Additional Degrees Research Articles

Extending the spectral operation of multimode and polarization-independent power splitters through subwavelength nanotechnology

Power splitters play a crucial role in virtually all photonic circuits, enabling precise control of on-chip signal distribution. However, state-of-the-art solutions typically present trade-offs in terms of loss, bandwidth, and fabrication robustness, especially when targeting multimode operation. Here, we present a novel multimode 3-dB power splitter based on a symmetric Y-junction assisted by two regions of subwavelength grating metamaterials with different geometries. The proposed device demonstrates high-performance for multimode and dual-polarization operation with relaxed fabrication tolerances by leveraging the additional degrees of freedom offered by two distinct geometries of subwavelength metamaterials to control mode evolution. Our design achieves, to the best of our knowledge, the widest operational bandwidth reported to date for a nanophotonic multimode silicon power splitter. Simulations for a standard 220-nm-thick silicon-on-insulator platform predict minimal excess loss (< 0.2 dB) for the fundamental and the first-order transverse-electric modes over an ultra-broad 700 nm bandwidth (1300 – 2000 nm). For the fundamental transverse–magnetic mode, losses are less than 0.3 dB in the 1300 – 1800 nm range. Experimental measurements validate these predictions in the 1430 – 1630 nm wavelength range, demonstrating losses < 0.4 dB for all three modes, even in the presence of fabrication deviations of up to ± 10 nm. We believe that this device is suitable for the implementation of advanced photonic applications requiring high–-performance distribution of optical signals, such as programmable photonics, multi-target spectroscopy and quantum key distribution.

CuIn (Se,Te)2 Absorbers With Bandgaps &lt;1 eV for Bottom Cells in Tandem Applications

ABSTRACTThin‐film solar cells reach high efficiencies and have a low carbon footprint in production. Tandem solar cells have the potential to significantly increase the efficiency of this technology, where the bottom‐cell is generally composed of a Cu(In,Ga)Se2 absorber layer with bandgaps around 1 eV or higher. Here, we investigate CuIn(Se1 − xTex)2 absorber layers and solar cells with bandgaps below 1 eV, which will bring the benefit of an additional degree of freedom for designing current‐matched two‐terminal tandem devices. We report that CuIn(Se1 − xTex)2 thin films can be grown single phase by co‐evaporation and that the bandgap can be reduced to the optimum range (0.92–0.95 eV) for a bottom cell. From photoluminescence spectroscopy, it is found that no additional non‐radiative losses are introduced to the absorber when adding Te. However, losses occur in the final solar cell due to non‐optimized interfaces. Nevertheless, a device with 9% power conversion efficiency is demonstrated with a bandgap of 0.97 eV and , the highest efficiency so far for chalcopyrites with band gap &lt;1 eV. Interface recombination is identified as a major recombination channel for larger Te contents. Thus, further efficiency improvements can be expected with improved absorber/buffer interfaces.

Musculoskeletal imaging fellowship program directors: A study of educational paths, and scholarly engagement in the United States

PurposeThe overall aim of the study is to analyze and provide a comprehensive understanding of the demographics, educational backgrounds, and scholarly activities of musculoskeletal imaging fellowship program directors across the United States. MethodsA list of all members of the Society of Skeletal Radiology was obtained and musculoskeletal imaging fellowship program directors across the US were included. Publicly available online sources were used to gather demographic and educational information about each musculoskeletal imaging fellowship program director, which included the online curriculum vitae from the program websites, Health Grades, Doximity, and Elsevier's Scopus database. Demographic and educational data including age, gender, educational background (medical school, residency, fellowship), additional degrees, academic rank, prior leadership positions, and metrics of scholarly activity were recorded. Fellowships in diagnostic musculoskeletal radiology along with additional degrees were recorded. A two-tailed unpaired t-test was used to calculate the difference between means of scholarly activity between male and female PDs. ResultsIn this study encompassing 92 programs across the United States, the majority (88) were dedicated to pure Musculoskeletal (MSK) Imaging Fellowship, while one each offered combined training in MSK and Body Imaging, MSK, and Emergency Imaging, MSK Sports, and Interventional Spine, and Pediatric MSK Imaging. Program directors were identified for 90 out of 92 programs, revealing a regional distribution of 29 in the South (31.5 %), 24 in the North East (26.1 %), 20 in the Midwest (21.74 %) and 19 in the West (20.65 %). Gender analysis unveiled a predominantly male representation, with 71 male directors compared to 17 female directors, while age ranged from 30 to 70 years, with a mean age of 47.17 ± 7.4 years. Medical school backgrounds predominantly featured MD degrees (80), followed by IMG (7) and DO (4) degrees, with the most common IMG source being India. Faculty positions were mainly distributed among Assistant Professors (35), Associate Professors (32), and Professors (11). Research output metrics showcased a mean of 41.943 publications and an h-index of 10.625. Extra degrees were obtained by 31 directors, with common additions being other fellowships, MBAs, MS degrees, and PhDs. Notably, some directors held previous or current leadership positions, while a few had completed residencies outside of Radiology or pursued fellowships beyond MSK Imaging. ConclusionMusculoskeletal imaging fellowship program directors across the United States are predominantly male, with approximately 8 % having graduated from international medical schools. The most common training pathway for these directors is completing a diagnostic radiology residency followed by a musculoskeletal radiology fellowship. This study highlighted the gender disparity within this leadership group and emphasized the diverse educational backgrounds that contribute to the field of musculoskeletal imaging.

Cutting corners: hypersphere sampling as a new standard for cosmological emulators

Cosmological emulators of observables such as the Cosmic Microwave Background (CMB) spectra and matter power spectra commonly use training data sampled from a Latin hypercube. This method often incurs high computational costs by covering less relevant parts of the parameter space, especially in high dimensions where only a small fraction of the parameter space yields a significant likelihood. In this paper, we make use of hypersphere sampling, which instead concentrates sample points in regions with higher likelihoods, significantly enhancing the efficiency and accuracy of emulators. A novel algorithm for sampling within a high-dimensional hyperellipsoid aligned with axes of correlation in the cosmological parameters is presented. This method focuses the distribution of training data points on areas of the parameter space that are most relevant to the models being tested, thereby avoiding the computational redundancies common in Latin hypercube approaches. Comparative analysis using the connect emulation tool demonstrates that hypersphere sampling can achieve similar or improved emulation precision with more than an order of magnitude fewer data points and thus less computational effort than traditional methods. This was tested for both the ΛCDM model and a 5-parameter extension including Early Dark Energy, massive neutrinos, and additional ultra-relativistic degrees of freedom. Our results suggest that hypersphere sampling holds potential as a more efficient approach for cosmological emulation, particularly suitable for complex, high-dimensional models.

A microstructural defect-orientation informed phase field model

Micro-cracks, micro-voids and other such defects, which typically coalesce to form macroscopic cracks, could be represented through incompatible, local rotations of material points, i.e. micro-regions. Specifically, based on a micropolar or Cosserat continuum-like hypothesis that requires attaching directors to material points, we track the evolving frame rotation and hence the microstructural orientation during quasi-brittle damage. We introduce a critical energy release rate incorporating the wryness tensor, which in turn is a function of the micro-rotation field and its gradient within the damaged region. The (pseudo) rotation field appears as additional degrees of freedom to describe a frame field, whose evolution is particularly significant within a diffused region of evolving damage as obtained through a phase-field formulation of brittle fracture. We emphasize that, unlike micropolar continua where it contributes to elastic energy, the wryness tensor appears only in the fracture energy in our approach. Thus, without damage, the solid conforms to the classical continuum. By making suitable modifications to the terms within the elastic energy and applying the principle of virtual work, we arrive at the governing partial differential equations (PDEs). For assessing the proposed framework, we choose a specific form of energy density and demonstrate, through numerical examples, the effect of the newly introduced parameters. The classical phase-field model is readily recovered by switching off the micro-rotation. Additionally, we explore a potential application of this model in representing and propagating initial defects.

Femtosecond optical vortex-induced flower-shaped surface relief structures in an azo-polymer film

We study the formation of surface relief structures in azo-polymers generated via two-photon induced photoisomerization using a femtosecond near-infrared optical vortex laser beam. These structures exhibit exotic flower-like shapes with petals along the azimuthal direction, and they are formed from spatial mode instability, which is associated with third-order nonlinear effects in the azo-polymer. This process is a unique and exotic interaction between light and matter, which may be applied to the development of advanced optical data storage technologies. Here, an additional degree of freedom is offered by the number of formed petals, which themselves are a function of the topological charge of the optical vortex beam.

Indication of Sharp and Strong Phase Transitions from NICER Observations

In this Letter, we present a new, weakly model-dependent test for “standard” equation-of-state (EoS) models that disfavor sharp and strong phase transitions by using NS mass and radius observations. We show the radii of two NSs observed by NICER (PSR J0740+6620 and PSR 0030+0451) are correlated if these two NSs are built upon standard EoS models. The radii of NSs with different masses are sensitive to the pressures at different densities, and the pressures at different densities are strongly correlated in standard EoS models. We further show that the correlation of the NS radii can be significantly weakened when additional degrees of freedom concerning the first-order phase transitions are added into the EoSs. We propose a new quantity, D L, which measures the extent to which the linear correlation of the radii of two NSs is weakened. Our method gives a 48% identification probability (with a 5% false alarm rate) of finding beyond-standard EoS models in NICER observations. Future observations with higher measurement accuracy can confirm or rule out this identification. Our method is generalizable to any pair of NS masses and can be employed with other sets of observations in the future.

Interference between multipolar two-photon transitions in quantum emitters near plasmonic nanostructures

In the vicinity of plasmonic nanostructures that support highly confined light fields, spontaneous emission processes, such as two-photon spontaneous emission (TPSE), exhibit higher-order multipolar emission pathways beyond the dipolar one. These multipolar emission channels occur simultaneously and can interfere with each other. We develop a novel framework that computes these interference effects for TPSE of a quantum emitter close to an arbitrary nanostructure. The model is based on the computation of Purcell factors that can be calculated with conventional electromagnetic simulations, which avoids complex analytic calculations for the environment. For a transition of a hydrogen-like emitter close to a graphene nanotriangle, we demonstrate a breakdown of the dipolar selection rule in the TPSE process. This breakdown is due to a huge enhancement of the two-electric dipole (2ED) and of the two-electric quadrupole (2EQ) transitions. We observe an important interference between these multipolar transitions, as it increases the total rate by 67%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$67 \\, \\%$$\\end{document}. In the end, our framework is a complete tool to design emitters and nanostructures for TPSE, where the exploitation of previously ignored interference effects provides an additional degree of freedom, for example to boost desired transitions and to supress undesirable ones.

Sensing signal augmentation by flow rate modulation of carrier gas for accurate differentiation of complex odours

ABSTRACT For olfactory sensors, clear differentiation of complex odour samples requires diverse information. To obtain such information, hardware modifications, such as introducing additional channels with different physical/chemical properties, are usually needed. In this study, we present a new approach to augmenting the sensing signals of an olfactory sensor by modulating the flow rate of the carrier gas. The headspace vapour of complex odours is measured using a sensing system of nanomechanical sensor (Membrane-type Surface stress Sensor, MSS). The resulting data set is quantitatively evaluated using the Davies-Bouldin index (DBI) of principal component analysis (PCA). The increasing number of sensing signals obtained at different gas flow rates leads to a decrease in the DBI, achieving better cluster separation between different odours. Such gas flow effects can be attributed to several factors, including the sample evaporation and the equilibrium of the gas-liquid and gas-solid interfaces. Proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS) experiments reveal that the compositions of odour samples vary with the different gas flow rates. It is demonstrated that a simple technique for modulating gas flow rates can significantly improve the differentiation performance of complex odours, providing an additional degree of freedom in olfactory sensing.

Irreversible Boltzmann samplers in dense liquids: Weak-coupling approximation and mode-coupling theory.

Exerting a nonequilibrium drive on an otherwise equilibrium Langevin process brings the dynamics out of equilibrium but can also speed up the approach to the Boltzmann steady state. Transverse forces are a minimal framework to achieve dynamical acceleration of the Boltzmann sampling. We consider a simple liquid in three space dimensions subjected to additional transverse pairwise forces, and quantify the extent to which transverse forces accelerate the dynamics. We first explore the dynamics of a tracer in a weak coupling regime describing high temperatures. The resulting acceleration is correlated with a monotonous increase of the magnitude of odd transport coefficients (mobility and diffusivity) with the amplitude of the transverse drive. We then develop a nonequilibrium version of the mode-coupling theory able to capture the effect of transverse forces, and more generally of forces created by additional degrees of freedom. Based on an analysis of transport coefficients, both odd and longitudinal, both for the collective modes and for a tracer particle, we find a systematic acceleration of the dynamics. Quantitatively, the gain, which is guaranteed throughout the ergodic phase, turns out to be a decreasing function of temperature beyond a temperature crossover, in particular as the glass transition is approached. Our theoretical results are in good agreement with available numerical results.

Observation of the enhanced dual-split photonic spin Hall effect in wavelength domain via a helical fiber grating

To date, the photonic spin Hall effect (PSHE) has been studied and observed only in the space and momentum domains. Direct observation of the PSHE in the wavelength domain remains unexplored. In this work, we demonstrate both theoretically and experimentally the enhanced PSHE in the wavelength domain via a helical long-period fiber grating (HLPG), where the spin-dependent dual-split in the transmission spectrum of the utilized HLPG has been observed. This is unlike the PSHEs reported thus far, where a mono-splitting of the light is observed in either the space or the momentum domains. The proposed method provides an additional degree of freedom to observe the PSHE, which paves the way for exploiting all fiber-based HLPGs in chiral photonics, chiral sensors, and fine precise measurements.

Altermagnetism Induced by Sliding Ferroelectricity via Lattice Symmetry-Mediated Magnetoelectric Coupling.

Altermagnets, distinct from conventional ferromagnets or antiferromagnets, have recently attracted attention as the third category of collinear magnets, which exhibit the coexistence of zero net magnetization and spin polarization due to their unique lattice symmetries. Meanwhile, the additional layer degrees of freedom in multilayer sliding ferroelectrics offer opportunities for coupling with lattice symmetries, paving the way for an innovative approach to constructing multiferroic lattices. In this study, altermagnetic tuning in SnS2/MnPSe3/SnS2 heterostructures is achieved by breaking and restoration of lattice inversion symmetry through sliding ferroelectric switching. First-principles calculations reveal that the spin density and corresponding time-reversal symmetry of MnPSe3 can be manipulated by lattice symmetry, triggering phase transitions between antiferromagnetism and altermagnetism. This research establishes a novel form of magnetoelectric coupling mediated by lattice symmetry and provides a theoretical basis for the design of miniature information processing and memory devices based on altermagnetism.

Designed Spin-Texture-Lattice to Control Anisotropic Magnon Transport in Antiferromagnets.

Spin waves in magnetic materials are promising information carriers for future computing technologies due to their ultra-low energy dissipation and long coherence length. Antiferromagnets are strong candidate materials due, in part, to their stability to external fields and larger group velocities. Multiferroic antiferromagnets, such as BiFeO3 (BFO), have an additional degree of freedom stemming from magnetoelectric coupling, allowing for control of the magnetic structure, and thus spin waves, with the electric field. Unfortunately, spin-wave propagation in BFO is not well understood due to the complexity of the magnetic structure. In this work, long-range spin transport is explored within an epitaxially engineered, electrically tunable, 1D magnonic crystal. A striking anisotropy is discovered in the spin transport parallel and perpendicular to the 1D crystal axis. Multiscale theory and simulation suggest that this preferential magnon conduction emerges from a combination of a population imbalance in its dispersion, as well as anisotropic structural scattering. This work provides a pathway to electrically reconfigurable magnonic crystals inantiferromagnets.

Spatio-temporal physics-informed neural networks to solve boundary value problems for classical and gradient-enhanced continua

Recent advances have prominently highlighted physics informed neural networks (PINNs) as an efficient methodology for solving partial differential equations (PDEs). The present paper proposes a proof of concept exploring the use of PINNs as an alternative to finite element (FE) solvers in both classical and gradient-enhanced solid mechanics. To this end, spatio-temporal PINNs are designed to represent continuous solutions of boundary value problems within spatio-temporal space. These PINNs directly incorporate the equilibrium and constitutive equations in their differential and rate forms, bypassing the requirement for incremental implementation. This simplifies application of PINNs to solve complex mechanical problems, particularly those involved in the context of gradient-enhanced continua. Moreover, traditional meshing is no longer required as it is replaced by a point cloud, making it possible to overcome meshing drawbacks. The results of this investigation prove the effectiveness of the proposed methodology, especially with regards to non-monotonic loading conditions and irreversible plastic deformation. Compared to classical FE approaches, the proposed spatio-temporal PINNs are more readily applied to complex problems, which are tackled in their raw form. This is especially true for gradient-enhanced continuum problems, where there is no need to introduce additional degrees of freedom as in classical FE approaches. However, PINNs training generally requires more computation time, a challenge that can be mitigated by employing the concept of transfer learning as shown in this paper. This concept, which is very useful when performing parametric studies, involves applying knowledge grained from solving one problem to another different but related one. The use of PINNs as mechanical solvers is shown to be highly promising in the forthcoming era, where advancements in GPU technology can further enhance their performance in terms of computation time.

A novel heterogeneous particle addition method based on laser cladding hybrid wire arc additive manufacturing: improvement performance of stainless steel components

ABSTRACT The direct preparation of large components by laser cladding (LC) is not economical, but if it is used as a means of trace element addition and combined with the high efficiency advantages of wire arc additive manufacturing (WAAM), efficient manufacturing and high degree of freedom design of components can be achieved. In this study, high toughness and high plasticity stainless steel components were successfully prepared by combining WAAM and LC. The microstructure in the hybrid deposited specimens evolved into a single austenite, and the proportion of cubic and {001}<100 > textures increased. The mechanical properties obtained were significantly greater than those recommended for use by ASTM A479. The toughness of the hybrid deposited specimens was significantly improved, with a maximum increase in yield strength of 32%, exceeding 350 MPa. The elongation increased by a maximum of 12.7%, reaching 89.2% in the horizontal direction.

International medical graduates in orthopaedic surgery: An opportunity to improve diversity and inclusion?

Background/aimsRacial and ethnic minorities are under-represented in orthopaedic surgery despite efforts to promote diversity and inclusion in the specialty. The purpose of this study was to determine the proportion of international medical graduates (IMGs) in the surgical workforce and future residency pipeline. We further analyze IMG applicant qualifications relative to their US-based counterparts to assess the viability of recruiting IMG candidates as one strategy to advance diversity and inclusion in orthopaedic surgery. MethodsPhysician workforce data from the American Medical Association and residency match data from the National Resident Match Program were analyzed for Orthopaedic Surgery. Trends in the proportion of IMG applicants were compared with those from other specialties. Qualifications of applicants were compared including board exam scores, number of abstracts/publications, and additional graduate degrees. ResultsIn 2020, orthopaedic surgery had the lowest percentage of IMGs relative to otolaryngology (5.8 %, p < 0.001), neurosurgery (12.1 %, p < 0.001), obstetrics & gynecology (14.0 %, p < 0.001), and general surgery (19.1 %, p < 0.001). From 1986 to 2021, IMG Graduates who matched into orthopaedic surgery increased from 1 (0.3 %) to 8 (0.9 %). Compared to other surgical specialties, orthopaedic surgery had among the lowest annual rates of incoming IMG residents. In 2021, most respondents to the orthopaedic surgery residency program directors survey reported never selecting IMG applicants for interview (74 % for non-US IMG applicants and 53 % for US IMG applicants). From 2020 to 2021, non-US IMG applicants (17 %) and US IMG applicants (26 %) had lower match rates than DO Senior (74 %) and MD Senior (80 %) applicants (p < 0.001). In 2020, matched non-US IMGs had similar board scores as matched US MD Senior applicants, but more abstracts/publications. ConclusionThe recruitment of IMGs into orthopaedic surgery residency remains limited and lower than other surgical specialties. IMGs have similar board scores and more abstracts/publications, thus representing a potential pipeline for workforce diversity. More research is needed to understand the special needs of IMGs in the orthopaedic surgery match.

Cascade Synthesis of Fe-N2-Fe Dual-Atom Catalysts for Superior Oxygen Catalysis.

Dual-atom catalysts (DACs) have been proposed to break the limitation of single-atom catalysts (SACs) in the synergistic activation of multiple molecules and intermediates, offering an additional degree of freedom for catalytic regulation. However, it remains a challenge to synthesize DACs with high uniformity, atomic accuracy, and satisfactory loadings. Herein, we report a facile cascade synthetic strategy for DAC via precise electrostatic interaction control and neighboring vacancy construction. We synthesized well-defined, uniformly dispersed dual Fe sites which were connected by two nitrogen bonds (denoted as Fe-N2-Fe). The as-synthesized DAC exhibited superior catalytic performances towards oxygen reduction reaction, including good half-wave potential (0.91 V), high kinetic current density (21.66 mA cm-2), and perfect durability. Theoretical calculation revealed that the DAC structure effectively tunes the oxygen adsorption configuration and decreases the cleavage barrier, thereby improving the catalytic kinetics. The DAC-based zinc-air batteries exhibited impressive power densities of 169.8 and 52.18 mW cm-2 at 25 °C and -40 °C, which is 1.7 and 2.0 times higher than those based on Pt/C+Ir/C, respectively. We also demonstrated the universality of our strategy in synthesizing other M-N2-M DACs (M=Co, Cu, Ru, Pd, Pt, and Au), facilitating the construction of a DAC library for different catalytic applications.

Environmental permittivity-asymmetric BIC metasurfaces with electrical reconfigurability

Achieving precise spectral and temporal light manipulation at the nanoscale remains a critical challenge in nanophotonics. While photonic bound states in the continuum (BICs) have emerged as a powerful means of controlling light, their reliance on geometrical symmetry breaking for obtaining tailored resonances makes them highly susceptible to fabrication imperfections, and their generally fixed asymmetry factor fundamentally limits applications in reconfigurable metasurfaces. Here, we introduce the concept of environmental symmetry breaking by embedding identical resonators into a surrounding medium with carefully placed regions of contrasting refractive indexes, activating permittivity-driven quasi-BIC resonances (ε-qBICs) without altering the underlying resonator geometry and unlocking an additional degree of freedom for light manipulation through active tuning of the surrounding dielectric environment. We demonstrate this concept by integrating polyaniline (PANI), an electro-optically active polymer, to achieve electrically reconfigurable ε-qBICs. This integration not only demonstrates rapid switching speeds and exceptional durability but also boosts the system’s optical response to environmental perturbations. Our strategy significantly expands the capabilities of resonant light manipulation through permittivity modulation, opening avenues for on-chip optical devices, advanced sensing, and beyond.

A New Sum-Channel Radiating Element for a Patch-Monopole Monopulse Feed

This article describes a new design for the sum-channel, circularly-polarized, radiating patch element of a multimode patch-monopole monopulse feed. Such feeds are suitable for the prime-focus illumination of a deep symmetric reflector. A relatively simple and compact feed design allows for a compact single-mirror antenna with monopulse tracking. The feed is about a wavelength in diameter, also making it suitable for illuminating smaller antennas, for example, in LEO-satellite ground (client) stations. The design applies a slotted circular patch as a circularly-polarized sum-channel element. The design variables are optimized mainly for the sum-channel aperture illumination efficiency in an S-band satellite ground station. After a few cut-and-try iterations, the final feed prototype was produced and measured. In addition to an additional degree of freedom in the geometry and potentially easier fabrication, the new sum-channel radiating-element shape allows for a slightly better monopulse channel isolation, and a higher radiation-pattern symmetry compared to the previous design.

Anisotropic Third Harmonic Generation in 2D Tin Sulfide

AbstractThe in‐plane anisotropic properties of 2D group IV monochalcogenides offer an additional degree of freedom which can be advantageous in optoelectronic applications. Here, it is demonstrated that the third harmonic generation (THG) produced by ultrathin tin (II) sulfide (SnS) is in‐plane anisotropic with respect to the direction of the excitation linear polarization. The polarization‐resolved THG (P‐THG) measurements are described with a nonlinear optics model, which accounts for the orthorhombic crystal structure of the 2D SnS. The relative magnitudes of the χ(3) tensor components are calculated by recording and simultaneously fitting two orthogonal polarization components of the P‐THG signals. Furthermore, the “THG anisotropy ratio” is introduced, which compares the THG intensity produced when the excitation linear polarization is along the armchair crystallographic direction, with the case when it is along the zigzag direction. The experimental findings provide quantitative information on the anisotropic nature of the THG process in various SnS flakes. Nonlinear anisotropic 2D materials can be used in future optoelectronic devices, where anisotropic polarization sensitivity is required. Having an optical tool that quantitatively probes the effect of the in‐plane anisotropy among different 2D materials, could be of considerable importance for evaluating the performance of such materials and devices.