Spectral Ranges Determination for Detection of the Fire Radiation for Flame Detector Based on the Spectral Pyrometry Method

Spectral pyrometry was used to determine the surface temperature distribution of Si, Nb, Cu, and graphite samples when they were locally heated by continuous radiation of an Nd:YAG laser (λ = 1.064 μm). With prolonged exposure to radiation, a stationary temperature field was established in the samples. The thermal spectra were recorded with a small spectrometer in the visible range in the temperature range above 850 K. The optical fiber used to transmit the radiation spectrum to the spectrometer had an additional diaphragm with a diameter of 1 mm located at a certain distance from the fiber end, which ensured the locality of the recorded spectra. The optical fiber moved continuously along the sample, and the spectrometer recorded up to 100 spectra with a frequency of 5-10 Hz. The temperature profile of the samples was calculated based on the results of processing the spectra using the Spectral Pyrometry program.

Download Full-text

Measurement of Laser Radiation Attenuation in Metallized Optical Fibers in Visible and Near-IR Spectral Ranges

2020 International Conference Laser Optics (ICLO) ◽

10.1109/iclo48556.2020.9285567 ◽

2020 ◽

Author(s):

P.S. Cherpak ◽

R.I. Shaidullin ◽

O.A. Ryabushkin

Keyword(s):

Laser Radiation ◽

Optical Fibers ◽

Radiation Attenuation ◽

Near Ir ◽

Spectral Ranges

Download Full-text

Integrated Optical Phased Arrays for Beam Forming and Steering

Applied Sciences ◽

10.3390/app11094017 ◽

2021 ◽

Vol 11 (9) ◽

pp. 4017

Author(s):

Yongjun Guo ◽

Yuhao Guo ◽

Chunshu Li ◽

Hao Zhang ◽

Xiaoyan Zhou ◽

...

Keyword(s):

Near Infrared ◽

Phased Arrays ◽

Mechanical Stability ◽

Building Blocks ◽

High Yield ◽

Beam Forming ◽

Integrated Optical ◽

Optical Phased Arrays ◽

Infrared Spectral ◽

Spectral Ranges

Integrated optical phased arrays can be used for beam shaping and steering with a small footprint, lightweight, high mechanical stability, low price, and high-yield, benefiting from the mature CMOS-compatible fabrication. This paper reviews the development of integrated optical phased arrays in recent years. The principles, building blocks, and configurations of integrated optical phased arrays for beam forming and steering are presented. Various material platforms can be used to build integrated optical phased arrays, e.g., silicon photonics platforms, III/V platforms, and III–V/silicon hybrid platforms. Integrated optical phased arrays can be implemented in the visible, near-infrared, and mid-infrared spectral ranges. The main performance parameters, such as field of view, beamwidth, sidelobe suppression, modulation speed, power consumption, scalability, and so on, are discussed in detail. Some of the typical applications of integrated optical phased arrays, such as free-space communication, light detection and ranging, imaging, and biological sensing, are shown, with future perspectives provided at the end.

Download Full-text

Soil weathering behavior assessed by combined spectral ranges: Insights into aggregate analysis

Geoderma ◽

10.1016/j.geoderma.2021.115154 ◽

2021 ◽

Vol 402 ◽

pp. 115154

Author(s):

Clécia Cristina Barbosa Guimarães ◽

José A. M. Demattê ◽

Antônio Carlos de Azevedo ◽

Ricardo Simão Diniz Dalmolin ◽

Alexandre ten Caten ◽

...

Keyword(s):

Soil Weathering ◽

Aggregate Analysis ◽

Spectral Ranges

Download Full-text

Silicon in the solar corona

Symposium - International Astronomical Union ◽

10.1017/s0074180900179513 ◽

1965 ◽

Vol 23 ◽

pp. 115-123

Author(s):

K. G. Widing ◽

J. R. Porter

Keyword(s):

Solar Corona ◽

Relative Intensity ◽

Line Emission ◽

X Ray ◽

Resonance Transitions ◽

Spectral Ranges

Resonance lines of coronal ions of silicon are prominent in the spectral ranges 40–62 Å and 254–356 Å.An unexpected feature of the soft X-ray spectrum is the weakness or absence of the resonance lines of iron in ionization stages XI through XV.A second feature is the prominence of lines of the type (3d → 2p) relative to the resonance transitions (3p → 2s) in Li-like and Beryllium-like spectra. It is suggested that the upper levels (3d) are excited by quadrupole collisions from the ground 2s or 2s2levels.The intensity of the soft X-ray lines relative to the resonance lines in the 300 Å region seems to be more consistent with temperatures well above one million degrees than with temperatures as low as 700000°K, but the data are not adequate for a precise comparison. The relative intensity of the line emission from the various stages of silicon ionization may be interpreted as indicating that the ionization of silicon peaks in stages IX and X.The abundances of C, Mg, S, and Al relative to silicon do not seem to be greatly different from the chromospheric abundances reported by Pottasch or with the photospheric abundances.

Download Full-text