Photonics

Research

Jump to: Other

10 pages, 2741 KiB

Open AccessArticle

Quantitative Characterization of Age-Related Changes in Peripheral Vessels of a Human Palm Using Raster-Scan Optoacoustic Angiography

by Valeriya Perekatova, Mikhail Kirillin, Svetlana Nemirova, Anna Orlova, Alexey Kurnikov, Aleksandr Khilov, Ksenia Pavlova, Viacheslav Kazakov, Vadim Vildanov, Ilya Turchin and Pavel Subochev

Photonics 2022, 9(7), 482; https://doi.org/10.3390/photonics9070482 - 11 Jul 2022

Cited by 2 | Viewed by 1304

Abstract

The analysis of age-related changes in skin vessels based on optoacoustic angiographic images during the in vivo skin monitoring of healthy volunteers at different ages is reported. As a result of a quantitative analysis of the three-dimensional OA images, the age-associated differences in [...] Read more.

The analysis of age-related changes in skin vessels based on optoacoustic angiographic images during the in vivo skin monitoring of healthy volunteers at different ages is reported. As a result of a quantitative analysis of the three-dimensional OA images, the age-associated differences in the following image parameters were revealed: image intensity, ratio of blood content at different characteristics depths, total vessel length, and number of branches. The reported approach can be effectively employed for automatic assessment and monitoring of age-related vascular changes in the skin and underlying tissues. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

21 pages, 4056 KiB

Open AccessArticle

Combined Non-Invasive Optical Oximeter and Flowmeter with Basic Metrological Equipment

by Andrey Tarasov, Denis Lapitan and Dmitry Rogatkin

Photonics 2022, 9(6), 392; https://doi.org/10.3390/photonics9060392 - 2 Jun 2022

Cited by 3 | Viewed by 1804

Abstract

Optical non-invasive diagnostic methods and equipment are used today in many medical disciplines. However, there is still no generally accepted and unifying engineering theory of such systems. Today, they are developed most empirically and do not always have the desired effectiveness in clinics. [...] Read more.

Optical non-invasive diagnostic methods and equipment are used today in many medical disciplines. However, there is still no generally accepted and unifying engineering theory of such systems. Today, they are developed most empirically and do not always have the desired effectiveness in clinics. Among reasons for their insufficient clinical efficiency, we can claim the limited set of measured parameters, the poorly substantiated technical design parameters, and the lack of metrological certification, which all together lead to large uncertainties and inaccuracies in diagnostic data. The purpose of this study is to develop a new instrument for non-invasive optical oximetry by means of substantiating and creating amore informative tissue oximeter with an enhanced number of measured parameters and equipped with the basic metrological tools—imitational measures. The combination of two related optical diagnostic techniques—a tissue oximetry, including a cerebral one, and a fluctuation flowmetry on a single hardware platform—was used. Theoretical modeling of light transport in tissues was applied to substantiate the main technical design parameters of the device. For each measuring channel, relevant imitation measures for metrological verification and adjustment have been proposed. Some common principles for the operation of such equipment are described in the article, as well. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

16 pages, 4231 KiB

Open AccessArticle

Optical Coherence Tomography Angiography and Attenuation Imaging for Label-Free Observation of Functional Changes in the Intestine after Sympathectomy: A Pilot Study

by Lev Matveev, Elena Kiseleva, Mikhail Baleev, Alexander Moiseev, Maxim Ryabkov, Arseniy Potapov, Evgeniya Bederina, Marina Sirotkina, Vladislav Shalin, Igor Smirnov, Natalia Gladkova and Vladimir Zaitsev

Photonics 2022, 9(5), 304; https://doi.org/10.3390/photonics9050304 - 29 Apr 2022

Cited by 2 | Viewed by 1691

Abstract

We present in this study optical coherence tomography angiography (OCTA) and OCT attenuation imaging (OCTAI) for in vivo non-destructive visualization of intramural blood and lymphatic vessels of the intestine wall. Rabbit small intestine in the norm and after thoracolumbar sympathectomy served as the [...] Read more.

We present in this study optical coherence tomography angiography (OCTA) and OCT attenuation imaging (OCTAI) for in vivo non-destructive visualization of intramural blood and lymphatic vessels of the intestine wall. Rabbit small intestine in the norm and after thoracolumbar sympathectomy served as the object of the intraoperative study. Compared to OCTA real-time imaging, OCTAI takes several minutes and can be termed as “nearly real time”. OCTAI signal processing was modified to take into account the signal-to-noise ratio and the final thickness of the intestine wall. The results showed that, after sympathectomy, changes in functioning of intramural blood and lymphatic vessels were observed with a high statistical significance. The occurrence of trauma-induced constriction of the blood and lymphatic vessels led to an especially pronounced decrease in the length of small-caliber (<30 µm) blood vessels (p < 10⁻⁵), as well as in the volumetric density of lymphatic vessels (on average by ~50%) compared to their initial state. Remarkably, OCTA/OCTAI modalities provide the unique ability for “nearly-instant detection” of changes in functional status of the tissues, long before they become visible on histology. The proposed approach can be used in further experiments to clarify the mechanisms of changes in intestinal blood and lymph flows in response to trauma of the nervous system. Furthermore, potentially it can be used intraoperatively in patients requiring express diagnosis of the state of intramural blood and lymph circulation. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

12 pages, 7132 KiB

Open AccessCommunication

Amplitude Zone Plate in Adaptive Optics: Proposal of the Principle

by Vasily Matkivsky, Alexsandr Moiseev, Pavel Shilyagin and Grigory Gelikonov

Photonics 2022, 9(3), 163; https://doi.org/10.3390/photonics9030163 - 7 Mar 2022

Viewed by 1987

Abstract

One of the main elements in hardware-based adaptive optics systems is a deformable mirror. There is quite a large number of such mirrors based on different principles and exhibiting varying performance. They constitute a significant portion of the cost of the final optical [...] Read more.

One of the main elements in hardware-based adaptive optics systems is a deformable mirror. There is quite a large number of such mirrors based on different principles and exhibiting varying performance. They constitute a significant portion of the cost of the final optical devices. In this study, we consider the possibility of replacing an adaptive mirror with the adaptive amplitude Fresnel zone plate, implemented using a digital light-processing matrix. Since such matrices are widely used in mass industry products (light projectors), their costs in large batches are 1–2 orders of magnitude lower than the cost of inexpensive deformable mirrors. Numerical modeling for scanning an optical coherence tomography system with adaptive optics is presented. It is shown that wavefront distortions with high spatial frequencies and large amplitudes can be corrected using an amplitude Fresnel zone plate. The results are compared with piezoelectric and microelectromechanical system mirrors. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

9 pages, 2717 KiB

Open AccessArticle

Toward Real-Time Giga-Voxel Optoacoustic/Photoacoustic Microscopy: GPU-Accelerated Fourier Reconstruction with Quasi-3D Implementation

by Pavel Subochev, Florentin Spadin, Valeriya Perekatova, Aleksandr Khilov, Andrey Kovalchuk, Ksenia Pavlova, Alexey Kurnikov, Martin Frenz and Michael Jaeger

Photonics 2022, 9(1), 15; https://doi.org/10.3390/photonics9010015 - 29 Dec 2021

Cited by 8 | Viewed by 1640

Abstract

We propose a GPU-accelerated implementation of frequency-domain synthetic aperture focusing technique (SAFT) employing truncated regularized inverse k-space interpolation. Our implementation achieves sub-1s reconstruction time for data sizes of up to 100 M voxels, providing more than a tenfold decrease in reconstruction time as [...] Read more.

We propose a GPU-accelerated implementation of frequency-domain synthetic aperture focusing technique (SAFT) employing truncated regularized inverse k-space interpolation. Our implementation achieves sub-1s reconstruction time for data sizes of up to 100 M voxels, providing more than a tenfold decrease in reconstruction time as compared to CPU-based SAFT. We provide an empirical model that can be used to predict the execution time of quasi-3D reconstruction for any data size given the specifications of the computing system. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

8 pages, 1939 KiB

Open AccessArticle

Simultaneous Enhancement of Contrast and Power of Femtosecond Laser Pulses by Nonlinear Interferometer

by Yasser Nada and Efim Khazanov

Photonics 2021, 8(11), 520; https://doi.org/10.3390/photonics8110520 - 19 Nov 2021

Viewed by 1540

Abstract

We showed that the nonlinear Mach–Zehnder interferometer may be used not only for enhancing temporal contrast, as proposed earlier, but also for increasing pulse power due to efficient pulse compression. The interferometer introduces into the output pulse a nonlinear phase equal to π/2. [...] Read more.

We showed that the nonlinear Mach–Zehnder interferometer may be used not only for enhancing temporal contrast, as proposed earlier, but also for increasing pulse power due to efficient pulse compression. The interferometer introduces into the output pulse a nonlinear phase equal to π/2. This allows increasing laser power by a factor of 1.5 only by means of a chirped mirror. Use of an additional nonlinear plate leads to a multi-fold power increase retaining the contrast enhancement. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

9 pages, 1773 KiB

Open AccessCommunication

Investigation of the Effect of Temperature Stabilization in Radiation–Heat Converters Based on a Strong Absorbing Coating

by Natalia Sapogova, Vladimir Bredikhin, Andrey Afanasiev, Vladislav Kamensky and Nikita Bityurin

Photonics 2021, 8(10), 423; https://doi.org/10.3390/photonics8100423 - 2 Oct 2021

Cited by 3 | Viewed by 1366 | Correction

Abstract

Light–heat converters are promising for further development of contact laser surgery. The simplest converter consists of an optical fiber with a strong absorbing layer at the tip. We studied the time dependence of the tip temperature at different CW laser powers and revealed [...] Read more.

Light–heat converters are promising for further development of contact laser surgery. The simplest converter consists of an optical fiber with a strong absorbing layer at the tip. We studied the time dependence of the tip temperature at different CW laser powers and revealed that, in several seconds, the temperature evolution becomes almost power-independent. Mathematical modeling showed that laser ablation of the tip coating is the main reason for this phenomenon. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

13 pages, 2492 KiB

Open AccessArticle

Thermal, Optical, and IR-Emission Properties of Extremely Low Hydroxyl TeO₂-WO₃-Bi₂O₃-La₂O₃-xEr₂O₃ Glasses for Mid-Infrared Photonics

by Vitaly V. Dorofeev, Vasily V. Koltashev, Sergei E. Motorin, Alexander D. Plekhovich and Arkady V. Kim

Photonics 2021, 8(8), 320; https://doi.org/10.3390/photonics8080320 - 9 Aug 2021

Cited by 9 | Viewed by 2493

Abstract

A series of glass samples of the tungsten–tellurite system TeO₂-WO₃-Bi₂O₃-(4-x) La₂O₃-xEr₂O₃, x = 0; 0.4; 0.5; 0.7; 1.2; 2; 4 mol%, C_Er = 0 - 15 [...] Read more.

A series of glass samples of the tungsten–tellurite system TeO₂-WO₃-Bi₂O₃-(4-x) La₂O₃-xEr₂O₃, x = 0; 0.4; 0.5; 0.7; 1.2; 2; 4 mol%, C_Er = 0 - 15 × 10²⁰ cm⁻³ were synthesized from high-purity oxides in an oxygen flow inside a specialized sealed reactor. In all samples of the series, an extremely low content of hydroxyl groups was achieved (~n × 10¹⁶ cm⁻³, more than 4 orders of magnitude lower than the concentration of erbium ions), which guarantees minimal effects on the luminescence properties of Er³⁺. The glasses are resistant to crystallization up to 4 mol% Er₂O₃, and the glass transition temperatures do not depend on the concentration of erbium oxide when introduced by replacing lanthanum oxide. Thin 0.2 mm plates have high transmittance at a level of 20% in the 4.7–5.3 µm range, and the absorption bands of hydroxyl groups at about 2.3, 3, and 4.4 µm, which are typical for ordinary tellurite glass samples, are indistinguishable. The introduction of erbium oxide led to an insignificant change in the refractive index. Er₂O₃-concentration dependences of the luminescence intensities and lifetimes near the wavelengths of 1.53 and 2.75 μm were found for the ⁴I₁₃_/₂–⁴I₁₅_/₂ and ⁴I₁₁_/2–⁴I₁₃_/_{2 /}transitions of the Er³⁺ ion. The data obtained are necessary for the development of mid-infrared photonics; in particular, for the design of Er³⁺-doped fiber lasers. Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

► Show Figures

Figure 1

Other

Jump to: Research

1 pages, 181 KiB

Open AccessCorrection

Correction: Sapogova et al. Investigation of the Effect of Temperature Stabilization in Radiation–Heat Converters Based on a Strong Absorbing Coating. Photonics 2021, 8, 423

by Natalia Sapogova, Vladimir Bredikhin, Andrey Afanasiev, Vladislav Kamensky and Nikita Bityurin

Photonics 2022, 9(8), 548; https://doi.org/10.3390/photonics9080548 - 5 Aug 2022

Viewed by 719

Abstract

There was an error in the original publication [...] Full article

(This article belongs to the Special Issue Advances in Modern Photonics)

Journal Menu

Journal Browser

Advances in Modern Photonics

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (9 papers)

Research

Other

Further Information

Guidelines

MDPI Initiatives

Follow MDPI