A Direct Molding Technique to Fabricate Silica Micro-Optical Components

1998 ◽  
Vol 546 ◽  
Author(s):  
Choon-Keat Terence Lee ◽  
Michael J. Vasile ◽  
Jost Goettert
Keyword(s):  
Sacrificial Layer ◽  
Replication Process ◽  
Release Process ◽  
Optical Components ◽  
X Ray ◽  
Depth Profiles ◽  
Linear Dimensions ◽  
Organosilicon Polymer ◽  
Layer Technique ◽  
Transmission Test

AbstractA technology for the direct molding and release of silica micro-optical components in polymethyl methacrylate (PMMA) molds is developed. The objectives of this work are to bypass some of the usual steps in deep x-ray lithography (DXRL) and to determine the suitability of GR650 resin (methylpolysilsequioxane) for molding thick, high aspect ratio structures. The process is initiated by DXRL exposure of PMMA, followed by spin-on glass application, a cure at 85°C to set the shape of the resin, followed by demolding. The cure is below the glass transition temperature of PMMA and the demolding process allows re-use of the mold. There is no need for electroforming in the replication process. PMMA molds with thickness of 250, 350 and 500 um were fabricated by DXRL and standard resist development. A novel metal sacrificial layer technique is used in the release process with initial yield of about 50%. Microoptical elements that were fabricated include lenses, prisms, grating structures and transmission test structures. These components are cured above 400°C after release, to convert the organosilicon polymer to a silica-like material. Weight loss from the high temperature cure was in the range of 15 to 25%, while linear dimensions of the components decreased by about 1%. Composition of the molded, cured structures was measured by XPS depth profiles.

MICRO CAPILLARY ARRAY ELECTROPHORESIS CHIP BY MOVING MASK LIGA TECHNOLOGY

2004 ◽  
Vol 01 (01) ◽  
pp. 39-46
Author(s):  
HUI YOU ◽  
SHOUJI SHINOHARA ◽  
KENNICHI ENAMI ◽  
SHINSUKE SHIBATA ◽  
OSAMU TABATA ◽  
...  
Keyword(s):  
Adhesive Bonding ◽  
Dna Analysis ◽  
Adhesive Layer ◽  
Fabrication Process ◽  
Optical Components ◽  
X Ray ◽  
Laser Induced Fluorescence Detection ◽  
Capillary Array Electrophoresis ◽  
Liga Technology ◽  
Capillary Array

The concept and the fabrication process of a micro capillary array electrophoresis (μ-CAE) for DNA analysis were stated. The chip was mainly made of plastic and fabricated by the innovatory LIGA technology which included moving mask deep X-ray lithography, electroplating and hot embossing, and assembled by an adhesive bonding, in which the adhesive layer solidified and formed firm bond under UV exposure. The micro channel array with high aspect ratio is the key part, whose wall should have a slight inclination to ensure the demoulding. It was demonstrated that moving mask deep X-ray lithography (M2DXL) technology could successfully control the inclination and enabled to integrate micro optical components such as micro lens into the chip, which improved detection performance greatly. The fabrication process was experimented and some initial prototype chips have been obtained. Fluidic test and electrophoresis test with laser-induced fluorescence detection has been done on the prototype. The results confirm that the μ-CAE by moving mask LIGA process is realizable and it has great potential in high-throughput, which may lead to ultra-fast DNA analysis.

Low-cost thermo-chemical process of TiO2 powder purification: Study of iterative gettering effect

2021 ◽  
Author(s):  
Nesrine Jaouabi ◽  
Wala Medfai ◽  
Marouan Khalifa ◽  
Rabia Zaghouani ◽  
Hatem Ezzaouia
Keyword(s):  
Porous Layer ◽  
Sacrificial Layer ◽  
Low Cost ◽  
Nir Spectroscopy ◽  
Tio2 Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Density Reduction ◽  
Transmission Electron ◽  
Layer Effect

The titanium dioxide (TiO2) purity is very important for the TiO2-based applications making essential the impurities density reduction. In this study, we propose an efficient purification process of TiO2 powder in order to reduce impurities. The low-cost proposed approach is based on an iterative gettering (IG) process combining three main steps: (1) a porous TiO2 sacrificial layer formation (p-TiO2), (2) a rapid thermal annealing (RTA) of p-TiO2 powder in an infrared oven at 950°C under air permitting the residual impurities diffusion to the porous layer surface and (3) etching in acid solution to remove the porous layer. Effect of the proposed gettering process on purification efficiency was evaluated by different characterization techniques such as the transmission electron microscopy (TEM), the energy dispersive x-ray spectroscopy (EDX), the UV–Visible-NIR spectroscopy, the X-ray diffraction (XRD) and atomic absorption spectroscopy (AAS). The obtained results showed the efficient removal of metal impurities, such as Cu, Al, P, and Fe confirming the efficiency of the process improving the purity from 89% to 99.96%.

Photoactive amphiphiles for the assembly of supramolecular architectures

2015 ◽  
Vol 185 ◽  
pp. 471-479 ◽  
Author(s):  
B. P. Jarman ◽  
F. Cucinotta
Keyword(s):  
Visible Spectrum ◽  
Solid Materials ◽  
Visible Absorption ◽  
Optical Components ◽  
Absorption And Emission ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Uv Visible ◽  
Absorption And Emission Spectroscopy ◽  
Molecular Organisation

The presented study reports the use of photoactive templating structures for the design of porous frameworks with built-in optical functionalities. The materials have been synthesised and characterised using powder X-ray diffractometry, UV-visible absorption and emission spectroscopy. The latter shows that, by varying the relative amount of an amphiphilic chromophore in the micellar templates, it is possible to tune the light absorption and emission properties over the visible spectrum, by means of controlling the molecular organisation and the excitonic coupling of aggregated species. This enables versatile solid materials that can be used as optical components for light-harvesting and converting systems to be obtained .

Copper(I) Halide Nanoparticle-dispersed Glasses Prepared by Copper Staining

2005 ◽  
Vol 20 (9) ◽  
pp. 2480-2485 ◽  
Author(s):  
Kohei Kadono ◽  
Tatsuya Suetsugu ◽  
Takeshi Ohtani ◽  
Toshihiko Einishi ◽  
Takashi Tarumi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Surface Region ◽  
Borosilicate Glasses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Depth Profiles ◽  
Transmission Electron ◽  
Heat Treated ◽  
Glass Heat

Copper(I) chloride and bromide nanoparticle-dispersed glasses were prepared by means of a conventional copper staining. The staining was performed by the following process: copper stain was applied on the surfaces of Cl−- or Br−-ion-containing borosilicate glasses, and the glasses were heat-treated at 510 °C for various times. Typical exciton bands observed in the absorption spectra of the glasses after the heat treatment indicated that CuCl and CuBr particles were formed in the surface region of the glasses. The average sizes of the CuCl and CuBr particles in the glasses heat-treated for 48 h were estimated at 4.8 and 2.7 nm, respectively. The nanoparticles were also characterized by x-ray diffraction and transmission electron microscopy. Depth profiles of Cu and CuBr concentration in the glass heat-treated for 48 h were measured. Copper decreased in concentration monotonously with depth, reaching up to 60 μm, while the CuBr concentration had a maximum at about 25 μm in depth.

scholarly journals The fractional Fourier transform as a simulation tool for lens-based X-ray microscopy

2018 ◽  
Vol 25 (3) ◽  
pp. 717-728 ◽  
Author(s):  
Anders Filsøe Pedersen ◽  
Hugh Simons ◽  
Carsten Detlefs ◽  
Henning Friis Poulsen
Keyword(s):  
Fourier Transform ◽  
Fractional Fourier Transform ◽  
Imaging System ◽  
Single Step ◽  
Fourier Optics ◽  
Simulation Tool ◽  
Optical Components ◽  
X Ray ◽  
Chromatic Aberrations ◽  
On Line

The fractional Fourier transform (FrFT) is introduced as a tool for numerical simulations of X-ray wavefront propagation. By removing the strict sampling requirements encountered in typical Fourier optics, simulations using the FrFT can be carried out with much decreased detail, allowing, for example, on-line simulation during experiments. Moreover, the additive index property of the FrFT allows the propagation through multiple optical components to be simulated in a single step, which is particularly useful for compound refractive lenses (CRLs). It is shown that it is possible to model the attenuation from the entire CRL using one or two effective apertures without loss of accuracy, greatly accelerating simulations involving CRLs. To demonstrate the applicability and accuracy of the FrFT, the imaging resolution of a CRL-based imaging system is estimated, and the FrFT approach is shown to be significantly more precise than comparable approaches using geometrical optics. Secondly, it is shown that extensive FrFT simulations of complex systems involving coherence and/or non-monochromatic sources can be carried out in minutes. Specifically, the chromatic aberrations as a function of source bandwidth are estimated, and it is found that the geometric optics greatly overestimates the aberration for energy bandwidths of around 1%.

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