Trapping of resonant metallic nanoparticles with engineered vectorial optical field

AbstractOptical trapping and manipulation using focused laser beams has emerged as a powerful tool in the biological and physical sciences. However, scaling this technique to metallic nanoparticles remains challenging due to the strong scattering force and optical heating effect. In this work, we propose a novel strategy to optically trap metallic nanoparticles even under the resonant condition using engineered optical field. The distribution of the optical forces can be tailored through optimizing the spatial distribution of a vectorial optical illumination to favour the stable trapping of a variety of metallic nanoparticles under various conditions. It is shown that this optical tweezers has the ability of generating negative scattering force and supporting stable three-dimensional trapping for gold nanoparticles at resonance while avoiding trap destabilization due to optical overheating. The technique presented in this work offers a versatile solution for trapping metallic nanoparticles and may open up new avenues for optical manipulation.

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Polarization-sensitive photodetectors based on three-dimensional molybdenum disulfide (MoS2) field-effect transistors

Nanophotonics ◽

10.1515/nanoph-2020-0401 ◽

2020 ◽

Vol 9 (16) ◽

pp. 4719-4728

Author(s):

Tao Deng ◽

Shasha Li ◽

Yuning Li ◽

Yang Zhang ◽

Jingye Sun ◽

...

Keyword(s):

Molybdenum Disulfide ◽

Field Effect ◽

High Performance ◽

Field Effect Transistors ◽

Three Dimensional ◽

Polarized Light ◽

Optical Field ◽

Two Dimensional ◽

Polarization Ratio ◽

Two Dimensional Materials

AbstractThe molybdenum disulfide (MoS2)-based photodetectors are facing two challenges: the insensitivity to polarized light and the low photoresponsivity. Herein, three-dimensional (3D) field-effect transistors (FETs) based on monolayer MoS2 were fabricated by applying a self–rolled-up technique. The unique microtubular structure makes 3D MoS2 FETs become polarization sensitive. Moreover, the microtubular structure not only offers a natural resonant microcavity to enhance the optical field inside but also increases the light-MoS2 interaction area, resulting in a higher photoresponsivity. Photoresponsivities as high as 23.8 and 2.9 A/W at 395 and 660 nm, respectively, and a comparable polarization ratio of 1.64 were obtained. The fabrication technique of the 3D MoS2 FET could be transferred to other two-dimensional materials, which is very promising for high-performance polarization-sensitive optical and optoelectronic applications.

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Membrane fusion studied by colloidal probes

European Biophysics Journal ◽

10.1007/s00249-020-01490-5 ◽

2021 ◽

Vol 50 (2) ◽

pp. 223-237 ◽

Cited By ~ 1

Author(s):

Hannes Witt ◽

Filip Savić ◽

Sarah Verbeek ◽

Jörn Dietz ◽

Gesa Tarantola ◽

...

Keyword(s):

Membrane Fusion ◽

Optical Tweezers ◽

Three Dimensional ◽

Biological Processes ◽

Supported Membranes ◽

Supported Bilayers ◽

Force Microscopy ◽

Advantages And Disadvantages ◽

Atomic Force ◽

Colloidal Probes

AbstractMembrane-coated colloidal probes combine the benefits of solid-supported membranes with a more complex three-dimensional geometry. This combination makes them a powerful model system that enables the visualization of dynamic biological processes with high throughput and minimal reliance on fluorescent labels. Here, we want to review recent applications of colloidal probes for the study of membrane fusion. After discussing the advantages and disadvantages of some classical vesicle-based fusion assays, we introduce an assay using optical detection of fusion between membrane-coated glass microspheres in a quasi two-dimensional assembly. Then, we discuss free energy considerations of membrane fusion between supported bilayers, and show how colloidal probes can be combined with atomic force microscopy or optical tweezers to access the fusion process with even greater detail.

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Photothermally induced transparency

Science Advances ◽

10.1126/sciadv.aax8256 ◽

2020 ◽

Vol 6 (8) ◽

pp. eaax8256 ◽

Cited By ~ 2

Author(s):

Jinyong Ma ◽

Jiayi Qin ◽

Geoff T. Campbell ◽

Ruvi Lecamwasam ◽

Kabilan Sripathy ◽

...

Keyword(s):

Electromagnetically Induced Transparency ◽

Thermal Response ◽

Nonlinear Behavior ◽

Optical Field ◽

Optical Resonator ◽

Mechanical Resonators ◽

Remarkable Effect ◽

Optical Heating ◽

Fast Light ◽

Induced Transparency

Induced transparency is a common but remarkable effect in optics. It occurs when a strong driving field is used to render an otherwise opaque material transparent. The effect is known as electromagnetically induced transparency in atomic media and optomechanically induced transparency in systems that consist of coupled optical and mechanical resonators. In this work, we introduce the concept of photothermally induced transparency (PTIT). It happens when an optical resonator exhibits nonlinear behavior due to optical heating of the resonator or its mirrors. Similar to the established mechanisms for induced transparency, PTIT can suppress the coupling between an optical resonator and a traveling optical field. We further show that the dispersion of the resonator can be modified to exhibit slow or fast light. Because of the relatively slow thermal response, we observe the bandwidth of the PTIT to be 2π × 15.9 Hz, which theoretically suggests a group velocity of as low as 5 m/s.

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Assembly of multicomponent structures from hundreds of micron-scale building blocks using optical tweezers

Microsystems & Nanoengineering ◽

10.1038/s41378-021-00272-z ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Jeffrey E. Melzer ◽

Euan McLeod

Keyword(s):

Optical Tweezers ◽

Three Dimensional ◽

Building Blocks ◽

Optical Tweezer ◽

Device Fabrication ◽

Positional Accuracy ◽

Component Structure ◽

Material Development ◽

Critical Process Parameters ◽

Optical Positioning

AbstractThe fabrication of three-dimensional (3D) microscale structures is critical for many applications, including strong and lightweight material development, medical device fabrication, microrobotics, and photonic applications. While 3D microfabrication has seen progress over the past decades, complex multicomponent integration with small or hierarchical feature sizes is still a challenge. In this study, an optical positioning and linking (OPAL) platform based on optical tweezers is used to precisely fabricate 3D microstructures from two types of micron-scale building blocks linked by biochemical interactions. A computer-controlled interface with rapid on-the-fly automated recalibration routines maintains accuracy even after placing many building blocks. OPAL achieves a 60-nm positional accuracy by optimizing the molecular functionalization and laser power. A two-component structure consisting of 448 1-µm building blocks is assembled, representing the largest number of building blocks used to date in 3D optical tweezer microassembly. Although optical tweezers have previously been used for microfabrication, those results were generally restricted to single-material structures composed of a relatively small number of larger-sized building blocks, with little discussion of critical process parameters. It is anticipated that OPAL will enable the assembly, augmentation, and repair of microstructures composed of specialty micro/nanomaterial building blocks to be used in new photonic, microfluidic, and biomedical devices.

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Weakening of resistance force by cell–ECM interactions regulate cell migration directionality and pattern formation

Communications Biology ◽

10.1038/s42003-021-02350-4 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Masaya Hagiwara ◽

Hisataka Maruyama ◽

Masakazu Akiyama ◽

Isabel Koh ◽

Fumihito Arai

Keyword(s):

Cell Migration ◽

Pattern Formation ◽

Epithelial Cells ◽

Optical Tweezers ◽

Three Dimensional ◽

Lung Epithelial Cells ◽

Resistance Force ◽

Collective Cell Migration ◽

Physical Forces ◽

Cellular Movement

AbstractCollective migration of epithelial cells is a fundamental process in multicellular pattern formation. As they expand their territory, cells are exposed to various physical forces generated by cell–cell interactions and the surrounding microenvironment. While the physical stress applied by neighbouring cells has been well studied, little is known about how the niches that surround cells are spatio-temporally remodelled to regulate collective cell migration and pattern formation. Here, we analysed how the spatio-temporally remodelled extracellular matrix (ECM) alters the resistance force exerted on cells so that the cells can expand their territory. Multiple microfabrication techniques, optical tweezers, as well as mathematical models were employed to prove the simultaneous construction and breakage of ECM during cellular movement, and to show that this modification of the surrounding environment can guide cellular movement. Furthermore, by artificially remodelling the microenvironment, we showed that the directionality of collective cell migration, as well as the three-dimensional branch pattern formation of lung epithelial cells, can be controlled. Our results thus confirm that active remodelling of cellular microenvironment modulates the physical forces exerted on cells by the ECM, which contributes to the directionality of collective cell migration and consequently, pattern formation.

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Numerical study of the turbulent natural convection of nanofluids in a partially heated cubic cavity

Thermal Science ◽

10.2298/tsci200513057l ◽

2021 ◽

pp. 57-57

Author(s):

Zakaria Lafdaili ◽

Sakina El-Hamdani ◽

Abdelaziz Bendou ◽

Karim Limam ◽

Bara El-Hafad

Keyword(s):

Nusselt Number ◽

Natural Convection ◽

Heat Exchange ◽

Metallic Nanoparticles ◽

Volume Fraction ◽

Numerical Study ◽

Three Dimensional ◽

Stability Characteristic ◽

Horizontal Strip ◽

Turbulent Natural Convection

In this work we study numerically the three-dimensional turbulent natural convection in a partially heated cubic cavity filled with water containing metallic nanoparticles, metallic oxides and others based on carbon.The objective is to study and compare the effect of the addition of nanoparticles studied in water and also the effect of the position of the heated partition on the heat exchange by turbulent natural convection in this type of geometry, which can significantly improve the design of heat exchange systems for better space optimization. For this we have treated numerically for different volume fractions the turbulent natural convection in the two cases where the cavity is heated respectively by a vertical and horizontal strip in the middle of one of the vertical walls. To take into account the effects of turbulence, we used the standard turbulence model ? - ?. The governing equations are discretized by the finite volume method using the power law scheme which offers a good stability characteristic in this type of flow. The results are presented in the form of isothermal lines and current lines. The variation of the mean Nusselt number is calculated for the two positions of the heated partition as a function of the volume fraction of the nanoparticles studied in water for different Rayleigh numbers.The results show that carbon-based nanoparticles intensify heat exchange by convection better and that the position of the heated partition significantly influences heat exchange by natural convection. In fact, an improvement in the average Nusselt number of more than 20% is observed for the case where the heated partition is horizontal.

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Novel Strategy for Antifouling Paints with Zero Endocrine Disrupting Chemical (EDC) Elution based on Interpenetrating Polymer Networks (IPNs)

MRS Proceedings ◽

10.1557/proc-873-k3.17 ◽

2005 ◽

Vol 873 ◽

Author(s):

Masanobu Naito ◽

Takashi Nakai ◽

Takuma Kawabe ◽

Kenji Mori ◽

Daisuke Furuta ◽

...

Keyword(s):

Polymer Networks ◽

Three Dimensional ◽

Silica Matrix ◽

Interpenetrating Polymer Networks ◽

Repellent Activity ◽

Antifouling Paints ◽

Endocrine Disrupting Chemical ◽

Endocrine Disrupting ◽

Novel Strategy ◽

Fouling Organisms

AbstractEnvironmentally friendly organic-inorganic hybrid materials with repellent activity against marine fouling organisms have been developed using interpenetrating polymer networks (IPNs), composed of a three-dimensional silica matrix of tetraethoxysilane (TEOS) and chain-like polymers, such as poly(methylmethacrylate) (PMMA) and poly(vinylacetate) (PVAc). The repellent activity of the IPNs reached a maximum of approximately 90% relative to that of tetrabutyl tin oxide (TBTO). Simple bioassays using blue mussels and algae were used to screen out the adequate proportions of those components.

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Multifunctional metasurfaces integrating near-field display and 3D holography

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac3b11 ◽

2021 ◽

Author(s):

Wenjuan Du ◽

Zhilang Lou ◽

Xuesong Chen ◽

Long Chen ◽

Dongliang Tang

Keyword(s):

Near Field ◽

Three Dimensional ◽

Optical Field ◽

Amplitude Control ◽

3D Images ◽

Full Wave ◽

Complex Functions ◽

Channel Information ◽

Amplitude Modulator ◽

Optical Applications

Abstract Metasurfaces have versatile manipulation capabilities in the optical field and provide the possibility of building a compact optical device with various complex functions. They have been regarded as ideal candidates to construct a miniaturized optical system with high density and multi-channel information. In this work, reflective all-metallic multifunctional metasurfaces consisting of aluminum nanorods are designed by simultaneously realizing the near-filed display and three-dimensional (3D) holography. Specifically, in the proposed design, each nanorod acts as a complex amplitude modulator to provide continuous amplitude control and binary phase control. By carefully optimizing the orientations of nanorods, a multifunctional metasurface can be designed to display a near-field grayscale pattern and far-field 3D images simultaneously. Numerical results by a full-wave simulation validate the good performance of the proposed design. The proposed method could provide more degree of freedom to designs of lightweight devices, which could be employed in optical applications, such as the virtual or augmented reality display and anti-counterfeit technology.

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