Signal-to-noise ratio improvement of photonic time-stretch coherent radar enabling high-sensitivity ultrabroad W-band operation

2018 ◽  
Vol 43 (23) ◽  
pp. 5869 ◽  
Author(s):  
Na Qian ◽  
Weiwen Zou ◽  
Siteng Zhang ◽  
Jianping Chen
Keyword(s):  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Signal To Noise ◽  
W Band ◽  
Noise Ratio ◽  
Coherent Radar

A Carbon-Based DNA Framework Nano–Bio Interface for Biosensing with High Sensitivity and a High Signal-to-Noise Ratio

ACS Sensors ◽  
2020 ◽  
Vol 5 (12) ◽  
pp. 3979-3987
Author(s):  
Jing Su ◽  
Wenhan Liu ◽  
Shixing Chen ◽  
Wangping Deng ◽  
Yanzhi Dou ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Carbon Based

scholarly journals Single-molecule optical absorption imaging by nanomechanical photothermal sensing

2018 ◽  
Vol 115 (44) ◽  
pp. 11150-11155 ◽  
Author(s):  
Miao-Hsuan Chien ◽  
Mario Brameshuber ◽  
Benedikt K. Rossboth ◽  
Gerhard J. Schütz ◽  
Silvan Schmid
Keyword(s):  
Single Molecule ◽  
Shot Noise ◽  
Signal To Noise Ratio ◽  
Local Heating ◽  
Single Molecules ◽  
High Sensitivity ◽  
Temperature Sensitive ◽  
Signal To Noise ◽  
Promising Alternative ◽  
Noise Ratio

Absorption microscopy is a promising alternative to fluorescence microscopy for single-molecule imaging. So far, molecular absorption has been probed optically via the attenuation of a probing laser or via photothermal effects. The sensitivity of optical probing is not only restricted by background scattering but it is fundamentally limited by laser shot noise, which minimizes the achievable single-molecule signal-to-noise ratio. Here, we present nanomechanical photothermal microscopy, which overcomes the scattering and shot-noise limit by detecting the photothermal heating of the sample directly with a temperature-sensitive substrate. We use nanomechanical silicon nitride drums, whose resonant frequency detunes with local heating. Individual Au nanoparticles with diameters from 10 to 200 nm and single molecules (Atto 633) are scanned with a heating laser with a peak irradiance of 354 ± 45 µW/µm2 using 50× long-working-distance objective. With a stress-optimized drum we reach a sensitivity of 16 fW/Hz1/2 at room temperature, resulting in a single-molecule signal-to-noise ratio of >70. The high sensitivity combined with the inherent wavelength independence of the nanomechanical sensor presents a competitive alternative to established tools for the analysis and localization of nonfluorescent single molecules and nanoparticles.

NQR Studies of Atomic Arrangements and Chemical Bonding in Glasses

1990 ◽  
Vol 45 (3-4) ◽  
pp. 268-272 ◽  
Author(s):  
Donghoon Lee ◽  
S. J. Gravina ◽  
P. J. Bray
Keyword(s):  
Chemical Bonding ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Large N ◽  
Noise Ratio ◽  
Very High

Abstract A very high sensitivity continuous wave NQR spectrometer was developed to detect pure NQR transitions at low frequencies (down to 200 kHz). A signal-to-noise ratio of more than 100 to 1 has been achieved at about 1.36 MHz for crystalline B 2 0 3 . Two large n B responses have been found in vitreous B 2 0 3 (NMR detected only one site) with linewidths of less than 30 kHz. 27 A1 NQR spectra were obtained for OC-A1203 (Corundum), the mineral andalusite (a form of A1203 • Si0 2), and a glass having the composition of anorthite (CaO • A1203 • 2Si0 2).

scholarly journals High sensitivity photo receiver design

2004 ◽  
Vol 17 (1) ◽  
pp. 121-131
Author(s):  
Zbigniew Bielecki ◽  
Wladyslaw Kolosowski ◽  
Edward Sedek
Keyword(s):  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Low Noise ◽  
Operating Conditions ◽  
Receiver Design ◽  
Signal To Noise ◽  
Optical Detectors ◽  
Noise Ratio ◽  
Photo Receiver

The paper describes low noise preampliers designed for optical detectors Analysis of operating conditions affecting signal-to-noise ratio has been carried out. Each preamplier was carefully optimized to work with particular type of the detector.

scholarly journals High Sensitivity Snapshot Spectrometer Based on Deep Network Unmixing

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7038
Author(s):  
Hui Xie ◽  
Zhuang Zhao ◽  
Jing Han ◽  
Lianfa Bai ◽  
Yi Zhang
Keyword(s):  
Neural Network ◽  
Light Intensity ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Hadamard Transform ◽  
High Signal ◽  
Signal To Noise ◽  
Compact Structure ◽  
Reconstructed Signal ◽  
Noise Ratio

Spectral detection provides rich spectral–temporal information with wide applications. In our previous work, we proposed a dual-path sub-Hadamard-s snapshot Hadamard transform spectrometer (Sub-s HTS). In order to reduce the complexity of the system and improve its performance, we present a convolution neural network-based method to recover the light intensity distribution from the overlapped dispersive spectra, rather than adding an extra light path to capture it directly. In this paper, we construct a network-based single-path snapshot Hadamard transform spectrometer (net-based HTS). First, we designed a light intensity recovery neural network (LIRNet) with an unmixing module (UM) and an enhanced module (EM) to recover the light intensity from the dispersive image. Then, we used the reconstructed light intensity as the original light intensity to recover high signal-to-noise ratio spectra successfully. Compared with Sub-s HTS, the net-based HTS has a more compact structure and high sensitivity. A large number of simulations and experimental results have demonstrated that the proposed net-based HTS can obtain a better-reconstructed signal-to-noise ratio spectrum than the Sub-s HTS because of its higher light throughput.

scholarly journals High-speed multichannel MAÉS analyzers based on BLPP-2000 and BLPP-4000 photodectector arrays

2019 ◽  
Vol 85 (1II)) ◽  
pp. 96-102
Author(s):  
S. A. Babin ◽  
D. O. Selyunin ◽  
V. A. Labusov
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Atomic Emission ◽  
Signal To Noise ◽  
Emission Analysis ◽  
Photodetector Array ◽  
Noise Ratio ◽  
Hybrid Assemblies ◽  
Photodetector Arrays

The main directions in the development of the spectral systems for scintillation atomic emission analysis of powdered geological samples are aimed at increase in the sensitivity, spectral resolution, and speed of the spectrum analyzers to reduce the detection limits. The goal of the study is developing of high-speed MAÉS analyzers with hybrid assemblies of the arrays of 14 multichannel photodetectors of two types: high-sensitivity BLPP-2000 and BLPP-4000 photodetector array with high spatial resolution and theoretical estimation of the signal-to-noise ratio when recording scintillation and integral spectra with aforementioned photodetectors. The high-speed MAÉS analyzers with BLPP-2000 and BLPP-4000 photodetector arrays are designed so as to provide parallel readout of photodetectors in hybrid assemblies. They consist of 14 BLPP 2000 or BLPP 4000 photodetectors and records the spectra in the 190 – 350 nm wavelength range on a «Grand» spectrometer. The minimum exposure time is 0.9 and 1.7 msec, respectively. It is shown that in measurements of spectral-line intensities using BLPP-2000, the signal-to-noise ratio is 3 times higher in integral analysis and 5 times higher in scintillation analysis compared to measurements with BLPP-4000 photodetector array.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Experiments in Bright-Field Imaging with Hollow-Cone Illumination

1981 ◽  
Vol 39 ◽  
pp. 226-227
Author(s):  
W. Kunath ◽  
K. Weiss ◽  
E. Zeitler
Keyword(s):  
Signal To Noise Ratio ◽  
Carbon Support ◽  
Electronic System ◽  
Optic Axis ◽  
Hollow Cone ◽  
Signal To Noise ◽  
Bright Field ◽  
Noise Ratio ◽  
Single Field ◽  
Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

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