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Project titleTechnology of high-performing laser technology for metasurfaces and metacoating fabrication

AffiliationInstitution of Russian Academy of Sciences Institute of Automation and Control Processes, Far Eastern Branch, RAS,

Research area 02 - PHYSICS AND SPACE SCIENCES, 02-204 - Nano- and microstructures

Keywordsmetacoating and metasurfaces, nano- and femtosecond pulses, kHz - MHz repetition rates, high-speed scanning, laser beam multiplexing, microlens rasters, submicron focusing, high-performing nanofabrication

Annotation
Nowadays, a conceptual revolution in optics is taking place, due to the transition from bulk optical elements towards nanometer-thick planar arrangements of nanoscale plasmonic and/or dielectric elements (nanoantennas or meta-atoms), referred to as meta-surfaces. In recent years, such nanostructured surfaces and meta-surfaces have already been optimized to operate in the IR and optical range of the spectrum, remaining an extremely hot research topic. Research interest in this area persists as it is evidenced by appearance of more than 2,000 related papers since the beginning of the current project in 2016. This is due to the fact that, along with technically relevant planarization of the common bulk optics and related miniaturization of optical devices, the metasurfaces offer new possibilities in realization of novel sensory devices, enhancement of nonlinear effects as well as shaping and manipulation of the optical radiation at the nanoscale. In particular, the evident way towards further developments is this area relies on fabrication of nanostructures (or meta-atoms) with more complicated geometry and elemental composition, which could potentially expand functionality of the existing metasurfaces, realize novel materials exhibiting unique properties, as well as confirm the previously predicted theoretical concepts. In particular, several important topics include metasurfaces based on arrays of dielectric and hybrid plasmon-dielectric meta-atoms for wavefront shaping, allowing to realize Huygens metasurfaces, ultrathin metalenses and other optical elements, dynamically reconfigurable metasurfaces, metasurfaces for simulation of the topological insulators and enhancing the nonlinear optical effects, metasurfaces possessing high-Q resonances for sensory applications as well as 3D arrangements of meta-atoms. Meanwhile, at the current stage further progress in this area beyond the proof-of-concept experiments appears to be impossible without high-performing economically justified methods allowing fabrication and replication of diverse metasurfaces. This feature defines the extremely high practical significance of this ongoing interdisciplinary project aimed at developing high-speed laser printing of the 2D and 3D metasurfaces consisting of ordered arrangements of plasmonic, dielectric and hybrid nano-antennas. Successful elaboration of various techniques for high-speed laser printing of typical reflective- and transmissive-type meta-surfaces at an average printing rate up to 10 million elements per second and at submicron lateral resolution in the previous project will allow us to realize high-speed printing of meta-surfaces based on complex-shaped nano-elements in the ongoing project. Such complex-shaped nanoelements will be fabricated, for the first time, using structured laser beams (in particular, Laguerre-Gauss beams and vortex beams of different order) while high printing rate will be realized using the previously developed (for laser beams with a Gaussian profile) efficient combination of laser beam multiplexing and high-speed printing which will be also potentially applicable for structured laser beams. Meanwhile, multiplexing of complex-shaped laser beams will require the development of novel optimized diffraction optical elements which will be one of the key research direction of the ongoing project. The fabricated arrays of complex micro- and nano-elements will provide both a significant expansion of the produced metasurfaces functionality and the opportunity to search and observe new promising effects, as well as will allow us to adopt the developed high-speed and relatively cheap fabrication technology to new promising materials.

Expected results
The main result of the ongoing project consists in development of a scalable, high-performing and inexpensive technology allowing to produce 2D and 3D meta-surfaces via combination of several previously developed approaches boosting laser printing rate as well as “structured” laser beams - to fabricate novel types of plasmon, dielectric and hybrid meta-atoms. Realization of this project paves the way towards fundamental and applied knowledge base, which is a key element allowing to develop easy-to-implement flexible laser-based technology for printing and replicating various 2D meta-surfaces and 3D metamaterials, as well as to attest various types of metasurface-based optical, nonlinear optical and sensory devices. Development of laser-based technologies for the fabrication of plasmon, dielectric and hybrid meta-surfaces is expected to stimulate development of novel theoretical and numerical approaches used to describe and optimize the properties of the meta-surfaces, as such development will provide the direct way to experimentally verify various theoretical concepts and predictions. Practical significance of the project is related to potential appearance of a large-scale economically justified fabrication technology allowing to produce various types of meta-surfaces exhibiting unique properties, as well as related sensory and optical devices. Social significance of the project is substantiated by its main aim related to the further development of this novel research direction in Russia having high scientific and practical significance in the such rapidly evolving areas as laser physics, diffraction optics, nanophotonics, and metamaterials. Successful realization of the project is expected to contribute to improvement of skills of young researchers involved onto this international project, and potentially will stimulate the growth both the number of start-ups and new vacancies in the innovative sector of the Russian economy. Again, the successful scientific activity planned in the ongoing project will be maintained by joint research team from the Institute of Automation and Control Processes (IACP FEB RAS), Far Eastern Federal University (FEFU), P. N. Lebedev Physical Institute (LPI RAS), and Samara National University, while an additional specialist from Sydney University of Technology will be included to enrich team skills in metamaterials. Joint research team has the necessary background and collaboration experience as well as advanced technical facilities to conduct researches on laser nanofabrication, including processing with “structured” laser beams, and the related experience in detailed theoretical description of the properties of diverse meta-surfaces and related devices. The collaborative interdisciplinary character of the proposed studies, involving also the participation of a top-level specialist in the theoretical description of meta-material properties, is expected to contribute to the efficient experience exchange of related diverse knowledge with young researches, students and PhDs as well as to increase the research and publication quality in the Russian Far East allowing to bring this important research area to a new level in Russia. The project is planned to end up with 8 scientific papers published in high-rated international journals (for example, Nanoscale, ACS Applied Materials and Interfaces, ACS Photonics, Optics Letters, etc.) that are included in the first quartile (Q1) of the Web of Science database in the related scientific areas.

Annotation of the results obtained in 2020
In accordance with the project’s activity plan within a final year, the main work was divided into the following directions: (1) realization and optimization of ultrafast parallel laser processing with multiplexed vortex- and Gaussian-shaped beams for fabrication of promising hybrid metal-semiconductor nanostructures, 2D and 3D metamaterials, functional sensors for realistic medical applications, etc. as well as (2) realization of interference-based laser beam multiplexing for filamentation-free fs/ps laser printing in liquids. Within both research directions, a number of significant fundamental and applied results were obtained. In particular, to realize parallel laser nanofabrication in air and liquid media, the research team has developed original and facile approaches for generating hexagonal arrays of the laser beams for filamentation-free ablative printing of large-scale nanostructure arrays, as well as 3D multiplexing of the vortex beams focused at different planes along the propagation axis. Using such complex configurations of the vortex and Gaussian beams, we realized ultrafast laser printing of the coaxial- and circular-shaped hole arrays produced in the metal films supported by IR-transparent substrates. Produced hole arrays were further tested as sensors for identification of the molecular analytes via surface-enhanced IR absorption (SEIRA), as well as for detecting variations of the refractive index of a bulk liquid, demonstrating a spectral sensitivity up to 2100 nm per refractive index unit. Using a diphenhydramine hydrochloride, a widespread antihistamine drug, we showed that such a sensor enhances the amplitude of the characteristic IR absorption bands of the analyte by 3 orders of magnitude – in the case of the spectral matching of these bands with plasmon resonance of the coaxial holes. Taking into account (i) simplicity and high speed of the laser printing, (ii) tolerance of the optical properties of the coaxial microholes to potential microfabrication imperfections, (iii) possibility of adjusting the resonant wavelength within the practically relevant “fingerprinting” spectral region, as well as (iv) provided enhancements factor of ≈1000 (which is comparable with those provided by nano-textured substrates produced by expensive lithography-based techniques), the developed laser printing technology can find application in the serial production of the substrates for medical analytics associated with the SEIRA-based identification of various molecular analytes The optimal processing regimes were elaborated for parallel fs-laser ablation of two-layer films (the top layer is Au with a thickness of 10, 20, and 30 nm thick, while the bottom one is 100-nm thick amorphous Si). The regimes reveal possibility of fabrication of several promising types of hybrid metal-semiconductor nanostructures and metasurfaces: (i) nano-strips of Au nanoparticles incorporated into nanocrystalline (nc)-Si films and arranged into arrays at a pitch down to 500 nm, as well as (ii) nc-Si microdiscs located inside the microholes in the Au film. By combining parallel vortex-beam laser printing with an Ar-beam etching and layer-by-layer magnetron deposition, we showed the possibility of high-performing fabrication of unique diamagnetic 3D metamaterials consisting of several ordered arrays of the Au nanorings separated by a dielectric spacer. Thus, the main results obtained within the last year of the project include (i) thoroughly investigated and optimized regimes of filamentation-free laser processing of plasmonic metal films in a liquids using interference-based multiplexing of the laser beams, (ii) methods for high-performance parallel laser fabrication as well as the fabricated coaxial hole array sensors for refractive index identification and SEIRA-based identification of molecular fingerprints at ultra-low concentrations as well as (iii) methods for ultrafast fs-laser printing of hybrid metal-semiconductor nanostructures and 3D metasurfaces, demonstrating diamagnetic properties in the mid-IR and THz spectral ranges.

Publications

1. D. Pavlov, A. Porfirev, S. Khonina, L.Pan, S.I. Kudryashov, A.A. Kuchmizhak Coaxial hole array fabricated by ultrafast femtosecond-laser processing with spatially multiplexed vortex beams for surface enhanced infrared absorption Applied Surface Science, - (year - 2020) https://doi.org/10.1016/j.apsusc.2020.148602

2. P.A. Danilov, A.A. Ionin, S.I. Kudryashov, A.A. Rudenko, N.A. Smirnov, A.P. Porfirev, A.A. Kuchmizhak, O.B. Vitrik, M.S. Kovalev, G.K. Krasin Femtosecond laser ablation of thin silver films in air and water under tight focusing Optical Materials Express, 10(10), 2717-2722 (year - 2020)

3. S. I. Kudryashov, A. A. Samokhvalov, Y. D. Golubev, D. S. Ivanov, M.E. Garcia, V. P Veiko, B. Rethfeld, V. Yu. Mikhailovskii Dynamic all-optical control in ultrashort double-pulse laser ablation. Applied Surface Science, - (year - 2020)

4. S. Kudryashov, P. Danilov, L. Schneider, J. Schille, U. Loeschner, A. Nastulyavichus, N. Smirnov, A. Kuchmizhak, O. Vitrik Ultrahigh-rate polygon-facilitated generation of colloidal gold nanoparticles by multi-MHz ultrashort-pulse laser trains: key optical factors Laser Physics Letters, - (year - 2021)

5. S.N. Khonina, A.V. Ustinov, M.S. Kirilenko, A. A. Kuchmizhak, and A.P. Porfirev Application of a binary curved fork grating for the generation and detection of optical vortices outside the focal plane Journal of the Optical Society of America B, 37(6) 1714-1721 (year - 2020)

6. D. Pavlov, A. Porfirev, A. Dyshliuk, A. Kuchmizhak Coaxial Aperture Arrays Produced by Ultrafast Direct Femtosecond Laser Processing with Spatially Multiplexed Cylindrical Vector Beams Solid State Phenomena, 312,148-155 (year - 2020)

Annotation of the results obtained in 2019
Within the project activity plan, we demonstrated an efficient approach allowing generation of linear arrays of ring-shaped laser beams for high-speed parallel fs-laser printing of IR metasurface elements. It is shown that the Multiplexing of azimuthally polarized laser beams was shown to give the best results in terms of packaging as well as symmetry and uniformity of the generated laser beams in array, which is due to the absence of a phase singularity and a longitudinal electric field component in such beams. The proposed approach permits multiplexing of ring-shaped beams within more complex patterns, for example, beams arranged in two lines with a half-period offset, which potentially allows their usage for laser processing of hexagonally arranged nano- and microstructures. The developed beam multiplexing strategy was applied in ultrafast parallel laser printing of IR metasurfaces consisting ordered arrays of coaxial-shape micro-holes drilled in thin gold films. Fabricated coaxial microhole arrays support strong lattice-type plasmon resonance, with its spectral position determined by both by the array period and the geometry of holes (I particular, the ratio between diameters of the outer hole and the inner disk). Good reproducibility and low cost fabrication being combined with tunability of the lattice-type plasmon resonance of the IR metasurfaces make the developed parallel laser printing, promising for the SEIRA-based plasmonic sensors. Also, detailed comparative studies of the ablation of the thin silicon- and glass-supported Ag and Au films by tightly focused fs laser pulses revealed that even for 1-mm thick capping layer of water filamentation and distortion of the Gaussian intensity distribution develops, when the peak laser power exceeds the critical self-focusing energy about 1 MW. Ablative formation of through microholes with smooth rim was shown to occur in a liquid at lower pulse energies, while at high pulse energies under the action of a shock wave developed in the liquid, delamination of the metal film can be observed. High-performing fs-laser fabrication of nanohole arrays simultaneously drilled in thin films via multi-beam interference was developed. For MHz pulse repetition rate and about 100 micro-beams in the interference pattern, the developed approach permitted to produce an array of nanoholes at processing rate of 10^7-10^8 elements per second. The developed approach is believed to be easily transferred to a liquid-medium processing arrangement which will allow to realize ultrafast laser printing of large-scale microhole arrays in air (lens above the liquid surface) or immersion surroundings within the next year of the project. Finally, we demonstrated a multifunctional sensor produced by ultrafast fs-laser parallel processing of thin Au films enabling detection of gases, local and bulk refractive index sensing, as well as the SEIRA-based fingerprinting of organic molecules via their characteristic IR absorption bands. The sensor was shown to detect ethanol vapors at threshold concentrations of 20 mg/L, as well as to provide spectral sensitivity to bulk refractive index changes of 1600 nm per refractive index unit at figure-of-merit of 12, and identification of thin dielectric layers with a thickness of less than 1 nm. Upon collective excitation of lattice-type plasmon resonances, an array of parabolic nanobumps provided significant enhancement of local EM-field amplitude providing 60-fold increase of the intensity of characteristic IR absorption bands of the analyte.

Publications

1. A. Porfirev, S. Khonina, Y. Azizian-Kalandaragh, M. Kirilenko Efficient generation of arrays of closed-packed high-quality light rings Photonics and Nanostructures-Fundamentals and Applications, 37, 100736 (year - 2019)

2. D.V. Pavlov, A.Yu Zhizhchenko, M.Honda, M. Yamanaka, O.B. Vitrik, S.A. Kulinich, S. Juodkazis, S. I Kudryashov, A.A. Kuchmizhak Multi-Purpose Nanovoid Array Plasmonic Sensor Produced by Direct Laser Patterning Nanomaterials, 9, 1348 (year - 2019)

3. N. Smirnov, S. Kudryashov, P. Danilov, A. Nastulyavichus, A. Kuchmizhak, O. Vitrik, A. Rudenko; A. Ionin Femtosecond laser ablation of a thin silver film in air and water Optical and Quantum Electronics, - (year - 2020)

4. S.I. Kudryashov, P.A. Danilov, A.P. Porfirev, A.A. Rudenko, N.N. Melnik, A.A. Kuchmizhak, O.B. Vitrik, A.A. Ionin Оптические и структурные эффекты при многоимпульсной интерференционной фемтосекундной лазерной фабрикации метаповерхностей на тонкой пленке аморфного кремния Письма в ЖЭТФ, 110(11), 759 – 764 (year - 2019)

5. - Scientists develop high-precision sensor based on laser-textured gold film Phys.org, - (year - )

6. - Разработан высокочувствительный сенсор из золотой нанопленки Indicator, - (year - )