scholarly journals 1/f-noise-free optical sensing with an integrated heterodyne interferometer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ming Jin ◽  
Shui-Jing Tang ◽  
Jin-Hui Chen ◽  
Xiao-Chong Yu ◽  
Haowen Shu ◽  
...  
Keyword(s):  
Detection Limit ◽  
Detection System ◽  
Low Frequency ◽  
Frequency Noise ◽  
Label Free ◽  
Surface Charges ◽  
Heterodyne Interferometer ◽  
Nanoparticle Detection ◽  
Cavity Resonances ◽  
Antigen Antibody

AbstractOptical evanescent sensors can non-invasively detect unlabeled nanoscale objects in real time with unprecedented sensitivity, enabling a variety of advances in fundamental physics and biological applications. However, the intrinsic low-frequency noise therein with an approximately 1/f-shaped spectral density imposes an ultimate detection limit for monitoring many paramount processes, such as antigen-antibody reactions, cell motions and DNA hybridizations. Here, we propose and demonstrate a 1/f-noise-free optical sensor through an up-converted detection system. Experimentally, in a CMOS-compatible heterodyne interferometer, the sampling noise amplitude is suppressed by two orders of magnitude. It pushes the label-free single-nanoparticle detection limit down to the attogram level without exploiting cavity resonances, plasmonic effects, or surface charges on the analytes. Single polystyrene nanobeads and HIV-1 virus-like particles are detected as a proof-of-concept demonstration for airborne biosensing. Based on integrated waveguide arrays, our devices hold great potentials for multiplexed and rapid sensing of diverse viruses or molecules.

scholarly journals Measurements of Low Frequency Noise of Infrared Photo-Detectors with Transimpedance Detection System

2014 ◽  
Vol 21 (3) ◽  
pp. 461-472 ◽  
Author(s):  
Łukasz Ciura ◽  
Andrzej Kolek ◽  
Waldemar Gawron ◽  
Andrzej Kowalewski ◽  
Dariusz Stanaszek
Keyword(s):  
Dark Current ◽  
Detection System ◽  
Power Spectra ◽  
Low Frequency ◽  
Frequency Noise ◽  
Noise Power ◽  
Low Frequency Noise ◽  
Leakage Resistance ◽  
Noise Measurements ◽  
Hgcdte Detector

Abstract The paper presents the method and results of low-frequency noise measurements of modern mid-wavelength infrared photodetectors. A type-II InAs/GaSb superlattice based detector with nBn barrier architecture is compared with a high operating temperature (HOT) heterojunction HgCdTe detector. All experiments were made in the range 1 Hz - 10 kHz at various temperatures by using a transimpedance detection system, which is examined in detail. The power spectral density of the nBn’s dark current noise includes Lorentzians with different time constants while the HgCdTe photodiode has more uniform 1/f - shaped spectra. For small bias, the low-frequency noise power spectra of both devices were found to scale linearly with bias voltage squared and were connected with the fluctuations of the leakage resistance. Leakage resistance noise defines the lower noise limit of a photodetector. Other dark current components give raise to the increase of low-frequency noise above this limit. For the same voltage biasing devices, the absolute noise power densities at 1 Hz in nBn are 1 to 2 orders of magnitude lower than in a MCT HgCdTe detector. In spite of this, low-frequency performance of the HgCdTe detector at ~ 230K is still better than that of InAs/GaSb superlattice nBn detector.

Sub-Zeptofarad Sensitivity Scanning Capacitance Microscopy Sensor

2007 ◽  
Author(s):  
H. Dongmo ◽  
P. Hammond ◽  
J. Weaver
Keyword(s):  
Detection System ◽  
Dynamic Change ◽  
Low Frequency ◽  
Sample Surface ◽  
Operating Frequency ◽  
Capacitance Measurement ◽  
Frequency Noise ◽  
Measurement Sensitivity ◽  
Scanning Capacitance Microscopy ◽  
Insulator Layers

Abstract Scanning Capacitance Microscopy (SCM) is an Atomic Force Microscopy (AFM) based technique that simultaneously records topography and local capacitance with high spatial resolution. This tool is based on the high frequency MOS capacitor theory, and is routinely used in failure analysis to discern the 2D carrier profiles and/or defects in insulator layers of semiconductor devices. An ac voltage induces a dynamic change in capacitance formed by the SCM tip and oxidized semiconductor sample surface. Because of the small contact area, sensitivity of the capacitance measurements must be lower than 10-18 F in a 1 kHz bandwidth. SCM sensors capable of such sensitivity are commonly based on the Radio Corporation of America (RCA) capacitance sensor, and rely on the detection of the frequency shift of a resonator. High operating frequency for the resonator significantly improves the measurement sensitivity. In this article, we describe a sensor for SCM with sub-zeptofarad (< 10-21 F) sensitivity based on the designs of Tran et. al., but realized using a phase – sensitive detection system. This results in improved low frequency noise in the capacitance measurement. This design has an operating frequency of 3 GHz when unloaded and a resonator Q around 110, resulting in an improvement of the system sensitivity over the conventional RCA CED sensor, and may be used in a commercial AFM system. The performance of this sensor is discussed and two-dimensional dopant profile from a semiconductor structure is presented. The limitations of bulk resonator SCM systems are discussed and the prospects for monolithic sensors are described in the context of a 0.35 µm SiGe BiCMOS process.

Sound Transmission Control of a Cylindrical Structure Using Acoustic Resonators

2012 ◽  
Vol 226-228 ◽  
pp. 203-209
Author(s):  
De Yu Li ◽  
Li Jian Ou
Keyword(s):  
Noise Reduction ◽  
Cylindrical Cavity ◽  
Experimental Evaluation ◽  
Low Frequency ◽  
Frequency Noise ◽  
Control Performance ◽  
Transmission Control ◽  
Cylindrical Structure ◽  
Acoustic Resonators ◽  
Cavity Resonances

This paper presents a passive method to control low-frequency noise in a cylindrical structure by using multi-modal T-shaped acoustic resonators. The feasibility of noise transmission control on the cylindrical structure is investigated, including a detailed experimental evaluation of the control performance using a single resonator and a resonator array consisted of different resonators. Finally, six long T-shaped acoustic resonators are used to target the first four lowest cylindrical cavity resonances, and up to 9 dB noise reduction is achieved, and broadband improvement of noise reduction is also observed.

Porous Silicon Immunosensor for Label-Free Detection of SpaA

2010 ◽  
Vol 44-47 ◽  
pp. 2472-2476
Author(s):  
Tao Jiang ◽  
Xiao Yi Lv ◽  
Fu Ru Zhong ◽  
Jia Qing Mo ◽  
Yi Xian Tu ◽  
...  
Keyword(s):  
Detection Limit ◽  
Porous Silicon ◽  
Reflection Spectrum ◽  
High Specificity ◽  
Red Shift ◽  
Label Free ◽  
Controlled Experiments ◽  
Label Free Detection ◽  
Antigen Antibody ◽  
Immune Antibody

A novel immunosensor based on porous silicon (PSi) for antigen detection was reported in this paper. The antigen (SpaA) and the specificity of the antibodies are employed as the target and the probe in our laboratory, respectively. The immunosensor structure was prepared using bioconjungation. After the antigen-antibody reaction, the red shift of the reflection spectrum of the immunosensor increases in proportion to the concentration of SpaA. The sensitivity of this immunosensor is 41nm/ µg•ml-1 and the detection limit is 2.44×102pg•ml-1, they are better compared with our previous work by using this method. Controlled experiments were also presented with non-immune antibody and the results show that this immunosensor possesses high specificity.

Estimating the Quality of Thermionic Cathodes for Microwave Vacuum Tubes Using the Low-Frequency Noise Parameters

Vestnik MEI ◽  
2018 ◽  
Vol 5 (5) ◽  
pp. 120-127
Author(s):  
Mikhail D. Vorobyev ◽  
◽  
Dmitriy N. Yudaev ◽  
Andrey Yu. Zorin ◽  
◽  
...  
Keyword(s):  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Parameters ◽  
Thermionic Cathodes ◽  
Vacuum Tubes

Simulation of Low Frequency Noise in a CCTWT

1999 ◽  
Author(s):  
Charles K. Birdsall ◽  
J. P. Varboncoeur ◽  
P. J. Christensen
Keyword(s):  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise

Label-Free Electrochemical Detection of DNA Hybridization Related to Anthrax Lethal Factor by using Carbon Nanotube Modified Sensors

2019 ◽  
Vol 15 (4) ◽  
pp. 502-510 ◽  
Author(s):  
Hakan Karadeniz ◽  
Arzum Erdem
Keyword(s):  
Detection Limit ◽  
Dna Hybridization ◽  
Lethal Factor ◽  
Modified Electrodes ◽  
Label Free ◽  
Carbon Paste ◽  
Chip Technology ◽  
Anthrax Lethal Factor ◽  
Hybridization Time ◽  
Electrochemical Monitoring

Background: Anthrax Lethal Factor (ANT) is the dominant virulence factor produced by B. anthracis and is the major cause of death of infected animals. In this paper, pencil graphite electrodes GE were modified with single-walled and multi-walled carbon nanotubes (CNTs) for the detection of hybridization related to the ANT DNA for the first time in the literature. Methods: The electrochemical monitoring of label-free DNA hybridization related to ANT DNA was explored using both SCNT and MCNT modified PGEs with differential pulse voltammetry (DPV). The performance characteristics of ANT-DNA hybridization on disposable GEs were explored by measuring the guanine signal in terms of optimum analytical conditions; the concentration of SCNT and MCNT, the concentrations of probe and target, and also the hybridization time. Under the optimum conditions, the selectivity of probe modified electrodes was tested and the detection limit was calculated. Results: The selectivity of ANT probes immobilized onto MCNT-GEs was tested in the presence of hybridization of probe with NC no response was observed and with MM, smaller responses were observed in comparison to full-match DNA hybridization case. Even though there are unwanted substituents in the mixture samples containing both the target and NC in the ratio 1:1 and both the target and MM in the ratio 1:1, it has been found that ANT probe immobilized CNT modified graphite sensor can also select its target by resulting with 20.9% decreased response in comparison to the one measured in the case of full-match DNA hybridization case Therefore, it was concluded that the detection of direct DNA hybridization was performed by using MCNT-GEs with an acceptable selectivity. Conclusion: Disposable SCNT/MCNT modified GEs bring some important advantages to our assay including easy use, cost-effectiveness and giving a response in a shorter time compared to unmodified PGE, carbon paste electrode and glassy carbon electrode developed for electrochemical monitoring of DNA hybridization. Consequently, the detection of DNA hybridization related to the ANT DNA by MCNT modified sensors was performed by using lower CNT, probe and target concentrations, in a shorter hybridization time and resulting in a lower detection limit according to the SCNT modified sensors. In conclusion, MCNT modified sensors can yield the possibilities leading to the development of nucleic acid sensors platforms for the improvement of fast and cost-effective detection systems with respect to DNA chip technology.

Noise source location and scaling of subsonic upper-surface blowing

2020 ◽  
Vol 19 (3-5) ◽  
pp. 191-206
Author(s):  
Trae L Jennette ◽  
Krish K Ahuja
Keyword(s):  
Strouhal Number ◽  
Noise Source ◽  
Low Frequency ◽  
Directivity Pattern ◽  
Source Location ◽  
Dipole Source ◽  
Frequency Noise ◽  
Noise Sources ◽  
Trailing Edge ◽  
Trailing Edge Noise

This paper deals with the topic of upper surface blowing noise. Using a model-scale rectangular nozzle of an aspect ratio of 10 and a sharp trailing edge, detailed noise contours were acquired with and without a subsonic jet blowing over a flat surface to determine the noise source location as a function of frequency. Additionally, velocity scaling of the upper surface blowing noise was carried out. It was found that the upper surface blowing increases the noise significantly. This is a result of both the trailing edge noise and turbulence downstream of the trailing edge, referred to as wake noise in the paper. It was found that low-frequency noise with a peak Strouhal number of 0.02 originates from the trailing edge whereas the high-frequency noise with the peak in the vicinity of Strouhal number of 0.2 originates near the nozzle exit. Low frequency (low Strouhal number) follows a velocity scaling corresponding to a dipole source where as the high Strouhal numbers as quadrupole sources. The culmination of these two effects is a cardioid-shaped directivity pattern. On the shielded side, the most dominant noise sources were at the trailing edge and in the near wake. The trailing edge mounting geometry also created anomalous acoustic diffraction indicating that not only is the geometry of the edge itself important, but also all geometry near the trailing edge.

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