Two-Photon Laser Micro-Nano Fabrication; Understanding from Single-Voxel Level

2002 ◽  
Vol 758 ◽  
Author(s):  
Satoshi Kawata ◽  
Hong-Bo Sun

ABSTRACTFor laser nanofabrication using two-photon photopolymerization, a deep understanding of the nature of focal spots that are related to two-photon excitation is essential for achieving a high spatial resolution in three dimensions. Here we report the use of a technology we call ascending scan for characterizing the three-dimensional size and shape of single polymerization elements (voxels), and introduce several features of voxels that have not been fully noticed before. These findings are important for tailoring nanofeatures according to design.

2012 ◽  
Vol 302 (1) ◽  
pp. H287-H298 ◽  
Author(s):  
Stephen H. Gilbert ◽  
David Benoist ◽  
Alan P. Benson ◽  
Ed White ◽  
Steven F. Tanner ◽  
...  

It has been shown by histology that cardiac myocytes are organized into laminae and this structure is important in function, both influencing the spread of electrical activation and enabling myocardial thickening in systole by laminar sliding. We have carried out high-spatial resolution three-dimensional MRI of the ventricular myolaminae of the entire volume of the isolated rat heart after contrast perfusion [dimeglumine gadopentate (Gd-DTPA)]. Four ex vivo rat hearts were perfused with Gd-DTPA and fixative and high-spatial resolution MRI was performed on a 9.4T MRI system. After MRI, cryosectioning followed by histology was performed. Images from MRI and histology were aligned, described, and quantitatively compared. In the three-dimensional MR images we directly show the presence of laminae and demonstrate that these are highly branching and are absent from much of the subepicardium. We visualized these MRI volumes to demonstrate laminar architecture and quantitatively demonstrated that the structural features observed are similar to those imaged in histology. We showed qualitatively and quantitatively that laminar architecture is similar in the four hearts. MRI can be used to image the laminar architecture of ex vivo hearts in three dimensions, and the images produced are qualitatively and quantitatively comparable with histology. We have demonstrated in the rat that: 1) laminar architecture is consistent between hearts; 2) myolaminae are absent from much of the subepicardium; and 3) although localized orthotropy is present throughout the myocardium, tracked myolaminae are branching structures and do not have a discrete identity.


1997 ◽  
Vol 3 (S2) ◽  
pp. 305-306
Author(s):  
David W. Piston

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. It provides three-dimensional resolution and eliminates background equivalent to an ideal confocal microscope without requiring a confocal spatial filter, whose absence enhances fluorescence collection efficiency. This results in inherent submicron optical sectioning by excitation alone. In practice, TPEM is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10−5 limits the average input power to less than 10 mW, only slightly greater than the power normally used in confocal microscopy. Because of the intensity-squared dependence of the two-photon absorption, the excitation is limited to the focal volume.


2020 ◽  
Vol 9 (1) ◽  
pp. 1118-1136
Author(s):  
Zhenjia Huang ◽  
Gary Chi-Pong Tsui ◽  
Yu Deng ◽  
Chak-Yin Tang

AbstractMicro/nano-fabrication technology via two-photon polymerization (TPP) nanolithography is a powerful and useful manufacturing tool that is capable of generating two dimensional (2D) to three dimensional (3D) arbitrary micro/nano-structures of various materials with a high spatial resolution. This technology has received tremendous interest in cell and tissue engineering and medical microdevices because of its remarkable fabrication capability for sophisticated structures from macro- to nano-scale, which are difficult to be achieved by traditional methods with limited microarchitecture controllability. To fabricate precisely designed 3D micro/nano-structures for biomedical applications via TPP nanolithography, the use of photoinitiators (PIs) and photoresists needs to be considered comprehensively and systematically. In this review, widely used commercially available PIs are first discussed, followed by elucidating synthesis strategies of water-soluble initiators for biomedical applications. In addition to the conventional photoresists, the distinctive properties of customized stimulus-responsive photoresists are discussed. Finally, current limitations and challenges in the material and fabrication aspects and an outlook for future prospects of TPP for biomedical applications based on different biocompatible photosensitive composites are discussed comprehensively. In all, this review provides a basic understanding of TPP technology and important roles of PIs and photoresists for fabricating high-precision stimulus-responsive micro/nano-structures for a wide range of biomedical applications.


2015 ◽  
Vol 9 (1) ◽  
pp. 1-11
Author(s):  
Gábor Bakó ◽  
Gábor Kovács ◽  
Zsolt Molnár ◽  
Judit Kirisics ◽  
Eszter Góber ◽  
...  

The red mud disaster occurred on 4th October 2010 in Hungary has raised the necessity of rapid intervention and drew attention to the long-term monitoring of such threat. Both the condition assessment and the change monitoring indispensably required the prompt and detailed spatial survey of the impact area. It was conducted by several research groups - independently - with different recent surveying methods. The high spatial resolution multispectral aerial photogrammetry is the spatially detailed (high resolution) and accurate type of remote sensing. The hyperspectral remote sensing provides more information about material quality of pollutants, with less spatial details and lower spatial accuracy, while LIDAR ensures the three-dimensional shape and terrain models. The article focuses on the high spatial resolution, multispectral electrooptical method and the evaluation methodology of the deriving high spatial resolution ortho image map, presenting the derived environmental information database


2000 ◽  
Vol 39 (Part 1, No. 12A) ◽  
pp. 6763-6767 ◽  
Author(s):  
Mitsuru Watanabe ◽  
Saulius Juodkazis ◽  
Shigeki Matsuo ◽  
Junji Nishii ◽  
Hiroaki Misawa

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 531 ◽  
Author(s):  
Manuel Erena ◽  
José A. Domínguez ◽  
Joaquín F. Atenza ◽  
Sandra García-Galiano ◽  
Juan Soria ◽  
...  

The use of the new generation of remote sensors, such as echo sounders and Global Navigation Satellite System (GNSS) receivers with differential correction installed in a drone, allows the acquisition of high-precision data in areas of shallow water, as in the case of the channel of the Encañizadas in the Mar Menor lagoon. This high precision information is the first step to develop the methodology to monitor the bathymetry of the Mar Menor channels. The use of high spatial resolution satellite images is the solution for monitoring many hydrological changes and it is the basis of the three-dimensional (3D) numerical models used to study transport over time, environmental variability, and water ecosystem complexity.


2009 ◽  
Vol 1184 ◽  
Author(s):  
Luciano Andrey Montoro ◽  
Marina Leite ◽  
Daniel Biggemann ◽  
Fellipe Grillo Peternella ◽  
Kees Joost Batenburg ◽  
...  

AbstractThe knowledge of composition and strain with high spatial resolution is highly important for the understanding of the chemical and electronic properties of alloyed nanostructures. Several applications require a precise knowledge of both composition and strain, which can only be extracted by self-consistent methodologies. Here, we demonstrate the use of a quantitative high resolution transmission electron microscopy (QHRTEM) technique to obtain two-dimensional (2D) projected chemical maps of epitaxially grown Ge-Si:Si(001) islands, with high spatial resolution, at different crystallographic orientations. By a combination of these data with an iterative simulation, it was possible infer the three-dimensional (3D) chemical arrangement on the strained Ge-Si:Si(001) islands, showing a four-fold chemical distribution which follows the nanocrystal shape/symmetry. This methodology can be applied for a large variety of strained crystalline systems, such as nanowires, epitaxial islands, quantum dots and wells, and partially relaxed heterostructures.


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