feng, Maowen Song, Cheng Zhang, Lu Chen, Henri J. Lezec, Yanqing Lu, Amit Agrawal, Ting Xu
Summary: Monochromatic light has three fundamental properties: amplitude, phase, and polarization. A versatile transmission-mode all-dielectric metasurface platform is proposed in this work, capable of independently manipulating the phase and amplitude for two orthogonal states of polarization in the visible frequency range, enabling various light-field manipulation capabilities. This technology opens new possibilities in polarization optics, information encoding, and optical data storage.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Computer Science, Information Systems
Fanpeng Kong, Manuel Cegarra Polo, Andrew Lambert
Summary: We propose a fast and reconfigurable architecture for Shack-Hartmann wavefront sensing implemented on FPGA devices, which uses a stream-based center of gravity for spot displacement measurement. This method avoids the common trade-off between noise and bias errors and dynamic range caused by window size. It achieves high accuracy even when the spot moves across the sub-aperture boundary, resulting in an increased dynamic range. This architecture enables real-time wavefront sensing with low latency and high measurement accuracy on low-cost FPGA devices, making it a promising solution for multiple target objects and moderate scintillation conditions.
Article
Geochemistry & Geophysics
David Schvartzman, Sebastian M. Torres, Tian-You Yu
Summary: Key requirements for the future generation of weather surveillance radars include improved data quality and faster volumetric data updates. Phased array radar (PAR) is a candidate technology for meeting these requirements, with rotating phased array radar (RPAR) being a potential architecture that can enhance radar capabilities at a lower cost. However, the concept of operations for RPAR supporting observational needs needs to be developed. The Distributed Beams (DB) technique introduced in this article offers a way to reduce scan times or variance of radar-variable estimates by azimuthally spoiling the transmit beam while receiving multiple digital beams.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2021)
Article
Engineering, Electrical & Electronic
Jun Liu, Dian Jin, Weijian Liu, Danilo Orlando, Alfonso Farina
Summary: This paper addresses the problem of polarimetric adaptive detection in Gaussian disturbance with an unknown covariance matrix. A generalized likelihood ratio test (GLRT) based adaptive detector is proposed and the probabilities of detection and false alarm are analyzed. The simulation results show that the proposed GLRT has a constant false alarm rate property and the detection performance improves with an increase in the number of snapshots.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
Jian Zhou, Zhanling Wang, Chen Pang, Yongzhen Li, Xuesong Wang
Summary: This letter proposes a novel method to reconstruct the array pattern using fewer beam positions than elements, which reduces the pattern measurement cost of the PPAA while maintaining low reconstruction error and wide applicability. The effectiveness of the method is verified through the design of a 6x6 dual-polarized microstrip patch array and near-field measurement of a 4x4 microstrip patch array.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2021)
Article
Geochemistry & Geophysics
Zhe Li, Yan Zhang, Lesya Borowska, Igor R. Ivic, Djordje Mirkovic, Sudantha Perera, Guifu Zhang, Dusan S. Zrnic
Summary: This study combines theoretical analysis and actual measurements to evaluate the impacts of system modules on polarimetric data quality of phased array weather radars using a simulator. Biases of differential reflectivity, copolar correlation coefficient, and differential phase are used as data quality metrics, and comparisons between simulations and measurements are conducted.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2021)
Article
Multidisciplinary Sciences
Mohammad Alibakhshikenari, Bal S. Virdee, Dion Mariyanayagam, Valeria Vadala, Mohammad Naser-Moghadasi, Chan H. See, Iyad Dayoub, Sonia Aissa, Patrizia Livreri, Shah Nawaz Burokur, Anna Pietrenko-Dabrowska, Francisco Falcone, Slawomir Koziel, Ernesto Limiti
Summary: This study presents an innovative off-chip antenna design that achieves high gain and efficiency performance in the terahertz band with a wide operational bandwidth. By incorporating subwavelength circular dielectric slots and a metamaterial unit cell, the antenna's impedance bandwidth is doubled and average gain is increased by approximately 4 dB. Unlike traditional antennas, this technique significantly reduces energy losses. The antenna, with a size of 12.3 x 4.5 x 0.905 mm(3), operates in the 0.137-0.158 THz band with an average measured gain of 8.6 dBi and efficiency of 77%. These characteristics make it suitable for integration in sub-terahertz near-field electronic systems such as high-resolution radio frequency identification (RFID) devices.
SCIENTIFIC REPORTS
(2022)
Article
Engineering, Electrical & Electronic
Jian Zhou, Chen Pang, Zhanling Wang, Yongzhen Li, Xuesong Wang
Summary: In order to reduce the computation burden of optimal array patterns, a set of representative array patterns (RAPs) are proposed, whose number is smaller than that of active element patterns (AEPs). Each RAP corresponds to a representative beam. By optimizing the directions of these representative beams, the measured RAPs can substitute for all AEPs. Compared with using AEPs, the proposed method significantly reduces measurement cost and computation time. The stability of the proposed method under measurement errors is presented, and the method is verified on a practical C-band 4x4 dual-polarized microstrip patch array antenna.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Ammar Ahmed, Yimin D. Zhang
Summary: Novel generalized non-redundant sparse array design strategies are proposed to achieve the highest number of degrees-of-freedom for DOA estimation. The design framework provides non-redundant sparse array structures with minimum array aperture and maximum number of correlation lags, surpassing existing sparse array structures. Expansion in two new directions allows for arbitrary array aperture and reduced mutual coupling effects in the design.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2021)
Article
Acoustics
Alon Mamistvalov, Yonina C. Eldar
Summary: Efficient ultrasound systems can enhance clinical diagnosis capabilities by providing affordable and accessible high-quality images. This study introduces a compressed Fourier domain convolutional beamforming method, which reduces both array size and sampling rate while achieving high-resolution images.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2022)
Article
Optics
Yaling Yang, Yanli Zhang, Junyong Zhang, You Li, Dean Liu
Summary: Hartmann wavefront sensor is widely used in various fields, and a type of multifocal diffraction Taiji-lenslet array can improve measurement accuracy easily designed and manufactured via lithography, with great potential for application in the measurement of large-scale laser beams and optical elements.
Article
Engineering, Electrical & Electronic
Qianwei Zeng, Peng Yang, Hao Lin, Feng Yang, Shiwen Yang
Summary: A closed-form formulation for calculating the radiated power at sidebands of 4-D antenna arrays using a generalized element pattern has been derived, with u and v exponents greater than -1 and -1/2, respectively. The proposed expression is more efficient and accurate compared to numerical integration, as demonstrated through examples.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Hang Zheng, Chengwei Zhou, Zhiguo Shi, Guisheng Liao
Summary: This article proposes a sub-Nyquist tensor beamformer based on a coprimality constraint, which can handle the problem of ambiguous sidelobes caused by sparse sensor deployment and achieve better mainlobe enhancement and sidelobe attenuation.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2023)
Article
Optics
Andreas Niemeyer, Paul Schroff, Wonjun Choi, Jaecheol Cho, Andreas Naber, Wonshik Choi, Martin Wegener
Summary: In this study, the statistical wave properties of miniaturized versions of core-shell cloaking structures were investigated, revealing lower wave correlation for the neutral inclusion compared to a homogeneously disordered reference sample. Differences in statistics allowed for the identification of the neutral inclusion in the surrounding environment.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Yi Chen, Muamer Kadic, Martin Wegener
Summary: The authors introduce beyond-nearest-neighbour interactions as a mechanism for molding the flow of waves in acoustic metamaterials. They find that for strong third-nearest-neighbour interactions, this mechanism allows for engineering roton-like acoustical dispersion relations under ambient conditions.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Tobias Abele, Tobias Messer, Kevin Jahnke, Marc Hippler, Martin Bastmeyer, Martin Wegener, Kerstin Goepfrich
Summary: Through two-photon 3D laser printing, high precision hydrogel structures have been successfully manufactured inside preformed lipid vesicles, allowing for the deterministic positioning of cellular components. This technology can also create early functional architectures, such as transmembrane pores, for transporting biological cargo.
ADVANCED MATERIALS
(2022)
Article
Optics
Vincent Hahn, Tobias Messer, N. Maximilian Bojanowski, Ernest Ronald Curticean, Irene Wacker, Rasmus R. Schroeder, Eva Blasco, Martin Wegener
Summary: This study introduces a two-step absorption process using inexpensive light sources as an alternative to high-resolution fabrication by two-photon absorption with femtosecond lasers. The two-step absorption shows similar quadratic optical nonlinearity as two-photon absorption under suitable conditions, allowing for printing state-of-the-art 3D nanostructures. This work paves the way for drastic miniaturization and cost reduction of 3D laser nanoprinters while addressing issues associated with femtosecond lasers.
Article
Materials Science, Multidisciplinary
Alexander Muenchinger, Vincent Hahn, Dominik Beutel, Simon Woska, Joel Monti, Carsten Rockstuhl, Eva Blasco, Martin Wegener
Summary: This approach allows for the alignment of liquid crystal networks or elastomers in three dimensions during multi-photon laser printing, enabling the creation of 3D micro-heterostructures that exhibit large-amplitude elastic actuation under ambient conditions. It involves the use of a specialized sample cell with variable height and optical components to ensure a single well-defined laser focus for different electric field orientations.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Optics
Yi Huang, Minglong Li, Pu Tu, Haodong Zhu, Junyu Xia, Guangqiang He, ZhenYu Yang, Ming Zhao
Summary: In this study, two multi-value phase gratings (MVPGs) were numerically designed and experimentally fabricated. Compared to the traditional Damman grating (DG), MVPGs showed higher diffraction efficiency. The results demonstrated the potential of direct laser writing (DLW) technology in fabricating three-dimensional nano-scale diffractive optical elements.
Article
Optics
Vincent Hahn, Pascal Rietz, Frank Hermann, Patrick Mueller, Christopher Barner-Kowollik, Tobias Schloeder, Wolfgang Wenzel, Eva Blasco, Martin Wegener
Summary: In recent years, there has been a growing interest in high-speed, high-resolution optics-based 3D printing technology. By combining image projection with optical nonlinearity, researchers have successfully achieved high printing rates with small voxel volumes.
Article
Optics
Tie Hu, Xing Feng, Yunxuan Wei, Shengqi Wang, Yuhong Wei, Zhenyu Yang, Ming Zhao
Summary: Zoom metalens doublets offer compactness, strong zoom capability, and compatibility with CMOS, surpassing the advantages of traditional refractive zoom lenses. However, the issue of chromatic aberration limits their potential in broadband systems. In this study, we globally optimized the phase profiles in the visible range and successfully demonstrated a moire lens-based zoom metalens doublet that can work achromatically in the 440-640 nm band. This doublet achieves a continuous zoom range from 1x to 10x, while maintaining high focusing efficiency up to 86.5% and polarization insensitivity.
Article
Physics, Multidisciplinary
Vibhuti Rai, Lukas Gerhard, Nico Balzer, Michal Valasek, Christof Holzer, Liang Yang, Martin Wegener, Carsten Rockstuhl, Marcel Mayor, Wulf Wulfhekel
Summary: This article presents a new method to activate single molecules by decoupling them from a metallic substrate using the tip of a scanning tunneling microscope, thus achieving individual molecule luminescence. The emission performance of this method compares favorably in terms of quantum efficiency, stability, and reproducibility to that of single molecules deposited on thin insulating layers.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Natalie Munding, Magdalena Fladung, Yi Chen, Marc Hippler, Anthony D. Ho, Martin Wegener, Martin Bastmeyer, Motomu Tanaka
Summary: Cell behaviors depend on the elastic properties of the microenvironments, which differ from polymer-based substrates. Metamaterials, with adjustable elastic properties, offer a promising way to mechanically control stem cells. By designing microstructured bio-metamaterials based on a silicon elastomer-like photoresist and two-photon laser printing, the differential responses of human mesenchymal stem cells (hMSCs) correlate with the calculated elastic properties of the bio-metamaterials, suggesting the potential of using bio-metamaterials for cell behavior regulation.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Michael Fidelis Gross, Jonathan Ludwig Guenter Schneider, Yu Wei, Yi Chen, Sebastian Kalt, Muamer Kadic, Xiaoning Liu, Genkai Hu, Martin Wegener
Summary: In classical Cauchy elasticity, 3D materials have six eigenmodes of deformation. Extremal elastic materials are classified based on the number of easy eigenmodes out of these six, leading to hexamode (N=6), pentamode (N=5), tetramode (N=4), trimode (N=3), dimode (N=2), and monomode (N=1) materials. Pentamode metamaterials have attracted significant attention, and in this study, microstructured 3D polymer-based tetramode metamaterials were designed, characterized, and compared to theoretical expectations. The potential application as a compact and broadband polarizer for acoustical phonons at ultrasound frequencies was demonstrated.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
Richard Craster, Sebastien Guenneau, Muamer Kadic, Martin Wegener
Summary: Mechanical metamaterials, designed composites with elastic behaviors and effective mechanical properties beyond those of their individual ingredients, have made significant progress in the last decade due to advances in computational science and manufacturing. This review provides a tutorial on its mathematical basis and summarizes the state-of-the-art in both conceptual and experimental aspects.
REPORTS ON PROGRESS IN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Yi Chen, Ke Wang, Muamer Kadic, Sebastien Guenneau, Changguo Wang, Martin Wegener
Summary: Previous theory and experiment have shown that introducing strong nonlocal interactions in addition to local interactions into metamaterials can lead to unusual wave dispersion relations. In this study, the authors investigate the frequency-dependent acoustical phonon transmission in a slab of nonlocal metamaterial. They find a series of bound states in the continuum and sharp transmission resonances next to sharp transmission minima. The findings are validated by numerical calculations on three-dimensional metamaterial microstructures.
COMMUNICATIONS PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Ke Wang, Yi Chen, Muamer Kadic, Changguo Wang, Martin Wegener
Summary: By introducing a two-dimensional metamaterial platform, we utilize nonlocal effects as a powerful design tool to control the wave properties of metamaterials. The study shows that the lowest band can be engineered by Fourier synthesis, and waves can be transferred from a local metamaterial to a nonlocal metamaterial through a carefully designed transition region.
COMMUNICATIONS MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Tobias Frenzel, Vincent Hahn, Patrick Ziemke, Jonathan Ludwig Gunter Schneider, Yi Chen, Pascal Kiefer, Peter Gumbsch, Martin Wegener
Summary: This study solves three challenges of chiral metamaterials through providing an analytical model, using advanced manufacturing technology, and employing numerical modeling. By designing the chiral characteristic length, samples with sizes exceeding 10(5) micrometers have been successfully manufactured, changing the sample-size dependence.
COMMUNICATIONS MATERIALS
(2021)
