Organic light emitting devices (OLEDs) have some performances, such as low power consumption, ultra-light, fast re-sponse speed, high-definition, self-luminous and viewing angle, etc, which are expected to become a mainstream of the next generation of display devices. It is found that the microcavity structure can narrow the luminescence spectrum of the thin film and improve the luminescence color purity of the device effectively. We prepared a light-emitting device by using high vacuum deposition process and high-precision film thickness detector. This paper designed and prepared the green OLED devices based on double metallic mirrors in microcavity structures, of which the process was by vac-uum evaporation and double metallic mirrors of devices: Al/MO3 as device of anode and hole injection layer, and LiF/Al as device cathode and electron injection layers.

With the development of laser manufacturing technology, people can fabricate VLS plane gratings by holographic li-thography. Compared with traditional gratings, the light incident on different positions of the VLS grating can diffract light with different angles, which leads to astigmatism and focusing effect. The application of VLS plane gratings reduc-es the number of optical elements inside the instrument and improves the resolution of the instrument. It is widely used in vacuum ultraviolet, soft X ray, optical fiber communication, sensor and many other fields.

To solve the problems of nonlinear measurement of Faraday rotation existing in the power optical sensing, a new type of circular polarization grating is designed, in which the grating grooves are arranged along the radial direction in a ring. For the polarization grating, the TE wave (parallel to the grooves) has a high reflection and the TM wave (perpendicu-lar to the grooves) has a high transmission. Therefore, according to the Malus' law, when a linearly polarized light is transmitted through the grating, the output light gets the maximum and minimum intensities at the directions perpen-dicular and parallel to the polarization direction of the LP light, respectively. Because the grating is ring-shaped and the average space between adjacent grooves is in nanometer size, a linearly polarized light with any polarization direction can generate a ring-shaped intensity distribution image with dark and bright stripes after passing through the grating. In brief, the grating can be described as a radial polarizer in which the transmission axis is perpendicular to the azimuth angle that can be varied within 0~360 degree. When the azimuth angle changes, the intensity distribution will rotate accordingly, and its rotation angle is equal to the azimuth angle. Therefore, the polarization rotation can be linearly measured by detecting the rotation of the dark stripe center.

Photonic integrated circuit (or chip) is the foundation of the ultra-high speed and large capacity information network in the future. This leads to a hot point of optical research in recent years that is how to excite the nonlinear optical effect in the case of low threshold (mW or pJ order) and small scale (μm or less). As is known to all, the nonlinear optical ef-fect is too weak to be excited under normal conditions. That is why the nonlinear optics failed to develop before the appearance of laser. In other words, how to excite the nonlinear optical effect in the case of low threshold and small scale is difficult. In recent years, researchers found that the nonlinear optical effect could be greatly enhanced in the photonic crystals (PCs) which are expected to solve this problem.

Conventional optical systems (lenses, wave-plates and holograms) shape the wavefront of light within the range of an optical path that is much larger than the wavelength of light. The control of amplitude, phase and polarization of light depends on the dynamic optical path difference accumulated through the reflection, refraction and diffraction. Recently, planar ultrathin optical components have attracted tremendous attention by removing such traditional limitations. Among the competitive technologies, plasmonics is a promising field that enables the unique property of nanoscale confinement of electromagnetic fields. Plasmonic devices based on the manipulation of surface plasmons (SPs), a col-lective charge oscillation at metal/dielectric interfaces, have provided a confined environment for the full manipulation of light, and it is not surprising that this unique property of SPs has received considerable attentions. Meanwhile, engi-neered planar nanostructures, also named as metasurfaces, allow us to harness the light more smartly than any con-ventional ways. So far, a huge number of unprecedented optical components have been attained by the use of metasurfaces. As a result, plasmonic metasurfaces have become a whole new discipline within nanophotonics, because it can be perceived as a bridge connecting both electronics and optics, opening up opportunities for new and exciting applications.

In recent years, with the continuous progress of micro/nano fabrication technique, the interaction of material and elec-tromagnetic wave in the subwavelength scale has attracted widespread attention. Electromagnetic metamaterial is arti-ficial material composed of building blocks whose feature size is much smaller than the working wavelength, with the electromagnetic properties that does not exist in natural materials. As an important branch of electromagnetic met-amaterials, hyperbolic metamaterials become the focus of research for their unique characteristic to control near-field waves. By changing the size and arrangement of the components of hyperbolic metamaterials, the excitation intensity and direction of the surface plasmons (SPs) in them can be modulated, so that the unique dispersion curves can be achieved. Hyperbolic metamaterials have been used in many fields, such as subwavelength imaging, light localization and enhanced spontaneous emission. Hyperbolic metasurface is a new type of planar metamaterials with hyperbolic dispersion relationship and has many similarities in theory and applications with hyperbolic metamaterial. Compared with the bulk hyperbolic matematerials, hyperbolic metasurfaces exhibit more excellent performances because the large reduction in the longitudinal dimension limits the propagation of the electromagnetic waves in the two-dimensional plane.

Conventional refractive optical components such as lenses and prism modifying the wavefronts rely on light propaga-tion over distances much larger than the wavelength, which makes them bulky and weighty. To address this issue, bi-nary optics was proposed in the end of 1980s. Secondary waves created by binary optical components such as holo-grams diffract in free space and interfere in the far-field to form complex optical patterns. The phase of the secondary waves is modulated through propagation delay in a discrete and planar way. However, the chromatism in diffraction and the limited field of view due to the relatively large scale of phase modulation, limit the applications of the binary optical components.

Metasurfaces, the equivalent two-dimensional (2D) metamaterials, are thin-film functional devices constructed by subwavelength structures. Abrupt phase changes can be obtained in the planar metasurface structures over the subwavelength scale, which provide a new avenue to enable a variety of applications, including large scale planar imaging, electromagnetic virtual shaping and holographic display with large field of view. The arbitrary modulation abilities of phase, amplitude and polarization at the subwavelength scale, also the light weight, low loss, integratable and conformable design make the metasurfaces very attractive, compared to the traditional optical devices. In this paper, we review the mechanisms of the phase modulation and classify the metasurfaces based on them. The properties and the applications of each type of metasurfaces are also detailedly discussed. The challenges faced by metasurfaces and the areas which need to be further extended are also summarized.

As an important branch of electromagnetic metamaterials, hyperbolic metamaterials become the fo-cus of research for their unique property of controlling near-field waves. Hyperbolic metasurface is a new type of planar metamaterials with hyperbolic dispersion relationship and has many similarities in theory and applications with hyperbolic metamaterial. Compared with the bulk hyperbolic metamaterials, hyperbolic metasurfaces exhib-it more excellent performances because the large reduction in the longitudinal dimension limits the propagation of the electromagnetic waves in the two-dimensional plane. In the first part of this review, we introduce hyperbolic metamaterial with its theory, implementation and applications. The latter part of the review is about hyperbolic metasurfaces and their potential applications. We also point out the restrictions of the hyperbolic metamaterials and metasurfaces and the prospect of future applications.

Conventional optical systems (lenses, wave-plates and holograms) shape the wavefront of light within the range of an optical path that is much larger than the wavelength of light. The control of amplitude, phase and polarization of light depends on the dynamic optical path difference accumulated through the reflection, refrac-tion and diffraction. Recently, planar ultrathin optical components have attracted tremendous attention by remov-ing such traditional limitations. In this paper, we mainly review the recent progress of plasmonic metasurfaces with respect to wavefront shaping of free space and localized optical fields, including the fundamental mecha-nisms and applications. Both the drawbacks of existing technology and potential development are highlighted.

How to excite the nonlinear optical effect in the case of low threshold (mW or pJ order) and small scale (μm or less) is a topic field of optical research in recent years. The most direct application requirement is photonic integrated circuit, which is the foundation to realize the ultra-high speed and large capacity information network in the future. Photonic crystals (PCs) have the photonic band gap (PBG) just like the semiconductor band for elec-tronics, so it is known as "photonic semiconductors". PCs provide a novel and practical means of manipulating photons, therefore the possibility of photonic integrated circuit with low threshold arises. More and more nonline-ar effects have been found in PCs, such as photonic crystal slow light, the band gap soliton, electromagnetic in-duction transparency, second harmonic generation and optical bistability. This paper will focus on the summaries of some major achievements and advances about PCs that would promote the nonlinear photonic integrated de-vices. Certainly the related applications will be introduced and the future outlook of the nonlinear PCs will be discussed.

Reflection engineering plays an important role in optics. For conventional approaches, the reflection tuning is quite challenging in a loss-free component. Therefore, a simple approach to tune the reflection is highly desired in plenty of applications. In this paper, we propose a new design of metasurface with just one single layer dielectric structure to tune the reflection of an interface by destructive interference in a subwavelength scale. By arranging the orientation of nano-antennas, the reflectivity tuning from 20% to 90% can be achieved at the wavelength of 1550 nm. Moreover, such reflectivity tuning of the designed metasurface works at the tunable wavelength from 1500 nm to 1600 nm. This ultra-thin solution can achieve similar performance as the traditional bulky components without diffraction orders, while the design and fabrication are much simple and flexible. The ultra-thin and tunable properties indicate the great potentials of this method to be applied in laser fabrication, op-tical communication and optical integration.

Reflection engineering plays an important role in optics. For conventional approaches, the reflection tuning is quite challenging in a loss-free component. Therefore, a simple approach to tune the reflection is highly desired in plenty of applications. In this paper, we propose a new design of metasurface with just one single layer dielectric structure to tune the reflection of an interface by destructive interference in a subwavelength scale. By arranging the orientation of nano-antennas, the reflectivity tuning from 20% to 90% can be achieved at the wavelength of 1550 nm. Moreover, such reflectivity tuning of the designed metasurface works at the tunable wavelength from 1500 nm to 1600 nm. This ultra-thin solution can achieve similar performance as the traditional bulky components without diffraction orders, while the design and fabrication are much simple and flexible. The ultra-thin and tunable properties indicate the great potentials of this method to be applied in laser fabrication, op-tical communication and optical integration.

Spin-orbit optical phenomena pertain to the wider class of electromagnetic effects originating from the interaction of the photon spin with the spatial structure and propagation characteristics of an optical wave, medi-ated by suitable optical media. There are many emerging photonic applications of spin-orbit interactions (SOI) of light, such as control of the optical wave propagation via the spin, enhanced optical manipulation, and generation of structured optical fields. Unfortunately, current applications are based on symmetric SOI, that is, the behaviours of polarized photons with two opposite spins are opposite, leading to the limit of spin-based multiplexers. The symmetry of SOI can be broken in our proposed metasurfaces, consisting of spatially varying birefringence, which can arbitrarily and independently build SOI for two opposite spins without reduction of optical energy us-age. We obtain three kinds of dual-functional metasurfaces at visible and infrared wavelengths with high effi-ciency. Our concept of generation of asymmetric SOI for two spins, using anisotropic metasurfaces, will open new degrees of freedoms for building new types of spin-controlled multifunctional shared-aperture devices for the generation of complex structured optical fields.

Spin-orbit optical phenomena pertain to the wider class of electromagnetic effects originating from the interaction of the photon spin with the spatial structure and propagation characteristics of an optical wave, medi-ated by suitable optical media. There are many emerging photonic applications of spin-orbit interactions (SOI) of light, such as control of the optical wave propagation via the spin, enhanced optical manipulation, and generation of structured optical fields. Unfortunately, current applications are based on symmetric SOI, that is, the behaviours of polarized photons with two opposite spins are opposite, leading to the limit of spin-based multiplexers. The symmetry of SOI can be broken in our proposed metasurfaces, consisting of spatially varying birefringence, which can arbitrarily and independently build SOI for two opposite spins without reduction of optical energy us-age. We obtain three kinds of dual-functional metasurfaces at visible and infrared wavelengths with high effi-ciency. Our concept of generation of asymmetric SOI for two spins, using anisotropic metasurfaces, will open new degrees of freedoms for building new types of spin-controlled multifunctional shared-aperture devices for the generation of complex structured optical fields.

A tunable plasmofluidic lens consisting of nanoslit arrays on a metal film is proposed for subwave-length imaging in far field at different wavelengths. The nanoslit arrays with constant depths but varying widths could generate desired optical phase retardations based on the propagation property of the surface plasmon polaritons (SPPs) through the metal-dielectric-metal (MDM) nanoslit waveguide. We demonstrate the tunability of the plasmofluidic lens for subwavelength imaging by changing the surrounding dielectric fluid. This work pro-vides a novel approach for developing integrative tunable plasmofluidic lens for a variety of lab-on-chip applica-tions.

A tunable plasmofluidic lens consisting of nanoslit arrays on a metal film is proposed for subwave-length imaging in far field at different wavelengths. The nanoslit arrays with constant depths but varying widths could generate desired optical phase retardations based on the propagation property of the surface plasmon polaritons (SPPs) through the metal-dielectric-metal (MDM) nanoslit waveguide. We demonstrate the tunability of the plasmofluidic lens for subwavelength imaging by changing the surrounding dielectric fluid. This work pro-vides a novel approach for developing integrative tunable plasmofluidic lens for a variety of lab-on-chip applica-tions.

Near-field plates with the capabilities of modulating the near-field pattern and forcing the incident wave to a subwavelength spot have been experimentally investigated at microwave wavelengths. Their super-lensing properties result from the radiationless electromagnetic interference. However, the material’s loss and limitations of state-of-the-art nanofabricating technology pose great challenges to scale down the microwave near-field plates to the infrared or optical region. In this paper, a related but alternative approach based on metasurface is introduced which breaks the near-field diffraction limit at mid-infrared region (10.6 μm). The metasurface consists of periodic arrangement of chromium dipolar antennas with the same geometry but spa-tially varying orientations, which plays the dual roles in achieving the prescribed amplitude modulation and the abrupt π phase change between the subwavelength neighboring elements. As a result, a two dimensional sub-diffraction focus as small as 0.037λ2 at ~0.15λ above the metasurface is presented. In addition, the broadband response and ease fabrication bridge the gap between the theoretical investigation and valuable applications, such as near-field data storage, subdiffraction imaging and nanolithography.

Near-field plates with the capabilities of modulating the near-field pattern and forcing the incident wave to a subwavelength spot have been experimentally investigated at microwave wavelengths. Their super-lensing properties result from the radiationless electromagnetic interference. However, the material’s loss and limitations of state-of-the-art nanofabricating technology pose great challenges to scale down the microwave near-field plates to the infrared or optical region. In this paper, a related but alternative approach based on metasurface is introduced which breaks the near-field diffraction limit at mid-infrared region (10.6 μm). The metasurface consists of periodic arrangement of chromium dipolar antennas with the same geometry but spa-tially varying orientations, which plays the dual roles in achieving the prescribed amplitude modulation and the abrupt π phase change between the subwavelength neighboring elements. As a result, a two dimensional sub-diffraction focus as small as 0.037λ2 at ~0.15λ above the metasurface is presented. In addition, the broadband response and ease fabrication bridge the gap between the theoretical investigation and valuable applications, such as near-field data storage, subdiffraction imaging and nanolithography.

Paint removal from steel structure is executed for shipyards of marine and offshore engineering. Due to environmental unfriendliness and unhealthy drawbacks of sand blasting technique, laser ablation technique is proposed as a substituting method. By absorbing high energy of the 1064 nm pulsed laser, the paint is vaporized quickly. The ablated debris is then collected by using a suction pump. Initial metal surface of the steel is exposed when laser beam irradiates perpendicularly and scans over it. The cleaned surface fulfills the requirements of surface preparation standards ISO 8501 of SA2. The adhesion is further characterized with pull-off test after car-rying out painting with Jotamastic 87 aluminum paint. The repainting can be embedded onto the laser cleaned surface to bond much more tightly. The excellent adhesion strength of 20 MPa between repainted coating and the substrate is achieved, which is higher than what is required by shipyards applications.

Paint removal from steel structure is executed for shipyards of marine and offshore engineering. Due to environmental unfriendliness and unhealthy drawbacks of sand blasting technique, laser ablation technique is proposed as a substituting method. By absorbing high energy of the 1064 nm pulsed laser, the paint is vaporized quickly. The ablated debris is then collected by using a suction pump. Initial metal surface of the steel is exposed when laser beam irradiates perpendicularly and scans over it. The cleaned surface fulfills the requirements of surface preparation standards ISO 8501 of SA2. The adhesion is further characterized with pull-off test after car-rying out painting with Jotamastic 87 aluminum paint. The repainting can be embedded onto the laser cleaned surface to bond much more tightly. The excellent adhesion strength of 20 MPa between repainted coating and the substrate is achieved, which is higher than what is required by shipyards applications.

A new type of radially polarized grating is designed to solve the problems of nonlinear measurement of Faraday rotation existing in the power optical sensing. The distribution of the grating vector is in accordance with the special method, so that the polarization distribution of the polarized light can be transformed into the dis-tribution of light intensity, which rotates synchronously with polarization plane. The theory of polarization detec-tion is analyzed by using Jones matrix, and the parameters of the grating are simulated by rigorous coupled wave theory. Finally, the grating is fabricated and tested. The results show that the TM transmittance of the grating is greater than 80%, the extinction ratio is greater than 100, and the detection of the polarization state can be re-alized. It has the advantages of large linear measurement range and measurement results independent on the absolute intensity, so that it will be a new detection technology of polarization based on the image method.

Electrically controlled holographic varied-line-spacing (VLS) grating based on polymer dispersed liquid crystal (PDLC) is reported. Varied-line-spacing interference pattern is generated through interference between cylindrical wave and plane wave, and recorded in PDLC. Characteristics, such as spatial frequency, diffraction and electric-optic, are analyzed by experiments. The results show that the trend and range of grating period match well with the theoretical simulation. The relationships between diffraction efficiency and exposure intensity as well as exposure time are studied. The grating diffraction efficiency can be achieved more than 70% with spa-tial frequency from 530 mm-1 to 650 mm-1. Meanwhile, the grating has good electrically controlled property. The threshold voltage is 2.4 V/μm, and the rise time and fall time are 300 μs and 750 μs, respectively. The grating not only has advantages of ordinary VLS grating but also has electric-optic characteristics of PDLC. It has potential applications in the fields of optical fiber communication, photoelectric detection and spectrograph.

Green microcavity organic light-emitting diodes (OLEDs) are fabricated by using double metallic mir-rors in microcavity structures and double light-emitting structures. The structure of the device consists of Al(15 nm)/MoO3(4 nm)/2T-NATA(10 nm)/NPB(15 nm)/NPB:C545T(x%, 20 nm)/Alq3:C545T(4%, 20 nm)/Bphen(35 nm)/LiF(1 nm)/Al (200 nm), where x is the doping concentration. When the doping concentration is 3%, the device has the best photoelectric properties, which is named as device B1.The reference device B2 is prepared based on ITO, for the analysis of microcavity effect. B1 and B2 CIE are (0.2889, 0.620) and (0.3168, 0.5571), so the micro-cavity device could emit more green light. At 100 mA/cm2, the brightness of devices B1 and B2 is 5076 cd/m2 and 4818 cd/m2, and the maximum brightness of the both devices are 9277.7 cd/m2 and 10440 cd/m2. At 100 mA/cm2, luminance efficiency of devices B1 and B2 are 6.0 cd/A and 5.61 cd/A, and the luminance efficiency of the both devices are 8.6 cd/A and 7.97 cd/A. Compared with the reference devices, green microcavity device has a higher current efficiency and better color purity, which attributes to the microcavity effect.

Semiconductor-free microscale devices are expected to be realized, thanks to an engineered surface, called a metasurface. The team led by Prof. Dan Sievenpiper from University of California, San Diego has fabricated the first optically-controlled microelectronic device that consists of an engineered metasurface, rather than semiconductor. The metasurface is made of an array of gold mush-room-like nanostructures on an array of parallel gold strips. Using the metamaterials, 1000 percent increase in conductivity can be achieved when being activated by a low voltage and a low power laser. It is possible to break the limits on a device's conductivity, or electron flow ex-hibited by semiconductors.

Vortex light, featuring doughnut intensity distribution, helically structured wavefront and theoretically infinite topological charge, has significant potential applications in areas of optical communication, optical manipulation and detection of the rotating objects. Compared with the sin-gle channel vortex beam, the multi-channel vortex light can fulfill the improvement of the data storage capacity and safety, and increase the number of rotating objects and particles in detection and trapping.

A team of scientists led by Dragomir N. Neshev from The Australian National University, Friedrich Schiller Univer-sity Jena, Germany and Sandia National Laboratories, US has demonstrated a new way to electrically tune the spec-tral response of a Mie-resonant dielectric metasur-face. The metasurface paves the way for new different types of electro-optical devices, including dynamic displays and holograms.