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Category: nanotechnology – Page 92

Recovering lossless propagation: HKU physicists overcoming optical loss in polariton system with synthetic complex frequency waves

A collaborative research team co-led by Professor Shuang ZHANG, the Interim Head of the Department of Physics, The University of Hong Kong (HKU), along with Professor Qing DAI from National Center for Nanoscience and Technology, China, has introduced a solution to a prevalent issue in the realm of nanophotonics – the study of light at an extremely small scale. Their findings, recently published in the prestigious academic journal Nature Materials, propose a synthetic complex frequency wave (CFW) approach to address optical loss in polariton propagation. These findings offer practical solutions such as more efficient light-based devices for faster and more compact data storage and processing in devices such as computer chips and data storage devices, and improved accuracy in sensors, imaging techniques, and security systems.

Surface plasmon polaritons and phonon polaritons offer advantages such as efficient energy storage, local field enhancement, and high sensitivities, benefitting from their ability to confine light at small scales. However, their practical applications are hindered by the issue of ohmic loss, which causes energy dissipation when interacting with natural materials.

Over the past three decades, this limitation has impeded progress in nanophotonics for sensing, superimaging, and nanophotonic circuits. Overcoming ohmic loss would significantly enhance device performance, enabling advancement in sensing technology, high-resolution imaging, and advanced nanophotonic circuits.

A ghostly quasiparticle rooted in a century-old Italian mystery could unlock quantum computing’s potential—if only it could be pinned down

Already, the graphene efforts have offered “a breath of fresh air” to the community, Alicea says. “It’s one of the most promising avenues that I’ve seen in a while.” Since leaving Microsoft, Zaletel has shifted his focus to graphene. “It’s clear that this is just where you should do it now,” he says.

But not everyone believes they will have enough control over the free-moving quasiparticles in the graphene system to scale up to an array of qubits—or that they can create big enough gaps to keep out intruders. Manipulating the quarter-charge quasiparticles in graphene is much more complicated than moving the Majoranas at the ends of nanowires, Kouwenhoven says. “It’s super interesting for physics, but for a quantum computer I don’t see it.”

Just across the parking lot from Station Q’s new office, a third kind of Majorana hunt is underway. In an unassuming black building branded Google AI Quantum, past the company rock-climbing wall and surfboard rack, a dozen or so proto–quantum computers dangle from workstations, hidden inside their chandelier-like cooling systems. Their chips contain arrays of dozens of qubits based on a more conventional technology: tiny loops of superconducting wires through which current oscillates between two electrical states. These qubits, like other standard approaches, are beset with errors, but Google researchers are hoping they can marry the Majorana’s innate error protection to their quantum chip.

Nanoscale Power Plants: Turning Heat Into Power With Graphene Ribbons

Quantum physicist Mickael Perrin uses graphene ribbons to build nanoscale power plants that turn waste heat from electrical equipment into electricity.

When Mickael Perrin started out on his scientific career 12 years ago, he had no way of knowing he was conducting research in an area that would be attracting wide public interest only a few years later: quantum electronics.

“At the time, physicists were just starting to talk about the potential of quantum technologies and quantum computers,” he recalls. “Today there are dozens of start-ups in this area, and governments and companies are investing billions in developing the technology further. We are now seeing the first applications in computer science, cryptography, communications, and sensors.”

Turning glass into a ‘transparent’ light-energy harvester

What happens when you expose tellurite glass to femtosecond laser light? That’s the question that Gözden Torun at the Galatea Lab at Ecole Polytechnique Federale de Lausanne, in collaboration with Tokyo Tech scientists, aimed to answer in her thesis work when she made the discovery that may one day turn windows into single material light-harvesting and sensing devices. The results are published in Physical Review Applied.

Interested in how the atoms in the tellurite would reorganize when exposed to fast pulses of high energy femtosecond laser light, the scientists stumbled upon the formation of nanoscale tellurium and tellurium oxide crystals, both etched into the glass, precisely where the glass had been exposed. That was the eureka moment for the scientists, since a semiconducting material exposed to daylight may lead to the generation of electricity.

“Tellurium being semiconducting, based on this finding we wondered if it would be possible to write durable patterns on the tellurite glass surface that could reliably induce electricity when exposed to light, and the answer is yes,” explains Yves Bellouard who runs EPFL’s Galatea Laboratory. “An interesting twist to the technique is that no additional materials are needed in the process. All you need is tellurite glass and a femtosecond laser to make an active photoconductive material.”

Advanced full-color image sensor technology enables simultaneous energy harvesting and imaging

Organic-based optoelectronic technology is increasingly recognized as an energy-efficient solution for low-power indoor electronics and wireless IoT sensors. This is largely due to its superior flexibility and light weight compared to conventional silicon-based devices. Notably, organic photovoltaic cells (OPVs) and organic photodetectors (OPDs) are leading examples in this field.

OPVs have the remarkable ability to absorb energy and generate electricity even under very low light conditions, while OPDs are capable of capturing images. However, despite their potential, the development of these devices has thus far been conducted independently. As a result, they have not yet reached the level of efficiency necessary to be considered practical for next-generation, miniaturized devices.

A Korea Institute of Science and Technology (KIST) research team, led by Dr. Min-Chul Park and Dr. Do Kyung Hwang of the Center for Opto-Electronic Materials and Devices, Prof. Jae Won Shim and Prof. Tae Geun Kim of the School of Electrical Engineering at Korea University, Prof. JaeHong Park of the Department of Chemistry and Nanoscience at Ewha Womans University, have now developed an organic-based optoelectronic device.

Researchers develop nanofiber-based drug delivery system for skin cancer

Treating complex diseases such as skin cancer often requires simultaneous administration of multiple anticancer drugs. The delivery of such life-saving therapeutic drugs has evolved with the rise of nanotechnology-based drug carriers. Nanoplatforms offer numerous advantages, including increased bioavailability, lowered dosages, and improved biodistribution.

Now a team of researchers, led by Professor Myoung-Hwan Park from Sahmyook University in South Korea, has developed a light-responsive nanofiber-based novel (DDS) targeting skin cancer. The DDS was studied in a detailed manner, beginning with its synthesis and characterization to its biocompatibility, drug release profile, and efficacy against skin cancer. These research findings are published in the Journal of Drug Delivery Science and Technology.

Explaining the motivation behind the present research, Dr. Park states, “Conventional drugs can be efficiently delivered in a controlled manner through nano-engineered platforms, and such an approach increases the overall effectiveness of the treatment. This approach improves outcomes in cancer drug therapy by ensuring precise delivery at optimal dosages.”

Researchers uncover molecular mechanisms behind effects of MXene nanoparticles on muscle regeneration

Tissue engineering, which involves the use of grafts or scaffolds to aid cell regeneration, is emerging as a key medical practice for treating volumetric muscle loss (VML), a condition where a significant amount of muscle tissue is lost beyond the body’s natural regenerative capacity. To improve surgical outcomes, traditional muscle grafts are giving way to artificial scaffold materials, with MXene nanoparticles (NPs) standing out as a promising option.

MXene NPs are 2D materials primarily composed of transition-metal carbides and nitride. They are highly electrically conductive, can accommodate a wide range of functional groups, and have stacked structures that promote cell interactions and growth. While there have been practical demonstrations in the laboratory showcasing their ability to promote the reconstruction of skeletal muscles, the specific mechanism by which they do so remains unclear.

To address this gap, Associate Professor Yun Hak Kim from the Department of Anatomy and Department of Biomedical Informatics, alongside Professors Suck Won Hong, and Dong-Wook Han from the Department of Cogno-Mechatronics Engineering at Pusan National University developed nanofibrous matrices containing MXene NPs as scaffolds. They used DNA sequencing to reveal the genes and biological pathways activated by MXene NPs to aid in muscle regeneration.