scholarly journals Parallel Detection of Refractive Index Changes in a Porous Silicon Microarray Based on Digital Images

Sensors ◽  
2017 ◽  
Vol 17 (4) ◽  
pp. 750 ◽  
Author(s):  
Chuanxi Li ◽  
Zhenhong Jia ◽  
Peng Li ◽  
Hao Wen ◽  
Guodong Lv ◽  
...  
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Digital Images ◽  
Parallel Detection ◽  
Index Changes

scholarly journals Flow-Through Self-Standing Porous Silicon Sensor

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 17
Author(s):  
David Martín-Sánchez ◽  
Salvador Ponce-Alcántara ◽  
Jaime García-Rupérez
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Multilayer Structure ◽  
Reflectance Spectra ◽  
Flow Through ◽  
Index Changes ◽  
Lift Off ◽  
Theoretical Simulations ◽  
Silicon Sensor ◽  
Good Agreement

A self-standing porous silicon (PS) multilayer structure detached from the substrate by the lift-off method and integrated with a microfluidic cell is presented. Experiments of refractive index changes sensing flow through open-ended pores are reported. We continuously recorded the reflectance spectra of the PS membrane each 30 s and measured the shift as different substances flowed through the structure. The experimental sensitivity values are in good agreement with the theoretical simulations performed.

scholarly journals Applying Speckle Noise Suppression to Refractive Indices Change Detection in Porous Silicon Microarrays

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2975
Author(s):  
Ruyong Ren ◽  
Zhenhong Jia ◽  
Jie Yang ◽  
Nikola Kasabov
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Change Detection ◽  
Noise Suppression ◽  
Refractive Index Change ◽  
Speckle Noise ◽  
Detection Accuracy ◽  
Value Change ◽  
Nonlocal Means ◽  
Index Changes

The gray value method can be used to detect gray value changes of each unit almost parallel to the surface image of PSi (porous silicon) microarrays and indirectly measure the refractive index changes of each unit. However, the speckles of different noise intensities produced by lasers on a porous silicon surface have different effects on the gray value of the measured image. This results in inaccurate results of refractive index changes obtained from the change in gray value. Therefore, it is very important to reduce the influence of speckle noise on measurement results. In this paper, a new algorithm based on the concepts of probability-based nonlocal-means filtering (PNLM), gradient operator, and median filtering is proposed for gray value restoration of porous silicon microarray images. A good linear relationship between gray value change and refractive index change is obtained, which can reduce the influence of speckle noise on the gray value of the PSi microarray image, improving detection accuracy. This means the method based on gray value change detection can be applied to the biological detection of PSi microarray arrays.

scholarly journals Speckle Noise Removal in Image-based Detection of Refractive Index Changes in Porous Silicon Microarrays

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ruyong Ren ◽  
Zhiqing Guo ◽  
Zhenhong Jia ◽  
Jie Yang ◽  
Nikola K. Kasabov ◽  
...  
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Refractive Index Change ◽  
Speckle Noise ◽  
Noise Removal ◽  
Detection Sensitivity ◽  
Gray Level ◽  
Denoising Method ◽  
Index Changes ◽  
Gray Values

Abstract Based on porous silicon (PSi) microarray images, we propose a new method called the phagocytosis algorithm (PGY) for removing the influence of speckle noise on image gray values. In a theoretical analysis, speckle noise of different intensities is added to images, and a suitable denoising method is developed to restore the image gray level. This method can be used to reduce the influence of speckle noise on the gray values of PSi microarray images to improve the accuracy of detection and increase detection sensitivity. In experiments, the method is applied to detect refractive index changes in PSi microcavity images, and a good linear relationship between the gray level change and the refractive index change is obtained. In addition, the algorithm is applied to a PSi microarray image, and good results are obtained.

New Hierarchically Structured Optical Materials for Dynamic Refractive Index Changes

2003 ◽  
Author(s):  
Bradley F. Chmelka ◽  
Earl Danielson ◽  
Michael D. Wyrsta
Keyword(s):  
Refractive Index ◽  
Optical Materials ◽  
Index Changes

LINEAR AND NONLINEAR INTERSUBBAND OPTICAL ABSORPTION OF FINITE AND INFINITE SEMI-PARABOLIC QUANTUM WELLS

2011 ◽  
Vol 25 (07) ◽  
pp. 497-507 ◽  
Author(s):  
M. J. KARIMI ◽  
A. KESHAVARZ ◽  
A. POOSTFORUSH
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Optical Absorption ◽  
Quantum Well ◽  
Quantum Wells ◽  
Resonant Peak ◽  
Energy Eigenvalues ◽  
Finite Case ◽  
Infinite Case ◽  
Index Changes

In this work, the optical absorption coefficients and the refractive index changes for the infinite and finite semi-parabolic quantum well are calculated. Numerical calculations are performed for typical GaAs / Al x Ga 1-x As semi-parabolic quantum well. The energy eigenvalues and eigenfunctions of these systems are calculated numerically. Optical properties are obtained using the compact density matrix approach. Results show that the energy eigenvalues and the matrix elements of the infinite and finite cases are different. The calculations reveal that the resonant peaks of the optical properties of the finite case occur at lower values of the incident photon energy with respect to the infinite case. Results indicate that the maximum value of the refractive index changes for the finite case are greater than that of the infinite case. Our calculations also show that in contrast to the infinite case, the resonant peak value of the total absorption coefficient in the case of the finite well is a non-monotonic function of the semi-parabolic confinement frequency.

Optimal refractive index changes for cross-gain and cross-phase modulation

1998 ◽  
Author(s):  
Thomas Keating ◽  
Jeffrey R. Minch ◽  
Seoung-Hwan Park ◽  
Shun-Lien Chuang ◽  
Tawee Tanbun-Ek
Keyword(s):  
Refractive Index ◽  
Phase Modulation ◽  
Cross Phase Modulation ◽  
Index Changes

Refractive index changes of ion-implanted quartz

1983 ◽  
Vol 76 (2) ◽  
pp. K171-K174 ◽  
Author(s):  
H. Beez ◽  
D. Fasold ◽  
H. Karge
Keyword(s):  
Refractive Index ◽  
Index Changes ◽  
Ion Implanted
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