scholarly journals Homodyne Spectroscopy with Broadband Terahertz Power Detector Based on 90-nm Silicon CMOS Transistor

2021 ◽  
Vol 11 (1) ◽  
pp. 412
Author(s):  
Kęstutis Ikamas ◽  
Dmytro B. But ◽  
Alvydas Lisauskas
Keyword(s):  
Continuous Wave ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Integration Time ◽  
Thz Spectroscopy ◽  
Homodyne Detection ◽  
Cmos Transistor

Over the last two decades, photomixer-based continuous wave systems developed into versatile and practical tools for terahertz (THz) spectroscopy. The high responsivity to the THz field amplitude of photomixer-based systems is predetermined by the homodyne detection principle that allows the system to have high sensitivity. Here, we show that the advantages of homodyne detection can be exploited with broadband power detectors combined with two photomixer sources. For this, we employ a THz detector based on a complementary metal-oxide-semiconductor field-effect transistor and a broadband bow-tie antenna (TeraFET). At 500 GHz and an effective noise bandwidth of 1 Hz, the response from one photomixer-based THz source resulted in an about 43 dB signal-to-noise ratio (SNR). We demonstrate that by employing a homodyne detection system by overlaying the radiation from two photomixers, the SNR can reach up to 70 dB at the same frequency with an integration time 100 ms. The improvement in SNR and the spectroscopic evidence for water vapor lines demonstrated up to 2.2 THz allow us to conclude that these detectors can be successfully used in practical continuous wave THz spectrometry systems.

scholarly journals Scanning single-molecule counting system for Eprobe with highly simple and effective approach

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243319
Author(s):  
Takeshi Hanami ◽  
Tetsuya Tanabe ◽  
Takuya Hanashi ◽  
Mitsushiro Yamaguchi ◽  
Hidetaka Nakata ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Single Molecule ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Nucleic Acid Detection ◽  
Digital Measurement ◽  
Excitation Light ◽  
Target Nucleic Acid ◽  
Fluorescent Molecules

Here, we report a rapid and ultra-sensitive detection technique for fluorescent molecules called scanning single molecular counting (SSMC). The method uses a fluorescence-based digital measurement system to count single molecules in a solution. In this technique, noise is reduced by conforming the signal shape to the intensity distribution of the excitation light via a circular scan of the confocal region. This simple technique allows the fluorescent molecules to freely diffuse into the solution through the confocal region and be counted one by one and does not require statistical analysis. Using this technique, 28 to 62 aM fluorescent dye was detected through measurement for 600 s. Furthermore, we achieved a good signal-to-noise ratio (S/N = 2326) under the condition of 100 pM target nucleic acid by only mixing a hybridization-sensitive fluorescent probe, called Eprobe, into the target oligonucleotide solution. Combination of SSMC and Eprobe provides a simple, rapid, amplification-free, and high-sensitive target nucleic acid detection system. This method is promising for future applications to detect particularly difficult to design primers for amplification as miRNAs and other short oligo nucleotide biomarkers by only hybridization with high sensitivity.

scholarly journals High Dynamic Range Imaging with TDC-Based CMOS SPAD Arrays

Instruments ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 38 ◽  
Author(s):  
Majid Zarghami ◽  
Leonardo Gasparini ◽  
Matteo Perenzoni ◽  
Lucio Pancheri
Keyword(s):  
Dynamic Range ◽  
Single Photon ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
High Dynamic Range ◽  
Oxide Semiconductor ◽  
Photon Flux ◽  
Integration Time ◽  
Rate Dependent ◽  
High Dynamic

This paper investigates the use of image sensors based on complementary metal–oxide–semiconductor (CMOS) single-photon avalanche diodes (SPADs) in high dynamic range (HDR) imaging by combining photon counts and timestamps. The proposed method is validated experimentally with an SPAD detector based on a per-pixel time-to-digital converter (TDC) architecture. The detector, featuring 32 × 32 pixels with 44.64-µm pitch, 19.48% fill factor, and time-resolving capability of ~295-ps, was fabricated in a 150-nm CMOS standard technology. At high photon flux densities, the pixel output is saturated when operating in photon-counting mode, thus limiting the DR of this imager. This limitation can be overcome by exploiting the distribution of photon arrival times in each pixel, which shows an exponential behavior with a decay rate dependent on the photon flux level. By fitting the histogram curve with the exponential decay function, the extracted time constant is used to estimate the photon count. This approach achieves 138.7-dB dynamic range within 30-ms of integration time, and can be further extended by using a timestamping mechanism with a higher resolution.

scholarly journals Up-Conversion Sensing of 2D Spatially-Modulated Infrared Information-Carrying Beams with Si-Based Cameras

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3610
Author(s):  
Adrián J. Torregrosa ◽  
Emir Karamehmedović ◽  
Haroldo Maestre ◽  
María Luisa Rico ◽  
Juan Capmany
Keyword(s):  
Optical Communications ◽  
Near Infrared ◽  
Nonlinear Crystal ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Infrared Image ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Oxide Semiconductor ◽  
Free Space Optical

Up-conversion sensing based on optical heterodyning of an IR (infrared) image with a local oscillator laser wave in a nonlinear optical sum-frequency mixing (SFM) process is a practical solution to circumvent some limitations of IR image sensors in terms of signal-to-noise ratio, speed, resolution, or cooling needs in some demanding applications. In this way, the spectral content of an IR image can become spectrally shifted to the visible/near infrared (VIS/NWIR) and then detected with silicon focal plane arrayed sensors (Si-FPA), such as CCD/CMOS (charge-coupled and complementary metal-oxide-semiconductor devices). This work is an extension of a previous study where we recently introduced this technique in the context of optical communications, in particular in FSOC (free-space optical communications). Herein, we present an image up-conversion system based on a 1064 nm Nd3+: YVO4 solid-state laser with a KTP (potassium titanyl phosphate) nonlinear crystal located intra-cavity where a laser beam at 1550 nm 2D spatially-modulated with a binary Quick Response (QR) code is mixed, giving an up-converted code image at 631 nm that is detected with an Si-based camera. The underlying technology allows for the extension of other IR spectral allocations, construction of compact receivers at low cost, and provides a natural way for increased protection against eavesdropping.

A theoretical study of digital silicon photomultiplier utilization in diffuse optical imaging systems

2019 ◽  
Vol 64 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Taha Haddadifam ◽  
Mohammad Azim Karami
Keyword(s):  
Optical Imaging ◽  
Continuous Wave ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Diffuse Optical Imaging ◽  
Silicon Photomultiplier ◽  
Thoracic Imaging ◽  
Low Level

Abstract Digital silicon photomultiplier (dSiPM) is introduced for diffuse optical imaging (DOI) applications instead of conventional photomultiplier tubes and avalanche photodiodes (APDs) as a state-of-the-art detector. According to the low-level light regime in DOI applications, high sensitivity and high dynamic range (DR) image sensors are needed for DOI systems. dSiPM is proposed as a developing detector which can detect low-level lights. Also, an accurate equation is obtained for calculating the DR of dSiPMs. Different dSiPMs and the corresponding benefits are studied for DOI applications. Furthermore, a 120 dB DR dSiPM is chosen for use in DOI systems. It is shown that dSiPMs can be utilized in DOI configurations such as time domain (TD), frequency domain (FD) and continuous wave (CW) systems. Ultimately, by utilizing dSiPM in DOI systems, the DOI method can be used for thoracic imaging due to the high DR and signal-to-noise ratio (SNR) of the detector.

scholarly journals Photoacoustic Imaging with Capacitive Micromachined Ultrasound Transducers: Principles and Developments

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3617 ◽  
Author(s):  
Jasmine Chan ◽  
Zhou Zheng ◽  
Kevan Bell ◽  
Martin Le ◽  
Parsin Haji Reza ◽  
...  
Keyword(s):  
Photoacoustic Imaging ◽  
Signal To Noise Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Photoacoustic Signal ◽  
Motion Artifacts ◽  
Oxide Semiconductor ◽  
Ring Resonators ◽  
Ultrasound Transducers ◽  
Fabrication Technique ◽  
Acoustic Techniques

Photoacoustic imaging (PAI) is an emerging imaging technique that bridges the gap between pure optical and acoustic techniques to provide images with optical contrast at the acoustic penetration depth. The two key components that have allowed PAI to attain high-resolution images at deeper penetration depths are the photoacoustic signal generator, which is typically implemented as a pulsed laser and the detector to receive the generated acoustic signals. Many types of acoustic sensors have been explored as a detector for the PAI including Fabry–Perot interferometers (FPIs), micro ring resonators (MRRs), piezoelectric transducers, and capacitive micromachined ultrasound transducers (CMUTs). The fabrication technique of CMUTs has given it an edge over the other detectors. First, CMUTs can be easily fabricated into given shapes and sizes to fit the design specifications. Moreover, they can be made into an array to increase the imaging speed and reduce motion artifacts. With a fabrication technique that is similar to complementary metal-oxide-semiconductor (CMOS), CMUTs can be integrated with electronics to reduce the parasitic capacitance and improve the signal to noise ratio. The numerous benefits of CMUTs have enticed researchers to develop it for various PAI purposes such as photoacoustic computed tomography (PACT) and photoacoustic endoscopy applications. For PACT applications, the main areas of research are in designing two-dimensional array, transparent, and multi-frequency CMUTs. Moving from the table top approach to endoscopes, some of the different configurations that are being investigated are phased and ring arrays. In this paper, an overview of the development of CMUTs for PAI is presented.

scholarly journals Active Thermoelectric Vacuum Sensor Based on Frequency Modulation

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 15 ◽  
Author(s):  
Shu-Jung Chen ◽  
Yung-Chuan Wu
Keyword(s):  
Frequency Modulation ◽  
Signal To Noise Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Harmonic Signal ◽  
Phase Lock Loop ◽  
Oxide Semiconductor ◽  
Alternative Approach ◽  
Vacuum Sensor ◽  
Cmos Mems ◽  
Mems Process

This paper introduces a thermoelectric-type sensor with a built-in heater as an alternative approach to the measurement of vacuum pressure based on frequency modulation. The proposed sensor is fabricated using the TSMC (Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan) 0.35 μm complementary metal-oxide-semiconductor-microelectro-mechanical systems (CMOS–MEMS) process with thermocouples positioned central-symmetrically. The proposed frequency modulation technique involves locking the sensor output signal at a given frequency using a phase-lock-loop (PLL) amplifier to increase the signal-to-noise ratio (SNR) and thereby enhance the sensitivity of vacuum measurements. An improved first harmonic signal detection based on asymmetrical applied heating gives a precise measurement. Following calibration, the output voltage is in good agreement with the calibration values, resulting in an error of 0.25% under pressures between 0.1–10 Torr.

Piezoelectric Thin Films for Sensors, Actuators, and Energy Harvesting

MRS Bulletin ◽  
2009 ◽  
Vol 34 (9) ◽  
pp. 658-664 ◽  
Author(s):  
P. Muralt ◽  
R. G. Polcawich ◽  
S. Trolier-McKinstry
Keyword(s):  
Thin Films ◽  
Energy Harvesting ◽  
Microelectromechanical Systems ◽  
Low Voltage ◽  
High Sensitivity ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Mems Devices ◽  
Si Substrates ◽  
The Impact

AbstractPiezoelectric microelectromechanical systems (MEMS) offer the opportunity for high-sensitivity sensors and large displacement, low-voltage actuators. In particular, recent advances in the deposition of perovskite thin films point to a generation of MEMS devices capable of large displacements at complementary metal oxide semiconductor-compatible voltage levels. Moreover, if the devices are mounted in mechanically noisy environments, they also can be used for energy harvesting. Key to all of these applications is the ability to obtain high piezoelectric coefficients and retain these coefficients throughout the microfabrication process. This article will review the impact of composition, orientation, and microstructure on the piezoelectric properties of perovskite thin films such as PbZr1−xTixO3 (PZT). Superior piezoelectric coefficients (e31, f of −18 C/m2) are achieved in {001}-oriented PbZr0.52Ti0.48O3 films with improved compositional homogeneity on Si substrates. The advent of such high piezoelectric responses in films opens up a wide variety of possible applications. A few examples of these, including low-voltage radio frequency MEMS switches and resonators, actuators for millimeter-scale robotics, droplet ejectors, energy scavengers for unattended sensors, and medical imaging transducers, will be discussed.

High Sensitivity Dynamic Range Enhanced Complementary Metal–Oxide–Semiconductor Imager with Noise Suppression

2008 ◽  
Vol 47 (4) ◽  
pp. 2761-2766
Author(s):  
Satoru Adachi ◽  
Woonghee Lee ◽  
Nana Akahane ◽  
Hiromichi Oshikubo ◽  
Koichi Mizobuchi ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Noise Suppression ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Complementary Metal Oxide Semiconductor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor

Etching Process Effects of CMOS Transistor Gate Manufacturing Nanotechnology Fabrication Integration

2011 ◽  
Vol 83 ◽  
pp. 91-96
Author(s):  
Chun Jen Weng
Keyword(s):  
Metal Oxide ◽  
Complementary Metal Oxide Semiconductor ◽  
Critical Dimension ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Electrical Characteristics ◽  
Short Channel ◽  
Gate Structure ◽  
Channel Effects ◽  
Cmos Transistor

As the nanotechnology gate is scaling down, the fabrication technology of gate spacer for CMOS transistor becomes more critical in manufacturing processes. For CMOS technologies, sidewall spacers play an important role in the control of short channel effects by offsetting ion implantation profiles from the edge of the gate. A sidewall spacer patterning technology yields critical dimension variations of minimum-sized features much smaller than that achieved by optical Complementary Metal–Oxide–Semiconductor (CMOS) fabrication processes integration. The present study is to overcome the fabrication limitations and more particularly focus on etching processes integration on structural and formation processing for complementary metal oxide semiconductor nanofabrication process on gate spacer technology and electrical characteristics performance of nanotechnology gate structure were included. Based on the investigation of the etching effect and interface film variation on the electrical characteristics of the gate oxide on etching profile and their impacts on the sidewall transistor gate structure, a novel etching integration process for optimal controlled sidewall gate spacer fabrication was developed.

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