Doped metal oxide nanocrystals (MO NCs), such as Sn doped In2O3 (ITO) or doped zinc oxide (ZnO) and cadmium oxide (CdO) display localized surface plasmon resonances due to their carrier density around 10^21 cm^-3. Such optical properties are tunable across the near infrared spectral range upon doping control. The dynamic modulation becomes possible through the pseudo-capacitive charge injection by applying an electrochemical potential or through the interaction with light beyond their bandgap, i.e. photodoping. The latter allows accumulation of multiple electrons within one NC through the absorption of several photons, as the holes react with sacrificial hole scavengers. Capacitance values comparable to commercially available supercapacitor materials are extracted. In this presentation, I will discuss the fundamental physical and chemical processes underlying photodoping of MO NCs. I will further discuss the possibility of multi-charge transfer processes following photodopin and highlight open questions with regards to their implementation as novel light-driven multi-charge accumulation components in the next generation of solar energy devices.

The coupling of ZnO-based nanomaterials with organic photosensitizers (PS) is potentially interesting for cancer treatment under X-ray. In these conditions, ZnO nanoparticles (NPs) convert the X-ray into UV-Vis emission, promoting the PS excitation and producing reactive oxygen species (ROS). Main advantages for in vivo applications are ZnO photostability and biocompatibility, even if its efficient coupling with different PS (typically porphyrin) is still a controversial issue, as both a high ZnO luminescence yield and a good overlapping of ZnO emission-PS absorption spectra are necessary, along with a suitable energy transfer between ZnO and PS. In this perspective, the aim is the investigation of the optical properties of an ad-hoc system composed of porphyrin functionalized ZnO NPs anchored on SiO2 NPs (ZnO/SiO2). The goal is the understanding of the optimal conditions for a good energy transfer efficiency of ZnO-porphyrin structures, including the role of ZnO-PS proximity, to promote their application in anti-cancer therapies and imaging with ionizing radiations. First, amorphous ZnO NPs of 5-6 nm were anchored onto SiO2 NPs (~80 nm); then, ZnO/SiO2 was functionalized with different porphyrin contents (tetrakis(4-carboxyphenyl)porphyrin, TCPP, 0.3 – 3.0 wt%) by exploiting a silane grafting agent (3-aminopropyl)triethoxysilane. The structural characterization demonstrated that increasing TCPP amounts were bonded to SiO2 depending on the TCPP loading. The optical properties were preliminary tested in dimethylformamide, used as solvent reaction for TCPP anchoring on SiO2. The Photoluminescence Analysis (PL) revealed a high luminescence of ZnO NPs and the occurrence of a radiative energy transfer between ZnO and TCPP, that was not visible in a mechanical mixing of ZnO and TCCP, highlighting their optical interaction upon functionalization. Besides, TCPP emission was hugely enhanced under X-ray in the Radioluminescence (RL), whereas no enhancement was detectable in the mechanical mixing, that could be generated by both re-absorption of ZnO emitted photons and by ionizing radiation energy deposition in the porphyrin surroundings, whose efficiency depend on the TCPP arrangement and spatial distribution. In conclusion, this work paves the way to the deeper understanding of the correlation between the synthesis and the optical interactions of ZnO scintillator coupled with organic moieties to improve their luminescence performances.

Directional single-photon sources are of great interest for quantum communication and wireless optical nanocircuits. So far, directional nanoantennas are mostly fabricated by top-down approaches, typically expensive, time-consuming, non-scalable, and require state-of-the-art nanofabrication facilities. On the other hand, bottom-up approaches are relatively fast, inexpensive, and have great scalability. In particular, DNA origami method has been developed into a flexible, designable, and deterministic method for arranging plasmonic nanoparticles with molecular-level precision. These features make DNA origami an attractive method for the fabrication of directional optical nanoantennas. This work exploits DNA origami technology to construct single optical nanoantennas driven by single fluorescent molecules to obtain direction single-photon emission. The morphology and spatial arrangement of nanosized antenna elements are precisely controlled, and single quantum emitters are accurately attached to the hot spot of the antennas to provide local driving power in the optical frequency range. The presented method is a deterministic, precise, convenient, and cost-effective bottom-up fabrication method for mass production of the directional single-photon source.

Novel amorphous materials for photonics applications have been the main focus over the last decades because of the large spectrum of applications, which range from optical communication, lasers, photonic components, energy harvesting to medicine. Recently, the attention has shifted to the glass-ceramics (GCs) realm. These materials offer the advantages of glass production combined with the enhanced properties from the embedded crystals, solving several drawbacks of conventional ceramics, especially porosity. Enhanced non-linear optical effects have been demonstrated in alkali niobium-germanate, silicate and phosphate glasses and glass-ceramics. However, the crystallization behaviour depends strongly on the bulk compositions. Thus, understanding the pristine glass's physico-chemical properties is necessary to develop new materials of greater importance in photonic applications, especially for energy harvesting. Nevertheless, systematic studies on niobate-bearing glasses and glass-ceramics are surprisingly scarce. This contribution aims to provide an overview of glass-ceramic materials (amorphous and partially crystallized), which exhibit non-linear optical properties for use in electro-optical devices. The incorporation of alkali niobates in rare-earth–activated aluminosilicate glasses will be used as a model to conceptualize how glasses and their crystallization can be designed to enhance or create new properties.

We report the shaping of the polarization state of a femtosecond Bessel beam, which produces a high-intensity focus over a distance largely exceeding the Rayleigh range and less sensitive to Kerr effect than Gaussian beams. Here, we utilize a laser fabricated space variant half-waveplate based on well-designed nanograting distribution to create a Bessel beam exceeding 60 µm length with a helical polarization rotation from 0° to 180° along the propagating path. We use this beam to inscribe a high circular birefringence inscription in silica.

Various types of nanomaterials play currently important role in different fields of medicine. For example, silica–calcia system is a well-known basic composition of bioactive glass that is used in regenerative medicine. Glass nanostructures might show higher activity and broader range of applications in comparison to their well-known microsized counterparts. We present studies on nanoparticles (average diameter <100 nm) of bioactive glass showing photoluminescence due to a modified composition of silica–calcia system. The sol–gel route was used to fabricate the particles. To ensure photoactivity, the composition of glass was modified by addition of lanthanide ions, phthalocyanine complexes with metals, carbon structures, or zinc oxide. The optical properties (absorption and photoluminescence spectra) of the samples as well as their structural and morphological properties were examined. The results showed that glasses were active in different spectral ranges of electromagnetic spectrum – from ultraviolet to near infrared – depending on the activators. Photoactivity was presented as luminescent and photocatalytic properties as well as singlet oxygen generation. The bioactivity tests indicated that when particles were immersed in the simulated body fluid, ions release to the medium appeared and hydroxyapatite formation on the glass surface was observed. Described systems could be used, for example, for monitoring structural changes of the glass immersed in biological fluids, bioimaging, photodynamic therapy, or photocatalysis. Research was supported by the National Science Centre (Poland) grant No. 2016/22/E/ST5/00530.

An intriguing approach to add unique photonic properties to glass is the generation of luminescent particles in the glass. This is achieved either by doping of ex-situ prepared nanocrystals into glass or by in-situ growth of nanocrystals in the glass. This paper will present recent progress on direct doping of upconversion nanocrystals for fundamental investigations, various doping technique of diamond nano-/micro-crystals for magnetic field sensing as well as precipitation of gold nanoparticles for plasmonic-based applications.

The possibility of fabricating all-fiber nonlinear devices based on periodically poled silica fibers allows for overcoming most of the issues of free space nonlinear optics, such as thermal instabilities and high costs of nonlinear crystals. In this talk the most recent results related to the topic are presented, including some interesting applications of periodically poled fibers, such as the generation of high harmonics and of Frequency Combs when exploited in cavity configuration.

This Conference Presentation, Composite material glass photonics: from 2D materials to catalysts inside active optical fibres, was recorded at Photonics Europe Strasbourg France.

We propose a novel femtosecond laser writing approach allowing the fabrication of arbitrary long optical waveguides in coreless optical fibers, directly through the coating. In a silica fiber, we demonstrate a 4m-long single-mode waveguide operating at 1 µm. The refractive index distribution and the spatial mode are characterized. Using a cutback method, the propagation losses of the laser-inscribed waveguides are properly measured. This approach paves the way toward the fabrication of complex arrangement of cores in various optical fibers.

Compact laser sources are crucial for the next generation of photonic integrated circuits, where bulky mechanical components and other optical bench top systems can be realized on a single tiny chip. Similarly, biological sensing, environmental real-time monitoring and telecommunications all benefit from the advances seen in on-chip photonic components, in particular, active devices such as the amplifier and laser which have significant challenges in being implemented on a silicon substrate. The study of Erbium doped Aluminium Oxide (Al2O3:Er3+) has attracted significant interest from the research community due to its high solubility for rare-earth ions, wide optical transparency, and capability to be integrated as a hybrid coating or patterned into waveguides on a Si substrate using conventional fabrication techniques. Results point towards amorphous Al2O3 as an ideal candidate for further research into the discovery of amplifiers and lasers for photonic integrated circuits (PIC). Here, we report on the spectroscopic parameters as well as prospects for Al2O3:Er3+ doped films and their integration onto an existing low-loss waveguide platform for the realization of amplifiers and lasers. A review of past results will be given with pathways towards optimized films and improved laser performance in the future.

At present, the market of compact visible light sources (both coherent and incoherent) is dominated by wide-bandgap semiconductor devices. While the modern electroluminescent diodes (LEDs) allow obtaining the full palette of colors of visible light, the semiconductor laser diodes (LDs) cover this range only partially, enabling lasing in 400-488 nm, 510-520 nm, and 630-690 nm and leaving the remaining part of the visible spectrum not addressed. The missing wavelengths are to some extent complemented by DPSSLs with frequency conversion but suffer from lower efficiency and more complex design. The remaining spectral gaps are continuously the subject of intensive research and development works, which cover the investigation of a new light-emitting media, both semiconductors, and solid-state materials. Among these, dysprosium-doped glasses are of specific interest due to the unique possibility of obtaining yellow emission and lasing, hardly available to any other laser sources, specifically when compact design, high output power, and good beam quality are of concern. Additionally, the favorable energy scheme of this ion allows excitation with wide-bandgap InGaN/GaN semiconductor diodes emitting in the violet-blue range. In this work, we summarize the results of investigation and analysis of the luminescent properties in the visible, and specifically yellow part of the spectrum, of a set of optically active glasses doped with dysprosium ions. The investigated materials cover fluoride (ZBLAN), telluride (TZN), and silica glasses, as well as composite materials based on polymer matrices doped with active nanocrystals. The research was focused on a detailed analysis of major spectroscopic features – absorption, emission, and excitation spectra, fluorescence kinetics, pumping schemes, and deexcitation processes, followed by the analysis of potential lasing properties of investigated materials. ACKNOWLEDGMENT: The research presented here has been supported by the FOTECH-1 project granted by Warsaw University of Technology under the program Excellence Initiative: Research University (ID-UB).

Mid-infrared lasers operating near 3 µm are a subject of considerable research effort in recent years. The main reason is the broad range of potential applications for such sources in the field of medicine, environmental monitoring and free space communication. For many applications pulsed mid-infrared light sources with high output energy, short pulse duration (to reduce the impact of thermal background) and good pulse-to-pulse stability are preferred. A promising candidate for such pulsed light sources is a mid-infrared fiber laser realised using fluoride glass fibers doped with rare earth ions (for example erbium or dysprosium). In this contribution pulsed operation was obtained by implementing the Q-switching technique in a laser setup consisting of a fluoride fiber pumped with near infrared laser diodes. The obtained pulses have output energy above 100 µJ, with pulse width below 50 ns and repetition rate in the kilohertz range.

Fiber-based supercontinuum (SC) generation has been a subject of intense interest over the last decade, with a significant impact on both basic science and industry. New uses for SC fiber sources are constantly emerging due to their unique properties that combine high brightness, visible to mid-infrared (MIR) wavelength coverage, fiber delivery, and single-mode output. Recent years have seen significant progress in overcoming the current shortcomings of SC sources in terms of wavelength coverage towards the 2 to 20 mu molecular fingerprint mid-infrared (MIR) region and in the ultraviolet (UV) down to 100 nm, while also improving stability, noise, coherence, power density, and robustness. In this talk, we will review all the recent advances in supercontinuum generation in a range of specialty optical fibers including: fluoride, chalcogenide, telluride, and silicon-core fibers for the MIR; UV-grade silica fibers and gas-filled hollow-core fibers for the UV range; and all-normal dispersion fibers for ultra-low noise coherent SC generation. Significant developments have been made in reaching target UV and MIR wavelength ranges, and the fiber SC has matured considerably to become a truly disruptive technology able to meet a range of societal and industrial challenges.

Over the last decade, the ultrafast short-wave infrared (SWIR: 1600 – 2500 nm) laser market has been promisingly growing with Thulium-doped fibre systems as key players. An advantageous low-loss atmospheric transmission, a deep biological tissue penetration as well as various absorption lines of gases and biomolecules drive the demand on efficient light sources operating at this wavelength band. To unleash the full potential for expanding applications the laser system has to present highly integrated, cost-effective, rugged, compact turn-key solutions. Broadband wavelength tuneability can ensure a one more level of versatility for laser systems and extend areas of their applications. Principle limitations of achieving wide tuning wavelength ranges are generally defined by the spectral bandwidth of the gain and traditional tuneability techniques, typically relying on implementation of bulk and expensive tuning elements. In this presentation, we will present nearly 90 nm tuneability in ultrafast Tm-doped fibre laser spanning from 1873 to 1962 nm by implementing variable feedback for efficient control of the excitation level of the active medium. To realise self-mode-locking we explore a heavily-doped active fibre enriched with Tm ion clusters to reinforce its saturable absorption mechanism with 23% modulation depth and 95 MW/cm2 saturation intensity. We observed both experimentally and numerically intriguing implications on the saturation level, gain, and glass matrix. The highest laser efficiency is observed with 20% feedback, generating 580-fs soliton pulses at 1877 nm central wavelength with 1.5 nJ output pulse energy. Numerical model combining the nonlinear Shrödinger and population inversion rate equations for the gain medium helps to unveil nonlinear pulse evolution under the influence of dynamically varying gain spectrum. The resulting laser system presents a compact and straightforward approach to achieve laser generation with a broad wavelength tuneability, high laser stability, and power performance, which can be translated to unexplored so far wavelength ranges.

Ultrashort high-energy visible pulses have enabled unprecedented opportunities in temporally resolving ultrafast dynamics in physics, chemistry, and biology. Until now, high-energy sub-10 fs visible pulses have been mostly obtained through complex non-collinear optical parametric amplification setups, followed by some pulse post-compression technique. Here, we present an alternative approach, which relies on considering the typically-undesired multimode nature of large-core hollow-core capillary fibers (HCFs) as an essential asset. In our experiments, 1 mJ 175-fs-long pulses centered at 1035 nm, emitted by an Yb:KGW (Pharos – Light Conversion) laser, were coupled into a 3-m-long HCF (few-cycle Inc.) filled with Argon gas. At a selected pressure of 2.9 bar, a fast energy transfer from the laser broadened via self-phase modulation towards the arising visible light was observed starting at around 0.8 mJ laser pulse energy. At the maximum pulse energy of 0.94 mJ, a continuous spectrum of visible light between 800 nm and 400 nm was measured, with an overall energy of approximately 30 µJ. To understand this process, we implemented 3D carrier-resolved pulse propagation simulations based on the guided mode theory. The simulations predict the direct formation of a pulse of about 5 fs right at the exit of the fiber, considering the visible spectrum in the range 525 - 750 nm. We found that the presence of higher-order modes is crucial to generate such visible pulses and that the Kerr effect is the dominant nonlinearity enabling the modal energy transfer. Experimentally, we characterized the visible pulses by means of a transient-grating frequency-resolved optical gating setup (TG-FROG). At 0.94 mJ and 2.9 bar, a visible pulse duration of 4.6 fs was measured. We also implemented a cross-correlation TG-XFROG, using the separately-compressed laser light and the visible pulses, which demonstrates the possibility of directly implementing high-energy NIR-pump VIS-probe measurements on a sub-10-fs scale.

Wavelength conversion of 1065nm ns pulses in SF6- and CF4-filled photonic bandgap fiber is investigated. We obtain record conversion efficiency to the first stokes of ~70% in a 6m long fiber and observe polarization-dependent efficiency.

The increase of spectral purity for a laser (fibers, microsphere, integrated optics, etc.) is of major interest for various optical functions (sources, sensors, filters, optical clocks, etc.) and for different fields of application (optical communication, spectroscopy, defense, metrology, environment, health, etc.) as the system’s margin could be considerably improved. One of the most promising approach to generate compact and narrow linewidth lasers is based on the stimulated Brillouin scattering (SBS) optical nonlinearity. The establishment of SBS in an optical cavity gives rise to the emission of a Stokes wave, which is more coherent than the optical pump used in the linear process. Impressive noise performances have been reported in such Brillouin lasers. They are measured in terms of frequency noise and reduction factor higher than 40 dB may be reached when the noise level of Stokes wave is compared to that of the pump. Frequency noise analysis consists in studying the fluctuations of a laser optical frequency. (A derivative links phase noise and frequency noise). Measurements of the laser power spectral density in the electrical domain (DC-MHz) using an electrical spectrum analyzer give all the properties of the laser line (centered on its optical frequency). The wavelength-tunability could be a very attractive property for many applications. We realize such a tunable C-Band laser with excellent performances for the whole wavelength range. Its intrinsic laser linewidth is a few ten’s of mHz. Its integrated linewidth is in the kHz (or sub-kHz) range and it could be potentially improved by locking the laser signal to a better stable reference. The frequency noise reduction is above 60 dB. . Its integrated linewidth is in the kHz (or sub-kHz) range and it could be potentially improved by locking the laser signal to a better stable reference. The nice point of our approach is that different commercial tunable C-band sources may be used, for which we simply improved the spectral properties. The method can be generalized to other wavelength ranges.

The first ruby laser, developed by Theodore Maiman in 1960 initiated the era of laser technology, characterized by rapid progress in all fields benefiting from unique features of coherent radiation sources. Among various types of lasers developed so far, fiber lasers plays continuously increasing role in those areas where high output powers and high efficiency combined with single mode operation and excellent heat dissipation are of concern. In the recent years, fiber laser-based systems dominated the market of material processing (cutting, welding, hardening, etc.) and military systems, while rare-earth doped fiber amplifiers became a key element of modern telecommunication systems. It should be noted, however, that despite a large number of fiber lasers manufacturers around the world, there are only a few companies with technological skills enabling manufacturing the active fibers of sufficient quality. In this work we would like to show the progress of Polish research teams in this field. The R&D works, conducted for the last few years in cooperation with Laboratory of Fiber Optic Technology at the Faculty of Chemistry of Maria Curie-Skłodowska University, Lublin, Poland, enabled mastering the technology of manufacturing the first active optical fibers applicable to laser systems. In this work the overview of the technology will be presented together with the results of characterization of ytterbium, erbium, thulium and dysprosium doped optical fibers, dedicated to laser applications. The absorption/emission spectra and luminescence kinetics profiles of active preforms and optical fibers will be discussed and compared to the results obtained for commercially available samples. Also the results of amplification and laser experiments will be presented and perspectives of the active fiber technology in Poland will be discussed. This work has received partial support from the National Centre for Research and Development through project NMKM+ (TECHMATSTRATEG1/348438/16/NCBR/2018).

Luminescence of Bi3TeBO9 micro-crystals doped with Nd3+ ions D. Kasprowicz,1 T. Zhezhera,1 P. Głuchowski,2 M. Chrunik,3 A. Majchrowski,3 1Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznań, Poland, 2Institute of Low Temperature and Structure Research of Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland 3Institute of Applied Physics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw, Poland, е-mail: dobroslawa.kasprowicz@put.poznan.pl Bi3TeBO9 crystal is an excellent nonlinear optical material as well as an efficient host matrix for luminescent rare earth ions.1,2 Investigated Bi3TeBO9 crystalline powders were synthesized by means of the modified Pechini method. The vibrational properties of Bi3TeBO9 were studied using µ-Raman spectroscopy.3 Moreover, Bi3TeBO9 powders doped with Nd3+ ions show the efficient near-infrared quantum cutting process by cooperative down-conversion of active Bi3+ and Nd3+ ions. As a result, the investigated systems efficiently concentrate the ultraviolet/visible radiation in the near-infrared spectral range and can be potentially used as effective spectral converters in new multi-functional miniaturized optical devices. Acknowledgement This work was supported by the Research Project of the Polish Ministry of Sciences and Higher Education 0511/SBAD/2151. References [1] M. Xia, X. Jiang, Z. Lin, R. Li, J. Am. Chem. Soc. Journal, 2016, 138, 14190–14193. [2] M. Daub, M. Krummer, A. Hoffmann, L. Bayarjargal, H. Hillebrecht, Journal, Chem Eur J, 2016, 22, 1–8. [3] D. Kasprowicza, T. Zhezhera, A. Lapinski, M. Chrunik, A. Majchrowski, A.V. Kityk, Ya. Shchur, J. Alloys Comp., 2018, 782, 488–495.

ransparent glass-ceramics are still on the top in the field of functional photonic materials used in optical fiber technology. Generally, the glass-ceramic (GC) material consists of glass and suspended in amorphous volume nanocrystals doped with lanthanide ions. The controlled degree of crystallization is carried out in the process of heating materials at a specified temperature and at the right time of the experiment. Due to this, the glass-ceramic optical waveguide structures thus get better emission parameters (high quantum efficiency) compared to analogous amorphous structures, while maintaining the high optical quality. Nowadays, the GC optical fibers technology is complicated and consist many steps, wherein each stage of the experiment the material is thermal treated (melting → bulk annealing → drawing fibers → heat-treatment). As a result, this process is very complex and controlling the size and density of nanocrystals is difficult. In our work we focused on the possibility to develop glass-ceramic optical fibers by one-step fabrication process. This is an innovative approach to the issue of nucleation, as well as to the growth of nanocrystals during the cooling of the vitreous mass. In fact, the crystallization process control through selecting the rate of cooling from the supercooled liquid zone during optical fibre drawing has not yet been investigated systematically. The influence of selected crystallization mechanism (nucleation and growth rates) on luminescent properties of GC is a kind of alternative approach to the currently used multi-step methods. Our experiment opens new possibilities for obtaining transparent glass-ceramic optical fibers with a high-density of nanocrystals embedded in their structure.

In recent years Hollow Core fibres (HCF) technology has improved its performance indicators by orders of magnitude in many directions, making it a contender for the next generation of numerous fibre based optical devices, as well as an enabler for novel applications currently unthinkable with standard glass-guiding fibres. Loss wise, air guiding fibres with lower loss than fundamentally achievable in any other glass are now possible at wavelengths spanning from the visible to the VCSEL and laser delivery wavelengths of 850 and 1060 nm, respectively. At telecommunication wavelengths, the loss of HCFs is now down to 0.22dB/km, with a rate of progress that seems to indicate that further improvements are possible. And in the mid-infrared, HCFs made of silica of soft glasses with broad bandwidth and sub dB/m or lower are becoming available. Besides, the latest generation of HCFs is now capable of producing better polarization purity, transmitting higher CW powers over longer distances without incurring in nonlinear spectral degradation, and of transmitting high-capacity data signals over thousands of kilometers. We will review some of these recent highlights, with a particular emphasis on the results achieved in our group at the University of Southampton.

The talk will review application of light sources and materials to detect transmissible diseases with particular focus on Covid disease.

We present a novel approach to create spinodal-like structures appropriately modulating the instability of the solid state dewetting: many materials, indeed, featuring anomalous suppression of density fluctuations over large length scales are emerging systems known as disordered hyperuniform. The underlying hidden order renders them appealing for several applications, as light management and topologically protected electronic states. These applications require scalable fabrication, which is hard to achieve with available top-down approaches. These spinodal materials are used by a hybrid top-down/bottom-up approach based on sol-gel dip-coating and nano-imprint lithography for the faithful reproduction of the disordered metasurfaces in metal oxides (SiO2 and TiO2).

Nanoimprint lithography (NIL) is a method to (nano-) structure inorganic materials from sol-gel liquid formulations and colloidal suspensions onto a surface. This technique, first inspired by embossing techniques, was developed for soft polymer processing, as final or intermediate materials, but is today fully adapted to hard inorganic materials with a high dielectric constant, such as metal oxides, with countless chemical compositions provided by the sol−gel chemistry. Consequently, NIL has become a versatile, high-throughput, and highly precise fabrication method that is mature for lab developments and scaling up. I will first describe generalities of sol-gel dip coating and NIL method for metal oxides (e.g. SiO2, TiO2) and review some of the recent results we obtained in this field, including fabrication of ordered and disordered optical metasurfaces, structural color, anti-reflection coatings, refractive index sensing and enhanced light extraction.

Most practically used optical isolators are based on the magneto-optical Faraday effect. There also exist isolators based on different physical phenomena. In this work, we have experimentally demonstrated for the first time in our knowledge the new type of optical isolator based on Sagnac effect.