Article
Optics
Md Borhan Mia, Nafiz Jaidye, Ishtiaque Ahmed, Syed Z. Ahmed, Sangsik Kim
Summary: We propose a broadband integrated photonic polarization splitter and rotator (PSR) using adiabatically tapered coupled waveguides with subwavelength grating (SWG) claddings. The SWGs act as an anisotropic metamaterial, enabling efficient and broadband modal conversions. Experimental results show that the proposed PSR operates at wavelengths ranging from 1500 to 1750 nm, with an extinction ratio larger than 20 dB and insertion losses below 1.3 dB.
Article
Physics, Applied
Yinghui Ren, Xiaogang Wang, Chijie Xiao
Summary: This research analyzes the field enhancement properties of a subwavelength metallic groove and finds that the field enhancement varies periodically with groove depth. Additionally, rounding the sharp vertices at the inlet of the groove and the incident angle also affect the field enhancement.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Sixian Ren, Lei Zhou, Jinpeng Yang, Yun Zhou
Summary: The study introduces a novel polarizing color filter design based on a one-dimensional subwavelength grating, allowing for different colors of TM-polarized light transmission by adjusting the geometric parameter of period. Theoretical analyses show that cavity modes and guide mode resonant contribute to enhancing optical TM polarized light transmission.
Article
Nanoscience & Nanotechnology
Weixin Liu, Yiming Ma, Yuhua Chang, Bowei Dong, Jingxuan Wei, Zhihao Ren, Chengkuo Lee
Summary: This study developed an LWIR photonic platform for gas sensing, utilizing suspended silicon waveguides and subwavelength grating metamaterial claddings. The platform was shown to have low propagation and bending losses, and functional devices such as grating couplers and Y-junctions demonstrated high performance. Sensing capabilities were showcased with toluene vapor detection, achieving a limit of detection of 75 ppm. The platform showed promise for on-site medical and environmental applications with fast response and recovery times.
Article
Optics
S. Hadi Badri
Summary: A highly sensitive and selective CO2 gas sensor is developed based on a subwavelength grating (SWG) slot waveguide filled with Polyhexamethylene biguanide (PHMB). The sensitivity of the sensor is significantly higher than previous designs at S = 12.9 pm/ppm, attributed to the strong light-matter interaction in the slot gap filled with functional material. This novel structure can be utilized to design various sensors sensitive to different analytes.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Physics, Applied
Aibibula Abudula, Zhijun Sun
Summary: This report presents a metallic grating-incorporated Fabry-Perot cavity structure that exhibits asymmetric optical transmission (AOT) regardless of transmission modes. The asymmetric transmission is mainly attributed to the asymmetric coupling and decoupling of resonant surface plasmons (SPs) on both sides of the metallic grating with asymmetric media of different refractive indices. Additionally, by coupling the SP mode with the anti-resonance mode of the F-P cavity in orthogonal directions, the transmission characteristics of the structure for asymmetric transmission are further optimized, leading to a high contrast AOT achieved by locating the SP resonance position at the center of the anti-resonance band of the F-P cavity.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Multidisciplinary
Songsong Li, Yangyang Fu, Lei Gao, Jian-Hua Jiang, Yadong Xu
Summary: In this study, the concept of phase gradient metasurfaces is demonstrated to be a versatile approach for controlling light diffraction through small holes or slits. A single subwavelength metallic slit surrounded by air grooves of gradient depth is considered as an example. The phase gradient enables unidirectional excitation of surface plasmons, resulting in extraordinary optical transmission. Unidirectional radiation of an optical dipole inside the slit can be achieved by applying different phase gradients to both sides of the metal plate.
NEW JOURNAL OF PHYSICS
(2023)
Article
Optics
Danfeng Zhu, Han Ye, Yumin Liu, Jing Li, Yanrong Wang, Zhongyuan Yu
Summary: This study introduces a novel silicon-based asymmetric directional coupler, utilizing subwavelength grating anisotropic metamaterial in the 2 μm waveband. Mode conversions with high transmittance and mode purity are achieved, as well as a reciprocal optical diode with a high contrast ratio. A symmetric 3 dB mode converter and splitter is also presented, demonstrating high transmittance and low transmittance difference within the waveband.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
M. Y. Zaki, F. Sava, I. D. Simandan, A. T. Buruiana, C. Mihai, A. Velea, A. C. Galca
Summary: Cu2SnSe3 (CTSe) is a versatile material that can be used as an absorber layer in thin film solar cells or as a starting layer for the synthesis of CZTSe or CZTSSe compounds. However, obtaining CTSe single phase films with optimized properties for solar cells is challenging. In this study, different stack configurations were prepared and analyzed, and it was found that the SnSe2\Cu and Sn\Cu2Se stacks showed the best performance in terms of single phase formation, surface morphology, stoichiometric composition, and band gap.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Multidisciplinary Sciences
Jinhua Sun, Matthew Sadd, Philip Edenborg, Henrik Gronbeck, Peter H. Thiesen, Zhenyuan Xia, Vanesa Quintano, Ren Qiu, Aleksandar Matic, Vincenzo Palermo
Summary: The study introduces a novel Janus graphene for sodium ion storage, demonstrating a different mechanism of sodium storage compared to graphite and stacked graphene. Through density functional theory calculations and experimental validation, the synergic ionic bonds formation process between Na+ and graphene is revealed.
Article
Optics
Liang Zhang, Jinbiao Xiao
Summary: A compact and broadband mode demultiplexer using a subwavelength grating engineered multimode interference coupler is proposed, achieving low insertion loss and cross talk over a wide bandwidth by carefully choosing structural parameters. The device shows good fabrication tolerance and performance for TE0/TE1 input at 1550 nm within a short device length.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Haifeng Mao, Xianshan Dong, Yihui Liu
Summary: This paper presents a MEMS tunable hyperspectral Fabry-Perot filter based on a suspended tensile-strained single-layer dielectric two-dimensional subwavelength grating (2-D SWG) mirror. The fabricated mirror demonstrates high reflectivity and surface flatness, and a proof-of-concept tunable filter with a large wavelength tuning range and high peak transmission has been achieved. Compared to DBR-based tunable filters, the presented 2-D SWG mirror based tunable filter shows a higher figure-of-merit.
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
(2023)
Article
Chemistry, Multidisciplinary
Mei Wang, Chiwoo Park, Taylor J. Woehl
Summary: This study utilized liquid phase transmission electron microscopy to directly observe the self-assembly of platinum nanoparticles into dense 3D supraparticles over tens of seconds during colloidal nanoparticle synthesis. Varying interparticle interactions by changing precursor chemistry revealed that supraparticle formation was driven by weak attractive van der Waals forces balanced by short ranged repulsive steric interactions. Growth kinetic measurements and an interparticle interaction model showed that nanoparticle surface diffusion rates on the supraparticles were significantly faster than nanoparticle attachment.
Article
Optics
Jun Yang, Guozhen Zhang, Lu Xu, Ying LI, Guangsheng Deng, Zhiping Yin, Hongbo Lu
Summary: This work demonstrates a tunable cross-polarized transmission structure at the terahertz frequency and investigates the polarization state during modulation. By improving the resonance process in a Fabry-Perot-like resonant cavity, the proposed structure significantly enhances the polarization conversion performance.
Article
Physics, Applied
Mingxuan Wu, Qinghua Liao
Summary: An asymmetric transmission device combining gradient metasurface and subwavelength grating is proposed in this paper, showing high working efficiency and a high-contrast ratio up to 41 dB. All materials used in the device are dielectric.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Steffen Both, Martin Schaeferling, Florian Sterl, Egor A. Muljarov, Harald Giessen, Thomas Weiss
Summary: Nanophotonic chiral sensing, which exploits the strong light-matter interaction in nanophotonic resonators, has gained significant attention for its potential applications in life science and chemistry. However, a comprehensive understanding of the underlying interactions is still lacking. In this study, we present a general theory that describes chiral light-matter interactions in arbitrary resonators, providing deep insights for customization and enhancement of such interactions. Our theory efficiently predicts spectra and identifies two dominant contributions: chirality-induced resonance shift and changes in excitation and emission efficiencies of the resonator modes.
Article
Optics
Andrea Toulouse, Johannes Drozella, Pascal Motzfeld, Nils Fahrbach, Valese Aslani, Simon Thiele, Harald Giessen, Alois M. Herkommer
Summary: This research introduces the concepts, correction methods, and realizations of freeform multi-aperture wide-angle cameras fabricated by femtosecond direct laser writing (fsDLW). By splitting the field of view (FOV) into multiple apertures and using special lens shapes and catadioptric elements, a flat-form factor 180 degrees x 360 degrees camera can be created in the micrometer range. The study also presents methods for measuring and correcting freeform surfaces using confocal measurements and iterative fabrication via fsDLW. Additionally, approaches for digital distortion correction and image stitching are demonstrated, and two realizations of freeform multi-aperture wide-angle cameras are presented.
Article
Chemistry, Analytical
Emilio Corcione, Diana Pfezer, Mario Hentschel, Harald Giessen, Cristina Tarin
Summary: This paper explores the application of optical sensing methods for glucose measurement and improves the accuracy and reliability of glucose concentration prediction through advanced machine learning regression algorithms. The limitations of sensing are also discussed.
Article
Optics
Aashutosh Kumar, Asa Asadollahbaik, Jeongmo Kim, Khalid Lahlil, Simon Thiele, Alois M. Herkommer, Sile Nic Chormaic, Jongwook Kim, Thierry Gacoin, Harald Giessen, Jochen Fick
Summary: In this study, NaYF4:Eu nanorods with high aspect ratios were successfully manipulated and optically trapped using dual fiber optical tweezers, with a focus on trapping efficiency, alignment, cluster trapping, motion coupling, and emission characteristics. The europium emission was studied through polarization-resolved spectroscopy, determining the orientation of different emission lines with respect to the nanorod axes. The findings suggest that nanorod orientation can be determined by spectroscopic means.
PHOTONICS RESEARCH
(2022)
Article
Optics
Lucas Bremer, Carlos Jimenez, Simon Thiele, Ksenia Weber, Tobias Huber, Sven Rodt, Alois Herkommer, Sven Burger, Sven Hoefling, Harald Giessen, Stephan Reitzenstein
Summary: We conducted extended numerical studies to optimize the photon extraction and fiber-coupling efficiency of nanoscale quantum dot single-photon sources, achieving an overall photon coupling efficiency of up to 83%. Our work provides objective comparability for different fiber-coupled single-photon sources and proposes optimized geometries for practical and highly efficient quantum dot single-photon sources.
Article
Optics
Abdullah Alabbadi, Tobias Steinle, Harald Giessen
Summary: We present a compact and passively stable optical parametric oscillator that can directly generate sub-40 fs pulses, five times shorter than the 200 fs pump oscillator. By utilizing an intracavity all normal dispersion feedback fiber, we have achieved low-noise and coherent broadening beyond the bandwidth limitation of the parametric gain. The demonstrated spectral coverage ranges from 1.1 to 2.0 μm with excellent passive power and spectral stability below 0.1% rms, all in a compact footprint smaller than 14x14 cm(2).
Article
Chemistry, Multidisciplinary
Jiawen Li, Simon Thiele, Rodney W. Kirk, Bryden C. Quirk, Ayla Hoogendoorn, Yung Chih Chen, Karlheinz Peter, Stephen J. Nicholls, Johan W. Verjans, Peter J. Psaltis, Christina Bursill, Alois M. Herkommer, Harald Giessen, Robert A. McLaughlin
Summary: Multimodal microendoscopes enable simultaneous structural and molecular measurements in vivo, providing valuable insights into pathological changes associated with diseases. However, different optical imaging modalities have conflicting requirements for lens design, posing a challenge for the fabrication of miniaturized imaging probes. This study demonstrates an optical design using two-photon 3D printing to create a miniaturized lens that is optimized for both fluorescence and optical coherence tomography (OCT) imaging. The lens-in-lens design shows significant improvement in fluorescence sensitivity compared to conventional fiber-optic design approaches, and is successfully integrated into an intravascular catheter probe for simultaneous OCT and fluorescence imaging of a mouse artery in vivo.
Article
Materials Science, Multidisciplinary
Simon Ristok, Philipp Flad, Harald Giessen
Summary: 3D printing of micro-optics is a powerful method for fabricating sub-millimeter sized optics. By utilizing conformal low-temperature thermal atomic layer deposition, we are able to overcome the limitation of coating individual lenses in 3D printed optical systems. Our 4-layer design reduces the reflectivity of coated substrates in the visible range to below 1%. We find that the reflectivity is significantly reduced and transmission is enhanced, which is particularly important for low-light applications.
OPTICAL MATERIALS EXPRESS
(2022)
Article
Materials Science, Multidisciplinary
Philipp Karl, Sandra Mennle, Monika Ubl, Mario Hentschel, Philipp Flad, Jing-Wei Yang, Tzu-Yu Peng, Yu-Jung Lu, Harald Giessen
Summary: The development of photon-based technologies such as quantum cryptography and quantum computing relies on high-fidelity and fast photodetectors capable of detecting single photons. Superconducting nanowire single photon detectors, utilizing the superconducting-to-normal conducting phase transition, offer a promising solution. Using resonant plasmonic perfect absorber effects, these detectors can achieve high efficiency, polarization-independent absorption at a specific wavelength. Additionally, the target wavelength can be easily adjusted by modifying the detector's geometry.
OPTICAL MATERIALS EXPRESS
(2022)
Article
Chemistry, Multidisciplinary
Hongfeng Ma, Nicolas Dalloz, Amaury Habrard, Marc Sebban, Florian Sterl, Harald Giessen, Mathieu Hebert, Nathalie Destouches
Summary: This article explores the use of deep neural networks and laser processing technology to predict the optical properties of laser-induced plasmonic metasurfaces and achieve printing image multiplexing. The study validates the effectiveness of the deep learning approach and provides a simple mining algorithm for implementing multiplexing with multiple observation modes and colors. This research is important for optimizing laser processes in high-end applications such as security, entertainment, or data storage.
Article
Optics
Julian Schwab, Ksenia Weber, Johannes Drozella, Carlos Jimenez, Alois Herkommer, Lucas Bremer, Stephan Reitzenstein, Harald Giessen
Summary: This study discusses the coupling efficiency of single-photon sources into single-mode fibers using 3D printed micro-optical lens designs. It optimizes lens systems for two different quantum light sources and evaluates the results in terms of maximum coupling efficiencies, misalignment effects, and thermo-optical influences.
Article
Chemistry, Analytical
Diana Pfezer, Julian Karst, Mario Hentschel, Harald Giessen
Summary: The detection and quantification of glucose in human blood or ocular fluid is crucial for diabetes patients. In this study, plasmonic nanoantennas and PCA were used to enhance the detection of glucose and other saccharides in complex aqueous environments. The results showed that the sensor achieved reliable detection and discrimination of saccharide concentrations down to physiological levels, which will greatly improve the detection of biomolecules in different complex environments.
Article
Quantum Science & Technology
Pavel Ruchka, Sina Hammer, Marian Rockenhauser, Ralf Albrecht, Johannes Drozella, Simon Thiele, Harald Giessen, Tim Langen
Summary: This paper introduces a new trapping concept for ultracold atoms in optical tweezers using micrometer-scale lenses 3D printed onto the tip of standard optical fibers. These lenses have unique properties that make them suitable for both trapping individual atoms and capturing their fluorescence with high efficiency. The vacuum compatibility and robustness of the structures were tested in an exploratory experiment and a magneto-optical trap for ultracold atoms was successfully formed, showing promise for portable atomic quantum devices.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Johannes Drozella, Andrea Toulouse, Pascal Motzfeld, Nils Fahrbach, Valese Aslani, Simon Thiele, Alois M. Herkommer, Harald Giessen
Summary: Modern two-photon-polymerization 3D printing technology allows for the creation of complex freeform optical surfaces with high control and accuracy. However, there may still be some systematic deviation due to volumetric changes during the polymerization and development process. This paper presents a method to include repeatable measurements and shape correction during the production process of monolithically created complex freeform lens systems. An example of its application for creating low profile multi-aperture large field of view objectives is also provided.
LASER-BASED MICRO- AND NANOPROCESSING XVI
(2022)
Article
Nanoscience & Nanotechnology
Pascal Dreher, David Janoschka, Alexander Neuhaus, Bettina Frank, Harald Giessen, Michael Horn-von Hoegen, Frank-J Meyer Zu Heringdorf
Summary: This study utilizes spectroscopic photoemission microscopy to detect and quantify the energy shift of electrons emitted from a surface plasmon polariton focus. The field strength of the surface plasmon polariton was determined without free parameters based on the shift of electron peaks as function of laser power.