Frequency range selection method of trans-impedance amplifier for high sensitivity lock-in amplifier used in the optical sensors

2016 ◽  
Author(s):  
Chang-In Park ◽  
Su-Jin Jeon ◽  
Nam-Pyo Hong ◽  
Young-Wan Choi
Keyword(s):  
Optical Sensors ◽  
High Sensitivity ◽  
Selection Method ◽  
Frequency Range ◽  
Lock In ◽  
Range Selection

scholarly journals Frequency Range Selection Method for Vibrational Spectra

2018 ◽  
Vol 9 (23) ◽  
pp. 6878-6882
Author(s):  
T. Q. Teodoro ◽  
M. A. J. Koenis ◽  
S. E. Galembeck ◽  
V. P. Nicu ◽  
W. J. Buma ◽  
...  
Keyword(s):  
Vibrational Spectra ◽  
Selection Method ◽  
Frequency Range ◽  
Range Selection

scholarly journals A THz Coupler based on Graphene Patterns with SU-8 Photoresist Dielectric Layer

2021 ◽  
Author(s):  
Elham Zandi
Keyword(s):  
Optical Sensors ◽  
Layer Structure ◽  
Equivalent Circuit Model ◽  
High Sensitivity ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Full Wave ◽  
Tunable Device ◽  
Indoor Communications ◽  
Simulation Results

Abstract Leveraging both method and concept, a novel multi-layer structure based on Graphene patterns and SU-8 photoresist dielectric is proposed at THz frequency range. By considering reflection and transmission channels as outputs, a simple THz coupler is provided. The structure is described exploiting equivalent circuit model while results are verified by full wave simulations. According to simulation results, the proposed device is able to reflect and transmit THz waves with high sensitivity versus gate biasing. The operation involves five bands in entire THz spectrum while the structure behavior can be adjusted by external gate biasing. Such a tunable device is in great demand to realize optical sensors and systems in several fields from indoor communications, security and medical imaging.

Enhanced Detection Sensitivity with Pulsed Laser Digital Signal Integration Algorithm

2006 ◽  
Author(s):  
A.C.T. Quah ◽  
J.C.H. Phang ◽  
L.S. Koh ◽  
S.H. Tan ◽  
C.M. Chua
Keyword(s):  
Fault Localization ◽  
Pulsed Laser ◽  
Digital Signal ◽  
Detection Sensitivity ◽  
Signal Integration ◽  
Laser Operation ◽  
Frequency Range ◽  
Integration Algorithm ◽  
Detection Systems ◽  
Lock In

Abstract This paper describes a pulsed laser induced digital signal integration algorithm for pulsed laser operation that is compatible with existing ac-coupled and dc-coupled detection systems for fault localization. This algorithm enhances laser induced detection sensitivity without a lock-in amplifier. The best detection sensitivity is achieved at a pulsing frequency range between 500 Hz to 1.5 kHz. Within this frequency range, the algorithm is capable of achieving more than 9 times enhancement in detection sensitivity.

scholarly journals Differentiating and quantifying exosome secretion from a single cell using quasi-bound states in the continuum

Nanophotonics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1081-1086 ◽  
Author(s):  
Abdoulaye Ndao ◽  
Liyi Hsu ◽  
Wei Cai ◽  
Jeongho Ha ◽  
Junhee Park ◽  
...  
Keyword(s):  
Single Cell ◽  
Optical Sensors ◽  
Figure Of Merit ◽  
Bound States ◽  
Single Cell Analysis ◽  
Optical Cavity ◽  
High Sensitivity ◽  
Cell Secretion ◽  
The Continuum ◽  
Refractive Index Detection

AbstractOne of the key challenges in biology is to understand how individual cells process information and respond to perturbations. However, most of the existing single-cell analysis methods can only provide a glimpse of cell properties at specific time points and are unable to provide cell secretion and protein analysis at single-cell resolution. To address the limits of existing methods and to accelerate discoveries from single-cell studies, we propose and experimentally demonstrate a new sensor based on bound states in the continuum to quantify exosome secretion from a single cell. Our optical sensors demonstrate high-sensitivity refractive index detection. Because of the strong overlap between the medium supporting the mode and the analytes, such an optical cavity has a figure of merit of 677 and sensitivity of 440 nm/RIU. Such results facilitate technological progress for highly conducive optical sensors for different biomedical applications.

Efficient chemosensors for toxic pollutants based on photoluminescent Zn(II) and Cd(II) metal-organic networks

2021 ◽  
Author(s):  
Luis David Rosales-Vazquez ◽  
Alejandro Dorazco-González ◽  
Victor Sanchez-Mendieta
Keyword(s):  
Optical Sensors ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Environmental Research ◽  
Toxic Pollutants ◽  
Sensitivity And Selectivity ◽  
Metal Organic ◽  
Analytical Tools ◽  
Organic Networks

Optical sensors with high sensitivity and selectivity, as important analytical tools for chemical and environmental research, can be accomplished by straightforward synthesis of luminescent one-, two- and three-dimensional Zn(II) and...

Lock-in regions of laminar flows over a streamwise oscillating circular cylinder

2018 ◽  
Vol 858 ◽  
pp. 315-351 ◽  
Author(s):  
Ki-Ha Kim ◽  
Jung-Il Choi
Keyword(s):  
Circular Cylinder ◽  
Aerodynamic Force ◽  
Lift Coefficient ◽  
Lower Boundary ◽  
Laminar Flows ◽  
Velocity Range ◽  
Frequency Range ◽  
Vortex Pattern ◽  
Moving Cylinder ◽  
Lock In

In this paper, flow over a streamwise oscillating circular cylinder is numerically simulated to examine the effects of the driving amplitude and frequency on the distribution of the lock-in regions in laminar flows. At $Re=100$, lock-in is categorized according to the spectral features of the lift coefficient as two different lock-in phenomena: harmonic and subharmonic lock-in. These lock-in phenomena are represented as maps on the driving amplitude–frequency plane, which have subharmonic lock-in regions and two harmonic lock-in regions. The frequency range of the subharmonic region is shifted to lower frequencies with increasing amplitude, and the lower boundary of this subharmonic region is successfully predicted. A symmetric harmonic region with a symmetric vortex pattern is observed in a certain velocity range for a moving cylinder. Aerodynamic features induced by different flow patterns in each region are presented on the driving amplitude–frequency plane. The lock-in region and aerodynamic features at $Re=200$ and $40$ are compared with the results for $Re=100$. A subharmonic region and two harmonic regions are observed at $Re=200$, and these show the same features as for $Re=100$ at a low driving amplitude. Lock-in at $Re=40$ also shows one subharmonic region and two harmonic regions. However, compared with the $Re=100$ case, the symmetric harmonic lock-in is dominant. The features of aerodynamic force at $Re=200$ and $40$ are represented on a force map, which shows similar characteristics in corresponding regions for the $Re=100$ case.

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 Frequency Response Stabilization and Comparative Studies of MET Hydrophone at Marine Seismic Exploration Systems

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1944 ◽  
Author(s):  
Egor Egorov ◽  
Anna Shabalina ◽  
Dmitry Zaitsev ◽  
Sergey Kurkov ◽  
Nikolay Gueorguiev
Keyword(s):  
Frequency Response ◽  
Field Tests ◽  
High Sensitivity ◽  
Seismic Exploration ◽  
Joint Stock Company ◽  
Experimental Sample ◽  
Frequency Range ◽  
Stock Company ◽  
Low Frequencies ◽  
Marine Seismic

Low frequency hydrophone with a frequency range of 1−300 Hz for marine seismic exploration systems has been developed. The operation principle of the hydrophone bases on the molecular electronic transfer that allows high sensitivity and low level self-noise at low frequencies (<10 Hz) to be achieved. The paper presents a stabilization method of the frequency response within the frequency range at a depth up to 30 m. Laboratory and marine tests confirmed the stated characteristics as well as the possibility of using this sensor in bottom marine seismic systems. An experimental sample of the hydrophone successfully passed a comparative marine test at Gelendzhik Bay (Black Sea) with the technical support of Joint-Stock Company (JSC) “Yuzhmorgeologiya”. One of the main results is the possibility of obtaining high-quality information in the field of low frequencies, which was demonstrated in the course of field tests.

scholarly journals Complementary Bursts, Coronal Inhomogeneities and New Microscopic Spectral Features of Solar Bursts in Type IV Bursts

1980 ◽  
Vol 86 ◽  
pp. 269-271
Author(s):  
H. S. Sawant ◽  
R. V. Bhonsle ◽  
S. S. Degaonkar ◽  
T. Takakura
Keyword(s):  
High Frequency ◽  
High Sensitivity ◽  
Line Of Sight ◽  
Spectral Features ◽  
Frequency Range ◽  
Type Iv ◽  
Linear Extent ◽  
Solar Bursts ◽  
Almost All ◽  
Density Irregularity

Complementary bursts (C.B's) have been observed in the decametric range during noise storms and/or type IV activity. These bursts essentially consist of two components, each component having a duration ~ 1 second. The first component shows weak emission or emission gap over a certain frequency range. The second component is observed after a certain delay. If the bursts are assumed to be generated at the fundamental, and if the radiation corresponding to the gap propagates through an electron density irregularity located close to the source along the line of sight, whose cross-section is less than the linear extent of the source, then almost all properties of the C.B.'s can be explained. High sensitivity, and high frequency and time resolution spectra of type IV bursts at 137 MHz revealed new microscopic spectral features displaying “wave-like” and “fork-like” shapes.

The Application of Signal Processing Techniques in Improving Spectrometer Detection Limit

2011 ◽  
Vol 148-149 ◽  
pp. 1045-1050
Author(s):  
Zhi Ying Wu ◽  
Yi Zhang ◽  
Zuo Yuan Shen
Keyword(s):  
Signal Processing ◽  
Detection Limit ◽  
High Sensitivity ◽  
Processing Technique ◽  
Laser Source ◽  
Sampled Data ◽  
High Concentration ◽  
Signal Processing Technique ◽  
Processing Techniques ◽  
Lock In

Improving spectrometer detection limit using statistical principle and signal-processing technique are described simply in this work. In the detection of gas photoacoustic(PA) signal, accurate partitions of the sampled data affect on the detection limit to some extent although Lock-in amplification technique with high SNR and microphone sensor with high sensitivity have been used. A model and the resulting algorithm are proposed from PA-signal samples. The techniques are validated at ppb level on PA spectrometer for NH3 breath detection in high concentration of CO2 and H2O based on tunable erbium-doped fiber laser (TEDFL) or for multicomponent trace gas detection based on waveguide CO2 laser or on other laser source.

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