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Category: nanotechnology – Page 28

Electro-optic cavities for in-situ measurement of cavity fields

Our hybrid EOC design extends these concepts by providing continuous tunability and the potential for adding active samples for investigations of intra-cavity light-matter interactions. In the ‘empty’ hybrid cavity investigated here, we observe a rich mode structure, spurring development of both a field-based model to quantify these cavity modes and their properties, as well as a complementary coupled-oscillator description to gain further understanding of the delicate interplay between the various sub-cavities, which thereafter constitute the hybrid EOC modes. Our detailed analysis of these theoretical vantage points will be highly valuable when considering the addition of an active material, after which the hybrid cavity optical response will become even more intricate. Integration of active materials into hybrid EOCs will yield novel access to light-matter interactions—namely access to energy exchange on sub-Rabi-cycle timescales, and furthermore local probing and even control over tunable light-matter superposition—the latter two unavailable when viewed by conventional cavity transmission techniques. Potential ‘active materials’ for these in-situ investigations of tunable light-matter interactions include conventional polar semiconductors40—oftentimes displaying very large oscillator strengths—atomically-thin monolayers or heterostructures ofion-metal dichalcogenides41, hybrid organic-inorganic 3D21,42 and 2D lead-halide perovskites43,44, and novel, magnetically-ordered systems45.

Implementation of EO sampling inside of THz cavities will also significantly advance further areas of contemporary research. As a prominent example, field-resolved probing inside a defined electromagnetic cavity will provide novel opportunities for measurements of electromagnetic vacuum field fluctuations46,47. Most notably, a high-quality factor EOC constitutes an advantageous testing ground for measurement of quantum vacuum fluctuations, by efficiently excluding sources of external radiation. Moreover, EOCs are not limited to either macroscopic environments or the THz spectral region. Although EO sampling is routinely employed up to the mid-IR spectral region9, it has recently been extended even into the visible range48, allowing for future broadband measurements of intra-cavity electric fields. Similar sampling techniques have been used to sample electric fields inside of metallic antenna-based cavities49,50, demonstrating that although on-chip photonic implementations lack the dynamic tunability, the general technique is readily implemented in other near-field contexts, including even tip-based nano-photonic applications51. Furthermore, EOCs utilizing quartz are uniquely suited candidates for chiral THz cavity phenomena52, due to quartz’s capability for straightforward and rapid measurement of vectorial electric field trajectories34.

In conclusion, we have established versatile and compact designs for a new class of active THz cavities, which allow for in-situ retrieval of intra-cavity electric fields. By developing a cavity-correction function formalism for these EOCs, we have demonstrated a rigorous and reliable method to extract absolute fields in a quantitative, and phase-resolved manner. Utilizing straightforward fabrication techniques, we tune the cavities’ quality factors and resonance frequencies. Furthermore, we have introduced a hybrid EOC, offering continuously-tunable cavity modes across the entire THz-frequency range, within a single device. This fundamental advancement lays the groundwork for accommodating additional active materials for in-situ measurement of and control over light-matter coupling. We understand the rich hybrid mode structure, including apparent signatures of strong coupling, via cavity-field and coupled-oscillator formalisms, which will be key to deciphering signatures of light-matter coupling in more complicated devices. Therefore, this work opens new dimensions of THz cavity physics, particularly in the realms of cavity-controlled ground-and excited state material properties. This includes possibilities such as cavity-enhanced THz emission, selectively-driven Floquet states53, and cavity-controlled nonlinear THz driving15,54, thus paving the way for comprehensive investigations of THz cavity quantum electrodynamics.

Reliable AI: System assists with making nanoparticle measurements to speed up research

Nanoparticle researchers spend most of their time on one thing: counting and measuring nanoparticles. Each step of the way, they have to check their results. They usually do this by analyzing microscopic images of hundreds of nanoparticles packed tightly together. Counting and measuring them takes a long time, but this work is essential for completing the statistical analyses required for conducting the next, suitably optimized nanoparticle synthesis.

Alexander Wittemann is a professor of colloid chemistry at the University of Konstanz. He and his team repeat this process every day. “When I worked on my , we used a large particle counting machine for these measurements. It was like a , and, at the time, I was really happy when I could measure three hundred nanoparticles a day,” Wittemann remembers.

However, reliable statistics require thousands of measurements for each sample. Today, the increased use of computer technology means the process can move much more rapidly. At the same time, the automated methods are very prone to errors, and many measurements still need to be conducted, or at least double-checked, by the researchers themselves.

AI speeds up nanoparticle research

A team of researchers at the University of Konstanz has succeeded in adapting an artificial intelligence (AI) system to reliably assist with making nanoparticle measurements which speeds up the research process significantly.

The findings have been published in Scientific Reports (“Pre-trained artificial intelligence-aided analysis of nanoparticles using the segment anything model”).

Nanoparticle researchers spend most of their time on one thing: counting and measuring nanoparticles. Each step of the way, they have to check their results. They usually do this by analyzing microscopic images of hundreds of nanoparticles packed tightly together. Counting and measuring them takes a long time, but this work is essential for completing the statistical analyses required for conducting the next, suitably optimized nanoparticle synthesis.

Nanozyme-Based Strategies against Bone Infection

Nanozymes are a class of nanomaterials that exhibit catalytic functions analogous to those of natural enzymes. They demonstrate considerable promise in the biomedical field, particularly in the treatment of bone infections, due to their distinctive physicochemical properties and adjustable catalytic activities. Bone infections (e.g., periprosthetic infections and osteomyelitis) are infections that are challenging to treat clinically. Traditional treatments often encounter issues related to drug resistance and suboptimal anti-infection outcomes. The advent of nanozymes has brought with it a new avenue of hope for the treatment of bone infections.

Quantum Imaging Just Got Faster, Smaller, and More Precise

A team of scientists has unlocked a new frontier in quantum imaging, using a nanoscale.

The term “nanoscale” refers to dimensions that are measured in nanometers (nm), with one nanometer equaling one-billionth of a meter. This scale encompasses sizes from approximately 1 to 100 nanometers, where unique physical, chemical, and biological properties emerge that are not present in bulk materials. At the nanoscale, materials exhibit phenomena such as quantum effects and increased surface area to volume ratios, which can significantly alter their optical, electrical, and magnetic behaviors. These characteristics make nanoscale materials highly valuable for a wide range of applications, including electronics, medicine, and materials science.

Unexpected Discovery Leads to a Catalyst That Improves Over Time

Scientists have developed a revolutionary catalyst that not only converts CO2 into valuable products but actually increases in activity over time.

Made from tin microparticles on a nanotextured carbon structure, this innovative electrocatalyst efficiently produces formate—a key compound for various industries. Unlike conventional catalysts that degrade, this one self-optimizes by breaking down into smaller tin nanoparticles, dramatically improving performance.

Breakthrough Catalyst for CO2 Conversion.

Solving the drug solubility problem with silica nanoparticles

Harvard University and the Chinese University of Hong Kong researchers have developed a technique that increases the solubility of drug molecules by up to three orders of magnitude. This could be a breakthrough in drug formulation and delivery.

Over 60% of pharmaceutical drug candidates suffer from poor water solubility, which limits their bioavailability and therapeutic viability. Conventional techniques such as particle-size reduction, solid dispersion, lipid-based systems, and mesoporous confinement often have drug-specific limitations, can be costly to implement, and are prone to stability issues.

The newly developed approach addresses these issues by leveraging the competitive adsorption mechanism of drug molecules and water on engineered silica surfaces. It avoids chemical modification of drug molecules or using additional solubilizing agents to achieve solubility, potentially replacing multiple drug delivery technologies.

From photons to protons: Team makes breakthrough in high-energy particle detection

Particle detectors play a crucial role in our understanding of the fundamental building blocks of the universe. They allow scientists to study the behavior and properties of the particles produced in high-energy collisions. Such particles are boosted to near the speed of light in large accelerators and then smashed into targets or other particles where they are then analyzed with detectors. Traditional detectors, however, lack the needed sensitivity and precision for certain types of research.

Researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have made a significant breakthrough in the field of high-energy particle detection in recent experiments conducted at the Test Beam Facility at DOE’s Fermi National Accelerator Laboratory (Fermilab).

They have found a new use for the superconducting nanowire photon detectors (SNSPDs) already employed for detecting photons, the fundamental particles of light. These incredibly sensitive and precise detectors work by absorbing individual photons. The absorption generates small electrical changes in the superconducting nanowires at very low temperatures, allowing for the detection and measurement of photons. Specialized devices able to detect individual photons are crucial for quantum cryptography (the science of keeping information secret and secure), advanced optical sensing (precision measurement using light) and quantum computing.

Life on Earth Depends on Networks of Ocean Bacteria

Another question is how bacteria form these tubes, and under what conditions. The tubes are not much longer than an individual cell, and Prochlorococcus, in particular, is thought to spread out in the water column. Muñoz-Marín and her team are curious about the concentrations of bacteria required for a network to form. “How often would it be possible for these independent cells to get close enough to each other in order to develop these nanotubes?” García-Fernandez asked. The current study shows that nanotubes do form among wild-caught cells, but the precise requirements are unclear.

Looking back at what people thought about bacterial communication when he began to study marine cyanobacteria 25 years ago, García-Fernandez is conscious that the field has undergone a sea change. Scientists once thought they saw myriad individuals floating alongside each other in immense space, competing with neighboring species in a race for resources. “The fact that there can be physical communication between different kind of organisms—I think that changes many, many previous ideas on how the cells work in the ocean,” he said. It’s a far more interconnected world than anyone realized.