Advances on Applications of Optics and Photonics – Selected Papers from the 4th International Conference on Applications of Optics and Photonics, AOP2019

A special issue of Photonics (ISSN 2304-6732).

Deadline for manuscript submissions: closed (31 October 2019) | Viewed by 51066

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Center of Physics of the Universities of Minho and Porto, School of Sciences, University of Minho, 4710-057 Braga, Portugal
Interests: optical metrology; image processing; thin films, micro- and nanostructures and systems; optics and science education
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Special Issue Information

Dear Colleagues,

The 4th International Conference on Applications of Optics and Photonics, AOP2019, will be held in Lisbon (Portugal), from 31 May–4 June, 2019. Since their first edition back in 2011, the AOP conferences have provided an excellent opportunity and an open and friendly environment to foster the establishment of the widest range of cooperation projects and relationships with colleagues and institutions involved in optics and photonics research from all around the world. Open to contributions from all domains of optics and photonics and application fields, we expect this conference to review the state-of-the art in these subjects and to foresee and discuss the future of research in optics and photonics. Thirty plenary and keynote lectures by world renowned researchers in all fields of optics and photonics will set the quality standards for a varied and exciting scientific program.

We are honored to serve as Guest Editors of this Special Issue to be published in Photonics that will contain a selection of papers submitted to and accepted at AOP2019. Its main scope is to provide a timely and broad collection of the most innovative topics discussed at the latest edition of the conference related to applications in optics and photonics. We warmly invite researchers to submit their contributions, both original research articles and review papers, to this Special Issue. Topics include, but are not limited to:

  • Nano-Photonics. Plasmonics. Theoretical optics, Quantum and Nonlinear Optics
  • Optical Communications and Sensors
  • Optical Fibers and Applications
  • Biophotonics and Biomedical and Medical Applications of Optics and Photonics
  • Ultrafast Lasers and Ultrafast Optics. Power Lasers
  • Optical Metrology, Image Processing and Industrial Applications
  • Optometry, Ophthalmic Optics, Color and Visual Sciences
  • Optoelectronics
  • Microwave Photonics
  • Photonics and Optical Instrumentation for Space and Astronomy
  • LiDAR and Optics and Photonics for Smart Mobility

Prof. Dr. Manuel Filipe P. C. M. Costa
Guest Editor

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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. Photonics is an international peer-reviewed open access monthly journal published by MDPI.

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Keywords

  • Nano-Photonics. Plasmonics. Theoretical Optics, Quantum and Nonlinear Optics
  • Optical Communications and Sensors
  • Optical Fibers and Applications
  • Biophotonics and Biomedical and Medical Applications of Optics and Photonics
  • Ultrafast Lasers and Ultrafast Optics. Power Lasers
  • Optical Metrology, Image Processing and Industrial Applications
  • Optometry, Ophthalmic Optics, Color and Visual Sciences
  • Optoelectronics
  • Microwave Photonics
  • Photonics and Optical Instrumentation for Space and Astronomy
  • LiDAR and Optics and Photonics for Smart Mobility

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Published Papers (14 papers)

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Research

8 pages, 2473 KiB  
Article
Image Encryption System Based on a Nonlinear Joint Transform Correlator for the Simultaneous Authentication of Two Users
by Juan M. Vilardy O., María S. Millán and Elisabet Pérez-Cabré
Photonics 2019, 6(4), 128; https://doi.org/10.3390/photonics6040128 - 14 Dec 2019
Cited by 5 | Viewed by 2735
Abstract
We propose a new encryption system based on a nonlinear joint transform correlator (JTC) using the information of two biometrics (one digital fingerprint for each user) as security keys of the encryption system. In order to perform the decryption and authentication in a [...] Read more.
We propose a new encryption system based on a nonlinear joint transform correlator (JTC) using the information of two biometrics (one digital fingerprint for each user) as security keys of the encryption system. In order to perform the decryption and authentication in a proper way, it is necessary to have the two digital fingerprints from the respective users whose simultaneous authentication is pursued. The proposed security system is developed in the Fourier domain. The nonlinearity of the JTC along with the five security keys given by the three random phase masks and the two digital fingerprints of the two users allow an increase of the system security against brute force and plaintext attacks. The feasibility and validity of this proposal is demonstrated using digital fingerprints as biometrics in numerical experiments. Full article
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18 pages, 3144 KiB  
Article
A Study into the Effects of Factors Influencing an Underwater, Single-Pixel Imaging System’s Performance
by Qi Chen, Anumol Mathai, Xiping Xu and Xin Wang
Photonics 2019, 6(4), 123; https://doi.org/10.3390/photonics6040123 - 27 Nov 2019
Cited by 18 | Viewed by 3518
Abstract
Underwater detection has always been a challenge due to the limitations caused by scattering and absorption in the underwater environment. Because of their great penetration abilities, lasers have become the most suitable technology for underwater detection. In all underwater laser applications, the reflected [...] Read more.
Underwater detection has always been a challenge due to the limitations caused by scattering and absorption in the underwater environment. Because of their great penetration abilities, lasers have become the most suitable technology for underwater detection. In all underwater laser applications, the reflected laser pulse which contains the key information for most of the system is highly degraded along the laser’s propagation path and during reflection. This has a direct impact on the system’s performance, especially for single-pixel imaging (SPI) which is very dependent on light-intensity information. Due to the complications in the underwater environment, it is necessary to study the influential factors and their impacts on underwater SPI. In this study, we investigated the influence of the angle of incidence, target distance, and medium attenuation. A systematic investigation of the influential factors on the reflectance and ranging accuracy was performed theoretically and experimentally. The theoretical analysis was demonstrated based on the bidirectional reflection distribution function (BRDF) and laser detection and ranging (LADAR) model. Moreover, 2D single-pixel imaging (SPI) systems were setup for experimental investigation. The experimental results agree well with the theoretical results, which show the system’s dependency on the reflection intensity caused by the angle of incidence, target distance, and medium attenuation. The findings should be a reference for works looking to improve the performance of an underwater SPI system. Full article
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9 pages, 1740 KiB  
Article
Image Encryption and Decryption Systems Using the Jigsaw Transform and the Iterative Finite Field Cosine Transform
by Juan M. Vilardy O., Leiner Barba J. and Cesar O. Torres M.
Photonics 2019, 6(4), 121; https://doi.org/10.3390/photonics6040121 - 26 Nov 2019
Cited by 9 | Viewed by 3311
Abstract
We propose the use of the Jigsaw transform (JT) and the iterative cosine transform over a finite field in order to encrypt and decrypt images. The JT is a nonlinear operation that allows one to increase the security over the encrypted images by [...] Read more.
We propose the use of the Jigsaw transform (JT) and the iterative cosine transform over a finite field in order to encrypt and decrypt images. The JT is a nonlinear operation that allows one to increase the security over the encrypted images by adding new keys to the encryption and decryption systems. The finite field is a finite set of integer numbers where the basic mathematical operations are performed using modular arithmetic. The finite field used in the encryption and decryption systems has an order given by the Fermat prime number 257. The iterative finite field cosine transform (FFCT) was used in our work with the purpose of obtaining images that had an uniform random distribution. We used a security key given by an image randomly generated and uniformly distributed. The JT and iterative FFCT was utilized twice in the encryption and decryption systems. The encrypted images presented a uniformly distributed histogram and the decrypted images were the same original images used as inputs in the encryption system. The resulting decrypted images had a high level of image quality in comparison to the image quality of the decrypted images obtained by the actual optical decryption systems. The proposed encryption and decryption systems have three security keys represented by two random permutations used in the JTs and one random image. The key space of the proposed encryption and decryption systems is larger. The previous features of the security system allow a better protection of the encrypted image against brute force and statistical analysis attacks. Full article
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9 pages, 917 KiB  
Article
Image Processing Operators Based on the Gyrator Transform: Generalized Shift, Convolution and Correlation
by Ronal A. Perez, Juan M. Vilardy O. and Cesar O. Torres M.
Photonics 2019, 6(4), 120; https://doi.org/10.3390/photonics6040120 - 16 Nov 2019
Cited by 4 | Viewed by 3139
Abstract
The gyrator transform (GT) is used for images processing in applications of light propagation. We propose new image processing operators based on the GT, these operators are: Generalized shift, convolution and correlation. The generalized shift is given by a simultaneous application of a [...] Read more.
The gyrator transform (GT) is used for images processing in applications of light propagation. We propose new image processing operators based on the GT, these operators are: Generalized shift, convolution and correlation. The generalized shift is given by a simultaneous application of a spatial shift and a modulation by a pure linear phase term. The new operators of convolution and correlation are defined using the GT. All these image processing operators can be used in order to design and implement new optical image processing systems based on the GT. The sampling theorem for images whose resulting GT has finite support is developed and presented using the previously defined operators. Finally, we describe and show the results for an optical image encryption system using a nonlinear joint transform correlator and the proposed image processing operators based on the GT. Full article
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8 pages, 1477 KiB  
Article
Lithographic Mask Defects Analysis on an MMI 3 dB Splitter
by Paulo Lourenço, Alessandro Fantoni, João Costa and Manuela Vieira
Photonics 2019, 6(4), 118; https://doi.org/10.3390/photonics6040118 - 9 Nov 2019
Cited by 7 | Viewed by 3551
Abstract
In this paper, we present a simulation study that intends to characterize the influence of defects introduced by manufacturing processes on the geometry of a semiconductor structure suitable to be used as a multimode interference (MMI) 3 dB power splitter. Consequently, these defects [...] Read more.
In this paper, we present a simulation study that intends to characterize the influence of defects introduced by manufacturing processes on the geometry of a semiconductor structure suitable to be used as a multimode interference (MMI) 3 dB power splitter. Consequently, these defects will represent refractive index fluctuations which, on their turn, will drastically affect the propagation conditions within the structure. Our simulations were conducted on a software platform that implements the Beam Propagation numerical method. This work supports the development of a biomedical plasmonic sensor, which is based on the coupling between propagating modes in a dielectric waveguide and the surface plasmon mode that is generated on an overlaid metallic thin film, and where the output readout is achieved through an a-Si:H photodiode. By using a multimode interference 1 × 2 power splitter, this sensor device can utilize the non-sensing arm as a reference one, greatly facilitating its calibration and enhancing its performance. As the spectral sensitivity of amorphous silicon is restricted to the visible range, this sensing device should be operating on a wavelength not higher than 700 nm; thus, a-SiNx has been the material hereby proposed for both waveguides and MMI power splitter. Full article
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10 pages, 2320 KiB  
Article
Biofunctionalized Polyelectrolyte Microcapsules Encoded with Fluorescent Semiconductor Nanocrystals for Highly Specific Targeting and Imaging of Cancer Cells
by Galina Nifontova, Daria Kalenichenko, Maria Baryshnikova, Fernanda Ramos Gomes, Frauke Alves, Alexander Karaulov, Igor Nabiev and Alyona Sukhanova
Photonics 2019, 6(4), 117; https://doi.org/10.3390/photonics6040117 - 8 Nov 2019
Cited by 9 | Viewed by 3891
Abstract
Fluorescent semiconductor nanocrystals or quantum dots (QDs) are characterized by unique optical properties, including a high photostability, wide absorption spectrum, and narrow, symmetric fluorescence spectrum. This makes them attractive fluorescent nanolabels for the optical encoding of microcarriers intended for targeted drug delivery, diagnosis, [...] Read more.
Fluorescent semiconductor nanocrystals or quantum dots (QDs) are characterized by unique optical properties, including a high photostability, wide absorption spectrum, and narrow, symmetric fluorescence spectrum. This makes them attractive fluorescent nanolabels for the optical encoding of microcarriers intended for targeted drug delivery, diagnosis, and imaging of transport processes on the body, cellular, and subcellular levels. Incorporation of QDs into carriers in the form of polyelectrolyte microcapsules through layer-by-layer adsorption of oppositely charged polyelectrolyte polymers yields microcapsules with a bright fluorescence signal and adaptable size, structure, and surface characteristics without using organic solvents. The easily modifiable surface of the microcapsules allows for its subsequent functionalization with capture molecules, such as antibodies, which ensures specific and selective interaction with cells, including tumor cells, with the use of the bioconjugation technique developed here. We obtained stable water-soluble nanolabels based on QDs whose surface was modified with polyethylene glycol (PEG) derivatives and determined their colloidal and optical characteristics. The obtained nanocrystals were used to encode polyelectrolyte microcapsules optically. The microcapsule surface was modified with humanized monoclonal antibodies (Abs) recognizing a cancer marker, epidermal growth factor receptor (EGFR). The possibility of effective, specific, and selective delivery of the microcapsules to tumor cells expressing EGFR has been demonstrated. The results show that the QD-encoded polyelectrolyte microcapsules functionalized with monoclonal Abs against EGFR can be used for targeted imaging and diagnosis. Full article
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7 pages, 1140 KiB  
Article
Optical Image Encryption System Using Several Tilted Planes
by Juan M. Vilardy O., Carlos J. Jimenez and Cesar O. Torres M.
Photonics 2019, 6(4), 116; https://doi.org/10.3390/photonics6040116 - 7 Nov 2019
Cited by 6 | Viewed by 3076
Abstract
A well-known technique for optical image encryption is the double random phase encoding (DRPE) technique, which uses two random phase masks (RPMs), one RPM at the input plane of the encryption system and the other RPM at the Fourier plane of the optical [...] Read more.
A well-known technique for optical image encryption is the double random phase encoding (DRPE) technique, which uses two random phase masks (RPMs), one RPM at the input plane of the encryption system and the other RPM at the Fourier plane of the optical system, in order to obtain the encrypted image. In this work, we propose to use tilted planes for the Fourier and the output planes of the optical DRPE encryption system with the purpose of adding two new security keys, which are the angles of the tilted planes. The optical diffraction on a tilted plane is computed using the angular spectrum of plane waves and the coordinate rotation in the Fourier domain. The tilted distributions at the intermediate and output planes of the optical DRPE encryption system are the second RPM and the encrypted image, respectively. The angles of the tilted planes allow improvement to the security of the encrypted image. We perform several numerical simulations with the purpose of demonstrating the validity and feasibility of the proposed image encryption system. Full article
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9 pages, 2613 KiB  
Article
Optical Image Encryption Using a Nonlinear Joint Transform Correlator and the Collins Diffraction Transform
by Juan M. Vilardy O., Ronal A. Perez and Cesar O. Torres M.
Photonics 2019, 6(4), 115; https://doi.org/10.3390/photonics6040115 - 7 Nov 2019
Cited by 7 | Viewed by 3072
Abstract
The Collins diffraction transform (CDT) describes the optical wave diffraction from the generic paraxial optical system. The CDT has as special cases the diffraction domains given by the Fourier, Fresnel and fractional Fourier transforms. In this paper, we propose to describe the optical [...] Read more.
The Collins diffraction transform (CDT) describes the optical wave diffraction from the generic paraxial optical system. The CDT has as special cases the diffraction domains given by the Fourier, Fresnel and fractional Fourier transforms. In this paper, we propose to describe the optical double random phase encoding (DRPE) using a nonlinear joint transform correlator (JTC) and the CDT. This new description of the nonlinear JTC-based encryption system using the CDT covers several optical processing domains, such as Fourier, Fresnel, fractional Fourier, extended fractional Fourier and Gyrator domains, among others. The maximum number of independent design parameters or new security keys of the proposed encryption system using the CDT increases three times in comparison with the same encryption system that uses the Fourier transform. The proposed encryption system using the CDT preserves the shift-invariance property of the JTC-based encryption system in the Fourier domain, with respect to the lateral displacement of both the key random mask in the decryption process and the retrieval of the primary image. The viability of this encryption system is verified and analysed by numerical simulations. Full article
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16 pages, 1034 KiB  
Article
Pupil Function in Pseudophakia: Proximal Miosis Behavior and Optical Influence
by Elsa Fonseca, Paulo Fiadeiro, Renato Gomes, Angel Sanchez Trancon, António Baptista and Pedro Serra
Photonics 2019, 6(4), 114; https://doi.org/10.3390/photonics6040114 - 6 Nov 2019
Cited by 2 | Viewed by 5321
Abstract
The pseudophakic eye lacks the ability to produce a refractive change in response to object proximity. Thus, individual anatomical features such as the pupil size play an important role in achieving functional vision levels. In this work, the range of pupil sizes at [...] Read more.
The pseudophakic eye lacks the ability to produce a refractive change in response to object proximity. Thus, individual anatomical features such as the pupil size play an important role in achieving functional vision levels. In this work, the range of pupil sizes at varying object distance was measured in pseudophakic participants. Furthermore, the impact of the measured values on eye optical quality was investigated using a computer simulation model. A binocular eye-tracker was used to measure the participants’ pupil sizes at six object distances, ranging from 0.33 m (i.e., vergence of 3.00 D) to 3.00 m (i.e., vergence of 0.33 D), while observing a Maltese cross with a constant angular size of 1 . In total, 58 pseudophakic participants were enrolled in this study (age mean ± standard deviation: 70.5 ± 11.3 years). The effects of object distance and age on pupil size variation were investigated using linear mixed effects regression models. Age was found to have a small contribution to individual variability. The mean infinite distance pupil size (intercept) was 4.45 ( 95 % CI: 2.74, 6.17) mm and the mean proximal miosis (slope) was 0.23 ( 95 % CI: −0.53, 0.08) mm/D. The visual acuity (VA) estimation for a distant object ranged from 0.1 logMAR (smallest pupil) to 0.04 logMAR (largest pupil) and the near VA ( 0.33 m) when mean proximal miosis was considered ranged from 0.28 logMAR (smallest pupil) to 0.42 logMAR (largest pupil). When mean distance pupil was considered, proximal miosis individual variability produced a variation of 0.04 logMAR for the near object and negligible variation for the distant object. These results support the importance of distance pupil size measurement for the prediction of visual performance in pseudophakia, while suggesting that proximal miosis has a negligible impact in VA variability. Full article
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10 pages, 3003 KiB  
Article
Photostable Anisometric Lanthanide Complexes as Promising Materials for Optical Applications
by Andrey Knyazev, Maxim Karyakin and Yuriy Galyametdinov
Photonics 2019, 6(4), 110; https://doi.org/10.3390/photonics6040110 - 25 Oct 2019
Cited by 10 | Viewed by 3917
Abstract
Uniform luminescent films with high optical quality are promising materials for modern molecular photonics. Such film materials based on β-diketonate complexes of lanthanides have the following application problem: rapid luminescence degradation under UV radiation, low thermostability, poor mechanical properties, and aggregation propensity. An [...] Read more.
Uniform luminescent films with high optical quality are promising materials for modern molecular photonics. Such film materials based on β-diketonate complexes of lanthanides have the following application problem: rapid luminescence degradation under UV radiation, low thermostability, poor mechanical properties, and aggregation propensity. An alternative approach to solving these problems is the use of anisometric analogues of β-diketonate compounds of lanthanides (III). The main advantage of such compounds is that they do not crystallize because of long hydrocarbon substituents in the structure of complexes, so they can be used to fabricate thin nano-, micro-, and macroscale uniform film materials by a melt-processing technique at relatively low temperatures, as well as by spin-coating. The method of fabrication of microscale luminescent film materials with controlled optical properties from anisometric analogues of Ln(DBM)3Phen and Ln(bzac)3Phen complexes (Ln = Eu, Tb) is proposed in this paper. Within the framework of this research, we developed original films which are highly uniform and transparent. An important advantage of these films is their high photostability and potential for applications as reusable luminescent sensors and light converters. Full article
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11 pages, 5189 KiB  
Article
A Refractive Index Sensor Based on a Fabry–Perot Interferometer Manufactured by NIR Laser Microdrilling and Electric Arc Fusion
by Marta Nespereira, João M. P. Coelho and José M. Rebordão
Photonics 2019, 6(4), 109; https://doi.org/10.3390/photonics6040109 - 24 Oct 2019
Cited by 4 | Viewed by 3603
Abstract
In-line Fabry–Perot cavities manufactured by a new technique using electric arc fusion of NIR laser microdrilled optical fiber flat tips were studied herein for refractive index sensing. Sensors were produced by creating an initial hole on the tip of a standard single-mode telecommunication [...] Read more.
In-line Fabry–Perot cavities manufactured by a new technique using electric arc fusion of NIR laser microdrilled optical fiber flat tips were studied herein for refractive index sensing. Sensors were produced by creating an initial hole on the tip of a standard single-mode telecommunication optical fiber using a Q-switched Nd:YAG laser. Laser ablation and plasma formation processes created 5 to 10 micron cavities. Then, a standard splicing machine was used to fuse the microdrilled fiber with another one, thus creating cavities with lengths around 100 micrometers. This length has been proven to be necessary to obtain an interferometric signal with good fringe visibility when illuminating it in the C-band. Then, the sensing tip of the fiber, with the resulting air cavity, was submitted to several cleaves to enhance the signal and, therefore, its response as a sensor, with final lengths between tens of centimeters for the longest and hundreds of microns for the shortest. The experimental results were analyzed via two signal analysis techniques, fringe visibility and fast Fourier transform, for comparison purposes. In absolute values, the obtained sensitivities varied between 0.31 nm−1/RIU and about 8 nm−1/RIU using the latter method and between about 34 dB/RIU and 54 dB/RIU when analyzing the fringe visibility. Full article
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8 pages, 3098 KiB  
Article
Monitoring of the Mechanism of Mn Ions Incorporation into Quantum Dots by Optical and EPR Spectroscopy
by Yuriy G. Galyametdinov, Dmitriy O. Sagdeev, Andrey A. Sukhanov, Violeta K. Voronkova and Radik R. Shamilov
Photonics 2019, 6(4), 107; https://doi.org/10.3390/photonics6040107 - 19 Oct 2019
Cited by 9 | Viewed by 3261
Abstract
Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis [...] Read more.
Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis of manganese-containing cadmium sulfide or zinc sulfide nanoparticles and their optical and magnetic properties is analyzed. Electron paramagnetic resonance was used to study the distribution of manganese ions in nanoparticles and the intensity of interaction between them depending on the conditions of synthesis of nanoparticles, the concentration of manganese, and the type of initial semiconductor. The increase of manganese concentration is shown to result in the formation of smaller CdS-based nanoparticles. Luminescent properties of nanoparticles were studied. The 580 nm peak, which is typical for manganese ions, becomes more distinguished with the increase of their concentration and the time of synthesis. Full article
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13 pages, 864 KiB  
Article
Objective User Visual Experience Evaluation When Working with Virtual Pixel-Based 3D System and Real Voxel-Based 3D System
by Karola Panke, Tatjana Pladere, Mara Velina, Aiga Svede and Gunta Krumina
Photonics 2019, 6(4), 106; https://doi.org/10.3390/photonics6040106 - 16 Oct 2019
Cited by 1 | Viewed by 3154
Abstract
Volumetric display shows promising implications for healthcare related applications as an innovative technology that creates real three-dimensional (3D) image by illuminating points in three-dimensional space to generate volumetric images without image separation. We used eccentric photorefractometry to objectively study ocular performance in a [...] Read more.
Volumetric display shows promising implications for healthcare related applications as an innovative technology that creates real three-dimensional (3D) image by illuminating points in three-dimensional space to generate volumetric images without image separation. We used eccentric photorefractometry to objectively study ocular performance in a practical environment by evaluating near work-induced refraction shift, accommodative microfluctuations, and pupil size for 38 young adults after viewing anaglyph, and volumetric 3D content for prolonged time. The results of our study demonstrate that participants who performed relative depth estimation task on volumetric 3D content were less likely to experience task-induced myopic refraction shift. For both 3D content types, we observed pupil constriction, that is possibly related to visual fatigue. For anaglyph 3D pupil constriction, onset was observed significantly sooner, compared to volumetric 3D. Overall, sustained work with 3D content, and small disparities or the fully eliminated possibility of accommodation-vergence conflict, not only minimizes near work-induced myopic shift, but also provide beneficial accommodation relaxation that was demonstrated in this study as hypermetropic shift for nearly half of participants. Full article
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8 pages, 2037 KiB  
Article
Evaluation of Nanoplasmonic Optical Fiber Sensors Based on D-Type and Suspended Core Fibers with Metallic Nanowires
by Diego Santos, Ariel Guerreiro and José Manuel Baptista
Photonics 2019, 6(3), 100; https://doi.org/10.3390/photonics6030100 - 13 Sep 2019
Cited by 6 | Viewed by 3023
Abstract
The introduction of metallic nanostructures in optical fibers has revolutionized the field of plasmonic sensors since they produce sharper and fine-tuned resonances resulting in higher sensitivities and resolutions. This article evaluates the performance of three different plasmonic optical fiber sensors based on D-type [...] Read more.
The introduction of metallic nanostructures in optical fibers has revolutionized the field of plasmonic sensors since they produce sharper and fine-tuned resonances resulting in higher sensitivities and resolutions. This article evaluates the performance of three different plasmonic optical fiber sensors based on D-type and suspended core fibers with metallic nanowires. It addresses how their different materials, geometry of the components, and their relative position can influence the coupling between the localized plasmonic modes and the guided optical mode. It also evaluates how that affects the spatial distributions of optical power of the different modes and consequently their overlap and coupling, which ultimately impacts the sensor performance. In this work, we use numerical simulations based on finite element methods to validate the importance of tailoring the features of the guided optical mode to promote an enhanced coupling with the localized modes. The results in terms of sensitivity and resolution demonstrate the advantages of using suspended core fibers with metallic nanowires. Full article
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