scholarly journals Development of a Multimode Field Deployable Lidar Instrument for Topographic Measurements of Unsaturated Soil Properties: Instrument Description

2019 ◽  
Vol 11 (3) ◽  
pp. 289 ◽  
Author(s):  
Sean Salazar ◽  
Cyrus Garner ◽  
Richard Coffman
Keyword(s):  
Soil Properties ◽  
Near Infrared ◽  
Infrared Light ◽  
Differential Absorption ◽  
Matric Potential ◽  
Detection Scheme ◽  
Fines Content ◽  
Laser Absorption ◽  
Remote Sensor

The hydrological and mechanical behavior of soil is determined by the moisture content, soil water (matric) potential, fines content, and plasticity. However, these parameters are often difficult or impractical to determine in the field. Remote characterization of soil parameters is a non-destructive data collection process well suited to large or otherwise inaccessible areas. A ground-based, field-deployable remote sensor, called the soil observation laser absorption spectrometer (SOLAS), was developed to collect measurements from the surface of bare soils and to assess the in-situ condition and essential parameters of the soil. The SOLAS instrument transmits coherent light at two wavelengths using two, continuous-wave, near-infrared diode lasers and the instrument receives backscattered light through a co-axial 203-mm diameter telescope aperture. The received light is split into a hyperspectral sensing channel and a laser absorption spectrometry (LAS) channel via a multi-channel optical receiver. The hyperspectral channel detects light in the visible to shortwave infrared wavelengths, while the LAS channel filters and directs near-infrared light into a pair of photodetectors. Atmospheric water vapor is inferred using the differential absorption of the on- and off-line laser wavelengths (823.20 nm and 847.00 nm, respectively). Range measurement is determined using a frequency-modulated, self-chirped, coherent, homodyne detection scheme. The development of the instrument (transmitter, receiver, data acquisition components) is described herein. The potential for rapid characterization of physical and hydro-mechanical soil properties, including volumetric water content, matric potential, fines content, and plasticity, using the SOLAS remote sensor is discussed. The envisioned applications for the instrument include assessing soils on unstable slopes, such as wildfire burn sites, or stacked mine tailings. Through the combination of spectroradiometry, differential absorption, and range altimetry methodologies, the SOLAS instrument is a novel approach to ground-based remote sensing of the natural environment.

Near Infrared Light Detectors Based on Uhvcvd Epitaxial Ge on Si (100)

1997 ◽  
Vol 486 ◽  
Author(s):  
L. Colace ◽  
G. Masini ◽  
F. Galluzzi ◽  
G. Assanto ◽  
G. Capellini ◽  
...  
Keyword(s):  
Near Infrared ◽  
Normal Incidence ◽  
Metal Structure ◽  
Atomic Scale ◽  
Infrared Light ◽  
Light Penetration ◽  
Silicon Chips ◽  
Metal Semiconductor Metal ◽  
Photo Detectors

AbstractIn the present work we investigate photo-detectors based on thick relaxed Ge layers, epitaxially grown on silicon after insertion of a low-temperature-grown Ge buffer layer. By using this procedure it was possible to grow films having thicknesses comparable with light penetration depth in the 1.3–1.6μm spectral range. The films exhibited flatness on the atomic scale. Two kinds of detectors were investigated: vertical heterojunction diodes and a planar Metal-Semiconductor-Metal structure. The detectors show a good responsivity at normal incidence at both 1.3 and 1.55μm. The photocurrent increases with the voltage applied, reaching a maximum responsivity of 0.24 A/W at 1.3μm under a bias of IV. A complete optoelectronic characterization of the fabricated devices is performed. The results confirm the feasibility of the proposed approach for the fabrication of 1.3–1.55μm near infrared photodetectors integrated on silicon chips.

Non-invasive characterization of chick embryo body and cardiac movements using near infrared light

2019 ◽  
Vol 12 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Alin Khaliduzzaman ◽  
Shinichi Fujitani ◽  
Naoshi Kondo ◽  
Yuichi Ogawa ◽  
Tateshi Fujiura ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Near Infrared ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Non Invasive

Non-Invasive Characterization of Human NeckTumors with Near-Infrared Light Spectroscopy

2002 ◽  
Author(s):  
U. Sunar ◽  
S. Nioka ◽  
X. Intes ◽  
J. Ripoll ◽  
L. Loevner ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Non Invasive

scholarly journals Multi-Channel Optical Receiver for Ground-Based Topographic Hyperspectral Remote Sensing

2019 ◽  
Vol 11 (5) ◽  
pp. 578 ◽  
Author(s):  
Sean Salazar ◽  
Richard Coffman
Keyword(s):  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Absorption Spectrometry ◽  
Optical Receiver ◽  
Infrared Range ◽  
Receiver Design ◽  
Remote Sensor ◽  
Rapid Characterization ◽  
Shortwave Infrared

Receiver design is integral to the development of a new remote sensor. An effective receiver delivers backscattered light to the detector while optimizing the signal-to-noise ratio at the desired wavelengths. Towards the goal of effective receiver design, a multi-channel optical receiver was developed to collect range-resolved, backscattered energy for simultaneous hyperspectral and differential absorption spectrometry (LAS) measurements. The receiver is part of a new, ground-based, multi-mode lidar instrument for remote characterization of soil properties. The instrument, referred to as the soil observation laser absorption spectrometer (SOLAS), was described previously in the literature. A detailed description of the multi-channel receiver of the SOLAS is presented herein. The hyperspectral channel receives light across the visible near-infrared (VNIR) to shortwave infrared (SWIR) spectrum (350–2500 nm), while the LAS channel was optimized for detection in a narrower portion of the near-infrared range (820–850 nm). The range-dependent field of view for each channel is presented and compared with the beam evolution of the SOLAS instrument transmitter. Laboratory-based testing of each of the receiver channels was performed to determine the effectiveness of the receiver. Based on reflectance spectra collected for four soil types, at distances of 20, 35, and 60 m from the receiver, reliable hyperspectral measurements were gathered, independent of the range to the target. Increased levels of noise were observed at the edges of the VNIR and SWIR detector ranges, which were attributed to the lack of sensitivity of the instrument in these regions. The suitability of the receiver design, for the collection of both hyperspectral and LAS measurements at close-ranges, is documented herein. Future development of the instrument will enable the combination of long-range, ground-based hyperspectral measurements with the LAS measurements to correct for absorption, due to atmospheric water vapor. The envisioned application for the instrument includes the rapid characterization of bare or vegetated soils and minerals, such as are present in mine faces and tailings, or unstable slopes.

Wavelength characterization of an acousto-optic notch filter for unpolarized near-infrared light

2018 ◽  
Vol 57 (10) ◽  
pp. C36 ◽  
Author(s):  
Jean-Claude Kastelik ◽  
Justine Champagne ◽  
Samuel Dupont ◽  
Konstantin B. Yushkov
Keyword(s):  
Near Infrared ◽  
Notch Filter ◽  
Infrared Light ◽  
Near Infrared Light

scholarly journals Labyrinth ice pattern formation induced by near-infrared irradiation

2019 ◽  
Vol 5 (3) ◽  
pp. eaav1598 ◽  
Author(s):  
Shlomit Guy Preis ◽  
Haim Chayet ◽  
Adam Katz ◽  
Victor Yashunsky ◽  
Avigail Kaner ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Formation Process ◽  
Dendritic Growth ◽  
Near Infrared ◽  
Ice Crystals ◽  
Phase System ◽  
Infrared Irradiation ◽  
Differential Absorption ◽  
Two Phase ◽  
Laser Absorption

Patterns are broad phenomena that relate to biology, chemistry, and physics. The dendritic growth of crystals is the most well-known ice pattern formation process. Tyndall figures are water-melting patterns that occur when ice absorbs light and becomes superheated. Here, we report a previously undescribed ice and water pattern formation process induced by near-infrared irradiation that heats one phase more than the other in a two-phase system. The pattern formed during the irradiation of ice crystals tens of micrometers thick in solution near equilibrium. Dynamic holes and a microchannel labyrinth then formed in specific regions and were characterized by a typical distance between melted points. We concluded that the differential absorption of water and ice was the driving force for the pattern formation. Heating ice by laser absorption might be useful in applications such as the cryopreservation of biological samples.

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