scholarly journals Novel LED-based radiation source and its application in diffuse reflectometry and polarization measurements

2022 ◽  
Vol 2149 (1) ◽  
pp. 012010
Author(s):  
I Santourian ◽  
T Quast ◽  
S Teichert ◽  
K-O Hauer ◽  
A Schirmacher
Keyword(s):  
Radiation Field ◽  
Spectral Range ◽  
Radiation Source ◽  
Signal To Noise Ratio ◽  
Temporal Stability ◽  
Spectral Radiance ◽  
Signal To Noise ◽  
Polarization Measurements ◽  
Radiance Factor ◽  
First Time

Abstract An LED sphere radiator (LED-SR) was constructed to improve the accuracy in spectral radiance factor measurements performed with the robot-based gonioreflectometer at PTB. Its properties with respect to the spectral range and coverage, the temporal stability, and the homogeneity of the radiation field are presented. Two types of matte ceramic reflection standards were used for spectral radiance factor validation measurements comparing the standardly used halogen sphere radiator (Halogen-SR) and the LED-SR. Due to its designed spectral range at the border between the visible and the UV-A spectral range, the LED-SR is well suited for many applications in diffuse reflectometry. Its use for absolute radiance factor measurements and investigations of the fluorescence properties of diffuse reflecting samples is shown. Reliable polarization-resolved measurements at wavelengths below 430 nm could be carried out with PTB’s gonioreflectometer for the first time due to the beneficial signal-to-noise ratio of the LED-SR.

scholarly journals A Monolithic Spatial Heterodyne Raman Spectrometer: Initial Tests

2020 ◽  
Vol 75 (1) ◽  
pp. 57-69
Author(s):  
Abigail Waldron ◽  
Ashley Allen ◽  
Arelis Colón ◽  
J. Chance Carter ◽  
S. Michael Angel
Keyword(s):  
Spectral Range ◽  
Spectral Resolution ◽  
Signal To Noise Ratio ◽  
Focal Length ◽  
High Spectral Resolution ◽  
Signal To Noise ◽  
Free Standing ◽  
Raman Spectrometer ◽  
Construction Techniques ◽  
The Stability

A monolithic spatial heterodyne Raman spectrometer (mSHRS) is described, where the optical components of the spectrometer are bonded to make a small, stable, one-piece structure. This builds on previous work, where we described bench top spatial heterodyne Raman spectrometers (SHRS), developed for planetary spacecraft and rovers. The SHRS is based on a fixed grating spatial heterodyne spectrometer (SHS) that offers high spectral resolution and high light throughput in a small footprint. The resolution of the SHS is not dependent on a slit, and high resolution can be realized without using long focal length dispersing optics since it is not a dispersive device. Thus, the SHS can be used as a component in a compact Raman spectrometer with high spectral resolution and a large spectral range using a standard 1024 element charge-coupled device. Since the resolution of the SHRS is not dependent on a long optical path, it is amenable to the use of monolithic construction techniques to make a compact and robust device. In this paper, we describe the use of two different monolithic SHSs (mSHSs), with Littrow wavelengths of 531.6 nm and 541.05 nm, each about 3.5 × 3.5 × 2.5 cm in size and weighing about 80 g, in a Raman spectrometer that provides ∼3500 cm−1 spectral range with 4–5 cm−1 and 8–9 cm−1 resolution, for 600 grooves/mm and 150 grooves/mm grating-based mSHS devices, respectively. In this proof of concept paper, the stability, spectral resolution, spectral range, and signal-to-noise ratio of the mSHRS spectrometers are compared to our bench top SHRS that uses free-standing optics, and signal to noise comparisons are also made to a Kaiser Holospec f/1.8 Raman spectrometer.

scholarly journals X-ray shadowgraphy applications in ablatively accelerated planar foil studies

1992 ◽  
Vol 10 (4) ◽  
pp. 685-688 ◽  
Author(s):  
V. A. Bolotin ◽  
I. N. Burdonsky ◽  
V. V. Gavrilov ◽  
A. Yu. Gol'tsov ◽  
E. V. Zhuzhukalo ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Spatial Resolution ◽  
Spectral Range ◽  
Focal Spot ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Plasma Flows ◽  
X Ray ◽  
Noise Ratio ◽  
Drive Laser Pulse

The article reviews experiments on flash X radiography of laser-accelerated foils. The spatial resolution, sensitivity, spectral range, and signal-to-noise ratio of measurements were carefully optimized and characterized. The method was used at the Mishen facility to measure a distribution of mass ablative rate across the focal spot and for observation of the transverse plasma flows during the drive laser pulse.

A double-pass Sisam spectrometer for the near infrared

1975 ◽  
Vol 346 (1646) ◽  
pp. 395-412 ◽  
Keyword(s):  
Spectral Range ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Double Pass ◽  
Optical Components ◽  
Common Axis ◽  
Noise Ratio ◽  
Real Gain

A double-pass Sisam spectrometer of simplified design is described in which the two gratings rotate about a common axis. Sample spectra are given and the performance of the instrument is assessed and compared with that predicted theoretically. A resolution of 0.05 cm -1 has been achieved at 1.6 µm, corresponding to 90% of the maximum theoretically attainable with the gratings and configuration used. This performance was maintained over a continuously scanned spectral range of 500 cm -1 without realignment of the optical components. The instrument thus offers a real gain in signal-to-noise ratio over the equivalent, practical slit spectrometer of a factor of between 30 and 1000.

Near-Infrared Photon Emission Spectroscopy Trends in Scaled SOI Technologies

2012 ◽  
Author(s):  
Ulrike Kindereit ◽  
Alan J. Weger ◽  
Franco Stellari ◽  
Peilin Song ◽  
Hervé Deslandes ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Spectral Range ◽  
Emission Spectroscopy ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Photon Emission ◽  
Process Technology ◽  
Signal To Noise ◽  
Infrared Photon ◽  
Maximum Signal

Abstract In this paper, near-infrared photon emission spectroscopy measurements from ring oscillators in 45 nm and 32 nm SOI process technology are compared. Employing a cryogenically cooled camera, the measurements cover a broad spectral range from 1200-2200 nm. Both leakage and switching emission, increase monotonically with the wavelength, suggesting measurements should be made at longer wavelengths than has historically been practiced. The paper discusses the optimum cut-off wavelength for maximum signal-to-noise ratio and the obvious importance of reduced ambient temperature for performing measurements.

scholarly journals On the Achievable Information Rate of Probabilistic Shaping QAM Order and Source Entropy in Visible Light Communication Systems

2020 ◽  
Vol 10 (12) ◽  
pp. 4299 ◽  
Author(s):  
Peng Zou ◽  
Fangchen Hu ◽  
Yiheng Zhao ◽  
Nan Chi
Keyword(s):  
Visible Light ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Visible Light Communication ◽  
Spectrum Efficiency ◽  
Information Rate ◽  
Computation Complexity ◽  
Signal To Noise ◽  
First Time ◽  
The Relationship

Probabilistic shaping (PS) is a powerful tool that can realize a flexible data rate and high spectrum efficiency. However, the performance of PS is closely related to the quadrature amplitude modulation (QAM) order, source entropy (SE), normalized generalized mutual information (NGMI), and achievable information rate (AIR). In this paper, we investigated the relationship between PS QAM order, SE, NGMI, and AIR performance for the first time in the visible light communication (VLC) system. Under a specific signal-to-noise ratio (SNR), the PS QAM order and SE in this paper can realize a high AIR at a preset NGMI threshold with the lowest computation complexity, which is just 0.1 bit smaller than the highest AIR. Simulation and experimental results show that the NGMI fluctuates between only ±0.005 of the preset NGMI threshold, which proves that the scheme proposed in this paper is feasible.

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