Optically controlled metasurfaces for dynamic dual-mode modulation

Researchers demonstrated a simple, optically controlled metadevice for dynamic dual-mode modulation of THz waves

2023-04-12

(Press-News.org) Dynamic control of terahertz (THz) waves at-will with an ultracompact device is important for THz technologies in biomedical imaging, telecommunications, detection, and beyond. However, tunable THz devices made of conventional materials are usually bulky, and they tend to have limited modulation depths and functionalities, due to weak interactions between naturally existing materials and THz waves. Metasurfaces – functional materials endowed with unparalleled flexibility to manipulate light at the deep-subwavelength scale – provide a powerful platform for dynamic control of THz waves.

Combining passive metasurfaces with different external-stimuli-controlled materials, optically controlled metadevices have attracted attention in this regard. Their attractive properties include ultrafast modulation speed and high modulation pixel resolution. Most optically controlled metadevices can achieve light modulation that is either selective or unselective of frequency. Dual-mode yet distinctly tunable light manipulation – say, upon adjusting an external knob in a simple device – is highly desired for applications in integrated optics.

As reported in Advanced Photonics, researchers from Fudan University’s Department of Physics recently established a novel metasurface-based approach that achieves dynamic dual-mode modulation of THz waves by varying the wavelength of pumping light with an additional knob. Specifically, their experiment demonstrated that a predesigned dielectric metasurface can realize mode-selective or mode-unselective modulations on incident THz waves, by switching the wavelength of the pump wavelength (e.g., 515 nm or 1030 nm). Their theoretical analyses revealed that such dual-mode modulation can be effectively controlled by carefully designing the spatial overlap between the wave-functions of the metasurface’s resonant modes and the regions perturbed by the pump-laser excitation at different wavelengths.

Inspired by their discovery of the mechanism, the researcher team further demonstrated two active metadevices with distinct light-modulation functionalities. In experiments and simulations, they first presented a device that can dynamically change the polarization state of incident THz waves dictated by both pump wavelength and pump fluence. Then, they presented a device that can encrypt optical information so that it displays a predesigned holographic pattern only when excited by a pump beam at a predetermined correct wavelength.

According to corresponding author Qiong He, Professor of Physics at Fudan University, “We anticipate that this work will stimulate many new tunable devices with distinct light-modulation functionalities.” He adds, “These functionalities may be useful for numerous applications, such as sensing, security, and next generation wireless communications.”

Read the Gold Open Access article by H. Zhou, S. Zhang, S. Wang, et al., “Optically controlled dielectric metasurfaces for dynamic dual-mode modulation on terahertz waves,” Adv. Photon. 5(2) 026005 (2023), doi 10.1117/1.AP.5.2.026005

END

[Attachments] See images for this press release:

Optically controlled metasurfaces for dynamic dual-mode modulation 2

ELSE PRESS RELEASES FROM THIS DATE:

Whether physical exertion feels ‘easy’ or ‘hard’ may be due to dopamine levels, study suggests

2023-04-12

Dopamine, a brain chemical long associated with pleasure, motivation and reward-seeking, also appears to play an important role in why exercise and other physical efforts feel “easy” to some people and exhausting to others, according to results of a study of people with Parkinson’s disease led by Johns Hopkins Medicine researchers. Parkinson’s disease is marked by a loss of dopamine-producing cells in the brain over time. The findings, published online April 1 in NPG Parkinson’s Disease, could, the researchers say, eventually lead to more effective ways to help people establish and stick with exercise ...

Open-label placebo improved outcomes for people in treatment for opioid use disorder

2023-04-12

BOSTON – There were more than 100,000 reported deaths from opioid overdoses in 2021, according to the Centers for Disease Control and Prevention. Methadone treatment remains one of the most reliable means of treating opioid use disorder, with success rates reportedly ranging from 60 to 90 percent for patients who stick with the long-term regimen. Adherence, though, remains a challenge. In a novel randomized clinical trial published in JAMA Network Open, senior author Ted J. Kaptchuk at Beth Israel Deaconess Medical Center ...

New agreement will help researchers study metal worlds of M-type asteroids

2023-04-12

ORLANDO, April 12, 2023 – A University of Central Florida researcher will be using the newly constructed Two-meter Twin Telescope (TTT) in the Canary Islands, Spain, to study metal-rich M-type asteroids. The work can inform the study of asteroids like 16 Psyche, an M-type, or metal, asteroid NASA is launching a mission in October 2023 to visit. The M-type asteroids offer both high concentrations of metals that could be harnessed to make structures in space as well as clues to the formation of ...

Innovative healthcare extension project enables community-based physicians to diagnose autism in young children

2023-04-12

As the number of children in need of access to timely evaluation and intervention for autism spectrum disorder (ASD) continues to rise, new research is showing how barriers to diagnoses and treatment can be reduced through an innovative training program first developed at the University of Missouri. ASD can be identified and diagnosed in young children by a well-trained clinician, and early diagnosis is vital to quickly establishing access to evidence-based therapies and interventions. However, long specialty center waitlists, distance, and ...

MD Anderson Research Highlights: AACR 2023 Special Edition

2023-04-12

HOUSTON ― The University of Texas MD Anderson Cancer Center’s Research Highlights showcases the latest breakthroughs in cancer care, research and prevention. These advances are made possible through seamless collaboration between MD Anderson’s world-leading clinicians and scientists, bringing discoveries from the lab to the clinic and back. This special edition features presentations by MD Anderson researchers at the American Association for Cancer Research (AACR) Annual Meeting 2023. In addition to these studies, forthcoming press releases will feature groundbreaking research on perioperative immunotherapy for operable lung cancer (Abstract CT005), ...

Scientists sequence genome of little skate, the stingray’s cousin

2023-04-12

Rutgers geneticists, working with an international team of scientists, have conducted the most comprehensive sequencing yet of the complete DNA sequence of the little skate – which, like its better-known cousin, the stingray, has long been viewed as enigmatic because of its shape. The scientists, writing in Nature, reported that by studying the intricacies of Leucoraja erinacea’s genome, they have gained a far better understanding of how the fish evolved from its ancestor – which possessed a much narrower body – over a period of 300 million years to become a flat, winged bottom-dweller. “We ...

The brain’s support cells may play a key role in OCD

2023-04-12

A type of cell usually characterized as the brain’s support system appears to play an important role in obsessive-compulsive disorder-related behaviors, according to new UCLA Health research published April 12 in Nature. The new clue about the brain mechanisms behind OCD, a disorder that is incompletely understood, came as a surprise to researchers. They originally sought to study how neurons interact with star-shaped “helper” cells known as astrocytes, which are known to provide support and protection to neurons. However, ...

Pragmatica-Lung Study, a streamlined model for future cancer clinical trials, begins enrolling patients

2023-04-12

The National Cancer Institute, part of the National Institutes of Health (NIH), has helped launch a phase 3 randomized clinical trial (NCT05633602) of a two-drug combination to treat patients with advanced non-small cell lung cancer (NSCLC). Called the Pragmatica-Lung Study (or S2302), this is one of the first NCI-supported clinical trials to use a trial design that removes many of the barriers that prevent people from joining clinical trials. This “pragmatic” approach aims to increase accessibility ...

Oral barrier is similar in ceramide composition to skin barrier

2023-04-12

Acylceramides and protein-bound ceramides are vital for the formation of the oral barrier in mice, similar to their role in skin, protecting from infection. The skin is the body’s first line of defense against the environment, particularly against pathogens, chemicals, and allergens. It is now known that a class of biological molecules called acylceramides and their metabolites, protein-bound ceramides, are essential to the formation of this barrier. The outermost tissues of the mouth are closely related to the skin and have similar functions—an oral barrier. However, little ...

How did Earth get its water?

2023-04-12

Washington, DC—Our planet’s water could have originated from interactions between the hydrogen-rich atmospheres and magma oceans of the planetary embryos that comprised Earth’s formative years, according to new work from Carnegie Science’s Anat Shahar and UCLA’s Edward Young and Hilke Schlichting. Their findings, which could explain the origins of Earth’s signature features, are published in Nature. For decades, what researchers knew about planet formation was based ...