—We report the first demonstration of photothermally excited vanadium dioxide (VO 2 ) RF switches. The switches operate from dc to 65 GHz. VO 2 is a phase-change material with a volatile insulator–metal transition (IMT) at 68 ◦ C, and it is a promising technology for millimeter-wave (mmWave) switching applications that require low-loss performance. However, the traditional activation of VO 2 switches using microheaters results in undesirable parasitic capacitance. We propose heating VO 2 with a laser, which decouples the excitation method from electro-magnetic (EM) design. The coplanar waveguide (CPW) switches exhibit low-loss, ultrawideband performance, with < 0.43-dB insertion loss (IL) and > 17.7-dB return loss in the ON state and > 17.2-dB isolation in the OFF state from 10 MHz to 65 GHz. The figure of merit defined as 1/(2 π R ON C OFF ) is extracted as 12.4 THz. We achieve switching times in the microsecond range using a continuous-wave 786-nm semiconductor laser.

Ultrawideband, Photothermally Excited mmWave Vanadium Dioxide Switches

: We report a novel four-port optical router that exploits non-linear properties of vanadium dioxide (VO 2 ) phase-change material to achieve asymmetrical power threshold response with power limiting capability. The scope of this study lies within the concept, modeling, and simulation of the device, with practical considerations in mind for future experimental devices. The waveguide structure, designed to operate at the wavelength of 5.0 µm, is composed of a silicon core with air and silicon dioxide forming the cladding layers. Two ring resonators are employed to couple two straight waveguides, thus four individual ports. One of the ring resonators has a 100-nm-thick VO 2 layer responsible for non-linear behavior of the device. The router achieves 56.5 and 64.5 dB of power limiting at the forward and reverse operating modes, respectively. Total transmission in the inactivated mode is 75%. Bi-stability and latching behavior are demonstrated and discussed.

Thermo-optic VO 2 -based silicon waveguide mid-infrared router with asymmetric activation thresholds and large bi-stability

CHIA-WEI TU,1 MASOUD KAVEH,2 MARTIN FRÄNZL,3 QIAN GAO,4 HARK-HOE TAN,4,5 CHENNUPATI JAGADISH,4,5 HEIDRUN SCHMITZER,6 AND HANS PETER WAGNER1,7,∗ 1Department of Physics, University of Cincinnati, Cincinnati, OH 45221, USA 2Department of Physics & Astronomy, James Madison University, Harrisonburg, VA 22807, USA 3Department of Physics, University of Leipzig, Leipzig 04109, Germany 4Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2601, Australia 5ARC Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2601, Australia 6Department of Physics, Xavier University, Cincinnati, OH 45207, USA 7Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH 45221, USA ∗wagnerhp@uc.edu

Unique reflection from birefringent uncoated and gold-coated InP nanowire crystal arrays: supplement

: We report the ﬁrst observation of cascaded forward Brillouin scattering in a microresonator platform. We have demonstrated 25 orders of intramodal Stokes beams separated by a Brillouin shift of 34.5 MHz at a sub-milliwatt threshold at 1550 nm. An As 2 S 3 microsphere of diameter 125 μ m with quality factor 1 × 10 6 was used for this demonstration. Theoretical modeling is used to support our experimental observations of Brillouin shift and threshold power. We expect our work will advance the ﬁeld of forward stimulated Brillouin scattering in integrated photonics.

Cascaded Forward Stimulated Brillouin Scattering in a Chalcogenide Microsphere

: Experimental and theoretical studies of colloidal nanoparticles have primarily focused on accurate characterization and simulation of observable characteristics, such as resonant wavelength. In this paper, we tackle the optimal design of colloidal-nanoparticle ensembles: what is the largest possible per-volume optical cross-section, which designs might achieve them, and can such response be experimentally demonstrated? We combine theory and experiment to answer each of these questions. We derive general bounds on the maximum cross-sections per volume, and we apply an analytical antenna model to show that resonant nanorods should nearly achieve such bounds. We use a modified seed-mediated synthesis approach to synthesize ensembles of gold nanorods with small polydispersity, i.e., small variations in size and aspect ratio. Polydispersity is the key determinant of how closely such ensembles can approach their respective bounds yet is difficult to characterize experimentally without near-field measurements. We show that a certain “extinction metric,” connecting extinction cross-section per volume with the radiative efficiencies of the nanoparticles, offers a quantitative prediction of polydispersity via quantities that can be rapidly measured with far-field characterization tools. Our predictions apply generally across all plasmonic materials and offer a roadmap to the largest possible optical response of nanoparticle ensembles.

Towards maximum optical efficiency of ensembles of colloidal nanorods

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Ark

Author Tools

Chat about Author

Papers

Thermo-optic VO 2 -based silicon waveguide mid-infrared router with asymmetric activation thresholds and large bi-stability

Unique reflection from birefringent uncoated and gold-coated InP nanowire crystal arrays: supplement

Cascaded Forward Stimulated Brillouin Scattering in a Chalcogenide Microsphere

Towards maximum optical efficiency of ensembles of colloidal nanorods