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].

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].

Nature of light scattering in dental enamel and dentin at visible and near-infrared wavelengths

1995 ◽  
Vol 34 (7) ◽  
pp. 1278 ◽  
Author(s):  
Daniel Fried ◽  
Richard E. Glena ◽  
John D. B. Featherstone ◽  
Wolf Seka
Keyword(s):  
Light Scattering ◽  
Near Infrared ◽  
Dental Enamel ◽  
Infrared Wavelengths

Static light scattering properties of a ZnO nanosphere aqueous suspension at visible and near-infrared wavelengths

2017 ◽  
Vol 15 (1) ◽  
pp. 012901-12906 ◽  
Author(s):  
Haopeng Wu Haopeng Wu ◽  
Jiulin Shi Jiulin Shi ◽  
Feng Yan Feng Yan ◽  
Junjie Yang Junjie Yang ◽  
Yubao Zhang Yubao Zhang ◽  
...  
Keyword(s):  
Light Scattering ◽  
Near Infrared ◽  
Aqueous Suspension ◽  
Static Light Scattering ◽  
Infrared Wavelengths

Enhancement of OCT imaging by blood optical clearing in vessels – A feasibility study

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Olga Zhernovaya ◽  
Valery V. Tuchin ◽  
Martin J. Leahy
Keyword(s):  
Light Scattering ◽  
Blood Vessels ◽  
Feasibility Study ◽  
Biological Tissues ◽  
Intradermal Injection ◽  
Light Transport ◽  
Optical Clearing ◽  
Intravenous Injections ◽  
Oct Imaging ◽  
System Operating

AbstractThe results of a feasibility study of the application of PEG-300 and fructose as two independent optical clearing agents for the reduction of light scattering in biological tissues are presented.An OCT system operating at 1300 nm was used to study optical clearing effects. InThe intradermal injection of fructose in combination with the intravenous injection of PEG-300 led to a rapid optical clearing effect. In the experiments on miceThe experiments on mice have clearly demonstrated that intradermal and intravenous injections of optical clearing agents enhanced light transport through the skin and blood vessels.

Tissue Optical Clearing Devices: Effects of Water Content on the Hyperelastic Mechanical Properties of Ex Vivo Porcine Skin

2010 ◽  
Author(s):  
William Vogt ◽  
Alondra Izquierdo-Roman ◽  
Christopher G. Rylander
Keyword(s):  
Near Infrared ◽  
Light Transmission ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Complex Structure ◽  
Heterogeneous Material ◽  
Index Of Refraction ◽  
Water Displacement ◽  
Optical Clearing ◽  
Tissue Optical Clearing

Skin is a highly anisotropic and heterogeneous material composed of water, proteins, and various cells arranged in several different layers. Because of this complex structure, there is a large mismatch in index of refraction between the tissue constituents, creating a highly scattering medium for near-infrared and visible light. “Tissue optical clearing” methods can improve light transmission through tissues, potentially improving optical imaging techniques and photoirradiative treatments [1]. Dehydration has been suggested as a possible mechanism of optical clearing [2], and previous work has demonstrated mechanical loading as a method of creating reversible localized water displacement in skin using novel tissue optical clearing devices (TOCDs) [3–4]. These TOCDs were hypothesized to increase light transmission by displacing water locally in the tissue, causing local dehydration. A model of the mechanical behavior of skin will enable improvement of current TOCDs that utilize local mechanical compression.

Multidomain Modeling of Spatial Distributions of Tissue Optical Properties During Indentation: Mechanical Tissue Optical Clearing Devices as Diagnostic Tools

2011 ◽  
Author(s):  
William C. Vogt ◽  
Alondra Izquierdo-Roman ◽  
Christopher G. Rylander
Keyword(s):  
Near Infrared ◽  
Soft Tissues ◽  
Light Transmission ◽  
Index Of Refraction ◽  
Diagnostic Tools ◽  
Infrared Range ◽  
Water Displacement ◽  
Optical Clearing ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

Soft tissues are highly heterogeneous materials comprised of water, proteins, and many types of cells. This composite configuration results in a large mismatch in index of refraction between tissue constituents, creating a high-scattering medium in the visible and near-infrared range. “Tissue optical clearing” can increase light transmission through these tissues, potentially improving both optical diagnostic and therapeutic procedures [1]. Dehydration has been shown to be a mechanism of optical clearing, and previous work has investigated mechanical loading as a method of creating reversible localized water displacement in skin using novel mechanical tissue optical clearing devices (TOCDs) [2]. In addition to potentially enhancing established light-based procedures, the principles of TOCD operation may provide a platform for a novel diagnostic tool capable of utilizing many different measurement types simultaneously.

scholarly journals Electromechanically reconfigurable optical nano-kirigami

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shanshan Chen ◽  
Zhiguang Liu ◽  
Huifeng Du ◽  
Chengchun Tang ◽  
Chang-Yin Ji ◽  
...  
Keyword(s):  
Near Infrared ◽  
Large Range ◽  
Three Dimensional ◽  
High Contrast ◽  
Si Substrate ◽  
High Modulation ◽  
Gold Nanostructure ◽  
Infrared Wavelengths ◽  
On Chip ◽  
Nano Electromechanical System

AbstractKirigami, with facile and automated fashion of three-dimensional (3D) transformations, offers an unconventional approach for realizing cutting-edge optical nano-electromechanical systems. Here, we demonstrate an on-chip and electromechanically reconfigurable nano-kirigami with optical functionalities. The nano-electromechanical system is built on an Au/SiO2/Si substrate and operated via attractive electrostatic forces between the top gold nanostructure and bottom silicon substrate. Large-range nano-kirigami like 3D deformations are clearly observed and reversibly engineered, with scalable pitch size down to 0.975 μm. Broadband nonresonant and narrowband resonant optical reconfigurations are achieved at visible and near-infrared wavelengths, respectively, with a high modulation contrast up to 494%. On-chip modulation of optical helicity is further demonstrated in submicron nano-kirigami at near-infrared wavelengths. Such small-size and high-contrast reconfigurable optical nano-kirigami provides advanced methodologies and platforms for versatile on-chip manipulation of light at nanoscale.

Spectral characteristics of leafy spurge (Euphorbia esula) leaves and flower bracts

Weed Science ◽  
2004 ◽  
Vol 52 (4) ◽  
pp. 492-497 ◽  
Author(s):  
E. Raymond Hunt ◽  
James E. McMurtrey ◽  
Amy E. Parker Williams ◽  
Lawrence A. Corp
Keyword(s):  
Remote Sensing ◽  
High Performance ◽  
Near Infrared ◽  
Spectral Characteristics ◽  
Leafy Spurge ◽  
Hyperspectral Remote Sensing ◽  
Total Carotenoids ◽  
Physiological Basis ◽  
Infrared Wavelengths ◽  
Pigment Concentrations

Leafy spurge can be detected during flowering with either aerial photography or hyperspectral remote sensing because of the distinctive yellow-green color of the flower bracts. The spectral characteristics of flower bracts and leaves were compared with pigment concentrations to determine the physiological basis of the remote sensing signature. Compared with leaves of leafy spurge, flower bracts had lower reflectance at blue wavelengths (400 to 500 nm), greater reflectance at green, yellow, and orange wavelengths (525 to 650 nm), and approximately equal reflectances at 680 nm (red) and at near-infrared wavelengths (725 to 850 nm). Pigments from leaves and flower bracts were extracted in dimethyl sulfoxide, and the pigment concentrations were determined spectrophotometrically. Carotenoid pigments were identified using high-performance liquid chromatography. Flower bracts had 84% less chlorophylla, 82% less chlorophyllb, and 44% less total carotenoids than leaves, thus absorptance by the flower bracts should be less and the reflectance should be greater at blue and red wavelengths. The carotenoid to chlorophyll ratio of the flower bracts was approximately 1:1, explaining the hue of the flower bracts but not the value of reflectance. The primary carotenoids were lutein, β-carotene, and β-cryptoxanthin in a 3.7:1.5:1 ratio for flower bracts and in a 4.8:1.3:1 ratio for leaves, respectively. There was 10.2 μg g−1fresh weight of colorless phytofluene present in the flower bracts and none in the leaves. The fluorescence spectrum indicated high blue, red, and far-red emission for leaves compared with flower bracts. Fluorescent emissions from leaves may contribute to the higher apparent leaf reflectance in the blue and red wavelength regions. The spectral characteristics of leafy spurge are important for constructing a well-documented spectral library that could be used with hyperspectral remote sensing.

scholarly journals Highly Efficient Near-Infrared Detector Based on Optically Resonant Dielectric Nanodisks

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 428
Author(s):  
Reza Masoudian Saadabad ◽  
Christian Pauly ◽  
Norbert Herschbach ◽  
Dragomir N. Neshev ◽  
Haroldo T. Hattori ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
High Speed ◽  
Near Infrared ◽  
Infrared Detector ◽  
High Quantum Efficiency ◽  
Fast Detection ◽  
High Quantum ◽  
Resonant Modes ◽  
Infrared Wavelengths ◽  
Dielectric Metasurface

Fast detection of near-infrared (NIR) photons with high responsivity remains a challenge for photodetectors. Germanium (Ge) photodetectors are widely used for near-infrared wavelengths but suffer from a trade-off between the speed of photodetection and quantum efficiency (or responsivity). To realize a high-speed detector with high quantum efficiency, a small-sized photodetector efficiently absorbing light is required. In this paper, we suggest a realization of a dielectric metasurface made of an array of subwavelength germanium PIN photodetectors. Due to the subwavelength size of each pixel, a high-speed photodetector with a bandwidth of 65 GHz has been achieved. At the same time, high quantum efficiency for near-infrared illumination can be obtained by the engineering of optical resonant modes to localize optical energy inside the intrinsic Ge disks. Furthermore, small junction capacitance and the possibility of zero/low bias operation have been shown. Our results show that all-dielectric metasurfaces can improve the performance of photodetectors.

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