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 Fabrication of silver helix microstructures in a large area by a two-photon absorption DLW method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoto Tsutsumi ◽  
Yusaku Takai ◽  
Kenji Kinashi ◽  
Wataru Sakai
Keyword(s):  
Elevation Angle ◽  
Photon Absorption ◽  
Silver Coating ◽  
Large Area ◽  
Helical Structures ◽  
Free Standing ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Direct Laser ◽  
Plating Method

AbstractLarge-area helix microstructures intended for metamaterials were fabricated using a negative photoresist, SU-8 using a two photon absorption direct laser writing (TPA-DLW). Two types of helix structures were fabricated. One type is those with no neighboring distance. In this case, compact helix structures with radius of 2.5 and 1.0 μm were fabricated. Another type is those with enough neighboring distance. The helix structures with shorter neighboring distance below 6.0 μm were collapsed, whereas those with longer neighboring distance more than 6.5 μm, free-standing helix structures could successfully be built. 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 fabricated helical structures were coated with silver using an electroless plating method to produce 3D metallic helix structures. Silver coating was measured using a EDX measurement. The obtained helical structures have the potential for metamaterials to control the handedness of a circularly polarized infrared beam.

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.

Fabrication of gold micro/nanostructures by femtosecond laser direct writing and chemical etching

2014 ◽  
Vol 23 (04) ◽  
pp. 1450048 ◽  
Author(s):  
Hongxin Zhang ◽  
Tianqing Jia ◽  
Kan Zhou ◽  
Jukun Liu ◽  
Donghai Feng ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Chemical Etching ◽  
Ethanol Solution ◽  
Photon Absorption ◽  
Direct Laser Writing ◽  
Direct Writing ◽  
Laser Writing ◽  
Two Photon Absorption ◽  
Direct Laser ◽  
Pentaerythritol Triacrylate

In this paper, we report gold micro/nanostructures fabricated by a method called lithographically patterned nanostructure by chemical etching (LPNCE). In the LPNCE method, the photoresist layer, composed of pentaerythritol triacrylate (PETA, monomer) and isopropyl thioxanthone (ITX, photoinitiator), is dropped on gold film, and subsequently polymerized via two-photon absorption of 800 nm femtosecond laser. Micro/nanostructures are fabricated by the direct laser writing. The unpolymerized photoresist is washed by isopropanol, and the exposed gold is dissolved by KI 3 aqueous solution. Finally, polymers are removed by NaOH ethanol solution. Arbitrary 2D gold micro/nanostructures can be fabricated quickly by the direct laser writing and chemical etching method. The good electro-conductibility of these micro/nanostructures guarantees wide applications in micro-electronic devices, plasmonics and biosensors, etc.

scholarly journals Structural Modifications in Free-Standing InGaN/GaN LEDs after Femtosecond Laser Lift-Off

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 897 ◽  
Author(s):  
Steffen Bornemann ◽  
Nursidik Yulianto ◽  
Tobias Meyer ◽  
Jan Gülink ◽  
Christoph Margenfeld ◽  
...  
Keyword(s):  
Photon Absorption ◽  
Successful Implementation ◽  
Free Standing ◽  
Absorption Mechanism ◽  
Short Pulses ◽  
Structural Modifications ◽  
Two Photon Absorption ◽  
Transmission Electron ◽  
Lift Off ◽  
The Impact

A laser lift-off (LLO) process has been developed for detaching thin InGaN/GaN lightemitting diodes (LED) from their original sapphire substrates by applying an ultrafast laser. LLO is usually based on intense UV irradiation, which is transmitted through the sapphire substrate and subsequently absorbed at the interface to the epitaxially grown GaN stack. Here, we present a successful implementation of a two-step LLO process with 350 fs short pulses in the green spectral range (520 nm) based on a two-photon absorption mechanism. Cathodo- and electroluminescence experiments have proven the functionality of the LLO-based chips. The impact of radiation on the material quality was analysed with scanning (SEM) and transmission electron microscopy (TEM), revealing structural modifications inside the GaN layer in some cases.

scholarly journals IP-Dip-Based SPR Structure for Refractive Index Sensing of Liquid Analytes

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1163
Author(s):  
Petra Urbancova ◽  
Dusan Pudis ◽  
Matej Goraus ◽  
Jaroslav Kovac
Keyword(s):  
Refractive Index ◽  
Photon Absorption ◽  
Resonance Structure ◽  
Angle Of Incidence ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Refractive Index Sensing ◽  
External Angle ◽  
Direct Laser ◽  
Index Unit

In this paper, we present a two-dimensional surface plasmon resonance structure for refractive index sensing of liquid analytes. The polymer structure was designed with a period of 500 nm and prepared in a novel IP-Dip polymer by direct laser writing lithography based on a mechanism of two-photon absorption. The sample with a set of prepared IP-Dip structures was coated by 40 nm thin gold layer. The sample was encapsulated into a prototyped chip with inlet and outlet. The sensing properties were investigated by angular measurement using the prepared solutions of isopropyl alcohol in deionized water of different concentrations. Sensitivity of 478–617 nm per refractive index unit was achieved in angular arrangement at external angle of incidence of 20°.

Three-dimensional buried polymer waveguides via femtosecond direct laser writing with two-photon absorption

2014 ◽  
Author(s):  
Duc H. H. Nguyen ◽  
Kerstin Kaleta ◽  
Stefan Hengsbach ◽  
Ute Ostrzinski ◽  
Karl Pfeiffer ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Photon Absorption ◽  
Direct Laser Writing ◽  
Polymer Waveguides ◽  
Laser Writing ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Direct Laser

Second order interference in two photon absorption

1996 ◽  
Vol 43 (9) ◽  
pp. 1765-1771 ◽  
Author(s):  
M. W. HAMILTON and D. S. ELLIOTT
Keyword(s):  
Second Order ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon
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