EUV lithography operates by harnessing light with an extraordinarily short wavelength—just 13.5 nanometers—which enables the creation of incredibly fine features on silicon wafers. The process begins when this EUV light is generated and meticulously channeled through an illumination system towards a reflective photomask imprinted with the target circuit design. Upon reflection, this patterned light passes through a projector system composed of precisely curved mirrors, which shrink and focus the intricate design onto a silicon wafer. Subsequent processing etches the illuminated pattern into the wafer’s surface, forming the foundational architecture of semiconductor chips. Crucial to pushing the envelope of miniaturization is the numerical aperture (NA) of these systems—a parameter that defines the range of angles over which the system can accept or emit light. Higher NA values correlate directly to finer resolution capabilities, enabling denser packing of transistors and circuit elements.

Despite the theoretical promise of high-NA EUV lithography, practical implementation has been fraught with challenges. The early explorations into high-NA configurations favored simple in-line setups wherein the photomask, projector, and wafer are aligned along a single optical axis. This streamlined arrangement, while intuitively appealing, introduced significant optical aberrations such as distortions and blurring that intensified with increasing NA. These so-called “mask 3D effects” arise due to the complex interplay of light reflections on the three-dimensional topography of the photomask, adversely affecting pattern fidelity and ultimately the electrical performance of the fabricated chips.

Confronting these longstanding obstacles, Professor Shintake embarked on an ambitious reimagining of the illumination and projection components integral to high-NA EUV lithography. His initial foray involved evaluating the feasibility of a minimalist projector design consisting of a single pair of mirrors—one concave and one convex—with the potential to deliver high-resolution imagery while suppressing aberrations. Although this simplistic approach did not yield immediate success, continued exploration led to a sophisticated two-stage projection configuration. Each stage utilizes a concave-convex mirror pair arranged to optimize optical performance. Remarkably, simulations revealed that carefully orchestrated multiple reflections between these mirrors could cancel out deleterious optical defects, preserving the high numerical aperture without compromising image quality.

These insights emerged from extensive computational modeling conducted using OpTaliX, an advanced optical simulation software. Through meticulous parameter optimization, including mirror curvature adjustments and precise spatial positioning, Shintake and his collaborators delineated an optical path that maintains high resolution while mitigating the distortive mask 3D effects. The theoretical framework underscores the power of optical engineering in overcoming fundamental diffraction and interference phenomena—challenges that have hampered high-NA EUV lithography efforts for decades.

Beyond the technical elegance of the design, the proposed system carries profound economic implications. Current state-of-the-art EUV lithography machines reportedly cost hundreds of millions of euros each, placing them out of reach for all but the largest semiconductor manufacturers. In stark contrast, Shintake’s approach promises to slash these costs dramatically—potentially to just a quarter of today’s expenditures—thus democratizing access to cutting-edge lithography and accelerating development cycles across the industry.

The ramifications extend well beyond chip manufacturing economics. The International Energy Agency forecasts that by 2030, global data center electricity consumption will double, driven largely by the proliferation of energy-intensive artificial intelligence applications. Higher-density chips fabricated with the new high-NA technology would feature electronic pathways shortened by virtue of their finer architectural detail, reducing signal travel distance and thereby minimizing energy loss during computation. Moreover, lower heat emission from these denser chips implies diminished cooling requirements, collectively resulting in meaningful reductions in power consumption and operational costs for data centers worldwide.

As part of his next research phase, Professor Shintake and his team aim to transition from simulation to realization by constructing a physical prototype of the novel high-NA EUV lithography system. This endeavor will necessitate overcoming engineering challenges such as fabricating mirrors with near-perfect reflectivity and minimal surface defects—criteria assumed in simulations but challenging to achieve in practice. Nonetheless, the initial groundwork laid by this study establishes a compelling blueprint for transforming semiconductor fabrication.

In addition to enabling finer patterning capabilities, the simplified in-line projector design enhances overall system robustness and manufacturability. By aligning the photomask, projector, and wafer along a single axis with optimized mirror pairs, the architecture reduces alignment complexities and optical component counts, thereby facilitating easier maintenance and potentially accelerating throughput rates on the manufacturing floor.

Innovations like Shintake’s not only refresh the physics of lithographic imaging but may also catalyze novel computing paradigms by significantly pushing the achievable limits of miniaturization. As industry demand for memory density and logic efficiency mounts exponentially, high-NA EUV lithography could unlock pathways to next-generation chip designs exhibiting superior speed, reduced energy consumption, and lower production costs, collectively powering advancements in artificial intelligence, quantum computing, and ubiquitous digital technologies.

Ultimately, this research signals a pivotal juncture for semiconductor manufacturing, harnessing the power of optical science to surmount entrenched technical and financial hurdles. By reducing the cost and complexity of high-NA EUV lithography, Professor Shintake’s innovation promises transformative impacts on the silicon industry and beyond—enabling faster, greener, and more affordable electronics that will underpin the data-centric future of society.

Subject of Research: High numerical aperture (high-NA) extreme ultraviolet (EUV) lithography systems for semiconductor chip manufacturing

Article Title: High-NA in-line projector for EUV lithography

News Publication Date: June 12, 2026

Web References: http://dx.doi.org/10.1117/1.JMM.25.2.023801

Image Credits: Andrew Scott, Okinawa Institute of Science and Technology (OIST)

Taylor-Couette flows represent one of the simplest yet most intricate forms of rotating turbulence. These flows form in the narrow gap between two independently spinning, coaxial cylinders. Despite the system’s geometric simplicity, the fluid motion inside exhibits a rich variety of complex, rotating turbulent vortices called Taylor rolls. These rolling currents resemble atmospheric phenomena such as typhoon spirals, combining horizontal rotation with turbulent vertical shafts. Because of their accessibility to experimental manipulation and relevance to many natural rotating fluid systems, Taylor-Couette flows have historically served as a benchmark for illuminating the fundamental characteristics of turbulence.

The cornerstone of understanding turbulence has been Kolmogorov’s theory, first articulated in 1941 by the mathematician Andrey Kolmogorov. His revolutionary insight was the concept of an energy cascade: when a turbulent fluid is stirred at a large scale, energy propagates downward through a hierarchy of progressively smaller vortices until it dissipates into heat at molecular scales. To quantify this cascade, Kolmogorov introduced the celebrated “-5/3 power law,” describing how the turbulent kinetic energy ( E(k) ) varies with wavenumber ( k )—a measure inversely related to eddy size. Within the inertial range of the cascade, this energy spectrum obeys a power law of the form ( E(k) \propto k^{-5/3} ), signaling scale invariance and universality in turbulent flows.

Remarkably, Kolmogorov’s power law has been verified across virtually every turbulent system studied experimentally—from atmospheric boundary layers to pipe flows and ocean currents—cementing its status as a universal descriptor of turbulence. The glaring exception, however, has been Taylor-Couette flows. Experimental data repeatedly failed to align with the -5/3 scaling, throwing a wrench in the otherwise elegant universality of Kolmogorov’s framework. This inconsistency has been a source of perplexity and heated debate for decades, raising discomforting questions about the limits of established turbulence theory.

To confront this paradox, a team led by Professor Pinaki Chakraborty at OIST embarked on a monumental nine-year project to develop a world-class experimental Taylor-Couette setup capable of unprecedented precision and control. The engineering challenges were formidable: the apparatus spins at thousands of revolutions per minute within temperature-controlled, coaxial cylinders, featuring delicate sensors able to withstand extreme shear and turbulence at Reynolds numbers (a dimensionless measure of flow complexity) up to (10^6), among the highest ever achieved in laboratory conditions. This state-of-the-art facility now provides a new gold standard for experimental turbulence research.

Analyzing the energy spectra obtained from this innovative setup with the traditional Kolmogorov inertial-range perspective initially reaffirmed the familiar discrepancy: the data stubbornly resisted fitting the canonical -5/3 power law. But rather than accept this as definitive evidence against Kolmogorov’s universality in TC flows, the researchers expanded their analytical lens. Instead of focusing solely on the inertial range, they considered the full range of small-scale behaviors—including the dissipation scales where energy converts into heat—guided by Kolmogorov’s more general hypotheses.

This broader approach draws upon the refined prediction that when energy spectra are non-dimensionalized using viscosity ( \nu ) and the Kolmogorov dissipation scale ( \eta ), the rescaled spectra should collapse onto a universal function ( F(k \eta) ) across different turbulent flows. In other words, despite varied large-scale behaviors, the small-scale turbulent motions should exhibit a universal pattern once viewed through the correct dimensionless variables. This advanced scaling removes the emphasis from the inertial range alone and incorporates the quantum of dissipation into the framework.

Applying this full rescaling to the Taylor-Couette data yielded a stunning breakthrough: the previously divergent spectra collapsed remarkably well onto the universal curve ( F(k \eta) ), exposing the elusive universality hiding in plain sight. Their evidence compellingly demonstrated that Kolmogorov’s framework holds true for TC flows at small scales as rigorously as for all other turbulent flows, resolving the long-standing contradiction and restoring faith in the theoretical foundation.

This reconciliation revitalizes Taylor-Couette systems as powerful experimental platforms for turbulence research. Because TC setups are closed systems free from external obstructions or pumps, they enable precise control over the fluid medium and additives such as sediments or polymers. This flexibility, combined with the now-verified universal framework, makes TC flows ideal for probing the interplay between turbulence and complex fluid properties, with direct implications ranging from industrial mixing to planetary atmospheres and accretion disks around stars.

Moreover, the OIST setup and the team’s findings provide the fluid dynamics community with a new reference benchmark. Researchers can now confidently apply Kolmogorov scaling laws to interpret TC turbulence data and explore phenomena such as energy transfer rates, vortex dynamics, and dissipation mechanisms under rotation. This deeper understanding can inform improved predictive models for a wide array of engineering and environmental systems characterized by rotational turbulence.

Professor Chakraborty emphasizes the significance: “By bridging this major theoretical gap, we have not only resolved a ‘sore thumb’ inconsistency in turbulence theory but also opened a pathway to systematically investigate complex, rotating turbulent flows. This has profound consequences—from enhancing weather forecasting models to guiding the design of energy-efficient turbines and understanding astrophysical disk formations.”

In summary, the team’s rigorous experimental approach combined with an expanded theoretical framework has successfully demonstrated the universality of Kolmogorov’s turbulence law in Taylor-Couette flows. This milestone underscores the continuing relevance of foundational fluid dynamics theories while showcasing how modern experimental ingenuity can push the boundaries of knowledge. As the scientific community digests these results, the OIST-TC apparatus stands ready to accelerate turbulence research, enabling discoveries that span coffee cups to galaxies.

Subject of Research: Not applicable

Article Title: Universality in the small scales of turbulent Taylor–Couette flow

News Publication Date: 5-Nov-2025

Image Credits: Barros et al., 2025

Keywords: Turbulence, Taylor-Couette flow, Kolmogorov theory, energy cascade, fluid dynamics, rotational turbulence, Reynolds number, energy spectrum, dissipation scale, turbulence universality

The crux of the researchers’ investigation lies in examining the communication breakdown between neurons across synaptic clefts, a critical aspect of brain function. When proteins associated with Alzheimer’s and Parkinson’s diseases accumulate, they wreak havoc on synaptic vesicle recycling, a process vital for efficient neurotransmission. This study identifies how disease-related proteins can significantly hinder the recycling process, leading to a cascade of synaptic dysfunction. Dr. Dimitar Dimitrov, the lead author of the study, emphasizes the implications these findings hold for understanding the disparate symptoms observed in both diseases, suggesting that interference in one neuronal circuit may manifest as memory impairment, while disruption in another may compromise motor control.

Neurotransmitters act as the brain’s chemical messengers, and their effective signaling depends heavily on the proper functioning of synaptic vesicles. These tiny, membranous packets encompass the neurotransmitters and play a crucial role in ensuring their transport and release. The dynamics of synaptic vesicle retrieval are thus fundamental to neuronal signaling. Without this intricate recycling mechanism, the stability and efficiency of communication between brain cells are compromised, producing profound effects on cognitive and motor functions.

The research underscores a specific molecular cascade that interferes with the retrieval of emptied vesicles crucial for maintaining neurotransmitter availability. As excess disease-related proteins accumulate within brain cells, they trigger an overproduction of microtubules, which are essential structural components of cells. However, when microtubules become overabundant, they can entrap critical proteins like dynamin. This protein is vital for the retrieval of synaptic vesicles, and its scarcity can severely affect the recycling process, thus inhibiting neuronal signaling and communication.

Moving beyond just elucidating the underlying mechanisms, this study has broader therapeutic implications for the treatment of Alzheimer’s and Parkinson’s diseases. By uncovering this shared biological pathway, the researchers have highlighted multiple pharmacological targets. Strategies to prevent protein accumulation, inhibit microtubule overproduction, or disrupt the binding of microtubules to dynamin could potentially pave the way for new treatment avenues. Such therapeutic interventions might alleviate some of the most debilitating effects faced by patients battling these neurodegenerative conditions.

The ongoing efforts of the OIST research team build upon a robust foundation of previous work exploring the role of microtubules in Parkinson’s disease and the interaction of dynamin with tau proteins in the context of Alzheimer’s disease. Their sustained inquiry into these mechanisms reflects a commitment to unraveling the complexities of neurodegenerative disorders. Moreover, recent studies suggest that a peptide designed to counteract synaptic damage caused by Alzheimer’s may also hold promise for ameliorating symptoms associated with Parkinson’s disease, hinting at an overlap in treatment strategies for these distinct yet interconnected afflictions.

In conclusion, the insights from this research elevate our understanding of the molecular underpinnings of both Alzheimer’s and Parkinson’s diseases, drawing connections that could inform upcoming therapeutic designs. The concept of a shared mechanism offers a refreshing perspective and underscores the potential for developing holistic approaches to treatment. As scientists continue to explore these molecular intricacies, patients and families affected by these diseases may soon witness advancements that could profoundly improve quality of life and daily functioning. The journey to unravel the complexities of the brain is far from over, but studies like this are crucial stepping stones toward creating effective interventions.

This groundbreaking study not only enriches our comprehension of synaptic dysfunction in neurodegenerative diseases but also marks a significant advancement in establishing a framework for future research endeavors focused on finding effective treatments. As we gather knowledge about the shared molecules and pathways involved, it becomes increasingly plausible to formulate effective therapeutic strategies that could potentially counteract the debilitating symptoms of these conditions, ultimately reshaping the therapeutic landscape for those affected.

Subject of Research: Cells
Article Title: Common Mechanism Underlying Synaptic Dysfunction Caused by Preformed Fibril-Induced Accumulation of α-Synuclein or Tau in a Culture Propagation Model
News Publication Date: 30-Sep-2025
Web References: OIST News Center
References: N/A
Image Credits: Credit: Kaori Serakaki/OIST

Complex fluids differ markedly from simple Newtonian fluids such as water or air. These materials possess attributes that straddle those of liquids and solids, often due to the presence of long-chain molecules called polymers. Polymers impart elasticity and internal structure to the fluid, profoundly altering how it reacts to external forces and flows. Everyday substances like shampoos, ketchup, and hand sanitizers fall into this category, demonstrating the pervasive nature of polymer fluids in both industry and daily life. Despite their prevalence, the turbulent behavior of polymer fluids has remained elusive and inadequately understood due to the complex interplay of fluid inertia and molecular elasticity.

Historically, the scientific community treated turbulence as emerging in two distinct guises depending on flow conditions. The first and most recognized form is inertial turbulence, a consequence of the fluid’s inertia dominating the flow regime. This type is characterized by violent, large-scale chaotic motions commonly observed in air and water when they move rapidly. The second is elastic turbulence, a more recently identified and less intuitive phenomenon that emerges from the elastic stresses created by stretched polymer molecules within the fluid. Unlike inertial turbulence, elastic turbulence can arise in flows with minimal inertia — essentially slow and gentle stirring — causing the flow to become chaotic due purely to elastic instabilities.

Until now, it was commonly assumed that inertial and elastic turbulence occurred exclusively under separate and well-defined conditions: inertial turbulence at high speeds and large scales, and elastic turbulence restricted to low velocities and small-scale flows dominated by polymer elasticity. However, OIST researchers have now upended this dichotomy by demonstrating that these two behaviors coexist simultaneously in polymeric fluids under turbulent conditions. Their pioneering work utilized high-resolution numerical simulations to delve deep into the dynamics of polymer fluids and revealed that turbulent flows are far richer and more complex than previously thought.

The breakthrough came through the use of state-of-the-art computational modeling capabilities that captured turbulent behavior across a vast range of spatial scales. By simulating polymeric fluid flow at unprecedented resolution, the research team discovered that inertial turbulence dominates at larger scales, driving chaotic motions familiar from classical fluid mechanics. Simultaneously, at the smallest sub-scales of the flow — scales previously inaccessible to detailed observation — elastic turbulence arises due to the polymer molecules’ elastic stresses. This coexistence means a single turbulent flow exhibits a dual nature, with the two turbulence types intricately interwoven depending on the observation scale.

Dr. Piyush Garg, the lead author, highlighted the computational challenges involved: “To capture the small-scale interactions where elastic turbulence emerges required highly detailed simulations beyond anything done before in this field. The computational resources necessary were immense, but essential to reveal this hidden phenomenon that eluded scientists for decades.” Such robust and finely-detailed modeling has only recently become feasible thanks to advances in numerical algorithms and high-performance computing infrastructure, enabling exploration into the complex multi-physics nature of polymer fluid turbulence.

The implications of this discovery are extensive. Firstly, it broadens the fundamental understanding of turbulence, a problem that remains one of the most influential and difficult in classical physics. The finding that elastic turbulence can infiltrate inertial flows reshapes how scientists conceptualize turbulence in polymer fluids and challenges prior simplified models that treated these states as mutually exclusive. This new perspective offers a unified framework bridging two previously disconnected fields of research in fluid dynamics and polymer science.

Practically, the insights gained into the dual nature of polymer turbulence could revolutionize industrial processes where control over fluid behavior is paramount. Industries ranging from chemical manufacturing and oil pipelines to biomedicine rely on polymer additives to manipulate flow properties like viscosity, drag, and mixing efficiency. Understanding how and where elastic and inertial turbulence overlap allows engineers to design better fluid systems, optimize performance, and reduce energy losses. In biomedical applications, such as drug delivery, these findings might improve the predictability and efficiency of how polymer-based carriers navigate complex biological environments.

Professor Marco Rosti, head of the Complex Fluids and Flows Unit at OIST and co-author of the study, emphasized the broader significance: “Our discovery bridges two distinct research areas and demonstrates the power of interdisciplinary collaboration. This is a testament to OIST’s environment where physicists, engineers, and computational scientists come together to tackle long-standing open problems.” Indeed, the ability to connect theoretical, computational, and experimental perspectives is key to advancing turbulence research, which has traditionally been fragmented across various subfields.

In addition to providing clarity on the elusive nature of polymer turbulence, this work sets the stage for future experimental validation and new theoretical developments. Researchers now have a precise hypothesis to test: that elastic turbulence is hidden within the fine-scale structures of inertial turbulent flows. Experimentalists equipped with high-resolution measurement techniques may be able to observe this coexistence directly, while theorists can work towards formulating models that capture this multiscale complexity.

This discovery also invites a reevaluation of previous experiments and industrial scenarios involving polymer flows. Cases where unexpected flow behaviors were observed might now be explained through the lens of simultaneous inertial and elastic turbulence. Importantly, the interplay of these two forms of turbulence adds a new dimension to turbulence control strategies, as interventions targeting one scale or mechanism might affect the other in unforeseen ways.

In summary, the OIST study has revealed that turbulence in polymeric fluids is not a straightforward either-or scenario but a nuanced coexistence of inertial and elastic turbulence across scales. This revelation expands the fundamental understanding of complex fluid dynamics and opens avenues for technological innovation wherever polymers interact with turbulent flows. By leveraging cutting-edge computational modeling and interdisciplinary insight, the team has uncovered a hidden layer of complexity that promises to redefine fluid dynamics research in the coming years.

Subject of Research: Not applicable

Article Title: Elastic Turbulence Hides in the Small Scales of Inertial Polymeric Turbulence

News Publication Date: 13-Aug-2025

Web References: http://dx.doi.org/10.1103/pbtf-rn7d

References: Rosti (2025), J. Fluid Mech., 1012, R5. CC BY-NC 4.0.

Image Credits: Rosti (2025), J. Fluid Mech., 1012, R5. CC BY-NC 4.0.

Keywords

Physics, Fluid dynamics