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 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.

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.

scholarly journals High-contrast photoacoustic imaging through scattering media using correlation detection of adaptive time window

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Liqi Yu ◽  
Jialin Sun ◽  
Xinjing Lv ◽  
Qi Feng ◽  
Huimei He ◽  
...  
Keyword(s):  
Light Scattering ◽  
Time Window ◽  
Photoacoustic Imaging ◽  
Signal To Noise Ratio ◽  
Photoacoustic Signal ◽  
High Contrast ◽  
Scattering Media ◽  
Window Method ◽  
Adaptive Time ◽  
Imaging Depth

AbstractPhotoacoustic imaging has the advantages of high contrast and deep imaging depth. However, with the increasing of imaging depth, the signal-to-noise ratio (SNR) of the detected signal decreases, due to the light scattering that seriously affects the recovery image quality. In this paper, we experimentally demonstrated that higher contrast photoacoustic imaging was achieved using photoacoustic wavefront shaping technology in the presence of light scattering and low SNR signals. The imaging contrast is improved from 1.51 to 5.30. More importantly, we propose a dynamic time window method for the photoacoustic signal extraction algorithm, named correlation detection of adaptive time window, which further improves the contrast of photoacoustic imaging to 9.57. Our method effectively improves the contrast of photoacoustic imaging through scattering media.

scholarly journals Bitstream Photon Counting Chirped AM Lidar with a Dual Unipolar Signal

2020 ◽  
Author(s):  
Brian Redman
Keyword(s):  
Integrated Circuits ◽  
Phase I ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Sinusoidal Signal ◽  
Oxide Semiconductor ◽  
Quadrature Phase ◽  
Simulation Results

This paper is a follow-up to three previous papers: the first introducing the new Bitstream Photon Counting Chirped Amplitude Modulation (AM) Lidar (PC-CAML) with the unipolar Digital Logic Local Oscillator (DLLO) concept, the second introducing the improvement thereof using the bipolar DLLO, and the third introducing the improvement of digital In-phase and Quadrature-phase (I/Q) demodulation.In that previous work, the signal was a single unipolar chirped sinusoidal or square wave. This paper introduces a new bitstream PC-CAML transceiver architecture that combines two unipolar chirped signals, referred to as the dual unipolar signal, to form a single bipolar signal in the receiver. (patent pending) This bipolar signal is mixed with the bipolar DLLOs in the in-phase (I) digital mixing and quadrature-phase (Q) digital mixing channels for digital I/Q demodulation for improved signal-to-noise ratio (SNR) compared to that when using a single unipolar signal.The simulation results presented in this paper indicate an SNR improvement for the dual unipolar chirped sinusoidal signal bitstream PC-CAML compared to that of the unipolar chirped sinusoidal signal bitstream PC-CAML (both with bipolar DLLOs and digital I/Q demodulation) of from about 3 dB to about 6 dB for signals below the onset of receiver saturation, and an improvement for maximum achievable SNR of about 13 dB if the receiver is allowed to saturate.The bitstream PC-CAML with a dual unipolar signal and bipolar DLLOs with digital I/Q demodulation architecture discussed in this paper adds complexity to the transmitter and receiver compared to the architectures presented in the previous papers. Whether or not this additional complexity is worth the improved SNR will have to be decided as part of system trade studies for particular systems and their applications.However, the new architecture still retains the key advantages of the previous bitstream PC-CAML architectures since it still replaces bulky, power-hungry, and expensive wideband RF analog electronics in the receiver with digital components that can be implemented in inexpensive silicon complementary metal-oxide-semiconductor (CMOS) read-out integrated circuits (ROICs) to make the bitstream PC-CAML with a DLLO more suitable for compact lidar-on-a-chip systems and lidar array receivers than previous standard PC-CAML systems.This paper introduces the dual unipolar signal and bipolar DLLOs with digital I/Q demodulation transceiver architecture for bitstream PC-CAML, and presents the initial SNR theory with comparisons to Monte Carlo simulation results.

scholarly journals A 5-nV/√Hz Chopper Negative-R Stabilization Preamplifier for Audio Applications

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 478
Author(s):  
Jamel Nebhen ◽  
Khaled Alnowaiser ◽  
Stephane Meillere
Keyword(s):  
Supply Voltage ◽  
Signal To Noise Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Technology ◽  
Low Noise ◽  
Oxide Semiconductor ◽  
Chopper Stabilization ◽  
Main Amplifier ◽  
Measurement Results ◽  
Low Noise Preamplifier

This paper presents a low-noise and low-power audio preamplifier. The proposed low-noise preamplifier employs a delay-time chopper stabilization (CHS) technique and a negative-R circuit, both in the auxiliary amplifier to cancel the non-idealities of the main amplifier. The proposed technique makes it possible to mitigate the preamplifier 1/f noise and thermal noise and improve its linearity. The low-noise preamplifier is implemented in 65 nm complementary metal-oxide semiconductor (CMOS) technology. The supply voltage is 1.2 V, while the power consumption is 159 µW, and the core area is 192 µm2. The proposed circuit of the preamplifier was fabricated and measured. From the measurement results over a signal bandwidth of 20 kHz, it achieves a signal-to-noise ratio (SNR) of 80 dB, an equivalent-input referred noise of 5 nV/√Hz and a noise efficiency factor (NEF) of 1.9 within the frequency range from 1 Hz to 20 kHz.

scholarly journals An Instrument for the Characterization and Calibration of Optical Sensors

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5141
Author(s):  
Enrico Gastasini ◽  
Niccolò Capecci ◽  
Francesco Lupi ◽  
Alessio Gagliardi ◽  
Sergio Saponara ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Sensitivity Threshold ◽  
New Instrument ◽  
Electronic Response ◽  
Control Electronics ◽  
And Control

This paper presents the development of a hardware/software system for the characterization of the electronic response of optical (camera) sensors such as matrix and linear color and monochrome Charge Coupled Device (CCD) or Complementary Metal Oxide Semiconductor (CMOS). The electronic response of a sensor is required for inspection purposes. It also allows the design and calibration of the integrating device to achieve the desired performance. The proposed instrument equipment fulfills the most recent European Machine Vision Association (EMVA) 1288 standard ver. 3.1: the spatial non uniformity of the illumination ΔE must be under 3%, and the sensor must achieve an f-number of 8.0 concerning the light source. The following main innovations have achieved this: an Ulbricht sphere providing a uniform light distribution (irradiation) of 99.54%; an innovative illuminator with proper positioning of color Light Emitting Diodes (LEDs) and control electronics; and a flexible C# program to analyze the sensor parameters, namely Quantum Efficiency, Overall System Gain, Temporal Dark Noise, Dark Signal Non Uniformity (DSNU1288), Photo Response Non-Uniformity (PRNU1288), Maximum achievable Signal to Noise Ratio (SNRmax), Absolute sensitivity threshold, Saturation Capacity, Dynamic Range, and Dark Current. This new instrument has allowed a camera manufacturer to design, integrate, and inspect numerous devices and camera models (Necta, Celera, and Aria).

scholarly journals All-Electronic Emitter-Detector Pairs for 250 GHz in Silicon

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5795
Author(s):  
Kęstutis Ikamas ◽  
Dmytro B. But ◽  
Albert Cesiul ◽  
Cezary Kołaciński ◽  
Tautvydas Lisauskas ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Electronic System ◽  
Oxide Semiconductor ◽  
Voltage Controlled Oscillator ◽  
Medical Markets ◽  
Harmonic Voltage ◽  
System Operating

The spread of practical terahertz (THz) systems dedicated to the telecommunication, pharmacy, civil security, or medical markets requires the use of mainstream semiconductor technologies, such as complementary metal-oxide-semiconductor (CMOS) lines. In this paper, we discuss the operation of a CMOS-based free space all-electronic system operating near 250 GHz, exhibiting signal-to-noise ratio (SNR) with 62 dB in the direct detection regime for one Hz equivalent noise bandwidth. It combines the state-of-the-art detector based on CMOS field-effect-transistors (FET) and a harmonic voltage-controlled oscillator (VCO). Three generations of the oscillator circuit are presented, and the performance characterization techniques and their improvement are explained in detail. The manuscript presents different emitter–detector pair operation modalities, including spectroscopy and imaging.

scholarly journals Bitstream Photon Counting Chirped AM Lidar with Digital I/Q Demodulation

2020 ◽  
Author(s):  
Brian Redman
Keyword(s):  
Integrated Circuits ◽  
Single Channel ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Oxide Semiconductor ◽  
Signal To Noise ◽  
Receiver Architecture ◽  
Noise Ratio

This paper is a follow-up to two previous papers, one introducing the new bitstream Photon Counting Chirped Amplitude Modulation (AM) Lidar (PC-CAML) with the unipolar Digital Logic Local Oscillator (DLLO) concept, and the other paper introducing the improvement thereof using the bipolar DLLO. In that previous work, there was only a single channel of digital mixing of the DLLO with the received photon counting signal. This paper introduces a new bitstream PC-CAML receiver architecture with an in-phase (I) digital mixing channel and a quadrature phase (Q) digital mixing channel for digital I/Q demodulation with the bipolar DLLO to improve the signal-to-noise ratio (SNR) by 3 dB compared to that for the single digital mixing channel with the bipolar DLLO and by 5.5 dB compared to that for the single digital mixing channel with the unipolar DLLO. (patent pending) The bipolar DLLO with digital I/Q demodulation architecture discussed in this paper retains the key advantages of the previous bitstream PC-CAML with a DLLO systems since it also replaces bulky, power-hungry, and expensive wideband RF analog electronics with digital components that can be implemented in inexpensive silicon complementary metal-oxide-semiconductor (CMOS) read-out integrated circuits (ROICs) to make the bitstream PC-CAML with a DLLO more suitable for compact lidar-on-a-chip systems and lidar array receivers than previous PC-CAML systems. This paper introduces the bipolar DLLO with digital I/Q demodulation receiver architecture for bitstream PC-CAML and presents the initial signal-to-noise ratio (SNR) theory with comparisons to Monte Carlo simulation results.

scholarly journals Photoacoustic Signal Enhancement: Towards Utilization of Low Energy Laser Diodes in Real-Time Photoacoustic Imaging

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3498 ◽  
Author(s):  
Rayyan Manwar ◽  
Matin Hosseinzadeh ◽  
Ali Hariri ◽  
Karl Kratkiewicz ◽  
Shahryar Noei ◽  
...  
Keyword(s):  
Photoacoustic Imaging ◽  
Signal To Noise Ratio ◽  
Laser Diodes ◽  
Cost Effective ◽  
Photoacoustic Signal ◽  
Low Energy ◽  
Low Snr ◽  
Energy Laser ◽  
Noisy Measurements ◽  
Low Energy Laser

In practice, photoacoustic (PA) waves generated with cost-effective and low-energy laser diodes, are weak and almost buried in noise. Reconstruction of an artifact-free PA image from noisy measurements requires an effective denoising technique. Averaging is widely used to increase the signal-to-noise ratio (SNR) of PA signals; however, it is time consuming and in the case of very low SNR signals, hundreds to thousands of data acquisition epochs are needed. In this study, we explored the feasibility of using an adaptive and time-efficient filtering method to improve the SNR of PA signals. Our results show that the proposed method increases the SNR of PA signals more efficiently and with much fewer acquisitions, compared to common averaging techniques. Consequently, PA imaging is conducted considerably faster.

Sign in / Sign up

Export Citation Format

Share Document