https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/ The latest from Physics » Ultrafast & Terahertz Photonics: Publications (tag [THz spectroscopy]) en-GB (C) 2026 University of Warwick Mon, 30 Mar 2026 08:11:42 GMT http://blogs.law.harvard.edu/tech/rss SiteBuilder2, University of Warwick, http://go.warwick.ac.uk/sitebuilder 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 biomedical highlight Lloyd-Hughes MacPherson Milot nanomaterials perovskites photoluminescence review THz components THz imaging THz spectroscopy ultrafast Untagged https://doi.org/10.1063/5.0319459 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Ou2026.jpg?maxWidth=200" alt="Diagram" style="margin-right: 20px;" border="0" align="right" /></p> <p><strong>H. Ou, E. Pickwell-MacPherson</strong> and <strong>J. Lloyd-Hughes</strong> <br />J. Appl. Phys. <strong>139</strong>, 123101 (Mar 2026) <button class="abstractButton" onclick="location.href='https://doi.org/10.1063/5.0319459';">web</button> <button class="abstractButton" onclick="location.href='https://pubs.aip.org/aip/jap/article-pdf/doi/10.1063/5.0319459/20954442/123101_1_5.0319459.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Ou2026')">Show abstract</button></p> <div id="Ou2026" style="display: none;">Generalized ellipsometry can uncover the optical properties of anisotropic materials, in which the light&ndash;matter interaction alters the polarization state. In the terahertz frequency range, generalized ellipsometry has been infrequently realized due to the challenge of rapidly controlling and measuring THz polarization. Here, we report the development and calibration of a high-efficiency terahertz time-domain generalized ellipsometer based on two dual-channel photoconductive antennas. The fiber-coupled multi-pixel devices act as source and detector and achieve a high data throughput with four independent terahertz pulses in a single optical delay scan, without the need for any bulky or slow polarization elements such as polarizers. Following a one-off system calibration, an accurate optical characterization of a uniaxially birefringent Al₂O₃ crystal serves to validate the method. Our technique benefits from efficient data throughput, full polarization-resolved capability, and reduced system complexity, paving the way to in situ and real-time monitoring applications.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1063/5.0319459" data-hide-no-mentions="true"></div> <div><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1063/5.0319459&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> THz spectroscopy THz components MacPherson Lloyd-Hughes 2026 Mon, 30 Mar 2026 08:07:58 GMT 8ac672c59d1fb7fa019d3dc90a5c7a26 https://iopscience.iop.org/article/10.1088/2515-7647/ae4b7a/meta <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Agarwal2026.jpg?maxWidth=150" alt="THz scab" style="margin-right: 10px;" border="0" align="right" /></p> <p class="mb-0"><strong>A. Agarwal</strong> and <strong>E. Pickwell-MacPherson</strong></p> <p>J. Phys. Photonics <strong>8</strong> 011001 <span class="cit-pageRange"> </span>(Mar 2026) <button class="abstractButton" onclick="location.href='https://dx.doi.org/10.1088/2515-7647/ae4b7a';">web</button> <button class="abstractButton" onclick="location.href='https://iopscience.iop.org/article/10.1088/2515-7647/ae4b7a/pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Agarwal2026')">Show abstract</button></p> <div id="Agarwal2026" style="display: none;">Terahertz (THz) sensing has gained significant attention as a non-ionizing modality capable of probing the superficial layers of biological tissue with high sensitivity to water content, structural changes, and biochemical composition. Its strong interaction with water makes it uniquely suited for investigating dermatological applications such as hydration assessment, wound and burn monitoring, and the detection and characterization of skin cancers. However, the shallow penetration depth of THz light, combined with the sensitivity of measurements to probe-skin coupling, contact pressure, and motion artifacts, poses persistent challenges for in vivo use. Overcoming these limitations requires carefully engineered hardware, robust measurement protocols, and advanced computational techniques tailored to biological variability. This article reviews the evolution of THz instrumentation for in vivo skin sensing, spanning early laboratory systems to emerging compact, handheld, robotic, and computationally enhanced platforms. Key developments in probe miniaturization, ergonomic design, and automated control of probe orientation and pressure are described, as these advances directly influence measurement reproducibility and clinical usability. We highlight recent progress in single-pixel imaging, which offers video-rate capabilities, the emergence of waveguide-integrated metamaterial sensors that push spatial resolution far below the diffraction limit, and THz ellipsometry that gives complementary contrast. In addition, we discuss the growing role of data-driven processing, compressed-sensing algorithms, and biophysical modeling in extracting clinically relevant parameters from THz measurements. Although promising, many of the emerging systems remain untested in in vivo dermatological scenarios, and challenges including motion artifacts, calibration stability, and inter-subject variability must be addressed. Continued interdisciplinary work between engineers, physicists, and clinicians is essential for transitioning THz systems toward practical, patient-compliant diagnostic tools.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1088/2515-7647/ae4b7a&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1088/2515-7647/ae4b7a" data-hide-no-mentions="true"></div> THz spectroscopy MacPherson THz imaging biomedical 2026 Mon, 30 Mar 2026 07:58:00 GMT 8ac672c49d3cb3aa019d3dbff27b01be https://www.nature.com/articles/s41467-026-68290-x <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Mou2026.png?maxWidth=150" alt="THz scab" style="margin-right: 10px;" border="0" align="right" /></p> <p class="mb-0"><strong>S. Mou, R.I. Stantchev</strong>, S. Saxena, <strong>H. Ou, S. Rane</strong>, S. Pain, J.D. Murphy, E. Hendry, <strong>J. Lloyd-Hughes</strong> and <strong>E. Pickwell-MacPherson</strong></p> <p>Nature Communications <strong>17</strong> 1571 <span class="cit-pageRange"> </span>(Jan 2026) <button class="abstractButton" onclick="location.href='https://www.nature.com/articles/s41467-026-68290-x';">web</button> <button class="abstractButton" onclick="location.href='https://www.nature.com/articles/s41467-026-68290-x.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Mou2026')">Show abstract</button></p> <div id="Mou2026" style="display: none;">Real-time, non-invasive imaging techniques are essential for advancing biomedical diagnostics and material analysis, yet existing terahertz (THz) systems often suffer from limited speed, bulky designs, and poor adaptability to in situ environments. Addressing these challenges, we present a fully fibre-coupled THz attenuated total internal reflection single-pixel imaging system, offering a compact, flexible, and robust platform for non-destructive spectroscopy and in vivo imaging. This all-fibre architecture enables seamless integration for in situ biomedical applications, including measurements directly on patients. Central to our design is a THz spatial light modulator based on an unpassivated silicon wafer, facilitating high-speed modulation and enabling video-rate imaging with a spatial resolution down to 360 μm. Despite being in the reflection geometry and using fibre-coupled light, our system achieves an imaging throughput exceeding 30,000 pixels per second for 64-by-64 images - over five-fold higher than the state of the art - representing a substantial improvement in real-time THz imaging capabilities.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1038/s41467-026-68290-x&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1038/s41467-026-68290-x" data-hide-no-mentions="true"></div> THz spectroscopy MacPherson Lloyd-Hughes THz imaging biomedical highlight 2026 Wed, 25 Feb 2026 12:24:00 GMT 8ac672c59c8dd0ec019c94c1d08c39b5 https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402011 <div class="news-thumbnail" style="float: left; margin-right: 10px; margin-bottom: 5px;"><img class="thumbnail" width="100" height="100" src="https://warwick.ac.uk/sitebuilder2/file/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications?sbrPage=%2Ffac%2Fsci%2Fphysics%2Fresearch%2Fcondensedmatt%2Fultrafastphotonics%2Fpublications&newsItem=8ac672c59b07d9a6019b1cce8b5e2b05" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Hutchinson2025.png?maxWidth=150" alt="2D-3D" style="margin-right: 10px;" border="0" align="right" /></p> <p class="mb-0"><strong>Jake D. Hutchinson</strong>, Marcin Giza, <strong>Nathaniel P. Gallop</strong>, Benjamin Vella, <strong>Edward Butler-Caddle, Shaoyang Wang, James Lloyd-Hughes,</strong> Pablo Docampo and <strong>Rebecca L Milot</strong></p> <p>Adv. Optical Materials <strong>13</strong> e02011 <span class="cit-pageRange"> </span>(Dec 2025) <button class="abstractButton" onclick="location.href='https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402011';">web</button> <button class="abstractButton" onclick="location.href='https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/adom.202402011';">pdf</button> <button class="abstractButton" onclick="showHide('Hutchinson2025')">Show abstract</button></p> <div id="Hutchinson2025" style="display: none;">The incorporation of Ruddlesden&ndash;Popper (RP)/3D perovskite heterostructures into photovoltaic cells has been shown to increase both the efficiency and stability of the devices. Here, a series of methylammonium lead triiodide (MAPbI3) thin films treated with varying 2-phenylethylammonium (PEA) concentrations are investigated with static and ultrafast spectroscopic techniques to reveal the mechanisms of the observed performance benefits. Transient absorption spectroscopy is employed to elucidate the effect of a surface RP layer on the excited state of the MAPbI3 films and reveal that several different RP structures are formed and participate in the charge-carrier dynamics. The passivation effects of PEA are investigated with optical pump&ndash;terahertz probe (OPTP) experiments using a variety of excitation conditions to simultaneously probe the surface and bulk recombination dynamics. Fitting models to the OPTP data for each excitation scheme allows the material parameters that govern the ultrafast dynamics to be quantified. It is found that as the PEA concentration increases, the surface recombination velocity exhibits a monotonic decrease, suggesting the RP layer is effective at passivating surface traps. Furthermore, the bulk monomolecular recombination rate is also found to decrease with the addition of PEA, indicating that the benefits of this passivation approach are not limited to the upper surface of the MAPbI3 films.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1002/adom.202402011" data-hide-no-mentions="true"></div> THz spectroscopy Milot perovskites Lloyd-Hughes ultrafast highlight 2025 Sun, 14 Dec 2025 12:20:00 GMT 8ac672c59b07d9a6019b1cce8b5e2b05 https://ieeexplore.ieee.org/document/10982400 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/ben2025.gif?maxWidth=200" alt="Diagram" style="margin-right: 20px;" border="0" align="right" /></p> <p><strong>B.G. Page, J.J. Young, A.I. Hernandez-Serrano, </strong> J. Hardwicke and <strong>E. Pickwell-MacPherson</strong> <br />IEEE Trans. THz Sci. Tech. <strong>15</strong>, 573 (May 2025) <button class="abstractButton" onclick="location.href='https://doi.org/10.1109/TTHZ.2025.3566562';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/ben2025.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Ben2025')">Show abstract</button></p> <div id="Ben2025" style="display: none;">Eczema and psoriasis are two of the most prevalent skin conditions in the United Kingdom. Typically, diagnosis and treatment assessment are evaluated based on qualitative measures such as skin appearance and patient feedback. Thus, there is a need for a robust and quantitative method of assessing treatment efficacy and monitoring improvements in skin condition. Terahertz (THz) sensing is a promising candidate, owing to its nonionising properties and high water sensitivity. However, THz sensing is heavily reliant upon signal processing techniques, in particular deconvolution methods used to extract skin-dependent parameters. Conventionally, double Gaussian deconvolution has been used, however this has been shown to oversmooth data and cause unnecessary signal suppression. In this study, an alternative approach, known as frequency-wavelet domain deconvolution, has been applied to in vivo THz skin measurements obtained in a clinical study. It is shown that this deconvolution method significantly enhances the usable signal, and improves the accuracy of the extracted impulse response function.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1109/TTHZ.2025.3566562" data-hide-no-mentions="true"></div> <div><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1109/TTHZ.2025.3566562&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> THz spectroscopy MacPherson biomedical 2025 Fri, 02 May 2025 09:50:00 GMT 8ac672c49809b12801981373f93f6d60 https://pubs.aip.org/aip/app/article/10/5/056101/3345527/Terahertz-harmonic-generation-and-nonlinear <div class="news-thumbnail" style="float: left; margin-right: 10px; margin-bottom: 5px;"><img class="thumbnail" width="100" height="100" src="https://warwick.ac.uk/sitebuilder2/file/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications?sbrPage=%2Ffac%2Fsci%2Fphysics%2Fresearch%2Fcondensedmatt%2Fultrafastphotonics%2Fpublications&newsItem=8ac672c59686280d01968d5587b162e0" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/riccardo2025.jpg?maxWidth=200" alt="Shaping" style="margin-right: 10px;" border="0" align="right" /></p> <p>R. Degli'Innocenti, Y. Lu, A.M. Zaman, <strong>J.M. Woolley, N. Chopra,</strong> W. Tadbier, W. Michailow, S. Hofmann and <strong>J. Lloyd-Hughes</strong> <br />APL Photonics <strong>10</strong> 056101 (May 2025) <button class="abstractButton" onclick="location.href='https://doi.org/10.1063/5.0264305';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/riccardo2025.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('riccardo2025')">Show abstract</button></p> <div id="riccardo2025" style="display: none;">We report on the terahertz (THz) harmonic generation in an active graphene/metamaterial device by using powerful ultrafast table-top THz time-domain spectroscopic systems. Complex nonlinear transmission spectra, comprising even and odd harmonics, emerge when the devices are tested with intense ultrafast THz pulses with peak electric fields in the range of 1&ndash;150 kV/cm. The odd and even harmonic features show a positive correlation with carrier concentration, allowing for efficient frequency tuning on top of tunable group delay dispersion. Interestingly, before the onset of saturation, observed at 20&ndash;25 kV/cm, the main resonance and the harmonic features exhibit an anti-crossing trend that can be further exploited for active frequency tuning. These results report a key milestone for the fundamental investigation of the nonlinearity of 2D materials. At the same time, they represent an important advance in the design of future integrated THz optoelectronics by providing novel functionalities for THz light generation and manipulation.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1063/5.0264305&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1063/5.0264305" data-hide-no-mentions="true"></div> THz spectroscopy nanomaterials Lloyd-Hughes 2025 Thu, 01 May 2025 19:31:00 GMT 8ac672c59686280d01968d5587b162e0 https://pubs.acs.org/doi/10.1021/acsphotonics.4c01934 <div class="news-thumbnail" style="float: left; margin-right: 10px; margin-bottom: 5px;"><img class="thumbnail" width="100" height="100" src="https://warwick.ac.uk/sitebuilder2/file/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications?sbrPage=%2Ffac%2Fsci%2Fphysics%2Fresearch%2Fcondensedmatt%2Fultrafastphotonics%2Fpublications&newsItem=8ac672c79445486c01945eda80b15aad" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/chopra2025.png?maxWidth=200" alt="Shaping" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>N. Chopra</strong> and <strong>J. Lloyd-Hughes</strong> <br />ACS Photonics <strong>12</strong> 917 <span class="citation_volume"></span><strong><span class="cit-volume"></span></strong><span class="cit-issue"> </span><span class="cit-pageRange"></span><strong><span class="citation_volume"></span></strong> (Jan 2025) <button class="abstractButton" onclick="location.href='https://pubs.acs.org/doi/10.1021/acsphotonics.4c01934';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/chopra2025.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('chopra2025')">Show abstract</button></p> <div id="chopra2025" style="display: none;">A dual-beam THz spectrometer is reported that substantially reduces the influence of systematic errors in THz time-domain spectroscopy such as those caused by variations in femtosecond laser power or the environmental temperature and humidity. Dual THz beams with single-cycle waveforms were generated simultaneously using a dual-pixel interdigitated photoconductive antenna, allowing the simultaneous acquisition of sample and reference data in the spectrometer using the same optical components. A low-aberration optical geometry ensured diffraction-limited spatial profiles for both beams despite their off-axis propagation and was validated experimentally by measuring frequency-dependent beam profiles and theoretically via physical optics calculations. Although the experimental amplitudes and absolute phase spectra of both beams were very similar, we further provided a correction procedure to eliminate these small differences. The robustness of the dual-beam spectrometer design was evaluated by measuring the complex transmission of a thin plastic sheet after intentionally introducing a change in the relative humidity of the THz beam path. The dual-beam THz spectrometer was effective at removing systematic errors in the amplitude and phase by simultaneously measuring the two THz beams under the same conditions.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1021/acsphotonics.4c01934&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1021/acsphotonics.4c01934" data-hide-no-mentions="true"></div> THz spectroscopy THz components Lloyd-Hughes 2025 Mon, 13 Jan 2025 08:49:00 GMT 8ac672c79445486c01945eda80b15aad https://pubs.acs.org/doi/10.1021/acs.langmuir.4c03103 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Goncalo2024.gif?maxWidth=50" alt="Diagram" style="margin-right: 20px;" border="0" align="right" /></p> <p><strong>G. Costa, </strong> E.M. Brogden, <strong>J.J. Young, H. Ou, A.I. Hernandez-Serrano, R. I. Stantchev,</strong> Stefan A.F. Bon and <strong>E. Pickwell-MacPherson</strong> <br />Langmuir <strong>40</strong>, 25023 (Nov 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1021/acs.langmuir.4c03103';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Goncalo2024.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Goncalo2024')">Show abstract</button></p> <div id="Goncalo2024" style="display: none;">The dynamics of the drying process of polymer latexes after casting as a wet film onto a substrate are important to track as they influence the physical and mechanical properties and performance of the dried polymer films. Current methods used to follow this drying process include gravimetric analysis, coupled with advanced techniques like GARField-NMR or optical coherence tomography. The latter two methods provide height and spatial information in the z-direction, normal to the substrate, and occasionally in the xz- or yz-planes. Terahertz time-domain spectroscopy (THz-TDS) is a welcome addition as it provides both the structural and spectroscopic information in the parallel xy-plane, filling the geometric gap. Herein, we utilize THz-TDS to study the drying and film formation process of various polymer latexes with a broad range of glass transition temperatures. We showcase the applicability of this technique in obtaining 2D parallel hydration maps of the drying dispersions, in the form of droplets, using latex-dependent calibration lines. Our findings display known phenomena arising from the drying of the colloidal dispersions.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1021/acs.langmuir.4c03103" data-hide-no-mentions="true"></div> <div><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1021/acs.langmuir.4c03103&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> THz spectroscopy MacPherson 2024 highlight Wed, 13 Nov 2024 13:45:00 GMT 8ac672c7980c09a70198134e2fe4222e https://opg.optica.org/boe/fulltext.cfm?uri=boe-15-9-5180&id=554566 <div class="news-thumbnail" style="float: left; margin-right: 10px; margin-bottom: 5px;"><img class="thumbnail" width="100" height="100" src="https://warwick.ac.uk/sitebuilder2/file/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications?sbrPage=%2Ffac%2Fsci%2Fphysics%2Fresearch%2Fcondensedmatt%2Fultrafastphotonics%2Fpublications&newsItem=8ac672c7980c09a701981346b7fe2215" alt="image"></div><p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/xuefei2024.jpg?maxWidth=200" alt="Diagram" style="margin-right: 20px;" border="0" align="right" /></p> <p><strong>X. Ding, A.I. Hernandez-Serrano, J.J. Young and E. Pickwell-MacPherson</strong> <br />Biomedical Optics Express <strong>15</strong>, 5180 (Aug 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1364/BOE.527731';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/Arturo2024b.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('Xuefei2024')">Show abstract</button></p> <div id="Xuefei2024" style="display: none;">The skin, being the body’s largest organ, plays a pivotal role in protecting the body against dangerous external factors. The maintenance of adequate hydration levels is essential for the skin to fulfill this protective function. However, skin hydration depends upon different biophysical factors and lifestyles, such as ethnicity, sex, age, water consumption, and many more. Consequently, methods to assess skin hydration in a precise and non-invasive manner are in high demand. In this paper, using a portable and handheld terahertz (THz) probe, we systematically examine the correlation between diverse biophysical factors and skin hydration profile in a population exceeding 300 participants. Through comparative analysis of THz light reflected from the skin against a dielectric model, we successfully extracted the thickness and hydration percentage of the outermost layer of the epidermis, the stratum corneum (SC). Our findings indicate that SC hydration and thickness are associated with variables such as daily water consumption, age, drinking coffee, and exercise. Additionally, our measurements reveal distinctions in the skin’s hydration properties concerning susceptibility to UV-induced effects by bringing in the Fitzpatrick skin types. This THz-based technique holds the potential for facile integration into clinical settings for the evaluation and diagnosis of various skin-related conditions.</div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1364/BOE.527731" data-hide-no-mentions="true"></div> <div><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1364/BOE.527731&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> THz spectroscopy MacPherson 2024 biomedical Tue, 13 Aug 2024 12:45:00 GMT 8ac672c7980c09a701981346b7fe2215 https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.22.024013 <p><img src="https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/butler-caddle2024.png?maxWidth=300" alt="Charge transport layers" style="margin-right: 10px;" border="0" align="right" /></p> <p><strong>E. Butler-Caddle,</strong> K.D.G.I. Jayawardena, A. Wijesekara, <strong>R.L. Milot</strong> and <strong>J. Lloyd-Hughes</strong> <br />Phys. Rev. Applied <span class="citation_volume"></span><strong>22<span class="cit-volume"></span></strong><span class="cit-issue"> </span><span class="cit-pageRange">024103</span><strong><span class="citation_volume"></span></strong> (Aug 2024) <button class="abstractButton" onclick="location.href='https://doi.org/10.1103/PhysRevApplied.22.024013';">web</button> <button class="abstractButton" onclick="location.href='https://warwick.ac.uk/fac/sci/physics/research/condensedmatt/ultrafastphotonics/publications/butler-caddle2024.pdf';">pdf</button> <button class="abstractButton" onclick="showHide('butler-caddle2024')">Show abstract</button></p> <div id="butler-caddle2024" style="display: none;">In perovskite solar cells, photovoltaic action is created by charge transport layers (CTLs) either side of the light-absorbing metal halide perovskite semiconductor. Hence, the rates for desirable charge extraction and unwanted interfacial recombination at the perovskite-CTL interfaces play a critical role for device efficiency. Here, the electrical properties of perovskite-CTL bilayer heterostructures are obtained using ultrafast terahertz and optical studies of the charge carrier dynamics after pulsed photoexcitation, combined with a physical model of charge carrier transport that includes the prominent Coulombic forces that arise after selective charge extraction into a CTL, and cross-interfacial recombination. The charge extraction velocity at the interface and the ambipolar diffusion coefficient within the perovskite are determined from the experimental decay profiles for heterostructures with three of the highest-performing CTLs, namely C60, PCBM and Spiro-OMeTAD. Definitive targets for the further improvement of devices are deduced: fullerenes deliver fast electron extraction, but suffer from a large rate constant for cross-interface recombination or hole extraction. Conversely, Spiro-OMeTAD exhibits slow hole extraction but does not increase the perovskite’s surface recombination rate, likely contributing to its success in solar cell devices.</div> <div align="left"><img src="https://api.elsevier.com/content/abstract/citation-count?doi=10.1103/PhysRevApplied.22.024013&amp;httpAccept=image%2Fjpeg&amp;apiKey=23942728d429d8cd622400c4a7485a23" border="0" /></div> <div class="altmetric-embed" data-badge-popover="right" data-badge-type="2" data-doi="10.1103/PhysRevApplied.22.024013" data-hide-no-mentions="true"></div> THz spectroscopy photoluminescence Milot 2024 perovskites Lloyd-Hughes ultrafast Tue, 06 Aug 2024 15:12:00 GMT 8a17841a9126f10e0191283fcb962d6c