A metasurface made from arsenic trisulfide nanowires (yellow) transfer an inbound near-infrared frequency (red) as well as its third harmonic ultraviolet frequency (violet), which would typically be taken in by the material. Credit: Duke University
Recently proven physics opens chalcogenide glasses to applications at noticeable and ultraviolet wavelengths.
Electrical engineers at Duke University have found that changing the physical shape of a class of products frequently utilized in electronics and near- and mid-infrared photonics– chalcogenide glasses– can extend their use into the noticeable and ultraviolet parts of the electromagnetic spectrum. Already commercially used in detectors, lenses and optical fibers, chalcogenide glasses might now find a house in applications such as underwater interactions, ecological monitoring and biological imaging.
The results were published in the journal Nature Communications.
As the name indicates, chalcogenide glasses include one or more chalcogens– chemical elements such as sulfur, selenium and tellurium. Their material properties make them a strong option for sophisticated electronic applications such as optical changing, ultra-small direct laser writing (believe small rewritable CDs) and molecular fingerprinting. Due to the fact that they highly soak up wavelengths of light in the noticeable and ultraviolet parts of electro-magnetic spectrum, chalcogenide glasses have long been constrained to the near- and mid-infrared with regard to their applications in photonics.
Moving forward, Litchinitser and her colleagues are working to see if they can engineer various shapes of chalcogenides that can carry these harmonic signals even much better than the preliminary nanostrips. They think that sets of long, thin, Lego-like blocks spaced certain ranges apart might create a stronger signal at both third and 2nd harmonic frequencies.
As the name implies, chalcogenide glasses contain one or more chalcogens– chemical elements such as tellurium, sulfur and selenium. But theres one member of the household they neglect: oxygen. Their product residential or commercial properties make them a strong choice for innovative electronic applications such as optical changing, ultra-small direct laser writing (think small rewritable CDs) and molecular fingerprinting. Since they strongly take in wavelengths of light in the ultraviolet and visible parts of electromagnetic spectrum, chalcogenide glasses have actually long been constrained to the near- and mid-infrared with regard to their applications in photonics.
” Chalcogenides have actually been utilized in the near- and mid-IR for a long period of time, however theyve constantly had this basic limitation of being lossy at visible and UV wavelengths,” stated Natalia Litchinitser, professor of electrical and computer engineering at Duke. “But current research study into how nanostructures affect the method these products react to light showed that there may be a method around these constraints.”
” We discovered that lighting up a metasurface made from sensibly developed nanowires with near-infrared light resulted in generation and transmission of both the initial frequency and its third harmonic, which was really unforeseen due to the fact that the third harmonic falls under the variety where the product need to be absorbing it.”– Natalia litchinitser
In current theoretical research into the properties of gallium arsenide (GaAs), a semiconductor frequently utilized in electronic devices, Litchinitser s collaborators, Michael Scalora of the US Army CCDC Aviation and Missile Center and Maria Vincenti of the University of Brescia forecasted that nanostructured GaAs might respond to light differently than its bulk or perhaps thin-film counterparts. Because of the manner in which high-intensity optical pulses connect with the nanostructured product, really thin wires of the product lined up beside one another might produce higher-order harmonic frequencies (much shorter wavelengths) that could take a trip through them.
Think of a guitar string that is tuned to resonate at 256 Hertz– otherwise called middle C. The researchers were proposing that if produced perfect, this string when plucked may also vibrate at frequencies one or two octaves greater in small amounts.
Litchinitser and her PhD student Jiannan Gao decided to see if the very same might be true for chalcogenide glasses. To check the theory, coworkers at the Naval Research Laboratory deposited a 300-nanometer-thin film of arsenic trisulfide onto a glass substrate that was next nanostructured utilizing electron beam lithography and reactive ion etching to produce arsenic trisulfide nanowires of 430 nanometers wide and 625 nanometers apart.
Despite the fact that arsenic trisulfide completely takes in light above 600 THz– approximately the color of cyan– the researchers discovered their nanowires were transmitting tiny signals at 846 THz, which is squarely in the ultraviolet spectrum.
” We discovered that illuminating a metasurface made from judiciously created nanowires with near-infrared light resulted in generation and transmission of both the initial frequency and its 3rd harmonic, which was really unanticipated due to the fact that the third harmonic falls under the range where the material must be absorbing it,” Litchinitser stated.
This counterintuitive result is due to the impact of nonlinear third-harmonic generation and its “phase locking” with the initial frequency. “The initial pulse traps the 3rd harmonic and sort of tricks the product into letting them both travel through with no absorption,” Litchinitser said.
Moving on, Litchinitser and her associates are working to see if they can craft different shapes of chalcogenides that can carry these harmonic signals even better than the preliminary nanostrips. For example, they believe that pairs of long, thin, Lego-like blocks spaced specific ranges apart might produce a more powerful signal at both third and 2nd harmonic frequencies. They also predict that stacking multiple layers of these metasurfaces on top of one another might boost the result.
If effective, the approach could unlock a large range of noticeable and ultraviolet applications for popular electronic material and mid-infrared photonic materials that have actually long been shut out of these greater frequencies.
Recommendation: “Near-Infrared to Ultra-Violet Frequency Conversion in Chalcogenide Metasurfaces” by Jiannan Gao, Maria Antonietta Vincenti, Jesse Frantz, Anthony Clabeau, Xingdu Qiao, Liang Feng, Michael Scalora and Natalia M. Litchinitser, 5 October 2021, Nature Communications.DOI: 10.1038/ s41467-021-26094-1.
This work was supported by Office of Naval Research (N00014-19-1-2163, N00014-20-1-2558), the Army Research Laboratory Cooperative Agreement (W911NF-20-2-0078), and the National Science Foundation (ECCS-1846766, OMA-1936276).
