scholarly journals Additive Manufacturing of Gold Nanostructures Using Nonlinear Photoreduction under Controlled Ionic Diffusion

2021 ◽  
Vol 22 (14) ◽  
pp. 7465
Author(s):  
Wera Di Cianni ◽  
María de la Mata ◽  
Francisco J. Delgado ◽  
Giovanni Desiderio ◽  
Sergio I. Molina ◽  
...  
Keyword(s):  
Metallic Nanoparticles ◽  
Scanning Speed ◽  
Fine Tuning ◽  
Photon Absorption ◽  
Gold Nanostructures ◽  
Gold Precursor ◽  
Hydrogel Matrix ◽  
Direct Laser ◽  
Fine Control ◽  
Diffusive Processes

Multiphoton photoreduction of photosensitive metallic precursors via direct laser writing (DLW) is a promising technique for the synthesis of metallic structures onto solid substrates at the sub-micron scale. DLW triggered by a two photon absorption process is done using a femtosecond NIR laser (λ = 780 nm), tetrachloroauric acid (HAuCl4) as a gold precursor, and isinglass as a natural hydrogel matrix. The presence of a polymeric, transparent matrix avoids unwanted diffusive processes acting as a network for the metallic nanoparticles. After the writing process, a bath in deionized water removes the gold precursor ions and eliminates the polymer matrix. Different aspects underlying the growth of the gold nanostructures (AuNSs) are here investigated to achieve full control on the size and density of the AuNSs. Writing parameters (laser power, exposure time, and scanning speed) are optimized to control the patterns and the AuNSs size. The influence of a second bath containing Au3+ to further control the size and density of the AuNSs is also investigated, observing that these AuNSs are composed of individual gold nanoparticles (AuNPs) that grow individually. A fine-tuning of these parameters leads to an important improvement of the created structures’ quality, with a fine control on size and density of AuNSs.

scholarly journals Regulating disordered plasmonic nanoparticles into polarization sensitive metasurfaces

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shulei Li ◽  
Mingcheng Panmai ◽  
Shaolong Tie ◽  
Yi Xu ◽  
Jin Xiang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Spatial Resolution ◽  
Metallic Nanoparticles ◽  
Near Infrared ◽  
Optical Memory ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Optical Diffraction ◽  
Plasmonic Nanoparticles ◽  
Direct Laser

Abstract Metasurfaces composed of regularly arranged and deliberately oriented metallic nanoparticles can be employed to manipulate the amplitude, phase and polarization of an incident electromagnetic wave. The metasurfaces operating in the visible to near infrared spectral range rely on the modern fabrication technologies which offer a spatial resolution beyond the optical diffraction limit. Although direct laser writing is an alternative to the fabrication of nanostructures, the achievement of regular nanostructures with deep-subwavelength periods by using this method remains a big challenge. Here, we proposed and demonstrated a novel strategy for regulating disordered plasmonic nanoparticles into nanogratings with deep-subwavelength periods and reshaped nanoparticles by using femtosecond laser pulses. The orientations of the nanogratings depend strongly on the polarization of the femtosecond laser light. Such nanogratings exhibit reflection and polarization control over the reflected light, enabling the realization of polarization sensitive optical memory and color display with high spatial resolution and good chromacity.

scholarly journals Femtosecond direct laser writing of gold nanostructures by ionic liquid assisted multiphoton photoreduction

2013 ◽  
Vol 3 (10) ◽  
pp. 1660 ◽  
Author(s):  
Wei-Er Lu ◽  
Yong-Liang Zhang ◽  
Mei-Ling Zheng ◽  
Yan-Peng Jia ◽  
Jie Liu ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Gold Nanostructures ◽  
Direct Laser Writing ◽  
Laser Writing ◽  
Direct Laser

Optical Waveguides Embedded in PCBs - A Real World Application of 3D Structures Written by TPA

2007 ◽  
Vol 1054 ◽  
Author(s):  
Ruth Houbertz ◽  
Herbert Wolter ◽  
Volker Schmidt ◽  
Ladislav Kuna ◽  
Valentin Satzinger ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Optical Waveguides ◽  
High Speed ◽  
Printed Circuit Boards ◽  
Data Transfer ◽  
Laser Pulses ◽  
Photon Absorption ◽  
Optical Data ◽  
Direct Laser ◽  
High Speed Data

ABSTRACTThe integration of optical interconnects in printed circuit boards (PCB) is a rapidly growing field worldwide due to a continuously increasing need for high-speed data transfer. There are any concepts discussed, among which are the integration of optical fibers or the generation of waveguides by UV lithography, embossing, or direct laser writing. The devices presented so far require many different materials and process steps, but particularly also highly-sophisticated assembly steps in order to couple the optoelectronic elements to the generated waveguides. In order to overcome these restrictions, an innovative approach is presented which allows the embedding of optoelectronic components and the generation of optical waveguides in only one optical material. This material is an inorganic-organic hybrid polymer, in which the waveguides are processed by two-photon absorption (TPA) processes, initiated by ultra-short laser pulses. In particular, due to this integration and the possibility ofin situpositioning the optical waveguides with respect to the optoelectronic components by the TPA process, no complex packaging or assembly is necessary. Thus, the number of necessary processing steps is significantly reduced, which also contributes to the saving of resources such as energy or solvents. The material properties and the underlying processes will be discussed with respect to optical data transfer in PCBs.

Fine-tuning of LA-ICP-QMS conditions for elemental mapping

2020 ◽  
Vol 35 (11) ◽  
pp. 2494-2497 ◽  
Author(s):  
Johannes T. van Elteren ◽  
Dino Metarapi ◽  
Martin Šala ◽  
Vid S. Šelih ◽  
Ciprian C. Stremtan
Keyword(s):  
Repetition Rate ◽  
High Speed ◽  
Scanning Speed ◽  
Fine Tuning ◽  
Acquisition Time ◽  
Elemental Mapping

For high-speed elemental mapping, LA-ICP-QMS conditions such as scanning speed, repetition rate and acquisition time are optimized as a function of the dosage and the washout time.

Femtosecond-laser direct writing for spatially localized synthesis of PPV

2017 ◽  
Vol 5 (14) ◽  
pp. 3579-3584 ◽  
Author(s):  
Oriana I. Avila ◽  
Juliana M. P. Almeida ◽  
Franciele R. Henrique ◽  
Ruben D. Fonseca ◽  
Gustavo F. B. Almeida ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Photon Absorption ◽  
Direct Laser Writing ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Thermal Reactions ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Direct Laser ◽  
Fs Laser

Conversion of PTHT into PPV is achieved by direct laser writing. Fs-laser pulses induce photo-thermal reactions due to two-photon absorption, resulting in the microscopic control of PPV polymerization. Such methodology is a promising way towards the fabrication of arbitrary polymeric microcircuits.

Design of Far-Red Sensitizing Squaraine Dyes Aiming Towards the Fine Tuning of Dye Molecular Structure

2016 ◽  
Vol 16 (4) ◽  
pp. 3282-3288 ◽  
Author(s):  
Takuya Morimoto ◽  
Naotaka Fujikawa ◽  
Yuhei Ogomi ◽  
Shyam S Pandey ◽  
Tingli Ma ◽  
...  
Keyword(s):  
Alkyl Chain ◽  
Wavelength Region ◽  
Fine Tuning ◽  
Solar Irradiation ◽  
Squaraine Dyes ◽  
Positional Variation ◽  
Fine Control ◽  
Photovoltaic Characteristics ◽  
Simulated Solar Irradiation ◽  
Factor Constant

Model squaraine dyes having sharp and narrow absorptions mainly in the far-red wavelength region has been logically designed, synthesized and used for their application as sensitizer in the dyesensitized solar cells (DSSC). In order to have fine control on energetics, dyes having same mother core and alkyl chain length varying only in molecular symmetry and position of substituent were designed. It has been found that even keeping all other structural factor constant, only positional variation of substituent leads to not only in the variation of energetics by 0.1 eV but affects the photovoltaic characteristics also. Optimum concentration of dye de-aggregating agent was found to be 100 times with respect to the sensitizing dye concentration. Amongst dyes utilized in this work best performance was obtained for unsymmetrical dye SQ-40 giving a photoconversion efficiency of 4.01% under simulated solar irradiation at global AM 1.5.

scholarly journals Fabrication of silver helix microstructures in a large area

2021 ◽  
Author(s):  
Naoto Tsutsumi ◽  
Yusaku Takai ◽  
Kenji Kinashi ◽  
Wataru Sakai
Keyword(s):  
Negative Refraction ◽  
Elevation Angle ◽  
Wavelength Region ◽  
Photon Absorption ◽  
Large Area ◽  
Helical Structures ◽  
Free Standing ◽  
Two Photon Absorption ◽  
Direct Laser ◽  
Periodic Microstructures

Abstract The fabrication of metamaterials working in the wavelength region from visible to infrared is very attractive for beam treatment toward negative refraction and beyond the diffraction limit. The two photon absorption direct laser writing (TPA-DLW) method is a powerful tool to fabricate metamaterials with compact, dense, intricate, and periodic microstructures on the micrometer and submicrometer scales and is sensitive in the wavelength region from visible to infrared. In this study, large-area helix microstructures intended for metamaterials were fabricated using a negative photoresist, SU-8. To stabilize the fabricated free-standing helix microstructures with a 1 µm radius, circular foundations with a radius of 1.3 µm and elevation angle of 10, 12, or 14 ° were built in advance. The foundation is useful to avoid collapsing the helix microstructures. Due to the useful foundation, over 18,000 helical structures were fabricated in a large area. The obtained helical structures have the potential for metamaterials to control the handedness of a circularly polarized infrared beam.

scholarly journals Nano-3D-printed Photochromic Objects

2020 ◽  
Author(s):  
Sebastian Ulrich ◽  
Xiaopu Wang ◽  
Markus Rottmar ◽  
René M. Rossi ◽  
Bradley J. Nelson ◽  
...  
Keyword(s):  
Click Reaction ◽  
Thermal Recovery ◽  
Fine Tuning ◽  
Excitation Wavelength ◽  
Color Changes ◽  
New Class ◽  
Direct Laser ◽  
Donor Acceptor ◽  
3D Printed ◽  
Post Modification

A new class of photoresist is described for direct laser writing of photoswitchable 3D microstructures. The material comprising off-stoichiometric thiol-ene photo-clickable resins enables rapid two-photon laser processing of highly complex structures and facile post-modification with photoswitches. The microstructures were functionalized with a series of donor-acceptor Stenhouse adducts (DASAs) photoswitches with different excitation wavelength. The versatility of thiol–ene photo-click reaction enabled fine-tuning of the network structure and physical properties as well as the type and concentration of DASA photoswitches. When exposed to visible light, these microstructures exhibit excellent photo-responsiveness and undergo reversible color-changing via photoisomerization of DASA moieties. We describe that the weak fluorescence of DASAs can be used as a reporter of photoswitching, color changes, and thermal recovery, allowing the reading of DASA-containing sub-micrometric structures in 3D. This work delivers a new approach for custom microfabrication of 3D photochromic objects with molecularly engineered color and responsiveness.

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