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Nature Communications Jun 2024Optical spatiotemporal vortices with transverse photon orbital angular momentum (OAM) have recently become a focal point of research. In this work we theoretically and...
Optical spatiotemporal vortices with transverse photon orbital angular momentum (OAM) have recently become a focal point of research. In this work we theoretically and experimentally investigate optical spatiotemporal vortices with radial and azimuthal quantum numbers, known as spatiotemporal Laguerre-Gaussian (STLG) wavepackets. These 3D wavepackets exhibit phase singularities and cylinder-shaped edge dislocations, resulting in a multi-ring topology in its spatiotemporal profile. Unlike conventional ST optical vortices, STLG wavepackets with non-zero and values carry a composite transverse OAM consisting of two directionally opposite components. We further demonstrate mode conversion between an STLG wavepacket and an ST Hermite-Gaussian (STHG) wavepacket through the application of strong spatiotemporal astigmatism. The converted STHG wavepacket is de-coupled in intensity in space-time domain that can be utilized to implement the efficient and accurate recognition of ultrafast STLG wavepackets carried various and This study may offer new insights into high-dimensional quantum information, photonic topology, and nonlinear optics, while promising potential applications in other wave phenomena such as acoustics and electron waves.
PubMed: 38937504
DOI: 10.1038/s41467-024-49819-4 -
Scientific Reports Jun 2024Aiming to extend the scope of utilizing glass in radiation shielding, this work investigates the radiation interaction response of a borate-based glass system. Four...
Aiming to extend the scope of utilizing glass in radiation shielding, this work investigates the radiation interaction response of a borate-based glass system. Four borate-glass samples of different substituting concentrations of calcium oxide ( )BO: NaO AlO BaO: CaO were prepared. To assess the shielding performance of the prepared glass samples, a high-purity germanium detector and different radioactive sources (different energies) were used. Via the narrow beam method, the linear attenuation coefficients (LACs) were experimentally measured. So, the transmission factor (TF), the half-value layer (HVL), the tenth value layer (TVL), the mean free path (MFP), and the radiation protection efficiency (RPE) were calculated for all prepared samples. It was observed that the increase of the concentration of calcium oxide in the proposed borate-based glass samples leads to improve their performance in shielding against radiation. At low energy, the RPE of the samples is almost 100%. However, it was observed that as energy of the radiation source increases, the shielding performance of the samples will decrease. High energy dependence was found when calculating TF, HVL, TVL, and MFP. They were increased with the increase of the energy of the incident photons. At 0.662 MeV, the TF values are equal to 79.26, 79.00, 79.72, and 78.43% for BNABC-1, BNABC-2, BNABC-3, and BNABC-4 in the same oder, respectively. The application of the proposed composition of borate-based glass as a transparent shield against low-energy ionizing radiation was highlighted.
PubMed: 38937501
DOI: 10.1038/s41598-024-63329-9 -
Nature Communications Jun 2024Recently there has been growing interest in using photonics to perform the linear algebra operations of neuromorphic and quantum computing applications, aiming at...
Recently there has been growing interest in using photonics to perform the linear algebra operations of neuromorphic and quantum computing applications, aiming at harnessing silicon photonics' (SiPho) high-speed and energy-efficiency credentials. Accurately mapping, however, a matrix into optics remains challenging, since state-of-the-art optical architectures are sensitive to fabrication imperfections. This leads to reduced fidelity that degrades as the insertion losses of the optical matrix nodes or the matrix dimensions increase. In this work, we present the experimental deployment of a 4 × 4 coherent crossbar (Xbar) as a silicon chip and validate experimentally its theoretically predicted fidelity restoration credentials. We demonstrate the experimental implementation of 10,000 arbitrary linear transformations achieving a record-high fidelity of 99.997% ± 0.002, limited mainly by the measurement equipment. Our work represents an integrated optical circuit providing almost unity and loss-independent fidelity in the realization of arbitrary matrices, highlighting light's credentials in resolving complex computations.
PubMed: 38937494
DOI: 10.1038/s41467-024-49768-y -
Scientific Data Jun 2024This data descriptor elaborates the details of a high-resolution digital bathymetric elevation model generated for the region, namely, Adam's Bridge, which encompasses a...
This data descriptor elaborates the details of a high-resolution digital bathymetric elevation model generated for the region, namely, Adam's Bridge, which encompasses a chain of shoals between Rameswaram Island, off the southeastern coast of Tamil Nadu, India, and Mannar Island, off the northwestern coast of Sri Lanka. The proposed dataset has taken advantage of the photon penetrability in the shallow waters by the green laser of ICESat-2 LiDAR to derive the seabed topography. Seafloor depths from ~0.2 million geolocated photons of ICESat-2 for the study area were accrued and interpolated to generate a 10 m digital bathymetric elevation model. Adam's Bridge, an isthmus and submerged reefal assemblage in shallow and super-shallow waters, is a feature of scientific curiosity. Our dataset has the potential to enhance the understanding of Adam's Bridge structure by providing substantial information to reconstruct its evolution.
PubMed: 38937490
DOI: 10.1038/s41597-024-03550-3 -
Nature Communications Jun 2024Heat shuttling phenomenon is characterized by the presence of a non-zero heat flow between two bodies without net thermal bias on average. It was initially predicted in...
Heat shuttling phenomenon is characterized by the presence of a non-zero heat flow between two bodies without net thermal bias on average. It was initially predicted in the context of nonlinear heat conduction within atomic lattices coupled to two time-oscillating thermostats. Recent theoretical works revealed an analog of this effect for heat exchanges mediated by thermal photons between two solids having a temperature dependent emissivity. In this paper, we present the experimental proof of this effect using systems made with composite materials based on phase change materials. By periodically modulating the temperature of one of two solids we report that the system akin to heat pumping with a controllable heat flow direction. Additionally, we demonstrate the effectiveness of a simultaneous modulation of two temperatures to control both the strength and direction of heat shuttling by exploiting the phase delay between these temperatures. These results show that this effect is promising for an active thermal management of solid-state technology, to cool down solids, to insulate them from their background or to amplify heat exchanges.
PubMed: 38937478
DOI: 10.1038/s41467-024-49802-z -
Nature Communications Jun 2024In 1971, Zel'dovich predicted the amplification of electromagnetic (EM) waves scattered by a rotating metallic cylinder, gaining mechanical rotational energy from the...
In 1971, Zel'dovich predicted the amplification of electromagnetic (EM) waves scattered by a rotating metallic cylinder, gaining mechanical rotational energy from the body. This phenomenon was believed to be unobservable with electromagnetic fields due to technological difficulties in meeting the condition of amplification that is, the cylinder must rotate faster than the frequency of the incoming radiation. Here, we measure the amplification of an electromagnetic field, generated by a toroid LC-circuit, scattered by an aluminium cylinder spinning in the toroid gap. We show that when the Zel'dovich condition is met, the resistance induced by the cylinder becomes negative implying amplification of the incoming EM fields. These results reveal the connection between the concept of induction generators and the physics of this fundamental physics effect and open new prospects towards testing the Zel'dovich mechanism in the quantum regime, as well as related quantum friction effects.
PubMed: 38937453
DOI: 10.1038/s41467-024-49689-w -
Photochemical & Photobiological... Jun 2024We reported herein the synthesis, characterization of hybrid conjugates composed of phthalimide (Phth) and acridine-1,8-diones (Acr) for optical and medical...
We reported herein the synthesis, characterization of hybrid conjugates composed of phthalimide (Phth) and acridine-1,8-diones (Acr) for optical and medical applications. For the synthetic procedure, a three-step synthetic strategy has been utilized. The optical properties of the examined 1,8-acridinedione-phthalimide connected molecules (AcrPhth 1-5) have been examined utilizing various spectroscopic techniques, e.g., steady-state absorption and fluorescence, and time-correlated single photon counting. The steady-state absorption studies showed that AcrPhth 1-5 absorbs the light in the UV and visible region. The fluorescence studies of AcrPhth 1-5 exhibited significant fluorescence quenching compared to the acridinedione control compounds (Acr 1-5) suggesting the occurrence of electron-transfer reactions from the electron donating acridinedione moiety (Acr) to the electron accepting phthalimide moiety (Phth). The rate and efficiency of the electron-transfer reactions were determined from the fluorescence lifetime measurements indicating the fast electron-transfer processes of the covalently connected AcrPhth 1-5 conjugates. Computational studies supported the intramolecular electron-transfer reaction of AcrPhth conjugates using ab initio B3LYP/6-311G methods. In the optimized structures, the HOMO was found to be entirely located on the Acr entity, while the LUMO was found to be entirely on the Phth entity. Further, the synthesized compounds were tested as photosensitizers for generating the singlet oxygen species, which is a key factor in the photodynamic therapy (PDT) applications. The nanosecond laser flash measurements enable us to detect the triplet-excited states of examined Acr and AcrPhth conjugates, determining the triplet quantum yields, and direct detecting the singlet oxygen in an accurate way. From this observation, the singlet quantum yields were found to be in the range of 0.12-0.27 (for Acr 1-5) and 0.07-0.19 (for AcrPhth 1-5 conjugates). The molecular docking studies revealed that compound AcrPhth 2 exhibited high binding affinity with for key genes (p53, TOP2B, p38, and EGFR) suggesting its potential as a targeted anticancer therapy.
PubMed: 38937393
DOI: 10.1007/s43630-024-00603-9 -
International Journal of Radiation... Jun 2024Pencil-beam scanning proton therapy has been considered as a potential modality for the 3D form of spatially-fractionated-radiation-therapy called lattice therapy....
PURPOSE
Pencil-beam scanning proton therapy has been considered as a potential modality for the 3D form of spatially-fractionated-radiation-therapy called lattice therapy. However, few practical solutions have been introduced in the clinic. Existing limitations include degradation in plan quality and robustness when using single-field versus multifield lattice plans, respectively. We propose a practical and robust proton lattice (RPL) planning method using multifield and evaluate its dosimetric characteristics compared to clinically acceptable photon lattice plans.
METHODS
Seven cases previously treated with photon lattice therapy were used to evaluate a novel RPL planning technique using two-orthogonal beams: a primary beam (PB) and a robust complementary beam (RCB) that deliver 67% and 33%, respectively, of the prescribed dose to vertices inside the gross-target-volume (GTV). Only RCB is robustly optimized for setup and range uncertainties. The number and volume of vertices, peak-to-valley dose ratios (PVDRs), and volume of low dose to GTV of proton and photon plans were compared. The RPL technique was then used in treatment of two patients and their dosimetric parameters are reported.
RESULTS
The RPL strategy was able to achieve the clinical planning goals. Compared to previously-treated photon plans, the average number of vertices increased by 30%, average vertex volume by 49% (18.2±25.9cc vs. 12.2±14.5cc, P=0.21), and higher PVDR (10.5±4.8 vs. 2.5±0.9, P<0.005) was achieved. In addition, RPL plans show more conformal dose with less low-dose to GTV (V30%: 60.9±7.2% vs. 81.6±13.9% and V10%: 88.3±4.5% vs. 98.6±3.6% [P<0.01]). The RPL plan for two treated patients showed PVDRs of 4.61 and 14.85 with vertices-to-GTV ratios of 1.52% and 1.30%, respectively.
CONCLUSION
A novel RPL planning strategy using a pair of orthogonal beams was developed and successfully translated to the clinic. The proposed method can generate better quality plans, a higher number of vertices, and higher PVDRs than currently used photon lattice plans.
PubMed: 38936634
DOI: 10.1016/j.ijrobp.2024.06.009 -
Cryobiology Jun 2024Isochoric (constant-volume or volumetrically confined) vitrification has shown potential as an alternative cryopreservation-by-vitrification technique, but the complex...
Isochoric (constant-volume or volumetrically confined) vitrification has shown potential as an alternative cryopreservation-by-vitrification technique, but the complex processes at play within the chamber are yet poorly characterized, and recent investigations have prompted significant debate around whether a truly isochoric vitrification process (in which the liquid remains completely confined by solid boundaries) is indeed feasible. Based on a recent thermomechanical simulation of a high-concentration MeSO solution, Solanki and Rabin (Cryobiology, 2023, 111, 9-15.) argue that isochoric vitrification is not feasible, because differential thermal contraction of the solution and container will necessarily drive generation of a cavity, corrupting the rigid confinement of the liquid. Here, we provide direct experimental evidence to the contrary, demonstrating cavity-free isochoric vitrification of a ∼3.5M vitrification solution by combined isochoric pressure measurement (IPM) and photon-counting x-ray computed tomography (PC-CT). We hypothesize that the absence of a cavity is due to the minimal thermal contraction of the solution, which we support with additional volumetric analysis of the PC-CT reconstructions. In total, this study provides experimental evidence both demonstrating the feasibility of isochoric vitrification and highlighting the potential of designing vitrification solutions that exhibit minimal thermal contraction.
PubMed: 38936595
DOI: 10.1016/j.cryobiol.2024.104935 -
Spectrochimica Acta. Part A, Molecular... Jun 2024In this article, the structural and nonlinear optical behaviour of a chalcone derivative, (2E)-1-(4-ethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one have been studied....
Augmenting the effect of solvents on optical nonlinearity by spectroscopic, DFT, solvatochromism and z-scan studies of push-pull chalcone: (2E)-1-(4-ethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one.
In this article, the structural and nonlinear optical behaviour of a chalcone derivative, (2E)-1-(4-ethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one have been studied. FT-IR, FT-Raman, and NMR spectroscopy were analyzed to validate the molecular structure. To predict the nonlinear optical characteristics of the chalcone, the DFT approach was used and the experimental results were corroborated by the computations. The bathochromic shift is obtained in linear absorbance spectra and is validated using TD-DFT. Also, the broad emission in the blue region demonstrates the blue light emission property of the sample. Using the finite-field method, the dipole moments, polarizability, first-order and second-order hyperpolarizability parameters have been computed. Ground and excited state dipole moments were quantified by solvatochromism. The third-order nonlinear optical characteristics of chalcone in polar and non-polar solvent media were examined using the open/closed-aperture z-scan technique. The chalcone displayed considerable two-photon absorption with a positive nonlinear absorption coefficient and a positive index of refraction due to the self-focussing effect. Furthermore, the optical limiting study manifests that the investigated chalcone might well be favourable for NLO applications.
PubMed: 38936213
DOI: 10.1016/j.saa.2024.124698