This PDF file contains the front matter associated with SPIE Proceedings Volume 12283, including the Title Page, Copyright information, Table of Contents, and Conference Committee listings.

In recent years, integrating multiple functionalities into a single metasurface has become an emerging approach in advanced metasurface research for information multiplexing. The typical approaches include supercell design and/or multilayer design, which are essentially an integration of several metasurfaces and the information capacity of each metasurface has not been increased yet. Here, by fully exploiting the design degrees of freedom of nanostructures and decoupling the optical properties of incident light, we show metasurfaces with single-cell design can act as different functional devices to manipulate different optical properties at the same time. Hence, we can integrate different metadevices such as nanoprints and holograms into a single metasurface, which can significantly improve the information density, functionality and security of metasurfaces. Our research provides a new strategy to design multifunctional metasurfaces without burdening the nanostructure design and manufacturing, and we expect that a variety of novel nanooptical applications such as multi-folded optical anticounterfeiting, high-density optical storage, ultracompact information encryption, ultraportable image display for AR/VR and so on will emerge from our approach.

Metasurfaces have been widely studied for arbitrary manipulation of the amplitude, phase and polarization of a field at the sub-wavelength scale. However, realizing a high efficiency metasurface with simultaneous and independent control of the amplitude and phase in visible remains a challenge. In this work, an ultrathin single-cell dielectric metasurface which can modulate complex amplitude in transmission mode is proposed. The amplitude is controlled by adjusting the dipoles and quadrupoles by tuning the geometric size, while the phase is manipulated based on the Pancharatnam-Berry phase (also called geometric phase) by rotating the meta-atom. It has been experimentally demonstrated that the quality of holographic image of complex-amplitude hologram encoded on the proposed metasurface is better than that of phase-only holograms (generated by angular spectrum method and Gerchberg–Saxton algorithm). The proposed metasurface expands the superior limits of various applications, including arbitrary beam shaping, 3D biological imaging, optical computing, and optics-on-chip devices.

Optical gyroscope is an important high-precision inertial measurement instrument, which plays significant role in defense, geological exploration and navigation. For high accuracy optical gyroscope system, a high-performance polarizer is strongly needed to filter only one polarization from Amplified Spontaneous Emission (ASE) source. Here, the plasmon-assisted structure is introduced by setting a thin metal layer above the silicon nitride (Si₃N₄) waveguide. The copper (Cu) is chosen as the metal layer material as it is compatible with the complementary metal-oxide-semiconductor (CMOS) fabrication process. The surface plasmons effect can simply be excited by TM polarization due to the electric field of TM polarization perpendicular to the metal layer, so that it can bring extra propagation loss. The TE polarization, on the contrary, fail to excite the surface plasmons effect as the electric field is parallel to the metal layer. To reduce the reflection caused by mode mismatch, the distance between metal layer and waveguide is increased by inserting a SiO₂ layer. The chemical mechanical planarization (CMP) process allows precise thickness control of the SiO₂ layer. The spiral waveguide structure is utilized to fully suppress TM polarization while the TE polarization can be well confined in broadened Si₃N₄ core with negligible propagation loss. The numerical results show that the working wavelength range is as large as 60 nm from 820 nm to 880 nm with the polarization extinction ratio > 30 dB and the insert loss < 0.5 dB. As far as we known, this is the first time to achieve ultra-high extinction ratio, ultra-low insertion loss, ultra-low reflection at the same time, and also achieve a working wavelength range larger than 60 nm at the center of 850 nm. Moreover, the proposed structure doesn’t require high alignment accuracy and is compatible with silicon-on-insulator fabrication technology.

This paper proposes a fiber optic surface plasmon resonance (SPR) sensor based on the heterostructure of MoS₂/WS₂. Transition metal dichalcogenides (TMDCs) have been widely studied due to their high carrier mobility, excellent photoelectric properties and good biocompatibility. A heterostructure is constructed by two types of TMDCs (MoS₂/WS₂) and is used to improve the performance of the Ag layer coated fiber optic SPR sensor. The heterostructure film increases the integral of the electric field intensity on the surface of the sensor, thus improving the sensitivity of the sensor. The finite element analysis shows that the sensitivity of the sensor is as high as 3127.18 nm/RIU and the figure of merit is up to 70.04 RIU-1. The proposed sensor exhibits promising potential in the field of biochemical detection.

We have theoretically studied the strong coupling of the surface plasmon polaritons (SPP) and magnetic polaritons (MP) modes in an Au grating/dielectric/Au resonance structure in the near-infrared waveband. Our results show that SPP and MP modes can strongly interact with each other at the metal grating/dielectric/metal (MDM) interface, leading to a large Rabi splitting. We also find that the light absorptivity in the high- and low-frequency branches within the anticrossing region are abnormally different. Moreover, the simulation results indicate that strong SPP-MP coupling can be tuned by modulating the geometric parameters of the structure. The unique characteristics of strong coupling of SPP and MP modes in this simple MDM hybrid structure will be helpful in the design of various polaritonic devices.

The switchable channel polarization conversion device is of wide use in microwave, infrared and optical regimes, while it still faces the difficulty to realize the controllable and stable performance. Here, we proposed a VO₂ based metastructure method to realize the polarization conversion performance. Owing to the inherent property of VO₂, 68℃ is a nature switching point, which endows the proposed converter with the characteristic of high temperature reflection and low temperature transmission. To proof our design paradigm, the linear polarization (LP) converter with 68℃ as the critical point is designed, which achieves the strong polarization conversion at the transmissive part for low temperature from 2.5THz to 3.0THz and reflective part for high temperature from 2.0THz to 2.5THz. Significantly, this simple manipulation method will have wide application in other bi-direction function design.

Recently, monolayer transition metal dichalcogenides (TMDs) with structures similar to graphene have emerged as a promising alternative material for integrated optoelectronic devices. However the low light absorption and low photoluminescence quantum yield of monolayer TMDs limit the interaction between light and matter. The plasmonic nanostructure can confine light into the nanometer scale, thus greatly enhancing the electric field intensity and significantly enhancing the interaction between light and matter. Here, we constructed the plasmonic nanocavities comprised of monolayer MoSe₂ and silver nanowire dimer, and studied the photoluminescence (PL) properties of monolayer MoSe₂ enhanced by Purcell effect. The results show that the PL intensity of the composite system composed of MoSe2 and silver nanowire dimer is three times stronger than that of bare MoSe₂ when excited by 532 nm laser. At the same time, we further proved that the nanowire dimer could enhance the PL strength of TMDs by PL mapping. In addition, we use finite difference time domain (FDTD) software simulate the electromagnetic field intensity distribution of the triangular-linear plasmonic cavity formed by the silver nanowires dimer and the substrate. The results demonstrate that the PL intensity of monolayer MoSe₂ was enhanced by Purcell effect. The theory explains the experimental results well, indicates that the system can be used as a new structure to enhance PL of TMDs. The nanowire dimer-monolayer transition metal dichalcogenides complex system presents new possibilities for efficient photodetectors, solar cells and two-dimensional material-based light-emitting devices.

Periodic nanoscale array structures are of great importance in various fields including photonic crystals, diffraction gratings, etc. In this study, a dielectric-film-based polarization modulation scheme on an orthogonal two-axis Lloyd’s mirrors interference system was proposed for patterning high-uniformity nanoscale two-dimensional (2D) grating over a large area. We established a beam reflection model of three media-layer structure of air-dielectric film (MgF₂)-metal substrate (Al) and calculated the integrative amplitude reflection coefficients. We systematically analyzed the spatial polarization states of the interference beams and determined the optimal exposure conditions to automatically eliminate the additional interference at certain incident angles. We plotted the optimal period of fabricable 2D grating at different thickness of dielectric film MgF₂, where a thickness of 66.3 nm was selected for experimental demonstration. Then, 2D gratings with various periods of 740 nm, 780 nm, 1000 nm, and 1250 nm were fabricated, which presented a high consistency with the simulation results and revealed the fabrication ability over a period range from 730 nm to 840 nm. This dielectric-film based polarization modulation mechanism enables to extend the fabricable 2D grating with a smaller pitch, which is corresponding to a larger area. The proposed dielectric-thin-film-based polarization modulation mechanism provides a promising approach for fabricating large-area, high-uniformity, 2D-crossed gratings with a high throughput.

Fano resonance with high quality (Q) factor is of great significance to enhance the interaction between light and matter. The all-dielectric metasurface has low loss and can be used to realize the Fano resonance with high Q-factor. Herein , we propose a novel metasurface and apply it to the optical refractive index sensor in the near infrared. It consists of a silicon layer based on four rectangular holes and the substrate is silica. By introducing a new rectangular hole, the symmetry of the structure is broken and two new Fano resonance peaks are excited at the same time. The maximum Q-factor is 7709 (at 1304.4 nm). It can be applied to optical refractive index sensor with sensitivity of 296.7 nm/RIU and FOM of 1483.5.

In this paper, a silicon-based wideband filter with a high sidelobe suppression is proposed. The filer comprises a microring resonator (MRR) with a single ring with a Bragg grating. The Bragg grating in a microring is formed by a subwavelength grating (SWG) waveguide consisting of two gratings of the same period but with different filling-factors to induce variation in refractive index towards the direction of the propagation. The proposed wideband filter using grating-assisted MRR has a 3-dB bandwidth of 1.0734 THz at the passband. A sidelobe suppression of 19.79 dB for passband filtering, low insertion loss of <0.6 dB, a low in-band ripple of less than 0.2 dB are obtained. The proposed scheme uses only one microring; hence, it is compact in size. The proposed filter is a promising candidate for optical communication systems such as coarse wavelength division multiplexing and other wideband applications.

Surface modifying complexes with nanolayer architecture are widely used in various fields of activity (optical systems, tribological pairs, cutting tools, etc.). In many cases, brittle fracture as a result of active cracking is the key or even the dominant mechanism for the destruction of such complexes. The report discusses the factors that can slow down the development of cracks in nanolayer systems and, thus, increase their resistance to brittle fracture. Both theoretical substantiation and practical examples of crack propagation inhibition are presented. The influence of the crystalline structure of the coating on the cracking pattern has been studied. The investigation has found the significant effect of the crystalline structure of the coating layers on the cracking pattern. It can be noticed that in addition to the nanolayer structure, the pattern of crack propagation can also be affected by the crystalline structure of the coating. With a decrease in the deformation energy, the intercrystalline interfaces have a greater influence on the crack growth direction, and the crack can stop, resting against a crystal boundary. Thus, during the further modeling, it is also important to take into account the influence of the crystalline structure of the nanolayers.

During operation, nanostructured materials can be exposed to high temperatures, which have a significant effect on their properties. Studying the effect of temperature on various properties of nanomaterials, in particular, tribological properties, is an important task, the solution of which will make it possible to select the optimal architecture for specific operating conditions. In this work, we studied the effect of nanostructure parameters on the tribological properties of materials in the temperature range from room temperature to 1000 ° C. The regularities of changes in the tribological properties of nanolayer structures were revealed, which made it possible to determine the dependence of the adhesive (molecular) component of the friction coefficient fM on temperature. The effect of the fM value at elevated temperatures and thermal stability of this parameter on the functional properties of products with a modified surface layer has been established.

Hot-electron photodetectors are attracting increasing interests due to the outstanding capability of detecting low-energy photons below the semiconductor bandgap, operating under room temperature without electrical bias and the potential to be integrated on a chip, which have unique advantages in the field of infrared photodetection. As an emerging strategy for photodetection, the realization of the broadband/efficient absorption and photodetection with easily constructed metal-semiconductor (M-S) nanosystems is of significance. In this study, we propose a hot-electron photodetector based on a thin Au film with a thickness of 10 nm on the disordered silicon nanowires (SiNWs), which is fabricated by the metal-assisted chemical etching. The average absorption of the hot-electron photodetector across the broad wavelength spectral band (i.e., 1200−2400 nm) is higher than 85%, which is contributed from the multiple localized plasmonic resonances in the disordered Au/Si NWs. Benefited from the small thickness of Au film (shorter than the hot electron mean free path), the generated hot electrons have a high transport probability to reach Schottky interface and participate in the interfacial charge transfer process. As a result, the hot-electron photodetector shows a broadband photodetection capability to the wavelength of 2000 nm under the room temperature. The unbiased responsivity reaches 1.2 mA/W at the wavelength of 1300 nm, which is twice of the grating-based hot-electron photodetector. Our proposed hot-electron photodetector based on disordered Au/Si NWs opens up an alternate path to further extend the detection wavelength of Si-based photodetectors with a low-cost and large-area fabrication process, promoting the practical application of hotelectron devices.