The main purpose of this study is to develop a batch producible hot embossing 3D nanostructured surface-enhanced Raman chip technology for high sensitivity label-free plasticizer detection. This study utilizing the AAO self-assembled uniform nano-hemispherical array barrier layer as a template to create a durable nanostructured nickel mold. With the hot embossing technique and the durable nanostructured nickel mold, we are able to batch produce the 3D Nanostructured Surface-enhanced Raman Scattering Chip with consistent quality. In addition, because of our SERS chip can be fabricated by batch processing, the fabrication cost is low. Therefore, the developed method is very promising to be widespread and extensively used in rapid chemical and biomolecular detection applications.
Fourier transform spectroscopy (FTS) is a potent analytical tool for chemical and biological analysis, but is limited
by system size, expense, and robustness. To make FTS technology more accessible, we present a compact, inexpensive
FTS system based on a novel liquid crystal (LC) interferometer. This design is unique because the optical path difference
(OPD) is controlled by voltage applied to the LC cell. The OPD is further improved by reflecting the polarized incident
light through the LC several times before reaching the second polarizer and measurement. This paper presents the
theoretical model and numerical simulations for the liquid crystal Fourier transform spectrometer (LCFTS), and
experimental results from the prototype. Based on the experimental results, the LCFTS performs in accordance with the
theoretical predictions, achieving a maximum OPD of 210μm and a resolution of 1nm at a wavelength of 630nm. The
instrumental response refresh rate is just under 1 second. Absorbance measurements were conducted for single and
mixed solutions of deionized water and isopropyl alcohol, demonstrating agreement with a commercial system and
literature values. We also present the LCFTS transmission spectra for varying concentrations of potassium permanganate
to show system sensitivity.
The modified optical disc process has been investigated and demonstrated to enable fast prototyping in fabricating molds
and replicating substrates with various microstructures including micro-chambers and micro-channels. A disc-like microfluidic
device was created and the testing results showed good performance in bonding and packaging. The switching of
the nozzle-like micro-valve was also validated to work well. Furthermore, the relevant procedures of liquid samples
loading, separating and mixing were also accomplished through food experiments.
The paper describes the development of a mesh waveguide sensor capable of measuring pressure force at the plantar
interface. The uniqueness of the system is in its batch fabrication process, which involves a microfabrication molding
technique with poly(dimethylsiloxane)(PDMS) as the optical medium. The pressure sensor consists of an array of
optical waveguides lying in perpendicular rows and columns separated by elastomeric pads. A map of normal stress was
constructed based on observed macro bending which causes intensity attenuation from the physical deformation of two
adjacent perpendicular waveguides. In this paper, optical and mechanical analysis of the bend loss will be presented.
We will also present the results using a two-layer neural network system for force and image construction of fourteen
different shape patterns and its corresponding four different applied forces.
A composite optical bend loss sensor for the measurement of pressure and shear has been developed. The sensor is
composed of two layers of fiberoptic mesh sensors that are molded into a thin polydimethylsiloxane (PDMS) substrate.
A 3-D displacement map is generated based on bent-induced intensity attenuations in the fibers when the sensor is
pressed. The new design overcame some of the coupling and instability problems in our previously reported
microfabricated optical bend loss sensor. Here we will report our preliminary study on the sensor including results from
the normal and shear load measurement. The paper will also discuss a RF based wireless data acquisition system that we
have developed and demonstrate its operation with the composite sensor.
A flexible high-resolution sensor capable of measuring the distribution of both shear and pressure at the plantar interface are needed to study the actual distribution of this force during daily activities, and the role that shear plays in causing plantar ulceration. We have previously developed a novel means of transducing plantar shear and pressure stress via a new microfabricated optical system. However, a force image algorithm is needed to handle the complexity of construction of two-dimensional planar pressure and shear images. Here we have developed a force image algorithm for a micromachined optical bend loss sensor. A neural network is introduced to help identify different load shapes. According to the experimental result, we can conclude that once the neural network has been well trained, it can correctly identify the loading shape. With the neural network, our micromachined optical bend loss Sensor is able to construction the two-dimensional planar force images.
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