scholarly journals Towards a Rationalization of Ultrafast Laser-Induced Crystallization in Lithium Niobium Borosilicate Glasses: The Key Role of The Scanning Speed

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 290
Author(s):  
Elisa Muzi ◽  
Maxime Cavillon ◽  
Matthieu Lancry ◽  
François Brisset ◽  
Ruyue Que ◽  
...  
Keyword(s):  
Scanning Speed ◽  
Crystal Glass ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Optical Modulators ◽  
Track Width ◽  
Fs Laser ◽  
Glass Matrices ◽  
The Impact ◽  
Induced Crystallization

Femtosecond (fs)-laser direct writing is a powerful technique to enable a large variety of integrated photonic functions in glass materials. One possible way to achieve functionalization is through highly localized and controlled crystallization inside the glass volume, for example by precipitating nanocrystals with second-order susceptibility (frequency converters, optical modulators), and/or with larger refractive indices with respect to their glass matrices (graded index or diffractive lenses, waveguides, gratings). In this paper, this is achieved through fs-laser-induced crystallization of LiNbO3 nonlinear crystals inside two different glass matrices: a silicate (mol%: 33Li2O-33Nb2O5-34SiO2, labeled as LNS) and a borosilicate (mol%: 33Li2O-33Nb2O5-13SiO2-21B2O3, labeled as LNSB). More specifically, we investigate the effect of laser scanning speed on the crystallization kinetics, as it is a valuable parameter for glass laser processing. The impact of scanning energy and speed on the fabrication of oriented nanocrystals and nanogratings during fs-laser irradiation is studied.Fs-laser direct writing of crystallized lines in both LNS and LNSB glass is investigated using both optical and electron microscopy techniques. Among the main findings to highlight, we observed the possibility to maintain crystallization during scanning at speeds ~ 5 times higher in LNSB relative to LNS (up to ~ 600 µm/s in our experimental conditions). We found a speed regime where lines exhibited a large polarization-controlled retardance response (up to 200 nm in LNSB), which is attributed to the texturation of the crystal/glass phase separation with a low scattering level. These characteristics are regarded as assets for future elaboration methods and designs of photonic devices involving crystallization. Finally, by using temperature and irradiation time variations along the main laser parameters (pulse energy, pulse repetition rate, scanning speed), we propose an explanation on the origin of 1) crystallization limitation upon scanning speed, 2) laser track width variation with respect to scanning speed, and 3) narrowing of the nanogratings volume but not the heat-affected volume.

scholarly journals Advanced Micro-Actuator/Robot Fabrication Using Ultrafast Laser Direct Writing and Its Remote Control

2020 ◽  
Vol 10 (23) ◽  
pp. 8563
Author(s):  
Sangmo Koo
Keyword(s):  
Three Dimensional ◽  
Processing Technique ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Precise Control ◽  
Two Photon ◽  
Non Invasive ◽  
Acoustic Control ◽  
Fs Laser ◽  
Invasive Control

Two-photon polymerization (TPP) based on the femtosecond laser (fs laser) direct writing technique in the realization of high-resolution three-dimensional (3D) shapes is spotlighted as a unique and promising processing technique. It is also interesting that TPP can be applied to various applications in not only optics, chemistry, physics, biomedical engineering, and microfluidics but also micro-robotics systems. Effort has been made to design innovative microscale actuators, and research on how to remotely manipulate actuators is also constantly being conducted. Various manipulation methods have been devised including the magnetic, optical, and acoustic control of microscale actuators, demonstrating the great potential for non-contact and non-invasive control. However, research related to the precise control of microscale actuators is still in the early stages, and in-depth research is needed for the efficient control and diversification of a range of applications. In the future, the combination of the fs laser-based fabrication technique for the precise fabrication of microscale actuators/robots and their manipulation can be established as a next-generation processing method by presenting the possibility of applications to various areas.

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.

Surface Microfabrication of Conventional Glass Using Femtosecond Laser for Microfluidic Applications

2017 ◽  
Vol 11 (6) ◽  
pp. 878-882 ◽  
Author(s):  
Takuma Niioka ◽  
◽  
Yasutaka Hanada
Keyword(s):  
High Resolution ◽  
Microfluidic Chip ◽  
High Speed ◽  
Single Cell Analysis ◽  
Glass Slide ◽  
Cell Analysis ◽  
Microfluidic Chips ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Fs Laser

Recently, a lot of attention has been paid to a single-cell analysis using microfluidic chips, since each cell is known to have several different characteristics. The microfluidic chip manipulates cells and performs high-speed and high-resolution analysis. In the meanwhile, femtosecond (fs) laser has become a versatile tool for the fabrication of microfluidic chips because the laser can modify internal volume solely at the focal area, resulting in three-dimensional (3D) microfabrication of glass materials. However, little research on surface microfabrication of materials using an fs laser has been conducted. Therefore, in this study, we demonstrate the surface microfabrication of a conventional glass slide using fs laser direct-writing for microfluidic applications. The fs laser modification, with successive wet etching using a diluted hydrofluoric (HF) acid solution, followed by annealing, results in rapid prototyping of microfluidics on a conventional glass slide for fluorescent microscopic cell analysis. Fundamental characteristics of the laser-irradiated regions in each experimental procedure were investigated. In addition, we developed a novel technique combining the fs laser direct-writing and the HF etching for high-speed and high-resolution microfabrication of the glass. After establishing the fs laser surface microfabrication technique, a 3D microfluidic chip was made by bonding the fabricated glass microfluidic chip with a polydimethylsiloxane (PDMS) polymer substrate for clear fluorescent microscopic observation in the microfluidics.

Novel Method of Laser Direct Writing for Precise Patterning of Human Dermal Fibroblasts

2010 ◽  
Author(s):  
Nathan R. Schiele ◽  
Douglas B. Chrisey ◽  
David T. Corr
Keyword(s):  
Cellular Proliferation ◽  
Dermal Fibroblasts ◽  
Growth Surface ◽  
Cell Contact ◽  
Direct Write ◽  
Human Dermal Fibroblasts ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Patterning Technique ◽  
The Impact

The ability to control a cell’s location, pattern geometry, and proximity to neighboring cells, in vitro, is highly desired to gain insight into cell-cell interactions, such as the modes of cellular signaling (direct cell contact, paracrine, or endocrine). A laser-based cell patterning technique, laser direct write, enables the precise spatial placement of living cells, with all the advantages of CAD/CAM control [1]. However, this technique is limited in usefulness due to the dependence on Matrigel® (BD Biosciences, Bedford, MA). The growth factor constituents of Matrigel® may interfere with many cellular processes under investigation and may preclude or greatly limit the utility of laser direct writing for precise cell cultures [2]. Therefore, to address this limitation, the objective of this study was to develop a Matrigel®-free laser direct writing method. Through the use of customized gelatin coatings on both the ribbon and receiving substrate, we effectively adapted the direct write technique to precisely pattern cells without the use of Matrigel®, as demonstrated with human dermal fibroblasts. The gelatin partially encapsulates the trypsinized cells on the ribbon, providing a volitization zone to protect the cells, and on the receiving substrate cushions the impact of transfer while maintaining moisture. Gelatin liquefies at 37°C, which allows it to be removed from the growth surface ensuring cellular proliferation, uninhibited by growth surface treatments. This represents a fundamental change from the original direct write technique in which cells must first form initial attachments to the ribbon via Matrigel® and then are written to a Matrigel® coated receiving substrate for their sustained growth. Additionally, we have developed a method to monitor the location of the patterned cells post-transfer to show that a gelatin coated-receiving substrate is effective as a patterning surface and ensures the registry of the pattern until cell attachment, even after the gelatin has been removed with the first growth medium application. This precise patterning technique can now be used in many biomedical applications, including those that involve cell types highly sensitive to growth factors, such as stem cells and cancer cells.

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