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        <title>Frontiers in Photonics | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/photonics</link>
        <description>RSS Feed for Frontiers in Photonics | New and Recent Articles</description>
        <language>en-us</language>
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        <pubDate>2026-04-06T21:42:50.896+00:00</pubDate>
        <ttl>60</ttl>
        <item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2026.1771907</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2026.1771907</link>
        <title><![CDATA[Correlation between forward and backward generated SHG images of biological tissue relating to collagen structure and biomechanics]]></title>
        <pubdate>2026-03-04T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Maryame Boutkhil</author><author>Dale Moulding</author><author>Travis William Sawyer</author><author>Abby Wilson</author>
        <description><![CDATA[Second Harmonic Generation (SHG) microscopy has emerged as a powerful label-free tool for studying collagen microstructure in biological tissues, with increasing interest in the backward-detected signal due to its potential for translation to in vivo imaging contexts. The origin of backward-SHG signal is not fully understood and, as such, interpretation of images remains challenging, as it represents complex optical interactions. This has led to misinterpretations of the collagen structure of biological tissues. Using a custom optical chamber allowing bidirectional SHG imaging of the cornea under controlled pressure, we assessed the spatial relationship between features in backward images and the underlying structural features of collagen in the paired forward images. Collagen waviness (crimp) was identified to be a key structural feature responsible for periodic bands of fluctuating signal intensity in the backward SHG images. Additionally, we demonstrate the potential of SHG imaging for investigating the biomechanical mechanisms relating to collagen and build-upon previous theoretical and experimental frameworks explaining forward and backward signal generation and current limitations in their interpretation.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2026.1696425</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2026.1696425</link>
        <title><![CDATA[Wavelength selection for laser design in mid-infrared spectroscopy]]></title>
        <pubdate>2026-02-18T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Miriam Aledda</author><author>Federico Marini</author><author>Bijay Kafle</author><author>Mehmet C. Erdem</author><author>Pranish Karki</author><author>Kristian H. Liland</author><author>Boris Zimmermann</author><author>Nils K. Afseth</author><author>Alessandra Biancolillo</author><author>Valeria Tafintseva</author><author>Kristin Tøndel</author><author>Volha Shapaval</author><author>Achim Kohler</author>
        <description><![CDATA[The development of miniaturized tunable laser sources for mid-infrared (MIR) spectroscopy has enabled portable, application-specific analytical devices. Recent advances in quantum cascade lasers (QCLs) and interband cascade lasers (ICLs) allow precise wavelength emission in narrow spectral regions, such as 1700–1600 cm−1, which is critical for protein characterization. In this study, we evaluate machine learning techniques for selecting the most informative wavelengths to guide the design of tunable laser systems, and for their ability to account for specific constraints such as the possibility to do fine and coarse laser wavelength tuning. We focus on optimizing variable selection for a laser-based device targeting peptide analysis and protein quality assessment in hydrolysates as a case study. We compare sparse modelling techniques (SPLS), filter-based (SPA, CovSel, g-CovSel), and compression methods (PVS, PVR), and propose a new algorithm (w-CovSel) to assess their ability to reduce noise and isolate key spectral features. Our results highlight the potential of providing data-driven approaches to obtain laser design which enables high-performance MIR instrumentation tailored to specific analytical tasks.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2026.1773615</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2026.1773615</link>
        <title><![CDATA[A perspective of advances in optical methods for biological sample characterization]]></title>
        <pubdate>2026-02-12T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Remy Avila</author><author>Eden Morales-Narváez</author><author>Pablo Loza-Alvarez</author>
        <description><![CDATA[Recent advances in optical methods for biological sample characterization reflect a profound shift driven by the convergence of photonic innovation, computational intelligence, and increasing biological complexity. In this Perspective, we present a concise overview and a forward-looking vision of five core domains that structure this Research Topic: advanced bioimaging technologies, next-generation optical biosensors, optical tweezers for nanoscale force measurements, particle tracking techniques, and artificial intelligence-driven data analysis. Rather than offering an exhaustive review, we highlight selected conceptual and technological developments, identify current limitations, and discuss emerging opportunities where integration across optical modalities and computational approaches may prove decisive. Particular emphasis is placed on multimodal and quantitative platforms, in situ and real-time measurements, high-throughput methodologies, and the growing role of physics-informed and on-the-fly artificial intelligence. By articulating common challenges and shared future directions across these five areas, this article aims to stimulate interdisciplinary dialogue, provide a unifying framework for the contributions collected in this Research Topic, and encourage further advances in optical technologies for probing complex biological systems.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2026.1714572</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2026.1714572</link>
        <title><![CDATA[Quantum-biological interface in biosensor design: detecting proteins with electrochemical aptasensor]]></title>
        <pubdate>2026-01-12T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Leonardo Peres Chiaradia Costa</author><author>Marina Ribeiro Batistuti Sawazaki</author><author>Bassam Bachour Junior</author><author>Marcelo Mulato</author>
        <description><![CDATA[Electrochemical biosensors are promising tools for clinical diagnostics, yet challenges remain in extending sensitivity, linear range, and stability, particularly in complex biological matrices. Here, we report an electrochemical aptasensor for dengue NS1 protein detection based on a self-assembled monolayer (SAM) of DNA aptamers, 6-mercapto-1-hexanol, and 6-ferrocenyl-hexanethiol, characterized using electrochemical capacitance spectroscopy (ECS). The aptamer:thiol ratio was optimized, with the 1:50 condition providing the best analytical performance. The platform achieved sensitivities of 0.18% ± 0.02% per decade in PBS and 0.21% ± 0.01% per decade in commercial human serum, within a linear range of 0.01–1,000 ng/mL. Limits of detection were 24.9 ng/mL in PBS and 25.8 ng/mL in serum. Although long-term stability decreased after 7–14 days, the sensor demonstrated robustness in both simple and complex medium. These results confirm the viability of aptamer-based ECS platforms for clinically relevant NS1 detection and represent a step toward integrating quantum-scale concepts into bioelectrochemical sensing.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1685128</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1685128</link>
        <title><![CDATA[Mach–Zehnder interferometers incorporating electrochromic molecules for controlled single-photon detection]]></title>
        <pubdate>2026-01-05T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Francesco Scotognella</author>
        <description><![CDATA[One particularly fruitful research in the fields of integrated photonics, carried out by a good number of physicists and engineers, concerns the study of different types of materials to be used to control the detection of photons, if not just single photons, in interferometers. In a Mach–Zehnder interferometer, which consists of two beam-splitters, two mirrors, and two detectors, a material that can cause a controlled change in the phase of light in one of the two arms of the interferometer consequently allows control of the probability of detection at the two detectors. In this work, we use an electrochromic molecule, N,N′-bis(cysteine)pyromellitic diimide (BCPD), that has a refractive index dependent on the applied electric field. We simulate the single-photon detection probability in a Mach–Zehnder interferometer with direct light transmission and a waveguide-based Mach–Zehnder interferometer, consisting of two 3-dB couplers connected by two optical channel waveguides. With the employment of the non-equilibrium Green’s function formalism, we have simulated the conductance of BCPD. The results could be of interest in quantum communication.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1730347</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1730347</link>
        <title><![CDATA[Photobiomodulation therapy in neuropathic pain: mechanisms, evidence, and future directions]]></title>
        <pubdate>2025-12-19T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Daniel O. Martins</author><author>Igor R. C. Rocha</author><author>Linda R. Watkins</author><author>Marucia Chacur</author>
        <description><![CDATA[Neuropathic pain (NP) is a chronic and disabling condition resulting from injury or disease of the somatosensory system. Characterized by sensory disturbances such as allodynia, hyperalgesia, and spontaneous pain, NP remains a major clinical challenge due to the limited efficacy and significant side effects of conventional pharmacological treatments. In recent years, photobiomodulation therapy (PBMT), also referred to as low-level laser therapy (LLLT), has emerged as a promising non-pharmacological strategy for managing NP. PBMT involves the application of red or near-infrared light to biological tissues, triggering a range of photochemical and photophysical responses that enhance mitochondrial function, reduce oxidative stress, modulate inflammation, and support neural repair. This review provides a comprehensive synthesis of the current evidence on PBMT for NP, integrating mechanistic insights with preclinical findings. We discuss the biological underpinnings of PBMT, including mitochondrial activation via cytochrome c oxidase, modulation of cytokines and oxidative stress markers, and upregulation of neurotrophic factors such as BDNF. Preclinical studies in well-established NP models (e.g., chronic constriction injury, spared nerve injury, diabetic neuropathy) demonstrate consistent analgesic effects and neuroprotective outcomes following both local and remote/systemic PBMT applications. We also highlight key limitations and knowledge gaps in the field, including the need for standardized protocols, greater exploration of remote PBMT strategies, and improved consideration of sex-based responses. Finally, we outline future directions, such as integration with multimodal therapies, personalized dosimetry, and the development of wearable and transcranial PBMT technologies. Together, the existing body of evidence supports PBMT as a safe and potentially effective tool for NP management, while underscoring the need for more rigorous and translational research.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1647467</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1647467</link>
        <title><![CDATA[Light-induced secretion and transformation of neurotransmitter dopamine]]></title>
        <pubdate>2025-10-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Shuanghong Wei</author><author>Chang Liu</author><author>Zuomeng Wu</author><author>Jianmin Si</author><author>Xingxing Huo</author><author>Cailiang Shen</author><author>Yi Zhen</author><author>Dongwei Liu</author><author>Lei Chen</author>
        <description><![CDATA[Dopamine (DA) is one of the most important neurotransmitters in the human body, which is becoming a key breakthrough for addressing myopia, neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease, and mental diseases such as depression and schizophrenia. However, the activity of DA shows diurnal and seasonal variations, which may be due to the influence of solar activity time on the biological clock of the suprachiasmatic nucleus. By irradiating ARPE-19 cells with red and near-infrared light of different wavelengths, we studied and confirmed that the secretion and transformation of the light-induced neurotransmitter DA significantly depend on light wavelength and light dose. LED-chip light sources with emission peaks at 620, 680, 730, 800, and 850 nm and phosphor-converted LED light sources with emission peaks at 710 and 830 nm were used. It was confirmed that both the red and near-infrared light with variant wavelengths and doses can induce DA secretion to some extent. Yet, the concentrations of DA induced by the wideband spectral light of W710 and SW830 are higher than those induced by the narrowband single-LED-chip light and remain relatively stable under variant light doses. Among all the light sources, the model SW830 light source is the best one. This paper proposes a noninvasive way to induce the secretion of neurotransmitter DA and paves a reliable way to treat myopia, neurodegenerative diseases, and other diseases by using the neurotransmitter DA and the basic knowledge of photophysiology.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1634102</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1634102</link>
        <title><![CDATA[Physics inspired neural network for optical property retrieval from diffuse reflectance]]></title>
        <pubdate>2025-09-25T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Mark Witteveen</author><author>Tiziano Natali</author><author>Theo J. M. Ruers</author><author>Behdad Dashtbozorg</author>
        <description><![CDATA[IntroductionOptical property retrieval in diffuse reflectance imaging, like diffuse reflectance spectroscopy (DRS) and hyperspectral imaging (HSI), often involves fitting measured spectra to analytical solutions using approximations such as Diffusion Theory (DT). This method, while accurate, is not always generalizable due to the assumptions inherent in DT and results in non-unique solutions for optical properties and physiological parameters. In addition, it is computationally intensive. Physics-inspired deep learning offers generalizable data descriptions guided by physical principles but requires extensive labelled data, which is hard to obtain, especially in medical contexts.MethodsWe propose a deep learning approach to retrieve physiological parameters from DRS and HSI spectra using DT-simulated training data. The DT-simulated data is synthesised using a range for the optical properties: Blood Volume Fraction (BVF), Saturation, water-fat ratio (WFR), average blood vessel radius (R), scattering amplitude (SA), and scattering slope (SL). The range for these parameters we have extracted from literature.ResultsOur feed-forward neural network achieved median relative errors of 4% and 2% for DRS and HSI, respectively.DiscussionResults suggest that the proposed method is robust and that retrieval of optical properties is possible with similar results to DT but also reducing operation time.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1636398</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1636398</link>
        <title><![CDATA[Absorption, scattering, and refractive index of blood and its components: a review]]></title>
        <pubdate>2025-08-21T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Gennadi Saiko</author><author>Faraz Sadrzadeh-Afsharazar</author><author>Timothy Burton</author><author>Scott Prahl</author><author>Alexandre Douplik</author>
        <description><![CDATA[Blood is a complex biofluid with distinct optical characteristics that underpin a range of diagnostic and monitoring technologies. This review examines the absorption, scattering, and refractive index properties of whole blood and its components across the visible and near-infrared spectrum. Blood’s optical properties are determined primarily by water, hemoglobin, and its encapsulation in red blood cells. Hemoglobins dominate blood’s light absorption in the 400–1,100 nm range, with sharp spectral differences between oxygenated and deoxygenated forms. Scattering in whole blood is primarily due to red blood cells and is influenced by hematocrit, oxygenation, shear rate, and osmolarity. Reduced scattering coefficients are close to 13 cm−1 in the whole visible range of the spectrum, and the anisotropy factor is close to unity, indicating highly forward-directed scattering. While other blood cells (white blood cells and platelets) do not contribute significantly to blood’s optical properties, their scattering properties are used in many biomedical applications. We also highlight the role of the geometry of experiment—including detour, sieve, and self-shielding phenomena—in shaping blood’s optical response. Multiple clinical technologies, such as pulse oximetry, are based on blood’s optical properties. Recently reported discrepancies between consumer and clinical devices highlight the need for more accurate models of blood optics for emerging biomedical and wearable sensing applications.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1638350</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1638350</link>
        <title><![CDATA[Terahertz photoconductive atomic force microscopy of few-layer graphene flakes]]></title>
        <pubdate>2025-08-06T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Erica Fragomeni</author><author>Fritz Berkmann</author><author>Maria Eleonora Temperini</author><author>Leonetta Baldassarre</author><author>Michele Ortolani</author><author>Valeria Giliberti</author><author>Tommaso Venanzi</author>
        <description><![CDATA[Reaching nanometric spatial resolution in terahertz (THz) nanoimaging provides a powerful tool for the characterization of photonic devices. Here, we couple a THz source to a conductive atomic force microscope to measure the THz photo-induced current with nanometric spatial resolution. We aim at measuring the THz photo-induced current of few-layer graphene flakes with a platinum nanometric probe that acts both as THz field-enhancement antenna and as metal counter-electrode that forms a nanojunction. The THz beam is generated at 0.61 THz by an amplifier-multiplier chain. THz photo-induced current signals are detected and compared with the current-voltage characteristics. With this method, we map nanometric charge puddles in few-layer graphene flakes, and observe evidence of THz rectification at the platinum-graphene nanojunction. The local junction characteristic can be used to assess the surface quality of 2D-material flakes.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1637399</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1637399</link>
        <title><![CDATA[Direct polarized luminescence from perovskite superlattices by manipulating transition dipole moment orientation]]></title>
        <pubdate>2025-07-04T00:00:00Z</pubdate>
        <category>Opinion</category>
        <author>Shaohua Yu</author><author>Jin Xu</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1614809</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1614809</link>
        <title><![CDATA[Enhanced surface emission in terahertz quantum cascade lasers using plasma layer assisted photonic crystal waveguides]]></title>
        <pubdate>2025-06-18T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Mingxi Chen</author><author>Tsung-Tse Lin</author><author>Li Wang</author><author>Hideki Hirayama</author><author>Chiko Otani</author>
        <description><![CDATA[Introduction:Surface-emitting terahertz quantum cascade lasers (THz QCLs) are highly promising for applications requiring high-quality far-field beams and controlled beam divergence. However, limited brightness and output power in conventional surface-emitting designs remain significant barriers to practical implementation. Although photonic crystal structures and distributed Bragg reflectors have been explored to enhance surface emission, intrinsic limitations in emission area scaling and brightness improvement persist. Thus, new strategies are essential to advance the performance of surface-emitting THz QCLs.Methods:This study proposes a plasma-assisted photonic crystal waveguide design to improve surface emission efficiency in THz QCLs. A three-dimensional TM-mode coupled wave theory (3D TM-mode CWT) model was developed, incorporating effective permittivity enhancement and a self-consistent iterative scheme to accurately simulate optical field distribution and interaction within the structure.Results:Simulations reveal that the introduction of a plasma layer effectively disrupts the optical field symmetry characteristic of conventional double-metal waveguides, promoting vertical emission. Through systematic optimization, a plasma layer thickness of 0.8 μm was identified as having the potential to achieve surface emission efficiencies exceeding those of conventional structures by over two orders of magnitude. This enhancement is realized without significantly increasing fabrication complexity.Discussion:The plasma-assisted photonic crystal waveguide design offers a viable pathway toward realizing high-brightness surface-emitting THz QCLs. Although challenges such as material growth control and thermal management remain, the substantial improvement in surface emission efficiency underscores the potential of this approach for future high-performance terahertz applications.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1592919</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1592919</link>
        <title><![CDATA[Editorial: Ocular imaging technology and application]]></title>
        <pubdate>2025-03-26T00:00:00Z</pubdate>
        <category>Editorial</category>
        <author>Xinyu Liu</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1546952</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1546952</link>
        <title><![CDATA[Shortwave infrared spatial frequency domain imaging for detection of changes in tissue hydration]]></title>
        <pubdate>2025-03-17T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Thomas T. Livecchi</author><author>Steven L. Jacques</author><author>Anahita Pilvar</author><author>Darren Roblyer</author><author>Mark C. Pierce</author>
        <description><![CDATA[IntroductionWater and lipid content in biological tissues are important biomarkers for understanding physiological processes and diseases. Spatial frequency domain imaging (SFDI) provides a non-invasive method to quantify these components over a wide field of view. This study introduces an LED-based shortwave infrared (SWIR) SFDI system to measure tissue hydration.MethodsThe system was first validated using water-lipid dilutions of known concentrations. Subsequently, SWIR-SFDI was applied to ex vivo porcine skin undergoing desiccation to observe the relationship between reduced scattering and measured water content changes. Finally, the dorsal hand was imaged in three human subjects before and after exercise to assess changes in tissue induced by perspiration.ResultsFor the water-lipid dilutions, the system accurately predicted chromophore concentrations, validating the approach. In the skin desiccation experiments, small decreases in water content led to pronounced reductions in the reduced scattering coefficient, whereas absorption showed limited sensitivity. In vivo results showed a marked decrease in reduced scattering following exercise, consistent with a loss of tissue hydration.DiscussionThe findings suggest that, under the specific circumstances tested here, the reduced scattering coefficient may be a more sensitive indicator of tissue hydration than absorption. This sensitivity to small changes in water content underscores the potential clinical utility of SWIR SFDI for non-invasive hydration assessment in biological tissues. This technique offers promising applications for clinical diagnostics and physiological monitoring.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1535015</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1535015</link>
        <title><![CDATA[Optical and electrical properties of thiarubrine A simulated via the Hückel method and the nonequilibrium Green’s function]]></title>
        <pubdate>2025-03-13T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Francesco Scotognella</author>
        <description><![CDATA[IntroductionThiarubrine A, a fascinating class of linear carbon chains, can be extracted from certain plants and are known for their photolabile pigment properties.MethodsIn this study, a modified Hückel method to investigate the optical properties of thiarubrine A has been employed, determining its absorption spectrum and wavelength-dependent complex refractive index. Additionally, using the nonequilibrium Green’s function formalism, the conductance of a single thiarubrine A molecule has been derived.Results and discussionLight absorption, complex refractive index dispersion, and conductance of thiarubrine A have been simulated. Exploiting its photolability, a light-induced switch in single-molecule conductance has been demonstrated through ultraviolet-visible irradiation, which produces a photoproduct containing a thiophene group. These findings enhance our understanding of the optical properties of naturally occurring polyynes and highlight their potential applications in single-molecule junctions for nanoelectronics.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1559430</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1559430</link>
        <title><![CDATA[Addressing the need for non-invasive lung assessment with time-resolved diffuse optics]]></title>
        <pubdate>2025-03-10T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Giulia Maffeis</author><author>Nicola Serra</author><author>Alessandro Bossi</author><author>Elisabetta Avanzi</author><author>Alberto Dalla Mora</author><author>Laura Di Sieno</author><author>Rinaldo Cubeddu</author><author>Antonio Pifferi</author><author>Paola Taroni</author>
        <description><![CDATA[Monitoring lungs functions is key for detecting several morbidities and pathologies. Photons in the 600–1,300 nm range might have the potential to reach lungs and provide compositional and functional information. Yet, few optical techniques have been challenged non-invasively so far. In this paper, we investigate the conditions to probe lungs using Time Domain Diffuse Optical Spectroscopy (TD-DOS). Counterintuitively, from Monte Carlo simulations we discovered that a higher absorption coefficient in the chest wall as compared to lungs increases sensitivity to deeper structures. In vivo measurements on the thorax of healthy volunteers during a forced breathing protocol, complemented with information on lung composition and previously evaluated in vivo spectra of porcine lung, suggest that this condition occurs above 1,100 nm. Multiple experimental setups were exploited to cover the 600–1,300 nm spectral range and test different source-detector distances (3–7 cm). All measurements exhibit oscillations consistent with the breathing rhythm, suggesting detection of lung expansion and compression. However, marked differences for different subjects and a complex dependence of the detected signal on the photon time-of-flight seem to allure to a non-trivial role of photon propagation through lungs, related–for instance–to the presence of alveoli and perhaps also to the overlying heterogeneous tissues. The unceasing development of time-resolved single-photon detectors with increasing performances above 1,000 nm, and a better understanding of lung optics–e.g., anomalous diffusion models–will help unravel the information from late, deep-travelling photons and lead to a novel photonic tool to probe the lungs non-invasively.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1548555</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1548555</link>
        <title><![CDATA[Large first hyperpolarizability of the Au@Ag core-shell nanoparticles as compared to the corresponding alloyed nanoparticles resulting from laser annealing]]></title>
        <pubdate>2025-03-03T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Isabelle Russier-Antoine</author><author>Christian Jonin</author><author>Emmanuel Benichou</author><author>Franck Bertorelle</author><author>Pierre-François Brevet</author>
        <description><![CDATA[In this work, the first hyperpolarizability of Aux@Ag100-x core-shell nanoparticles with x the gold molar fraction in percent and the gold core of which is 12 nm in diameter, is determined and compared to that of their corresponding laser annealed nanoparticles using hyper Rayleigh scattering experiments. Laser annealing transforms the initially composite Aux@Ag100-x core-shell nanoparticles into alloyed AuxAg100-x homogeneous nanoparticles, providing a reference for comparison. It is observed that the evolution with the relative molar ratio between gold and silver of the first hyperpolarizability magnitude of both the Aux@Ag100-x core-shell and the alloyed AuxAg100-x nanoparticles is driven by the SPR resonance enhancement occurring at the harmonic wavelength due to red shifting of the SPR band away from the harmonic wavelength. Furthermore, the first hyperpolarizability magnitude of the Aux@Ag100-x core-shell nanoparticles is found to be about three orders of magnitude larger than that of the annealed alloyed AuxAg100-x nanoparticles. This feature may be attributed to the existence of the two nonlinearities, namely, the surface nonlinearity due to the surrounding medium–silver layer interface and the silver–gold metal - metal interface constructively contributing due to their close localization. The core-shell morphology is thus highly beneficial in view of applications as compared to the alloyed one.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1544237</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1544237</link>
        <title><![CDATA[Editorial: Upgraded metallurgical grade silicon: quality, applications, and process economics]]></title>
        <pubdate>2025-02-10T00:00:00Z</pubdate>
        <category>Editorial</category>
        <author>Marisa Di Sabatino</author><author>Bruno Ceccaroli</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fphot.2025.1535133</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fphot.2025.1535133</link>
        <title><![CDATA[3D skin mapping for personalized dermatological treatment]]></title>
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