sensors-logo

Journal Browser

Journal Browser

Feature Papers in Optical Sensors 2024

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

Deadline for manuscript submissions: closed (31 December 2024) | Viewed by 14944

Special Issue Editors


E-Mail Website
Guest Editor
Consiglio Nazionale delle Ricerche, IMM Institute, via P Gobetti 101, I-40129 Bologna, Italy
Interests: optical fiber sensors; fiber optic communications; lasers; optical amplifiers; integrated optics; photonics and optoelectronics
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
School of Electrical and Electronic Engineering, Photonics Research Centre, Technological University Dublin, Grangegorman, D07 ADY7 Dublin, Ireland
Interests: optical sensing; whispering gallery mode effects in microfibre based resonators for chemical and bio-sensing; smart optical sensors for engineering applications; sensing of volatile organic compounds in environmental monitoring, medical diagnostics and industrial control; optics and applications of liquid crystals in photonics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Optical sensors are the subject of a huge number of studies and applications. Many well-established technologies, including free-space optics, integrated photonics, and fiber optics approaches, have been developed in recent decades to fabricate and develop increasingly more efficient optical sensors for applications ranging from industrial control to monitoring the environment, as well as biomedical use and even the Internet of Things.

The purpose of this Special Issue is to publish a set of papers that typify the most insightful and influential original articles, through which our section’s EBMs are able to discuss key topics in the field, particularly review contributions that demonstrate the advancement of optical sensing technology and successfully present new and consolidated application areas. Areas of interest include the evaluation of new sensors, new sensing principles, new applications, and new technologies, as well as review papers on the state of the art of well-established technologies for sensing. Topics of interest include group IV photonic sensors, optomechanical sensors, fiber-optic sensors, silicon photonics, plasmonic sensors, metasurfaces, and other related topics.

Dr. Gabriele Bolognini
Prof. Dr. Yuliya Semenova
Guest Editors

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 sensors
  • optomechanical sensors
  • fiber-optic sensors
  • silicon photonics
  • plasmonic sensors.

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (8 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

25 pages, 11729 KiB  
Article
Design Key Points of High-Performance Diffuse Reflectance Optical Sensors for Non-Invasive Blood Glucose Measurement
by Wenbo Liu, Tongshuai Han, Wenliang Chen, Jiayu Chen, Qing Ge, Di Sun, Jin Liu and Kexin Xu
Sensors 2025, 25(4), 998; https://doi.org/10.3390/s25040998 - 7 Feb 2025
Cited by 1 | Viewed by 595
Abstract
Optical sensors serve as pivotal components in the realm of non-invasive blood glucose measurement (NBGM) devices, where their efficacy directly influences the detection of weak glucose signals. This research introduces three fundamental design key points tailored for diffuse reflectance optical sensors employed for [...] Read more.
Optical sensors serve as pivotal components in the realm of non-invasive blood glucose measurement (NBGM) devices, where their efficacy directly influences the detection of weak glucose signals. This research introduces three fundamental design key points tailored for diffuse reflectance optical sensors employed for NBGM: depth resolution, detection signal-to-noise ratio, and human–sensor interface coupling. Guided by these design key points, we presented feasible design proposals for near-infrared diffuse reflectance sensors operating in the range of 1000–1700 nm. As an example, a sensor composed of five-ring detectors with a ring-shaped mask were made and tested on human skin. The innovative sensor developed herein holds promising potential for NBGM. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

14 pages, 2807 KiB  
Article
Sensing the Changes in Stratum Corneum Using Fourier Transform Infrared Microspectroscopy and Hyperspectral Data Processing
by Krzysztof Banas, Agnieszka M. Banas, Giorgia Pastorin, Ngai Mun Hong, Shikhar Gupta, Katarzyna Dziedzic-Kocurek and Mark B. H. Breese
Sensors 2024, 24(21), 7054; https://doi.org/10.3390/s24217054 - 31 Oct 2024
Cited by 1 | Viewed by 1553
Abstract
The stratum corneum (SC) forms the outermost layer of the skin, playing a critical role in preventing water loss and protecting against external biological and chemical threats. Approximately 90% of the SC consists of large, flat corneocytes, yet its barrier function primarily relies [...] Read more.
The stratum corneum (SC) forms the outermost layer of the skin, playing a critical role in preventing water loss and protecting against external biological and chemical threats. Approximately 90% of the SC consists of large, flat corneocytes, yet its barrier function primarily relies on the intercellular lipid matrix that surrounds these cells. Traditional methods for characterizing these lipids, such as Fourier transform infrared spectroscopy (FTIR), typically involve macroscopic analysis using attenuated total reflection (ATR) techniques. In this study, we introduce a novel approach for investigating SC samples at a microscopic level to gain detailed chemical insights and assess sample heterogeneity. Special emphasis is placed on advanced hyperspectral data pre-processing to ensure the accuracy and reliability of the results. We also evaluate methods for filtering out spectral data that significantly deviate from the mean and analyze the extracted mean spectra, the intensities of specific infrared peaks, and their ratios. The novelty of this work lies in its microscopic approach to analyzing the SC lipid matrix, diverging from the traditional macroscopic FTIR–ATR methods. By focusing on hyperspectral imaging and developing robust pre-processing techniques, this study provides more localized, high-resolution chemical insights. This microscopic perspective opens up the possibility of detecting subtle heterogeneities within the skin’s lipid matrix, offering deeper, previously unattainable understanding of the SC’s barrier function. Additionally, the exploration of spectral filtering methods enhances the precision of the analysis, paving the way for more refined and reliable investigations of skin structure and behavior in future research. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

12 pages, 918 KiB  
Article
Sensitivity and Performance of Uncooled Avalanche Photodiode for Thermoluminescent Dosimetry Applications
by Piotr Sobotka, Karol Bolek, Zuzanna Pawłowska, Bartłomiej Kliś, Maciej Przychodzki, Krzysztof W. Fornalski and Katarzyna A. Rutkowska
Sensors 2024, 24(19), 6207; https://doi.org/10.3390/s24196207 - 25 Sep 2024
Viewed by 1337
Abstract
Detecting extremely low light signals is the basis of many scientific experiments and measurement techniques. For many years, a high-voltage photomultiplier has been the only practical device used in the visible and infrared spectral range. However, such a solution is subject to several [...] Read more.
Detecting extremely low light signals is the basis of many scientific experiments and measurement techniques. For many years, a high-voltage photomultiplier has been the only practical device used in the visible and infrared spectral range. However, such a solution is subject to several inconveniences, including high production costs, the requirements of a supply voltage of several hundred volts, and a high susceptibility to mechanical damage. This paper presents two detection systems based on avalanche photodiodes, one cooled and the second operating at room temperature, in terms of their potential application in thermoluminescent dosimeter units. The results show that the detection system with an uncooled photodiode may successfully replace the photomultiplier tube commonly used in practice. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

18 pages, 7020 KiB  
Article
Instability Compensation of Recording Interferometer in Phase-Sensitive OTDR
by Konstantin V. Stepanov, Andrey A. Zhirnov, Tatyana V. Gritsenko, Roman I. Khan, Kirill I. Koshelev, Cesare Svelto and Alexey B. Pnev
Sensors 2024, 24(11), 3338; https://doi.org/10.3390/s24113338 - 23 May 2024
Cited by 1 | Viewed by 1448
Abstract
In the paper, a new method of phase measurement error suppression in a phase-sensitive optical time domain reflectometer is proposed and experimentally proved. The main causes of phase measurement errors are identified and considered, such as the influence of the recording interferometer instabilities [...] Read more.
In the paper, a new method of phase measurement error suppression in a phase-sensitive optical time domain reflectometer is proposed and experimentally proved. The main causes of phase measurement errors are identified and considered, such as the influence of the recording interferometer instabilities and laser wavelength instability, which can cause inaccuracies in phase unwrapping. The use of a Mach–Zender interferometer made by 3 × 3 fiber couplers is proposed and tested to provide insensitivity to the recording interferometer and laser source instabilities. It is shown that using all three available photodetectors of the interferometer, instead of just one pair, achieves significantly better accuracy in the phase unwrapping. A novel compensation scheme for accurate phase measurements in a phase-sensitive optical time domain reflectometer is proposed, and a comparison of the measurement signals with or without such compensation is shown and discussed. The proposed method, using three photodetectors, allows for very good compensation of the phase measurement errors arising from common-mode noise from the interferometer and laser source, providing a significant improvement in signal detection. In addition, the method allows the tracking of slow temperature changes in the monitored fiber/object, which is not obtainable when using a simple low-pass filter for phase unwrapping error reduction, as is customary in several systems of this kind. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

13 pages, 1516 KiB  
Article
Environmental Surveillance through Machine Learning-Empowered Utilization of Optical Networks
by Hasan Awad, Fehmida Usmani, Emanuele Virgillito, Rudi Bratovich, Roberto Proietti, Stefano Straullu, Francesco Aquilino, Rosanna Pastorelli and Vittorio Curri
Sensors 2024, 24(10), 3041; https://doi.org/10.3390/s24103041 - 10 May 2024
Cited by 5 | Viewed by 1706
Abstract
We present the use of interconnected optical mesh networks for early earthquake detection and localization, exploiting the existing terrestrial fiber infrastructure. Employing a waveplate model, we integrate real ground displacement data from seven earthquakes with magnitudes ranging from four to six to simulate [...] Read more.
We present the use of interconnected optical mesh networks for early earthquake detection and localization, exploiting the existing terrestrial fiber infrastructure. Employing a waveplate model, we integrate real ground displacement data from seven earthquakes with magnitudes ranging from four to six to simulate the strains within fiber cables and collect a large set of light polarization evolution data. These simulations help to enhance a machine learning model that is trained and validated to detect primary wave arrivals that precede earthquakes’ destructive surface waves. The validation results show that the model achieves over 95% accuracy. The machine learning model is then tested against an M4.3 earthquake, exploiting three interconnected mesh networks as a smart sensing grid. Each network is equipped with a sensing fiber placed to correspond with three distinct seismic stations. The objective is to confirm earthquake detection across the interconnected networks, localize the epicenter coordinates via a triangulation method and calculate the fiber-to-epicenter distance. This setup allows early warning generation for municipalities close to the epicenter location, progressing to those further away. The model testing shows a 98% accuracy in detecting primary waves and a one second detection time, affording nearby areas 21 s to take countermeasures, which extends to 57 s in more distant areas. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

11 pages, 3296 KiB  
Article
Distributed Temperature Sensing through Network Analysis Frequency-Domain Reflectometry
by Rizwan Zahoor, Raffaele Vallifuoco, Luigi Zeni and Aldo Minardo
Sensors 2024, 24(7), 2378; https://doi.org/10.3390/s24072378 - 8 Apr 2024
Cited by 3 | Viewed by 1793
Abstract
In this paper, we propose and demonstrate a network analysis optical frequency domain reflectometer (NA-OFDR) for distributed temperature measurements at high spatial (down to ≈3 cm) and temperature resolution. The system makes use of a frequency-stepped, continuous-wave (cw) laser whose output light is [...] Read more.
In this paper, we propose and demonstrate a network analysis optical frequency domain reflectometer (NA-OFDR) for distributed temperature measurements at high spatial (down to ≈3 cm) and temperature resolution. The system makes use of a frequency-stepped, continuous-wave (cw) laser whose output light is modulated using a vector network analyzer. The latter is also used to demodulate the amplitude of the beat signal formed by coherently mixing the Rayleigh backscattered light with a local oscillator. The system is capable of attaining high measurand resolution (≈50 mK at 3-cm spatial resolution) thanks to the high sensitivity of coherent Rayleigh scattering to temperature. Furthermore, unlike the conventional optical-frequency domain reflectometry (OFDR), the proposed system does not rely on the use of a tunable laser and therefore is less prone to limitations related to the laser coherence or sweep nonlinearity. Two configurations are analyzed, both numerically and experimentally, based on either a double-sideband or single-sideband modulated probe light. The results confirm the validity of the proposed approach. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

Review

Jump to: Research

44 pages, 14459 KiB  
Review
A Review: Laser Interference Lithography for Diffraction Gratings and Their Applications in Encoders and Spectrometers
by Linbin Luo, Shuonan Shan and Xinghui Li
Sensors 2024, 24(20), 6617; https://doi.org/10.3390/s24206617 - 14 Oct 2024
Cited by 6 | Viewed by 3457
Abstract
The unique diffractive properties of gratings have made them essential in a wide range of applications, including spectral analysis, precision measurement, optical data storage, laser technology, and biomedical imaging. With advancements in micro- and nanotechnologies, the demand for more precise and efficient grating [...] Read more.
The unique diffractive properties of gratings have made them essential in a wide range of applications, including spectral analysis, precision measurement, optical data storage, laser technology, and biomedical imaging. With advancements in micro- and nanotechnologies, the demand for more precise and efficient grating fabrication has increased. This review discusses the latest advancements in grating manufacturing techniques, particularly highlighting laser interference lithography, which excels in sub-beam generation through wavefront and amplitude division. Techniques such as Lloyd’s mirror configurations produce stable interference fringe fields for grating patterning in a single exposure. Orthogonal and non-orthogonal, two-axis Lloyd’s mirror interferometers have advanced the fabrication of two-dimensional gratings and large-area gratings, respectively, while laser interference combined with concave lenses enables the creation of concave gratings. Grating interferometry, utilizing optical interference principles, allows for highly precise measurements of minute displacements at the nanometer to sub-nanometer scale. This review also examines the application of grating interferometry in high-precision, absolute, and multi-degree-of-freedom measurement systems. Progress in grating fabrication has significantly advanced spectrometer technology, with integrated structures such as concave gratings, Fresnel gratings, and grating–microlens arrays driving the miniaturization of spectrometers and expanding their use in compact analytical instruments. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

23 pages, 8494 KiB  
Review
Advances in Group-10 Transition Metal Dichalcogenide PdSe2-Based Photodetectors: Outlook and Perspectives
by Tawsif Ibne Alam, Kunxuan Liu, Sumaiya Umme Hani, Safayet Ahmed and Yuen Hong Tsang
Sensors 2024, 24(18), 6127; https://doi.org/10.3390/s24186127 - 22 Sep 2024
Cited by 4 | Viewed by 2172
Abstract
The recent advancements in low-dimensional material-based photodetectors have provided valuable insights into the fundamental properties of these materials, the design of their device architectures, and the strategic engineering approaches that have facilitated their remarkable progress. This review work consolidates and provides a comprehensive [...] Read more.
The recent advancements in low-dimensional material-based photodetectors have provided valuable insights into the fundamental properties of these materials, the design of their device architectures, and the strategic engineering approaches that have facilitated their remarkable progress. This review work consolidates and provides a comprehensive review of the recent progress in group-10 two-dimensional (2D) palladium diselenide (PdSe2)-based photodetectors. This work first offers a general overview of the various types of PdSe2 photodetectors, including their operating mechanisms and key performance metrics. A detailed examination is then conducted on the physical properties of 2D PdSe2 material and how these metrics, such as structural characteristics, optical anisotropy, carrier mobility, and bandgap, influence photodetector device performance and potential avenues for enhancement. Furthermore, the study delves into the current methods for synthesizing PdSe2 material and constructing the corresponding photodetector devices. The documented device performances and application prospects are thoroughly discussed. Finally, this review speculates on the existing trends and future research opportunities in the field of 2D PdSe2 photodetectors. Potential directions for continued advancement of these optoelectronic devices are proposed and forecasted. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

Back to TopTop