scholarly journals Giant Extra-Ordinary Near Infrared Transmission from Seemingly Opaque Plasmonic Metasurface: Sensing Applications

Plasmonics ◽  
2021 ◽  
Author(s):  
Sagar Kumar Verma ◽  
Sachin K. Srivastava
Keyword(s):  
Near Infrared ◽  
Infrared Transmission ◽  
Sensing Applications

scholarly journals Giant Extra-Ordinary Near Infrared Transmission from Seemingly Opaque Plasmonic Metasurface: Sensing Applications

2021 ◽  
Author(s):  
Sagar Kumar Verma ◽  
Sachin Kumar Srivast
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
Light Transmission ◽  
Cost Effective ◽  
Interlayer Spacing ◽  
Subwavelength Structures ◽  
Infrared Transmission ◽  
Sensing Applications ◽  
Flexible Polymer ◽  
Extended Surface

Abstract In the present study, we report giant extra-ordinary transmission of near infra-red (NIR) light, more than 90%, through a seemingly opaque plasmonic metasurface, which consists of two metal nano-slits arrays (MNSAs) with alternate opening arrangements. By using perfect coupling of the plasmonic modes formed between the sharp edges of the upper and lower MNSAs of silver, a giant, wavelength selective transmission could be obtained. The study is accompanied by optimization of electromagnetic (EM) field coupling for different interlayer spacings and lateral overlap between the two MNSAs to understand their significance in light transmission through the metasurface. The interlayer spacing between the MNSAs works as the transmitting channel for light. The optimization of performance with different fill factors and plasmonic metals was performed as well. Because of the excitation of extended surface plasmons (ESPs) generated at both the MNSAs, the metasurface can be used for refractive index (RI) sensing as one of its applications by using a transparent and flexible polymer, such as polydimethylsiloxane (PDMS), as substrate. The maximum sensitivity which could be achieved for the optimal configuration of the metasurface was 1435.71 nm/RIU, with a figure of merit (FOM) of 80 RIU− 1 for 90.45% optical transmission of light for the refractive index variation of analyte medium from 1.33 to 1.38 RIU. The present study strengthens the concept of light funneling through subwavelength structures due to plasmons, which are responsible for light transmission through this seemingly opaque metasurface and finds use in highly sensitive, flexible, and cost effective EOT based sensors.

scholarly journals Estimation of composition of quinoa ( Chenopodium quinoa Willd.) grains by Near-Infrared Transmission spectroscopy

LWT ◽  
2017 ◽  
Vol 79 ◽  
pp. 126-134 ◽  
Author(s):  
Christian Encina-Zelada ◽  
Vasco Cadavez ◽  
Jorge Pereda ◽  
Luz Gómez-Pando ◽  
Bettit Salvá-Ruíz ◽  
...  
Keyword(s):  
Near Infrared ◽  
Chenopodium Quinoa ◽  
Infrared Transmission ◽  
Transmission Spectroscopy

Application of near Infrared Transmission Spectroscopy for the Determination of Some Quality Parameters of Apples

1994 ◽  
Vol 2 (4) ◽  
pp. 213-221 ◽  
Author(s):  
T. Lovász ◽  
P. Merész ◽  
A. Salgó
Keyword(s):  
Dry Matter ◽  
Near Infrared ◽  
Matter Content ◽  
Dry Matter Content ◽  
Quality Factors ◽  
Infrared Transmission ◽  
Transmission Method ◽  
Titratable Acid ◽  
Transmission Spectroscopy ◽  
Relative Standard

The acceptability of near infrared (NIR) transmission spectroscopy for the prediction of six quality factors of apples (firmness, refractive index, pH, titratable acid, dry matter and alcohol insoluble solids content) was investigated. The effects of storage conditions, cultivars and season on the accuracy of the NIR transmission method were also studied during the experiment. The accuracy of the calibration of all investigated parameters decreased during storage. The alteration of the characteristics of the spectra is possibly due to changes in the chemical composition and structure of apples between September and April. The calibration method was improved by developing a separate calibration for each cultivar per year. The calibrations of the different parameters are season-dependent except for the dry matter content. Using outlier diagnostics, the prediction accuracy can be generally improved by about 10%. The coefficient of variation for each parameter is compatible with the relative standard deviation for the reference methods except for the titratable acid content, showing the applicability of NIR transmission techniques. A relationship seems to exist between the maturity and the NIR transmission spectra of the apple.

scholarly journals Mode Sensitivity Exploration of Silica–Titania Waveguide for Refractive Index Sensing Applications

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7452
Author(s):  
Muhammad A. Butt ◽  
Andrzej Kaźmierczak ◽  
Cuma Tyszkiewicz ◽  
Paweł Karasiński ◽  
Ryszard Piramidowicz
Keyword(s):  
Refractive Index ◽  
High Performance ◽  
Near Infrared ◽  
Sol Gel ◽  
Cost Effective ◽  
Dip Coating ◽  
Infrared Wavelength ◽  
Refractive Index Sensing ◽  
Sensing Applications ◽  
Coating Method

In this paper, a novel and cost-effective photonic platform based on silica–titania material is discussed. The silica–titania thin films were grown utilizing the sol–gel dip-coating method and characterized with the help of the prism-insertion technique. Afterwards, the mode sensitivity analysis of the silica–titania ridge waveguide is investigated via the finite element method. Silica–titania waveguide systems are highly attractive due to their ease of development, low fabrication cost, low propagation losses and operation in both visible and near-infrared wavelength ranges. Finally, a ring resonator (RR) sensor device was modelled for refractive index sensing applications, offering a sensitivity of 230 nm/RIU, a figure of merit (FOM) of 418.2 RIU−1, and Q-factor of 2247.5 at the improved geometric parameters. We believe that the abovementioned integrated photonics platform is highly suitable for high-performance and economically reasonable optical sensing devices.

scholarly journals Deep learning para la clasificación de usos de suelo agrícola con Sentinel-2

2020 ◽  
pp. 35
Author(s):  
M. Campos-Taberner ◽  
F.J. García-Haro ◽  
B. Martínez ◽  
M.A. Gilabert
Keyword(s):  
Remote Sensing ◽  
Deep Learning ◽  
Near Infrared ◽  
Spatial Information ◽  
Learning Algorithm ◽  
Support Vector ◽  
Sensing Applications ◽  
Learning Techniques ◽  
Remote Sensing Applications ◽  
Sentinel 2

<p class="p1">The use of deep learning techniques for remote sensing applications has recently increased. These algorithms have proven to be successful in estimation of parameters and classification of images. However, little effort has been made to make them understandable, leading to their implementation as “black boxes”. This work aims to evaluate the performance and clarify the operation of a deep learning algorithm, based on a bi-directional recurrent network of long short-term memory (2-BiLSTM). The land use classification in the Valencian Community based on Sentinel-2 image time series in the framework of the common agricultural policy (CAP) is used as an example. It is verified that the accuracy of the deep learning techniques is superior (98.6 % overall success) to that other algorithms such as decision trees (DT), k-nearest neighbors (k-NN), neural networks (NN), support vector machines (SVM) and random forests (RF). The performance of the classifier has been studied as a function of time and of the predictors used. It is concluded that, in the study area, the most relevant information used by the network in the classification are the images corresponding to summer and the spectral and spatial information derived from the red and near infrared bands. These results open the door to new studies in the field of the explainable deep learning in remote sensing applications.</p>

Determination of Wavelength Accuracy in the Near-Infrared Spectral Region Based on NIST's Infrared Transmission Wavelength Standard SRM 1921

2000 ◽  
Vol 54 (3) ◽  
pp. 450-455 ◽  
Author(s):  
Stephen R. Lowry ◽  
Jim Hyatt ◽  
William J. McCarthy
Keyword(s):  
Reference Material ◽  
Standard Reference Material ◽  
Spectral Region ◽  
Near Infrared ◽  
Cost Effective ◽  
Infrared Transmission ◽  
Internal Reference ◽  
Mid Infrared ◽  
Infrared Spectral Region ◽  
Infrared Spectral

A major concern with the use of near-infrared (NIR) spectroscopy in many QA/QC laboratories is the need for a simple reliable method of verifying the wavelength accuracy of the instrument. This requirement is particularly important in near-infrared spectroscopy because of the heavy reliance on sophisticated statistical vector analysis techniques to extract the desired information from the spectra. These techniques require precise alignment of the data points between the vectors corresponding to the standard and sample spectra. The National Institute of Standards and Technology (NIST) offers a Standard Reference Material (SRM 1921) for the verification and calibration of mid-infrared spectrometers in the transmittance mode. This standard consists of a 38 μm-thick film of polystyrene plastic. While SRM 1921 works well as a mid-infrared standard, a thicker sample is required for use as a routine standard in the near-infrared spectral region. The general acceptance and proven reliability of polystyrene as a standard reference material make it a very good candidate for a cost-effective NIR standard that could be offered as an internal reference for every instrument. In this paper we discuss a number of the parameters in a Fourier transform (FT)-NIR instrument that can affect wavelength accuracy. We also report a number of experiments designed to determine the effects of resolution, sample position, and optics on the wavelength accuracy of the system. In almost all cases the spectral reproducibility was better than one wavenumber of the values extrapolated from the NIST reference material. This finding suggests that a thicker sample of polystyrene plastic that has been validated with the SRM 1921 standard would make a cost-effective reference material for verifying wavelength accuracy in a medium-resolution FT-NIR spectrometer.

scholarly journals Evaluation of Measurement Sites for Noninvasive Blood Glucose Sensing with Near-Infrared Transmission Spectroscopy

1999 ◽  
Vol 45 (9) ◽  
pp. 1621-1627 ◽  
Author(s):  
Jason J Burmeister ◽  
Mark A Arnold
Keyword(s):  
Blood Glucose ◽  
Body Fat ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Glucose Sensing ◽  
Infrared Transmission ◽  
Signal To Noise ◽  
Lower Lip ◽  
Percentage Of Body Fat ◽  
Noise Ratio

Abstract Six putative measurement sites were evaluated for noninvasive sensing of blood glucose by first-overtone near-infrared spectroscopy. The cheek, lower lip, upper lip, nasal septum, tongue, and webbing tissue between the thumb and forefinger were examined. These sites were evaluated on the basis of their chemical and physical properties as they pertain to the noninvasive measurement of glucose. Critical features included the effective optical pathlength of aqueous material within the tissue and the percentage of body fat within the optical path. Aqueous optical paths of 5 mm are required to measure clinically relevant concentrations of glucose in the first-overtone region. All of the tested sites met this requirement. The percentage of body fat affects the signal-to-noise ratio of the measurement and must be minimized for reliable glucose sensing. The webbing tissue contains a considerable amount of fat tissue and is clearly the worse measurement site. All other sites possess substantially less fat, with the least amount of fat in tongue tissue. For this reason, the tongue provides spectra with the highest signal-to-noise ratio and is, therefore, the site of choice on the basis of spectral quality.

scholarly journals Polymer-Based Microring Resonator with the Multimode Interference Coupler Operating at Very-Near-Infrared Wavelengths

2019 ◽  
Vol 9 (13) ◽  
pp. 2715 ◽  
Author(s):  
Huanlin Lv ◽  
Yuxin Liang ◽  
Zhenlin Wu ◽  
Xiuyou Han ◽  
Geert Morthier ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Potential ◽  
Microring Resonator ◽  
Multimode Interference ◽  
Q Factor ◽  
Fluorinated Polymer ◽  
Sensing Applications ◽  
Soft Mold ◽  
Multimode Interference Coupler ◽  
Infrared Wavelengths

A microring resonator with the multimode interference coupler is fabricated on the polymer platform by using UV-based soft nanoimprint technique. A unique class of fluorinated polymer, perfluoropolyether (PFPE), is employed for the fabrication of the flexible soft mold. By optimizing the proportion between Ormocore and the thinner maT, the microring resonator is fabricated almost without residual layer. The fabricated device with a Q-factor up to 2.3 × 104 is demonstrated for very-near-infrared wavelengths, which shows high potential for sensing applications.

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