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Special Issue "Towards Optoelectronic Technology: From Basic Research to Applications"

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A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Optical Sensors".

Deadline for manuscript submissions: 15 February 2024 | Viewed by 8451

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Special Issue Editor

Dr. Jacek Wojtas
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Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2 Str., 00-908 Warsaw, Poland
Interests: optoelectronic engineering; optical metrology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Optoelectronic technologies play a key role in a wide range of sophisticated systems and everyday devices, such as smartwatches and sensors that monitor the Martian atmosphere. A rapid development of these technologies is currently observed. On the one hand, it is driven by the needs of various and increasingly demanding applications, and on the other hand, it is inextricably linked to basic research.

This Special Issue provides a unique opportunity to combine the achievements of these two research areas: basic and application. Its main purpose is to review cutting-edge infrared technologies and state-of-the-art photonic devices and sensors that can be used in a wide variety of applications. One of the crucial areas of application is sensing technology, currently used in virtually all aspects of life. Sensors are applied in safety systems (perimeter protection, detection of hazardous substances, etc.), in industry for process control, and in medicine for diagnosis and monitoring.

A measurable effect of the SI will be the presentation of scientific discoveries and solutions to difficult engineering problems, but also the identification of directions for further development of the topics listed on the list of keywords.

Dr. Jacek Wojtas
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

photonic technologies
laser and detector technologies, nanotechnology
fiber-optics, optical metrology, and instrumentation
spectroscopy
microscopy
interferometry
thermography, optical tomography, reflectometry
photometry
optical sensing
optical testing
environmental, security, space, medical, and industrial applications

Published Papers (6 papers)

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Research

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Open AccessArticle

Two-Channel Detecting Sensor with Signal Cross-Correlation for FTIR Instruments

Krzysztof Achtenberg

Janusz Mikołajczyk

and

Zbigniew Bielecki

Sensors 2022, 22(22), 8919; https://doi.org/10.3390/s22228919 - 18 Nov 2022

Viewed by 1022

Abstract

This paper’s purpose was to demonstrate a performance of a novel approach in a low-noise optical sensor for an FTIR spectrometer. Methods: Compared to the standard FTIR detection setup, our sensor ensures a higher signal-to-noise ratio (SNR) and lower signal standard deviation by reducing the uncorrelated noise components (e.g., thermal and 1/f noises of the detection module). Its construction is based on two-channel detection modules and a processing unit with implemented cross-correlation signal analyses. Each module was built of LWIR HgCdTe photodiodes and low-noise transimpedance amplifiers. Results: the experiments demonstrated a decrease in a signal standard deviation of about 1.7 times with a 10 dB-improvement in the SNR. Conclusion: this result indicates our sensor’s main benefit, especially in registered “weak” and noisy interferograms. Full article

(This article belongs to the Special Issue Towards Optoelectronic Technology: From Basic Research to Applications)

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Open AccessArticle

Multi-Irradiance: A Method for Simultaneous Measurement of the Temperature and Spectral Emissivity of High-Temperature Targets in SWIR

and

Sensors 2022, 22(21), 8469; https://doi.org/10.3390/s22218469 - 03 Nov 2022

Viewed by 1087

Abstract

The currently used energy methods in spectral emissivity measurement are susceptible to the difference in temperature between the target and the reference blackbody. It is also limited by the state of the observation target and observation. This paper introduces the irradiance condition, while using the correlation between the information of emission energy and reflected energy of the high-temperature target. Based on the principle of radiative transmission and energy conservation, the relationship between the emissivity and bidirectional reflectance factor (BRF) was used to perform the retrieval of emissivity and temperature. An experimental device was designed, and graphite and rock were considered to verify the feasibility of the experimental scheme. The error of emissivity and temperature of both targets were, respectively, less than 5% and 0.5%, due to the Lambertian assumption, and the systematic errors had negligible impact on the retrieval. This verifies that the experimental observation method and scheme is reasonable. Full article

(This article belongs to the Special Issue Towards Optoelectronic Technology: From Basic Research to Applications)

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Open AccessArticle

A Diagnostic Method Based on Active Thermography for the Degradation Assessment of Power Plant Boiler Tubes

Sławomir Zator

Michał Tomaszewski

and

Mirosław Lasar

Sensors 2022, 22(21), 8401; https://doi.org/10.3390/s22218401 - 01 Nov 2022

Cited by 1 | Viewed by 1028

Abstract

Proper maintenance management of power infrastructure requires inspections, in order to gather knowledge about the facility’s current condition. For this purpose, periodic diagnostic tests are carried out, not only to determine the current state, but to also predict future conditions, and subsequently plan for the scope of necessary repair work. Currently, in the case of heat screens of power boilers, the diagnostic process takes many days, is very expensive, and usually does not cover the entire screen area. Therefore, it is necessary to develop new, noninvasive diagnostic methods. This study presents the concept and research for an alternative method of locating places with excessive energy boiler screen degradation that require replacement. It was assumed that the new method should be fast, require no scaffolding assembly, and permit checking of the entire screen surface; this is unlike the methods used currently, which require manual checking of selected screen tubes. The proposed method is based on active thermography, in which heat flux is forced by the liquid flowing inside the screen. Tests were carried out based on a model of an axial-symmetric system in the form of a tube, with controlled reductions in the wall thickness. An experiment was carried out many times by recording the pipe surface temperature in many characteristic places (different thicknesses of the tube walls) with a thermal imaging camera. A temperature change was forced by a controlled flow of hot or cold water. The methods of analysis were proposed and verified, allowing firstly, detection of places with a reduced wall thickness, and secondly, estimations of the wall thickness (i.e., excessive degradation). For the best-proposed model (one of the four analyzed), all of the thickness changes were detected, and the limit error of thickness obtained was 0.3 mm. Full article

(This article belongs to the Special Issue Towards Optoelectronic Technology: From Basic Research to Applications)

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Open AccessArticle

Polarization Calibration of a Microwave Polarimeter with Near-Infrared Up-Conversion for Optical Correlation and Detection

Francisco J. Casas

Patricio Vielva

R. Belen Barreiro

Enrique Martínez-González

and

G. Pascual-Cisneros

Sensors 2022, 22(20), 8080; https://doi.org/10.3390/s22208080 - 21 Oct 2022

Cited by 3 | Viewed by 1020

Abstract

This paper presents a polarization calibration method applied to a microwave polarimeter demonstrator based on a near-infrared (NIR) frequency up-conversion stage that allows both optical correlation and signal detection at a wavelength of 1550 nm. The instrument was designed to measure the polarization of cosmic microwave background (CMB) radiation from the sky, obtaining the Stokes parameters of the incoming signal simultaneously, in a frequency range from 10 to 20 GHz. A linearly polarized input signal with a variable polarization angle is used as excitation in the polarimeter calibration setup mounted in the laboratory. The polarimeter systematic errors can be corrected with the proposed calibration procedure, achieving high levels of polarization efficiency (low polarization percentage errors) and low polarization angle errors. The calibration method is based on the fitting of polarization errors by means of sinusoidal functions composed of additive or multiplicative terms. The accuracy of the fitting increases with the number of terms in such a way that the typical error levels required in low-frequency CMB experiments can be achieved with only a few terms in the fitting functions. On the other hand, assuming that the calibration signal is known with the required accuracy, additional terms can be calculated to reach the error levels needed in ultrasensitive B-mode polarization CMB experiments. Full article

(This article belongs to the Special Issue Towards Optoelectronic Technology: From Basic Research to Applications)

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Open AccessArticle

A Reliable Method of Measuring the Conversion Degrees of Methacrylate Dental Resins

Mirosław Kwaśny

Aneta Bombalska

and

Karolina Obroniecka

Sensors 2022, 22(6), 2170; https://doi.org/10.3390/s22062170 - 10 Mar 2022

Cited by 5 | Viewed by 1462

Abstract

The main aim of the study was to implement the most reliable method of measuring the degrees of conversion during photopolymerization of dental fillings. Contrary to the methods used so far, the method is based only on comparison with the monomer absorbance spectrum without reference bands. Another aim of the study was to prepare a comparative analysis of the polymerization kinetics of dental resins under various light sources and different environmental conditions (irradiance, light dose, temperature), with estimation of the degrees of conversion (DC) of the resins being the main metric. HRi Universal Enamel (UE2) and HRi Universal Dentine (UD2) were examined under two different types of light sources used in dentistry, LED and halogen. DC was measured by Fourier transform infrared spectroscopy (FTIR) in transmission mode from 5 s up to 7 days. Spectra were recorded from the parallel optical layers of samples that were placed between the KBr crystals. The results are expressed by the changes in the absorbance spectrum during the polymerization and the calculated conversion rates. The results of each experiment were averaged from three separate measurements of three samples, during which the samples were illuminated under identical conditions. The data were analyzed by performing ANOVA test comparisons between sample groups at the significance level α = 0.05. The degree of conversion of the UD2 resin was higher than that of UE2 for each experimental condition, but there was no statistically significant difference between the DC of those materials (p > 0.05). There was statistically significant difference (p < 0.01) in the DC caused by LED and halogen light sources producing the same light doses (38 J/cm²). This was the result of different features of light transmission to the filler in the resin composite. The efficacy of the LED source is twice as high as that of the halogen light source. Maximal DC without any other differences in conditions, such as resin type or light source, reached around 70% for temperatures of 22–37 °C. For 37 °C, this took 24 h, which is a contrast to the 7 days it took for 23 °C. The influences of different conditions and factors on reaction kinetics are only strong in the early and the rapid stage of conversion. The optimal time of irradiance using either light source is 20 s for a monolayer, and its thickness should not exceed 2 mm. Full article

(This article belongs to the Special Issue Towards Optoelectronic Technology: From Basic Research to Applications)

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Open AccessReview

Ultraviolet Photodetectors: From Photocathodes to Low-Dimensional Solids

and

Sensors 2023, 23(9), 4452; https://doi.org/10.3390/s23094452 - 02 May 2023

Cited by 1 | Viewed by 2029

Abstract

The paper presents the long-term evolution and recent development of ultraviolet photodetectors. First, the general theory of ultraviolet (UV) photodetectors is briefly described. Then the different types of detectors are presented, starting with the older photoemission detectors through photomultipliers and image intensifiers. More attention is paid to silicon and different types of wide band gap semiconductor photodetectors such as AlGaN, SiC-based, and diamond detectors. Additionally, Ga₂O₃ is considered a promising material for solar-blind photodetectors due to its excellent electrical properties and a large bandgap energy. The last part of the paper deals with new UV photodetector concepts inspired by new device architectures based on low-dimensional solid materials. It is shown that the evolution of the architecture has shifted device performance toward higher sensitivity, higher frequency response, lower noise, and higher gain-bandwidth products. Full article

(This article belongs to the Special Issue Towards Optoelectronic Technology: From Basic Research to Applications)

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