Finding high-Q resonant modes in a dielectric nanocavity
Scientists have developed a reliable way to discover the high-Q modes in a dielectric nanocavity
2021-03-22
(Press-News.org) Optical resonators provide the foundation of modern photonics and optics. Thanks to its extreme energy confinement, the high-Q-factor optical resonator optimizes light-matter interaction and photonic device performance by enabling low-threshold laser and enhanced nonlinear harmonic generation.
Two typical structures, the photonic crystal cavity and the whispering gallery cavity, are frequently used to obtain extremely high-Q factors. However, these structures may require dimensions that are comparable to--or several times larger than--the operating wavelength. Whether there is a general way to find out all high-Q modes in a dielectric nanocavity of arbitrary shape has been a fundamental question.
A research team from University of New South Wales Canberra, The Australian National University, and Nottingham Trent University recently developed a robust recipe for finding high-Q modes in a single dielectric nanocavity, as reported in Advanced Photonics.
Subwavelength high-index dielectric nanostructure
Subwavelength high-index dielectric nanostructures are a promising platform for realizing CMOS-compatible nanophotonics. These nanostructures are based on two main factors: support of electric and magnetic Mie-type resonances and reduced dissipation. A single dielectric nanoresonator (e.g., a disk with finite thickness) supports the high-Q mode (also known as the quasi-bound state in the continuum). By exploring the quasi-bound state in the continuum, Huang et al. found a way to easily find many high-Q modes, using Mie mode engineering to cause a hybridization of paired leaky modes, resulting in avoided crossing of high- and low-Q modes.
Robust, pair-wise approach
Interestingly, both the avoided crossing, and crossing of eigenfrequencies for the paired modes, led to the discovery of high-Q modes, representing a simple yet robust way of finding high-Q modes. The team experimentally confirmed high-Q modes in a single silicon rectangular nanowire. The measured Q-factor was as high as 380 and 294 for TE(3,5) and TM(3,5), respectively (see figure). The authors attribute the resultant high Q-factors to the suppression of radiation in the limited leaky channels or minimized radiation in momentum space.
According to senior author Andrey E. Miroshnichenko of the School of Engineering and Information Technology at University of New South Wales, "This work presents a straightforward method of finding out high-Q modes in a single dielectric nanocavity, which may find applications in integrated photonic circuits, such as ultra-low-threshold laser for on-chip light sources, strong coupling for polariton lasing, and enhanced second or third harmonic generations for night vision."
INFORMATION:
Read the open access research article: Lujun Huang, Lei Xu, Mohsen Rahmani, Dragomir N. Neshev, and Andrey E. Miroshnichenko, "Pushing the limit of high-Q mode of a single dielectric nanocavity," Adv. Photon. 3(1), 016004 (2021), doi 10.1117/1.AP.3.1.016004
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-03-22
The tuberculosis (TB) burden in the WHO European Region as a whole is decreasing, and is down 19% overall for 2015-2019, according to the latest WHO/European Centre for Disease Prevention and Control (ECDC) report Tuberculosis surveillance and monitoring in Europe 2021 (2019 data).
Regional TB mortality has gone down, declining by 9.4% between 2018 and 2019. This is notably higher than the average global decline in TB mortality (3.7%) and enough to have reached the End TB Strategy milestone of a 35% reduction by 2020 compared to 2015.
However, TB is second only to COVID-19 as an infectious disease that kills, and drug resistance is a major concern. There are also worrying indications that the COVID-19 pandemic may stall progress or cause significant setbacks in the fight against TB.
The ...
2021-03-22
Developing a standardized drying protocol for goldenseal could lead to more predictable health applications and outcomes by preserving the alkaloids found in the plant, which is native to Appalachia, according to Penn State researchers, who conducted a new study of the medicinal forest herb.
The roots and rhizomes of goldenseal -- Hydrastis canadensis -- have been used for hundreds of years as a source of antimicrobials and compounds to treat intestinal ailments, noted study co-author Eric Burkhart, associate teaching professor, ecosystem science ...
2021-03-22
Antibody injections are a highly desirable treatment for people with chronic diseases such as cancer, psoriasis, Crohn's disease and arthritis. And recently, antibodies have been in the news as a promising treatment for severe cases of COVID-19.
But the costly, time-consuming manufacturing process to produce antibodies prevents these treatments from being accessible to most patients.
Andrew Zydney, Bayard D. Kunkle Chair and professor of chemical engineering at Penn State, has identified a new method to manufacture antibodies, which could drive down the production cost. His research results were recently published in Biotechnology Progress.
"If you look at the top 10 best-selling medications, by annual sales, eight ...
2021-03-22
A new type of rock created during large and exceptionally hot volcanic eruptions has been discovered beneath the Pacific Ocean.
An international team of researchers including the University of Leeds unearthed the previously unknown form of basalt after drilling through the Pacific ocean floor.
The discovery suggests that ocean floor eruptions sourced in the Earth's mantle were even hotter and more voluminous than previously thought. Report co-author is Dr Ivan Savov, of Leeds' Institute of Geophysics and Tectonics, in the university's School of Earth and Environment.
He said: "In an era when we rightly admire discoveries made through space exploration, our findings show there are still many discoveries still to make on our ...
2021-03-22
The increasing frequency and severity of extreme weather events like droughts and floods have taken a toll on the midwestern U.S. in recent years, putting a major strain on the region's farmers. From 2001 to 2010, the Federal Crop Insurance Program, a government program created to protect farmers from crop loss, covered $4.1 billion in damages; in 2011 alone, the program paid out $10.8 billion.
With the largest U.S. crop -- corn -- conservatively estimated to drop in yield anywhere from 20 to 80 percent due to extreme weather exacerbated by climate change, insurance claims may skyrocket to levels that may not be sustainable. But researchers from the Yale School of the Environment (YSE) found that by considering soil properties when determining insurance premiums ...
2021-03-22
Less than a decade after unveiling the "Map of Life," a global database that marks the distribution of known species across the planet, Yale researchers have launched an even more ambitious and perhaps important project -- creating a map of where life has yet to be discovered.
For Walter Jetz, a professor of ecology and evolutionary biology at Yale who spearheaded the Map of Life project, the new effort is a moral imperative that can help support biodiversity discovery and preservation around the world.
"At the current pace of global environmental change, there is no doubt that many species will go extinct before we have ever learned ...
2021-03-22
Efficient conversion of CO2 is strategically significant for alleviating the energy crisis and achieving the goal of carbon neutrality. One promising conversion route is the hydrogenation of CO2 to methanol using a renewable energy-based "green hydrogen" source.
Traditional metal oxide catalysts for this reaction typically require a high temperature (>300 oC), which tends to promote undesired reverse water-gas shift (RWGS) side reactions, thus producing a large amount of CO as the by-product.
Introduction of transition metal components onto metal oxides can promote the activation of H2, thereby reducing the reaction temperature, but this also facilitates excessive hydrogenation of CO2 to CH4, leading to lowered methanol selectivity. Further improvement of the performance ...
2021-03-22
Physicians across the country have analyzed the emerging scientific data about the long-term effects of COVID-19, creating an initial knowledge base about the clinical experiences of so-called "long-haulers" - patients with COVID-19 who experience prolonged symptoms and/or the emergence of new ones well after the initial viral infection has resolved. A comprehensive review published today in Nature Medicine offers an initial glimpse of the multi-organ effects of long-term COVID-19 and suggests a framework for the care of COVID-19 long-haulers through dedicated, multidisciplinary clinics.
"It was important to respond to our patients' concerns and pay close attention to the symptoms they were experiencing beyond the acute phase of COVID-19," said Kartik Sehgal, MD, a lead ...
2021-03-22
Oncotarget published "Predictors of immunotherapy benefit in Merkel cell carcinoma" which reported that the authors retrospectively analyzed electronic health records and next-generation sequencing data of 45 patients treated at our institution from 2013 to 2020 to understand clinical and genomic correlates of benefit from immunotherapy.
They reported that their cohort predominantly included individuals with stage III disease at primary disease diagnosis and individuals with stage IV disease at recurrent/metastatic disease diagnosis.
Less advanced stages at primary disease diagnosis and shorter disease-free interval between completion of initial treatment and recurrence were each associated with greater odds of response.
Single-nucleotide ...
2021-03-22
Oncotarget published "Cytogenetic and molecular landscape and its potential clinical significance in Hispanic CMML patients from Puerto Rico" which reported that one hundred and eleven Hispanic CMML patients from Puerto Rico were diagnosed in our institute from 2009 to 2018. Karyotypes were available in one hundred and seven patients.
Compared to previously published data, Hispanic CMML patients in this study had significantly lower rates of overall cytogenetic abnormalities and trisomy 8.
Among one hundred and eleven Hispanic CMML patients, 40-gene myeloid molecular profile tests were performed in fifty-six CMML patients.
Previous studies indicated that mutated ASXL1, DNMT3A, NRAS, RUNX1, and SETBP1 may associate with an unfavorable prognosis ...
LAST 30 PRESS RELEASES:
[Press-News.org] Finding high-Q resonant modes in a dielectric nanocavity
Scientists have developed a reliable way to discover the high-Q modes in a dielectric nanocavity
