scholarly journals Gradiometer Using Separated Diamond Quantum Magnetometers

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 977
Author(s):  
Yuta Masuyama ◽  
Katsumi Suzuki ◽  
Akira Hekizono ◽  
Mitsuyasu Iwanami ◽  
Mutsuko Hatano ◽  
...  
Keyword(s):  
Room Temperature ◽  
Dynamic Range ◽  
Low Frequency ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Noise Spectrum ◽  
Nitrogen Vacancy ◽  
Weak Magnetic Fields ◽  
Highly Sensitive ◽  
Nv Center

The negatively charged nitrogen-vacancy (NV) center in diamonds is known as the spin defect and using its electron spin, magnetometry can be realized even at room temperature with extremely high sensitivity as well as a high dynamic range. However, a magnetically shielded enclosure is usually required to sense weak magnetic fields because environmental magnetic field noises can disturb high sensitivity measurements. Here, we fabricated a gradiometer with variable sensor length that works at room temperature using a pair of diamond samples containing negatively charged NV centers. Each diamond is attached to an optical fiber to enable free sensor placement. Without any magnetically shielding, our gradiometer realizes a magnetic noise spectrum comparable to that of a three-layer magnetically shielded enclosure, reducing the noises at the low-frequency range below 1 Hz as well as at the frequency of 50 Hz (power line frequency) and its harmonics. These results indicate the potential of highly sensitive magnetic sensing by the gradiometer using the NV center for applications in noisy environments such as outdoor and in vehicles.

A calibration and imaging strategy at 300 MHz with the Murchison Widefield Array (MWA)

2021 ◽  
Vol 38 ◽  
Author(s):  
Jaiden H. Cook ◽  
Nicholas Seymour ◽  
Marcin Sokolowski
Keyword(s):  
Dynamic Range ◽  
Low Frequency ◽  
High Dynamic Range ◽  
Primary Beam ◽  
Main Lobe ◽  
Beam Model ◽  
Highly Sensitive ◽  
Imaging Strategy ◽  
Murchison Widefield Array ◽  
Beam Patterns

Abstract At relatively high frequencies, highly sensitive grating sidelobes occur in the primary beam patterns of low frequency aperture arrays (LFAA) such as the Murchison Widefield Array (MWA). This occurs when the observing wavelength becomes comparable to the dipole separation for LFAA tiles, which for the MWA occurs at ${\sim}300$ MHz. The presence of these grating sidelobes has made calibration and image processing for 300 MHz MWA observations difficult. This work presents a new calibration and imaging strategy which employs existing techniques to process two example 300 MHz MWA observations. Observations are initially calibrated using a new 300 MHz sky-model which has been interpolated from low frequency and high frequency all-sky surveys. Using this 300 MHz model in conjunction with the accurate MWA tile primary beam model, we perform sky-model calibration for the two example observations. After initial calibration a self-calibration loop is performed by all-sky imaging each observation. We mask the main lobe of the all-sky image, and perform a sky-subtraction by estimating the masked image visibilities. We then image the main lobe of the sky-subtracted visibilities, which results in high dynamic range images of the two example observations. These images have been convolved with a Gaussian to a resolution of $2.4$ arcminutes, with a maximum sensitivity of ${{\sim}}31\,\textrm{mJy/beam}$ . The calibration and imaging strategy demonstrated in this work opens the door to performing science at 300 MHz with the MWA, which was previously an inaccessible domain. With this paper we release the code described below and the cross-matched catalogue along with the code to produce a sky-model in the range 70–1 400 MHz.

scholarly journals Ultra-high dynamic range quantum measurement retaining its sensitivity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
E. D. Herbschleb ◽  
H. Kato ◽  
T. Makino ◽  
S. Yamasaki ◽  
N. Mizuochi
Keyword(s):  
Dynamic Range ◽  
Large Range ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Current Field ◽  
Standard Measurement ◽  
Quantum Properties ◽  
Highly Sensitive ◽  
High Dynamic ◽  
Measurement Concept

AbstractQuantum sensors are highly sensitive since they capitalise on fragile quantum properties such as coherence, while enabling ultra-high spatial resolution. For sensing, the crux is to minimise the measurement uncertainty in a chosen range within a given time. However, basic quantum sensing protocols cannot simultaneously achieve both a high sensitivity and a large range. Here, we demonstrate a non-adaptive algorithm for increasing this range, in principle without limit, for alternating-current field sensing, while being able to get arbitrarily close to the best possible sensitivity. Therefore, it outperforms the standard measurement concept in both sensitivity and range. Also, we explore this algorithm thoroughly by simulation, and discuss the T−2 scaling that this algorithm approaches in the coherent regime, as opposed to the T−1/2 of the standard measurement. The same algorithm can be applied to any modulo-limited sensor.

scholarly journals Highly sensitive mutation quantification by high-dynamic-range capillary-array electrophoresis (HiDy CE)

Lab on a Chip ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1083-1091 ◽  
Author(s):  
Takashi Anazawa ◽  
Hiroko Matsunaga ◽  
Shuhei Yamamoto ◽  
Ryoji Inaba
Keyword(s):  
Dynamic Range ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Wild Type ◽  
Large Excess ◽  
Capillary Array Electrophoresis ◽  
Highly Sensitive ◽  
High Dynamic ◽  
Capillary Array

Mutant (MT) in a large excess of wild type (WT) was quantified with high-sensitivity (LOD of 0.004% MT/WT) and four-orders-of-magnitude dynamic range (0.01–100% MT/WT) by a high-dynamic-range capillary-array electrophoresis (HiDy CE).

scholarly journals Sensing Electrochemical Signals Using a Nitrogen-Vacancy Center in Diamond

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 358
Author(s):  
Hossein T. Dinani ◽  
Enrique Muñoz ◽  
Jeronimo R. Maze
Keyword(s):  
Electric Field ◽  
Electron Spin ◽  
Electrolyte Solution ◽  
High Sensitivity ◽  
Theoretical Work ◽  
Coherence Time ◽  
Nitrogen Vacancy ◽  
Local Concentration ◽  
Concentration Of Ions ◽  
Nv Center

Chemical sensors with high sensitivity that can be used under extreme conditions and can be miniaturized are of high interest in science and industry. The nitrogen-vacancy (NV) center in diamond is an ideal candidate as a nanosensor due to the long coherence time of its electron spin and its optical accessibility. In this theoretical work, we propose the use of an NV center to detect electrochemical signals emerging from an electrolyte solution, thus obtaining a concentration sensor. For this purpose, we propose the use of the inhomogeneous dephasing rate of the electron spin of the NV center (1/T2★) as a signal. We show that for a range of mean ionic concentrations in the bulk of the electrolyte solution, the electric field fluctuations produced by the diffusional fluctuations in the local concentration of ions result in dephasing rates that can be inferred from free induction decay measurements. Moreover, we show that for a range of concentrations, the electric field generated at the position of the NV center can be used to estimate the concentration of ions.

scholarly journals High-frequency rectifiers based on type-II Dirac fermions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Libo Zhang ◽  
Zhiqingzi Chen ◽  
Kaixuan Zhang ◽  
Lin Wang ◽  
Huang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
Dynamic Range ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Anisotropy Ratio ◽  
Dirac Fermions ◽  
Topological States ◽  
Topological Semimetals ◽  
Polarized Surface ◽  
Symmetry Protected

AbstractThe advent of topological semimetals enables the exploitation of symmetry-protected topological phenomena and quantized transport. Here, we present homogeneous rectifiers, converting high-frequency electromagnetic energy into direct current, based on low-energy Dirac fermions of topological semimetal-NiTe2, with state-of-the-art efficiency already in the first implementation. Explicitly, these devices display room-temperature photosensitivity as high as 251 mA W−1 at 0.3 THz in an unbiased mode, with a photocurrent anisotropy ratio of 22, originating from the interplay between the spin-polarized surface and bulk states. Device performances in terms of broadband operation, high dynamic range, as well as their high sensitivity, validate the immense potential and unique advantages associated to the control of nonequilibrium gapless topological states via built-in electric field, electromagnetic polarization and symmetry breaking in topological semimetals. These findings pave the way for the exploitation of topological phase of matter for high-frequency operations in polarization-sensitive sensing, communications and imaging.

scholarly journals Ab initiostructure determination of nanocrystals of organic pharmaceutical compounds by electron diffraction at room temperature using a Timepix quantum area direct electron detector

2016 ◽  
Vol 72 (2) ◽  
pp. 236-242 ◽  
Author(s):  
E. van Genderen ◽  
M. T. B. Clabbers ◽  
P. P. Das ◽  
A. Stewart ◽  
I. Nederlof ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Direct Methods ◽  
Liquid Nitrogen Temperature ◽  
High Dynamic Range ◽  
Electron Diffraction Data ◽  
High Signal

Until recently, structure determination by transmission electron microscopy of beam-sensitive three-dimensional nanocrystals required electron diffraction tomography data collection at liquid-nitrogen temperature, in order to reduce radiation damage. Here it is shown that the novel Timepix detector combines a high dynamic range with a very high signal-to-noise ratio and single-electron sensitivity, enablingab initiophasing of beam-sensitive organic compounds. Low-dose electron diffraction data (∼0.013 e− Å−2 s−1) were collected at room temperature with the rotation method. It was ascertained that the data were of sufficient quality for structure solution using direct methods using software developed for X-ray crystallography (XDS,SHELX) and for electron crystallography (ADT3D/PETS,SIR2014).

scholarly journals 2D Legendre Moments-Based Visual Control

2012 ◽  
Vol 162 ◽  
pp. 487-496 ◽  
Author(s):  
Aurelien Yeremou Tamtsia ◽  
Youcef Mezouar ◽  
Philippe Martinet ◽  
Haman Djalo ◽  
Emmanuel Tonye
Keyword(s):  
Visual Servoing ◽  
Dynamic Range ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Interaction Matrix ◽  
Geometric Moments ◽  
Control Scheme ◽  
Control Schemes ◽  
Legendre Moments ◽  
Set Of Points

Among region-based descriptors, geometric moments have been widely exploited to design visual servoing schemes. However, they present several disadvantages such as high sensitivity to noise measurement, high dynamic range and information redundancy (since they are not computed onto orthogonal basis). In this paper, we propose to use a class of orthogonal moments (namely Legendre moments) instead of geometric moments to improve the behavior of moment-based control schemes. The descriptive form of the interaction matrix related to the Legendre moments computed from a set of points is rst derived. Six visual features are then selected to design a partially-decoupled control scheme. Finally simulated and experimental results are presented to illustrate the validity of our proposal.

scholarly journals Methods for Voltage-Sensitive Dye Imaging of Rat Cortical Activity With High Signal-to-Noise Ratio

2007 ◽  
Vol 98 (1) ◽  
pp. 502-512 ◽  
Author(s):  
Michael T. Lippert ◽  
Kentaroh Takagaki ◽  
Weifeng Xu ◽  
Xiaoying Huang ◽  
Jian-Young Wu
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Field Potential ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
High Signal ◽  
Blue Dye ◽  
Voltage Sensitive Dye ◽  
Imaging Device

We describe methods to achieve high sensitivity in voltage-sensitive dye (VSD) imaging from rat barrel and visual cortices in vivo with the use of a blue dye RH1691 and a high dynamic range imaging device (photodiode array). With an improved staining protocol and an off-line procedure to remove pulsation artifact, the sensitivity of VSD recording is comparable with that of local field potential recording from the same location. With this sensitivity, one can record from ∼500 individual detectors, each covering an area of cortical tissue 160 μm in diameter (total imaging field ∼4 mm in diameter) and a temporal resolution of 1,600 frames/s, without multiple-trial averaging. We can record 80–100 trials of intermittent 10-s trials from each imaging field before the VSD signal reduces to one half of its initial amplitude because of bleaching and wash-out. Taken together, the methods described in this report provide a useful tool for visualizing evoked and spontaneous waves from rodent cortex.

scholarly journals A broadband two axis flux-gate magnetometer

1998 ◽  
Vol 41 (3) ◽  
Author(s):  
P. Palangio
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
High Sensitivity ◽  
Magnetic Sensors ◽  
Frequency Range ◽  
Field Station ◽  
Low Weight ◽  
Highly Sensitive ◽  
Flux Gate ◽  
Magnetic Field Variations

A broadband two axis flux-gate magnetometer was developed to obtain high sensitivity in magnetotelluric measurements. In magnetotelluric sounding, natural low frequency electromagnetic fields are used to estimate the conductivity of the Earth's interior. Because variations in the natural magnetic field have small amplitude(10-100 pT) in the frequency range 1 Hz to 100 Hz, highly sensitive magnetic sensors are required. In magnetotelluric measurements two long and heavy solenoids, which must be installed, in the field station, perpendicular to each other (north-south and east-west) and levelled in the horizontal plane are used. The coil is a critical component in magnetotelluric measurements because very slight motions create noise voltages, particularly troublesome in wooded areas; generally the installation takes place in a shallow trench. Moreover the coil records the derivative of the variations rather than the magnetic field variations, consequently the transfer function (amplitude and phase) of this sensor is not constant throughout the frequency range 0.001-100 Hz. The instrument, developed at L'Aquila Geomagnetic Observatory, has a flat response in both amplitude and phase in the frequency band DC-100 Hz, in addition it has low weight, low power, small volume and it is easier to install in the field than induction magnetometers. The sensivity of this magnetometer is 10 pT rms.

scholarly journals Electronic Optical Sky Surveys

1998 ◽  
Vol 179 ◽  
pp. 49-55
Author(s):  
T.A. McKay
Keyword(s):  
Dynamic Range ◽  
Large Fraction ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Low Noise ◽  
Computer Hardware ◽  
Optical Detectors ◽  
Small Fields ◽  
Technical Advances ◽  
High Dynamic

The introduction of of Charge Coupled Devices (CCDs) in the middle 1970s provided astronomy with nearly perfect (linear, high-sensitivity, low-noise, high dynamic-range, digital) optical detectors. Unfortunately, restrictions imposed by CCD production and cost has typically limited their use to observations of relatively small fields. Recently a combination of technical advances have made practical the application of CCDs to survey science. CCD mosaic cameras, which help overcome the size restrictions imposed by CCD manufacture, allow electronic access to a larger fraction of the available focal plane. Multi-fiber spectrographs, which couple the low-noise, high QE performance of CCDs with the ability to observe spectra for many objects at once, have improved the spectroscopic efficiency of telescopes by factors approaching half a million. An improved understanding of image distortion gives us telescopes on which we expect sub-arcsecond images a large fraction of the time. Finally, and perhaps most important, the performance of computer hardware continues to advance, to the point where analysis of multi-terabyte datasets, while still daunting, is at least conceivable.

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