PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

NRL discovers two-dimensional waveguides

NRL discovers two-dimensional waveguides
2024-02-15
(Press-News.org) WASHINGTON  –  The U.S. Naval Research Laboratory (NRL), in collaboration with Kansas State University, announce the discovery of slab waveguides based on the two-dimensional material hexagonal boron nitride. This milestone has been reported in the journal Advanced Materials.
 
Two-dimensional (2D) materials are a class of materials which can be reduced to the monolayer limit by mechanically peeling the layers apart. The weak interlayer attractions, or van der Waals attraction, allows the layers to be separated via the so-called “Scotch tape” method. The most famous 2D material, graphene, is a semimetallic material consisting of a single layer of carbon atoms. Recently, other 2D materials including semiconducting transition metal dichalcogenides (TMDs) and insulating hexagonal boron nitride (hBN) have also garnered attention. When reduced near the monolayer limit, 2D materials have unique nanoscale properties which are appealing for creating atomically thin electronic and optical devices.
 
“We knew using hexagonal boron nitride would lead to outstanding optical properties in our samples, none of us expected that it would also act a waveguide,” said Samuel Lagasse, Ph.D., Novel Materials and Applications Division. “Since hBN is used so widely in 2D material–based devices, this novel usage as an optical waveguide potentially has wide-ranging impacts.“
 
Graphene and TMD monolayers are both extremely sensitive to the surrounding environment. Therefore, researchers have sought to protect these materials by encapsulating them in a passivating layer. This is where hBN comes in: layers of hBN are able to “screen” impurities near graphene or TMD layers, leading to fantastic properties. In recent NRL-led work, the thickness of hBN surrounding a light-emitting TMD layer was carefully tuned in order to support optical waveguide modes.
 
Researchers at NRL carefully assembled stacks of 2D materials, known as “van der Waals heterostructures.” These heterostructures can have specialized properties due to the layering. Slabs of hBN were placed around single layers of TMDs, such as molybdenum diselenide or tungsten diselenide, which can emit light in the visible and near-infrared. The slabs of hBN were carefully tuned in thickness so that the emitted light would be trapped within the hBN and waveguided. When the light waveguides to the edge of the hBN, it can scatter out and be detected by a microscope.
 
The research was motivated by the challenges of optical measurements of 2D TMDs. When laser light is focused on TMDs, particles known as excitons are generated. Most excitons emit light out of the plane of the TMD, however an elusive type of exciton known as a “dark” exciton exists in some TMDs, emits in the plane of the TMD. NRL’s slab waveguides capture the light from the dark excitons, providing a way to study them optically.
 
“2D materials have exotic optoelectronic properties that will be useful to the Navy,” said Lagasse. “A large challenge is interfacing these materials with existing platforms without damaging them – these boron nitride waveguides are a step towards that realization.”
 
NRL researchers used two special types of optical microscopes to characterize the hBN waveguides. One setup allows researchers to spectroscopically resolve photoluminescence emitting from different spots of the waveguide. The other setup let them observe the angular distribution of the emitted light.
 
NRL researchers also developed 3D electromagnetic models of the waveguides. The modeling results provide a toolkit for designing future 2D devices that use slab waveguides.
           
           
About the U.S. Naval Research Laboratory

NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL is located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.

For more information, contact NRL Corporate Communications at (202) 480-3746 or nrlpao@nrl.navy.mil. 

END

[Attachments] See images for this press release:
NRL discovers two-dimensional waveguides NRL discovers two-dimensional waveguides 2

ELSE PRESS RELEASES FROM THIS DATE:

AIBS names 2024 emerging public policy leaders

AIBS names 2024 emerging public policy leaders
2024-02-15
The American Institute of Biological Sciences (AIBS) is pleased to announce that Alex Rich and Efraín Rodríguez-Ocasio have been selected to receive the 2024 AIBS Emerging Public Policy Leadership Award (EPPLA). The award recognizes graduate students in the biological sciences who have demonstrated leadership skills and an aptitude for working at the intersection of science and public policy.   Alex Rich is a Ph.D. student in neuroscience at Yale University in New Haven, Connecticut. Her research focuses on decision-making and disordered ...

Shuffling the deck for privacy

Shuffling the deck for privacy
2024-02-15
By integrating an ensemble of privacy-preserving algorithms, a KAUST research team has developed a machine-learning approach that addresses a significant challenge in medical research: How to use the power of artificial intelligence (AI) to accelerate discovery from genomic data while protecting the privacy of individuals.[1] “Omics data usually contains a lot of private information, such as gene expression and cell composition, which could often be related to a person’s disease or health status,” says KAUST’s Xin Gao. “AI models trained on this data – particularly deep learning models – have the potential to retain private ...

Root microbes may be the secret to a better tasting cup of tea

Root microbes may be the secret to a better tasting cup of tea
2024-02-15
You’d think the complex flavor in a quality cup of tea would depend mainly on the tea varieties used to make it. But a study appearing in the journal Current Biology on February 15 shows that the making of a delicious cup of tea depends on another key ingredient: the collection of microbes found on tea roots. By altering that assemblage, the authors showed that they could make good-quality tea even better. “Significant disparities in microbial communities, particularly nitrogen metabolism-related microorganisms, were identified in the roots of tea plants with varying qualities through ...

Winners of 4th annual Rising Black Scientists Awards announced

2024-02-15
Cell Press, Cell Signaling Technology (CST), and the Elsevier Foundation are proud to announce the winners of the 4th annual Rising Black Scientists Awards: Jaye Wilson of Yale University, Kevin Brown Jr. of California State University San Marcos, Senegal Mabry of Cornell University, and Akorfa Dagadu of the Massachusetts Institute of Technology. This year had the greatest number of submissions thus far, with the winners being selected from a pool of more than 350 applicants from across the life, health, physical, earth, environmental, and data sciences. Essays from the winners and honorees appear in the journals Cell and ...

Ancient retroviruses played a key role in the evolution of vertebrate brains

Ancient retroviruses played a key role in the evolution of vertebrate brains
2024-02-15
Researchers report February 15 in the journal Cell that ancient viruses may be to thank for myelin—and, by extension, our large, complex brains. The team found that a retrovirus-derived genetic element or “retrotransposon” is essential for myelin production in mammals, amphibians, and fish. The gene sequence, which they dubbed “RetroMyelin,” is likely a result of ancient viral infection, and comparisons of RetroMyelin in mammals, amphibians, and fish suggest that retroviral infection and genome-invasion ...

Researchers discover that a rare fat molecule helps drive cell death

Researchers discover that a rare fat molecule helps drive cell death
2024-02-15
Columbia researchers have found that a rare type of lipid is a key driver of ferroptosis, a form of cell death discovered by Columbia professor Brent Stockwell. The findings provide new detail on how cells die during ferroptosis and could improve understanding of how to stop ferroptosis in contexts where it is harmfully occurring– in neurodegenerative diseases, for example– or induce it in contexts where it could be useful, such as using it to kill dangerous cancer cells. The new research found that a rare type of ...

Plant disease: Mapping the spread of potato blight prior to the Irish potato famine *IMAGES*

2024-02-15
The first accurate maps of outbreaks of potato blight — a disease caused by the fungus-like pathogen Phytophthora infestans that was responsible for the Irish potato famine between 1845 and 1852 — in the USA between 1843 and 1845 are presented in a study published in Scientific Reports. The findings improve our understanding of the spread of potato blight before the disease reached Europe. Jean Ristaino and colleagues mapped outbreaks of potato blight in North America between 1843 and 1845 by analysing historic agricultural reports published in the USA during this period. The authors found that the disease was first reported ...

New treatment for a rare and aggressive cancer improves survival rates in breakthrough clinical trial

2024-02-15
An innovative treatment significantly increases the survival of people with malignant mesothelioma, a rare but rapidly fatal type of cancer with few effective treatment options, according to results from a clinical trial led by Queen Mary University of London.  The phase 3 clinical trial, led by Professor Peter Szlosarek at Queen Mary and sponsored by Polaris Pharmaceuticals, has unveiled a breakthrough in the treatment of malignant pleural mesothelioma (MPM), a rare and often rapidly fatal form ...

Weight loss treatment and longitudinal weight change among patients with obesity

2024-02-15
About The Study: In this study of primary-care patients with obesity, all weight management treatments (nutrition counseling, very low-calorie meal replacement, anti-obesity medications, and bariatric surgery) increased the patient-level probability of achieving 5% or greater weight loss, but current rates of utilization are low and insufficient to reduce weight at the population level.  Authors: Dina H. Griauzde, M.D., M.Sc., of the University of Michigan in Ann Arbor, is the corresponding author.  To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/  (doi:10.1001/jamanetworkopen.2023.56183) Editor’s ...

Traumatic brain injury and subsequent risk of brain cancer in US veterans of the Iraq and Afghanistan wars

2024-02-15
About The Study: Moderate or severe and penetrating traumatic brain injury (TBI) were associated with the subsequent development of brain cancer in this study of more than 1.9 million veterans of the Iraq and Afghanistan wars. However, mild TBI was not associated with later brain cancer diagnoses.  Authors: Ian J. Stewart, M.D., of the Uniformed Services University of Health Sciences in Bethesda, Maryland, is the corresponding author.  To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/  (doi:10.1001/jamanetworkopen.2023.54588) Editor’s ...

LAST 30 PRESS RELEASES:

SwRI-built instruments to monitor, provide advanced warning of space weather events

Breakthrough advances sodium-based battery design

New targeted radiation therapy shows near-complete response in rare sarcoma patients

Does physical frailty contribute to dementia?

Soccer headers and brain health: Study finds changes within folds of the brain

Decoding plants’ language of light

UNC Greensboro study finds ticks carrying Lyme disease moving into western NC

New implant restores blood pressure balance after spinal cord injury

New York City's medical specialist advantage may be an illusion, new NYU Tandon research shows

Could a local anesthetic that doesn’t impair motor function be within reach?

1 in 8 Italian cetacean strandings show evidence of fishery interactions, with bottlenose and striped dolphins most commonly affected, according to analysis across four decades of data and more than 5

In the wild, chimpanzees likely ingest the equivalent of several alcoholic drinks every day

Warming of 2°C intensifies Arctic carbon sink but weakens Alpine sink, study finds

Bronze and Iron Age cultures in the Middle East were committed to wine production

Indian adolescents are mostly starting their periods at an earlier age than 25 years ago

Temporary medical centers in Gaza known as "Medical Points" (MPs) treat an average of 117 people daily with only about 7 staff per MP

Rates of alcohol-induced deaths among the general population nearly doubled from 1999 to 2024

PLOS One study: In adolescent lab animals exposed to cocaine, High-Intensity Interval Training boosts aversion to the drug

Scientists identify four ways our bodies respond to COVID-19 vaccines

Stronger together: A new fusion protein boosts cancer immunotherapy

Hidden brain waves as triggers for post-seizure wandering

Music training can help the brain focus

Researcher develop the first hydride ion prototype battery

MIT researchers find a more precise way to edit the genome

‘Teen’ pachycephalosaur butts into fossil record

Study finds cocoa extract supplement reduced key marker of inflammation and aging

Obesity treatment with bariatric surgery vs GLP-1 receptor agonists

Nicotinamide for skin cancer chemoprevention

Novel way to ‘rev up’ brown fat burns calories, limits obesity in mice

USC Stem Cell-led team makes major advance toward building a synthetic kidney

[Press-News.org] NRL discovers two-dimensional waveguides