Mechanical Compression for Dehydration and Optical Clearing of Skin

2008 ◽  
Author(s):  
Chris W. Drew ◽  
Christopher G. Rylander
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Penetration Depth ◽  
Biological Tissue ◽  
Structural Modification ◽  
Incident Light ◽  
Optical Clearing ◽  
Treatment Techniques ◽  
Index Distribution ◽  
Tissue Optical Clearing

The highly disordered refractive index distribution in biological tissue causes multiple-scattering of incident light and inhibits optical penetration depth. “Tissue optical clearing” increases penetration depth of near-collimated light in biological tissue, potentially resulting in improved optical analysis and treatment techniques. Numerous methods of tissue optical clearing have been hypothesized using hyperosmostic agents [1]. These methods propose reduction in light scattering by means of dehydration of tissue constituents, replacement of interstitial or intracellular water with higher refractive agents, or structural modification or dissociation of collagen fibers [2,3]. It has been suggested that dehydration of tissue constituents alone can reduce light scattering by expulsing water between collagen fibrils, increasing protein and sugar concentrations, and decreasing refractive index mismatch [4].

Increased Light Transport in Skin Using Mechanical Compression

2009 ◽  
Author(s):  
Chris W. Drew ◽  
Alondra Izquierdo-Roman ◽  
Yajing Liu ◽  
Christopher G. Rylander
Keyword(s):  
Light Scattering ◽  
Structural Modification ◽  
Near Infrared ◽  
Morphological Structure ◽  
Light Transport ◽  
Optical Clearing ◽  
Treatment Techniques ◽  
Infrared Wavelengths ◽  
Tissue Optical Clearing ◽  
Highly Scattering Medium

The complex morphological structure of skin with its variations in the indices of refraction of components therein provides a highly scattering medium for visible and near-infrared wavelengths of light. “Tissue optical clearing” increases transmission of near-collimated light in biological tissue, potentially enabling improved optical analysis and treatment techniques. Numerous methods of tissue optical clearing have been hypothesized using hyperosmostic agents [1]. These methods propose reduction in light scattering by means of dehydration of tissue constituents, replacement of interstitial or intracellular water with higher refractive agents, or structural modification or dissociation of collagen fibers [2]. It has been suggested that dehydration of tissue constituents alone can reduce light scattering by expulsing water between collagen fibrils, increasing protein and sugar concentrations, and decreasing refractive index mismatch [3].

Stress Whitening in Polypropylene. I. Light Scattering Theory and Model Experiments

1995 ◽  
Vol 60 (11) ◽  
pp. 1875-1887 ◽  
Author(s):  
Jaroslav Holoubek ◽  
Miroslav Raab
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Incident Light ◽  
Polymeric Materials ◽  
Wavelength Dependence ◽  
Theoretical Background ◽  
Surrounding Matrix ◽  
Embedded Particles ◽  
The One ◽  
Stress Whitening

Theoretical background for an optical method is presented which makes it possible to distinguish unambiguously between voids and particles as light scattering sites in polymeric materials. Typical dependences of turbidity as a function of diameter of scattering elements, their volume fractions and also turbidity curves as a function of the wavelength of the incident light were calculated, based both on the Lorenz-Mie theory and the fluctuation theory. Such dependences calculated for polypropylene-containing voids on the one hand and particles, differing only slightly from the surrounding matrix in their refractive index, on the other hand, are markedly different. The most significant results are: (i) Turbidity is at least by two orders of magnitude larger for voids in comparison to embedded particles of ethylene-propylene (EPDM) rubber of the same size, concentration and at the same wavelength. (ii) The wavelength dependence of turbidity for EPDM particles and the inherent refractive index fluctuations in the polypropylene matrix is much steeper as compared to voids for all considered diameters (0.1-10 μm). Thus, the nature of stress whitening in complex polymeric materials can be determined from turbidity measurements.

scholarly journals Characterization of Volume Gratings Based on Distributed Dielectric Constant Model Using Mueller Matrix Ellipsometry

2019 ◽  
Vol 9 (4) ◽  
pp. 698 ◽  
Author(s):  
Hao Jiang ◽  
Zhao Ma ◽  
Honggang Gu ◽  
Xiuguo Chen ◽  
Shiyuan Liu
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Minimum Mean Square Error ◽  
Incident Light ◽  
Mueller Matrix ◽  
Distribution Functions ◽  
Refractive Index Distribution ◽  
Index Distribution ◽  
Constant Distribution ◽  
Volume Gratings

Volume grating is a key optical component due to its comprehensive applications. Other than the common grating structures, volume grating is essentially a predesigned refractive index distribution recorded in materials, which raises the challenges of metrology. Although we have demonstrated the potential application of ellipsometry for volume grating characterization, it has been limited due to the absence of general forward model reflecting the refractive index distribution. Herein, we introduced a distributed dielectric constant based rigorous coupled-wave analysis (RCWA) model to interpret the interaction between the incident light and volume grating, with which the Mueller matrix can be calculated. Combining with a regression analysis with the objective to match the measured Mueller matrices with minimum mean square error (MSE), the parameters of the dielectric constant distribution function can be determined. The proposed method has been demonstrated using a series of simulations of measuring the volume gratings with different dielectric constant distribution functions. Further demonstration has been carried out by experimental measurements on volume holographic gratings recorded in the composite of polymer and zinc sulfide (ZnS) nanoparticles. By directly fitting the spatiotemporal concentration of the nanoparticles, the diffusion coefficient has been further evaluated, which is consistent to the result reported in our previous investigations.

Circular polarized incident light scattering properties at optical clearing in tissues

2016 ◽  
Author(s):  
Dongsheng Chen ◽  
Nan Zeng ◽  
Yunfei Wang ◽  
Honghui He ◽  
Valery V. Tuchin ◽  
...  
Keyword(s):  
Light Scattering ◽  
Incident Light ◽  
Optical Clearing

Theoretical analysis on the development of opaque fibers based on Mie scattering

2012 ◽  
Vol 83 (4) ◽  
pp. 355-362 ◽  
Author(s):  
Ni Wang ◽  
Wenyan Pan ◽  
Meiwu Shi ◽  
Jianyong Yu
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Extinction Coefficient ◽  
Incident Light ◽  
Mie Scattering ◽  
Spherical Particles ◽  
Diameter Distribution ◽  
Matlab Program ◽  
Mie Scattering Theory ◽  
First Time

Mie scattering theory has been widely used to solve the problem of light scattering by single spherical particles in many fields. In this article, it was applied for the development of opaque fiber for the first time. Firstly, the spheroid particles were simplified as equivalent spherical particles. Then, the extinction coefficient was calculated using the Matlab program and the influences of the size parameter, refractive index and the wavelength of the incident light on the extinction coefficient were discussed in detail. Finally, the results indicated that the extinction coefficient depended greatly on the dimension and the refractive index of the particles, and also the wavelength of the incident light. For the development of the opaque fiber, it would be better to choose particles that had the higher refractive index and a certain diameter distribution to achieve the most effective light scattering.

scholarly journals A tunable refractive index matching medium for live imaging cells, tissues and model organisms

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Tobias Boothe ◽  
Lennart Hilbert ◽  
Michael Heide ◽  
Lea Berninger ◽  
Wieland B Huttner ◽  
...  
Keyword(s):  
Refractive Index ◽  
Image Quality ◽  
Light Microscopy ◽  
Penetration Depth ◽  
Cell Cultures ◽  
Model Organisms ◽  
Optical Clearing ◽  
Index Matching ◽  
Refractive Index Matching ◽  
Tunable Refractive Index

In light microscopy, refractive index mismatches between media and sample cause spherical aberrations that often limit penetration depth and resolution. Optical clearing techniques can alleviate these mismatches, but they are so far limited to fixed samples. We present Iodixanol as a non-toxic medium supplement that allows refractive index matching in live specimens and thus substantially improves image quality in live-imaged primary cell cultures, planarians, zebrafish and human cerebral organoids.

scholarly journals Toward Better Medical Diagnosis: Tissue Optical Clearing

2020 ◽  
Vol 2 (1) ◽  
pp. 13-21
Author(s):  
Omnia Hamdy ◽  
Rania M. Abdelazeem
Keyword(s):  
Refractive Index ◽  
Medical Diagnosis ◽  
Imaging Techniques ◽  
High Refractive Index ◽  
Biological Tissues ◽  
Optical Clearing ◽  
Research Areas ◽  
Body Tissues ◽  
Deep Imaging ◽  
Tissue Optical Clearing

Reaching efficient, safe and painless medical diagnosis procedure is a very valued goal for many research areas. Despite the great advantages of using optical imaging techniques in medical diagnosis including high safety and relative simplicity, it still suffers from relatively low resolution and penetration depth in the multiple scattering mediums such as biological tissues. Therefore, researchers began to devise ways to reduce the scattering properties of the tissue, hence increasing the imaging contrast. Optical clearing concept is introduced to do this job. This technique can reduce tissues scattering properties by using high refractive index chemicals, thus making the tissue transparent by equalizing the refractive index through that medium. In this paper, theory and techniques of optical clearing method are illustrated utilizing its benefits for deep imaging of different body tissues and organs.

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