The one-dimensional metallic photonic crystal film is an anisotropic metamaterial with an equivalent and uniform metal-medium multilayered structure. Compared with single-layer metal film, the one-dimensional metal photonic crystal film has a higher degree of freedom in terms of chromatic dispersion regulation and control. With the existing of surface plasmon polariton (SPP), directional transmission of evanescent waves can be achieved. This paper designed a one-dimensional metallic photonic crystal film, which was made of ITO and Ag layers. The thickness of each Ag films is less than 2 times the penetration depth of SPP. According to the effective medium theory of metallic photonic crystal, it is found that the equivalent dielectric constant of metallic photonic crystal structure in visible region can be greater than 0 by structural adjustment and its equivalent dielectric constant can be negative in microwave region. This makes metallic photonic crystal in visible region have higher transmitting performance due to the SPP coupling effect, as shown in Fig.(a). In infrared and microwave bands, due to the band gap, metallic photonic crystal shows good reflectivity (shielding effectiveness) in Fig.(b). Based on the effective medium theory, both FDTD and experimental results showed that, in metallic photonic crystal, lower metal component ratio corresponds to greater cutoff wavelength and center wavelength in visible light, wider transmission frequency band, and lower electromagnetic shielding effectiveness in microwave band. Results in this paper agreed with the SPP mode coupling theory, by which active design of transmission performance in visible light and electromagnetic shielding effectiveness in microwave band for metallic photonic crystal is possible. Additionally, the research shows that thinner metallic film layer corresponds to stronger SPP coupling effect and transmittance of visible light. When the metallic film thickness is less than the penetration depth of SPP, visible light transmission in wide frequency band can be achieved due to the smaller distance between the spacing of modes. Furthermore, when the pairs of metallic photonic crystal are 3.5, a good forbidden band can be well formed. With further increase of its pairs, no increase can be seen in the shielding performance of the metallic photonic crystal film. In conclusion, metallic photonic crystal film can be used to realize efficient transmission of visible light, and it also supports the active design of center wavelength, cutoff wavelength and bandwidth for the transmission of visible light. Thus, by adopting the metallic photonic crystal film, light and visual electromagnetic shielding materials with thin films can be created. This unique feature makes the metallic photonic crystal have wide application prospects in the field of visible electromagnetic shielding.

Plasmonic sensor based on metallic nanostructures is a promising platform for applications, such as biology, chemistry, materiality and photonics due to their attractive properties. In particular, the local electromagnetic field enhancement in metal nanostructures is highly correlated to the surrounding environment, providing a new way for the realization of high sensitive biosensors. However, the sensitivity of plasmonic sensors is usually limited by broad spectral features due to large radiative loss of metallic nanostructures in visible region. As a result of the interference between super-radiation and sub-radiation patterns, the radiation loss of the Fano resonance system can be greatly reduced or even completely inhibited. Such characteristic promises the Fano resonance a series of excellent electromagnetic properties such as narrow spectral linewidth, strong electromagnetic field enhancement and high refractive index sensitivity. In this paper, we present a structure of three layers consisting of an ellipsoidal silver pair separated from the silver reflector by a layer of silica. Moreover, we introduce structural asymmetry to generate the Fano resonance by rotating one of the elliptical silver cylinders. The Fano resonance in this structure is raised by the interference of dipole resonance aroused by the incident light and quadrupole mode aroused by the asymmetry of the ellipsoidal pair. Here, the dipole mode and quadrupole mode represent the super-radiation and sub-radiation pattern, respectively. The corresponding results are based on the finite element method (FEM) with solver CST Microwave Studio. Electromagnetic wave incidents normally to the surface from the positive side of the z axis and polarization of the incident light are along the x axis. Calculated results show that the distinct Fano-like line shape with sharp peak as narrow as 10.8 nm (FWHM) appears around a wavelength of 681 nm, and also at the same wavelength, two anti-phase currents appears along two asymmetric elliptical cylinders which indicate the arose of Fano resonance. We should point out that when the structure is symmetric, there’s on Fano resonance, and also with the increase of the asymmetry degree, the intensity of Fano resonance increases. According to formula for the refractive index sensitivity, the Fano mode exhibits refractive index sensitivity as large as 299 nm/RIU which is the basis of many applications. Moreover, due to the excitation of sharp spectral features, high figure of merit of 27.8 at the Fano resonance is obtained in a wide refractive index range of 1.0~1.1. The promising properties of this device would make it an effective high sensitivity microchip sensor.

The Bowtie aperture structure is widely applied in the realm of nanometer direct-writing lithography for obtaining the focusing spots beyond the diffraction limit. However, the shape of spots obtained is elliptic under the Bowtie structure because the electric field is enhanced and located only in perpendicular to the aperture gap. This characteristic impacts the applications of Bowtie structure. To attain high-resolution and circle-symmetric focusing spots, the double Bowtie structure is proposed. The electric field is enhanced and located in both x and y directions due to the symmetry characteristic of the double Bowtie aperture. The free electrons are accumulated at four tips of the gap of the double Bowtie aperture, which stimulate the localized surface plasmas (LSPs) and develop the double-dipole oscillation mode. This characteristic attributes to obtain circle-symmetry spots and enhance the electric field intensity of transmission light. The simulated results demonstrate that the electric field intensity of transmission light is 22 times than that of incidence. However, the electric field intensity of transmission light decays in the form of exponential with the increasing of the working distance.

In this paper, we demonstrate an auto accurate alignment method to align mask-substrate in the prototype of plasmonic lithography (PL), which is essential to multilayer nanostructure fabrication with high resolution, low cost, high efficiency and high throughput, such as circuit manufacturing and other multilayer applications. We obtain an alignment signal with sensitivity better than 20 nm by using the Moiré fringe image that is generated by overlaying two gratings with close periods. According to the diffract theory, Moiré fringe is independent of the illumination light wavelength and the length of the gap between the mask and the substrate, which makes it very suitable for the prototype of PL. However, only the alignment of Moiré fringes cannot guarantee the alignment of the mask and the substrate because the Moiré fringe repeats itself when the mask and substrate are offset by a fixed displacement. To eliminate the ambiguity, boxes and crosses alignment marks are designed beside the grating marks on the substrate and the mask, respectively. A two-step alignment scheme including coarse alignment and fine alignment is explored in the auto alignment system. In the stage of coarse alignment, the edge detection algorithm based on Canny operator is adopted to detect the edges’ image effectively and the alignment module calculates alignment deviation and controls sample stage to move until deviation is less than the expected deviation, guaranteeing the misalignment across substrate and mask within the measurement range of fine alignment. In the process of fine alignment, Fourier transform based on Moiré fringe image is obtained to calculate alignment deviation, and the auto alignment module use alignment deviation as feedback signal to align the mask and substrate. In this paper, we start, in Section 2, with the fundamental principle of Moiré fringe and its significant advantages. In Section 3 we introduce the structure and operation of the alignment system. We also demonstrate the fabrication procedures for the substrate and the auto alignment operation of PL in Section 4. In order to verify the feasibility of the proposed alignment method above, an overlay experiment is performed in Section 5. The experimental results of overlay indicate that PL can obtain sub-100 nm alignment accuracy over an area of 1 inch by using the proposed two-step alignment scheme. Furthermore, the auto alignment system and its process are also fully scalable for 4 inch or larger substrate processing. Via the substrate-mask mismatch compensation, better stages and precise environment control, it is expected that much higher overlay accuracy is feasible in the prototype of PL.

Sensors based on surface plasmon resonance (SPR) are widely recognized as valuable tools for sensing of liquid phase samples. It can be used in real-time monitoring of various biomolecular interactions, such as DNA hybridization and protein bindings since it is a simple, direct, real time and sensitive optical sensing technique used for probing refractive index changes. In recent years, Graphene (GR) has been applied in SPR sensors to improve the sensitivity. However, the detection sensitivity and accuracy of the sensors are lower for the loss of the electromagnetic field in GR which leads to the damping field and broad resonance peak in the SPR curve.

Based on the metal-insulator-metal (MIM) waveguide structures, a plasmonic filter and a sensor are designed by using an end-coupled ring-groove composited resonator (RGCR). It is well known that the perfect ring (PR) cavity can be regarded as a Fabry–Pérot resonator, and the transmission wavelengths of all the resonance modes are determined by its perimeter. According to the magnetic field distributions of the 1st and the 2nd resonance modes inside the PR cavity, a groove is added in the horizontal or the normal position of the ring cavity to manipulate the wavelength of the only expected mode in this paper. Specifically, when the groove locates at the anti-node of magnetic field, SPPs will be captured into the groove, and then the resonance wavelength is changed by the groove. On the contrary, when the groove locates at the node, the corresponding SPP mode will not be affected by the groove. When the inner and outer radius are 150 and 220 nm, the 1st and the 2nd resonance wavelengths for the PR cavity are 890.6 and 1784.4 nm, respectively. To manipulate the wavelengths of the modes, the groove is firstly placed at the top of the PR, where are the anti-node and the node for the 2nd and the 1st modes, respectively. The wavelength for the 2nd mode is linearly changed by the length of the groove, while the 1st mode keeps no change. Secondly, the groove is placed in the horizontal position, where the anti-nodes for both SPPs modes emerge. Likewise, it is investigated that the center wavelengths for both modes have linearly redshifted by increasing the length of the groove. In this case, the structure can be used as an on-chip optical filter with flexible wavelength manipulation. In addition, when the groove is rotated with an angle of π/4, Fano resonance will arise due to the mode interferences. Dual asymmetric sharp transmission peaks are achieved around the wavelength of the former 2nd resonance mode, and the resonance wavelengths for both Fano peaks are also tuned by the length of the groove. High figure of merit of 4.1×104 and high refractive-index sensitivity of 970 nm/RIU are obtained for the structure. Therefore, it is believed that the device can find wide applications in the biochemistry sensing area. It is also investigated that normal and abnormal dispersions are available at the peaks and dips, respectively. The corresponding spectra and the propagation characteristics are numerically investigated by using the finite-difference time-domain method. The proposed structure can provide important support for the development of highly integrated photonics circuits and on-chip optical sensors.

Surface enhanced Raman spectroscopy (SERS) has attracted a great amount of research interests in the past decades due to its fascinating use for finger-print molecules’ detection. Two main mechanisms, chemical and electromagnetic enhancement, are used to explain the SERS phenomenon. In particular, the latter mechanism is widely accepted as the dominated effect. In recent years, a new kind of intriguing platform built from “elevated” cavity or bowtie arrays has been developed for reliable SERS detection. Known as the lightning-rod effect, bowtie nanoantenna arrays are able to confine the optical radiation into nanoscale volumes, performing excellent field concentration, which can exhibit distinct SERS effect due to strong LSP resonance in the vicinity of sharp nanotips of nanoparticles and small gaps among neighboring nanoparticles. The “elevated” properties make the cavity or bowtie decouple from the substrate, which is expected to enhance near-field intensity. However, such “elevated” nanocavity array is limited to the weak tunability of plamonic resonance and complicated fabrication processes, such as electron-beam lithography (EBL) and focused ion beam (FIB) milling. Their main disadvantages of high cost and slow throughput are not practical for SERS applications. In this work, periodical silicon nanowires (SiNWs) integrated with metal-insulator-metal (MIM) layers are employed as SERS substrates. Laser interference lithography (LIL) combined with reactive ion etching (RIE) is used to fabricate large-area periodic nanostructures, followed by decorating the MIM layers. Compared to MIM disks array on Si surface, the SERS enhancement factor (EF) of the MIM structures on the SiNWs array can be increased up to 5 times, which is attributed to the enhanced electric field at the boundary of the MIM disks. Furthermore, high density of nanoparticles and nanogaps serving as hot spots on sidewall surfaces also contribute to the enhanced SERS signals. Meanwhile, SiNWs array boosts the adsorption of probing molecules within the detection volume and light scattering within the SiNWs. It is also found that the calculated electric field enhancement demonstrates a periodic variation of pillar height, which is due to the constructive or destructive interference between the incident and reflected light. Via changing the thickness of the insulator layer, the plasmonic resonance can be tuned. These factors contribute to the enhanced SERS signals. This 3D platform with large area, good periodicity and pillar height dependent electric field enhancement can provide guidance for further optimizing and engineering such “elevated” plasmonic nanostructures for practical SERS applications.

This paper mainly introduces the fabrication of nanoparticles by short pulsed laser ablation and its applications in the field of non-linear optics. With the characteristics of high purity, simple operation and wide applicability, the non-linear nanoparticles synthesized by short pulsed laser ablation show controllable size and size distribution, which has an unique role in non-linear optical materials. In order to further summarize this research area, this paper first introduces the optical non-linearity of the nanoparticles and the working principles of the pulsed lasers. Studies on non-linear optics illustrate various new optical phenomenas generated in the process of interaction between intense laser radiation and materials. Non-linear optical effects are derived from nonlinear polarization of molecules and materials. The physical mechanism of generating non-linear polarization mainly includes electron cloud distortion, induced acoustic motion, nuclear movement and optical Kerr effect, which result in anti-saturated absorption, self-focusing and two-photon absorption, and so on. Pulsed laser is produced by stimulated radiation with many advantages including high monochromaticity, high directivity, high strength and high coherence. The mechanism of interaction between pulsed laser and material is described as well, followed by analyzing the advantages of as-synthesized nanoparticles. The laser-materials interaction can lead to complex photo-thermal process, which makes the materials heated up, melt even on gasification, thus producing nanoparticles. So laser ablation has various advantages, such as simple setup, less operating steps, pollution-free process and applicable to most materials. What is more, the as-synthesized nanoparticles have high purity, small particle size and fairly uniform size distribution, and the size can be easily tuned by varying the laser processing parameters. The effects of processing parameters are also reviewed in detail. In general, the fabrication of nanoparticles is mainly affected by the following three factors: pulsed laser parameters (including intensity, pulse length, incidence angle and scanning speed, etc.), the performance of materials (absorption coefficient, chemical properties, melting point and crystallization temperature, etc.) and medium environment (vacuum, air and water, etc.). These parameters can be used to control the performance of nanoparticles. The current research status of various laser ablated nanoparticles is established for preparing different nanoparticles by pulsed laser ablation. The main types of nanoparticles include metal nanoparticles, metal oxide nanoparticles, carbon based nanoparticles and silica based nanoparticles. Researchers have taken these nanoparticles with excellent optical non-linearity highly into account and put the further research plans on the agenda. Synthesis of nanoparticles by pulsed laser ablation is significantly considered as an environmental-friendly and versatile method.

Metallic nanostructures can support the strongly confined interface waves: surface plasmon polaritons (SPPs). SPPs have recently been used in a variety of applications due to their abilities to guide light in the scale of nanometer. Whereas, intrinsic weak optical nonlinearities and short propagation lengths of SPPs hinder their applications in novel active plasmonic devices.

Tumor biomarker plays an important role in early diagnosis, treatment evaluation, and prognosis prediction for human medicine and cancers. At present, the human serum tumor biomarker detection methods have defections, such as radioactive contamination, complicated operation, long detection time and high cost, which limit the widespread applications in clinic screening. The LSPR biosensor, a novel type of optical fiber-based biosensor, uses an optical fiber or optical fiber bundle to transform biological recognition information into analytically useful signals in the LSPR spectrum, which is suitable for clinical detection because of the advantages of high sensitivity, high specificity, label free, portable equipment and lower cost. In this paper, the principle and research progress of local surface plasmon resonance biosensor, especially the main findings of our study group, are reviewed.

Semiconductor lasers are widely used for applications in biology, information storage, photonics and medical therapeutics. Along with the emerging area of nano-optics and nanophotonics, more compact lasers with size miniaturization attract significant interest. Last decades, many researchers tried to investigate the miniaturization technology of photon laser. The aiming is to obtain higher density devices integrated on smaller semiconductor chip. As the cavity size is reduced with respect to the emission wavelength, interesting physical effects, unique to electromagnetic cavities, arise. So, to scale down the semiconductor lasers in all three dimensions plays an important role in the developing of low-dimension, low-threshold, and ultrafast coherent light sources, as well as integrated nano-optoelectronic and plasmonic circuits. For this purpose, the nanolasers and smaller plasmonic nanolasers are developed during the last years. However, for the conventional semiconductor laser using dielectric cavity oscillator (photon cavity), the noticeable obstacle from diffraction limit confines the feature sizes of the nanodevices all the time, and makes them unable to get down to half wavelength level. These years, the invention of plasmonic nanolaser, where the light is enhanced by stimulated emission based on surface plasmon, can break through the bottleneck of optical diffraction limit and give out light with subwavelength scale. In this review, above all, the principle of cavity used in laser and the theory of the modal gain are illustrated generally. Besides, the important properties and the technical characters of the plasmonic nanolasers are introduced briefly. Then, the overall research progress of the plasmonic nanolasers are presented, which is explained by some typical plasmonic nanolasers, such as, surface palsmon-optical mode hybrid nanolaser, metal-dielectric heterogenic cavity plasmonic nanolaser, metal-insulator-semiconductor (MIS) subwavelength plasmonic nanolaser are introduced by turn. In addition, an updated overview of the latest developments, particularly in plasmonic nanolasers using the MIS configuration and other related metal-cladded semiconductor microlasers is presented. In particular, it has been experimentally demonstrated that the use of plasmonic cavities based on MIS nanostructures can indeed break the diffraction limit in all three dimensions. The research group proposed a new plasmonic nanolaser based on semiconductor nanowire/air spacer/metal film composited structure. This structure can get modes coupling between the surface plasmon on the metal and the high gain nanowire, which makes the enhancement effect increased obviously. It is shown that the structure can confine the output optical field to subwavength scale, and keep low transmission loss and high ability of the confinement. In this review, the experimental results are presented in detail. In the end, we give a contrast about the parameters and results for the new achievement in palsmonic nanolasers research area. Based on the recent development of the plasmonic nanolaser, we conclude about the developing trend. We also give some perspectives on the challenges and development trend for the plasmonic nanolasers. This review can provide useful guide for the research of plasmonic nanolasers.

The refraction and reflection are basic phenomena in the propagation of all kinds of waves, such as light waves, electromagnetic waves and acoustic waves, when they encounter the interface among different kinds of materials. Because of the rigorous limitation of classical laws, traditional optical components such as spherical lenses and parabolic mirrors must be designed with various non-planar geometric shapes to control the flow of light, which makes these devices bulky and heavy. During the last several hundred years, many efforts have been devoted to make optical components thin and lightweight. One particular example is the diffractive gratings and lenses, where the wavefront can be constructed by locally tuning the transmittance in a two-dimensional space. However, the diffractive devices are suffering from the low diffraction efficiency and large chromatic dispersion, making them difficult to be used in practical optical systems.

Researchers have designed a device, allowing to use light to manipulate its mechanical properties.

The assemble of microgears provides the advantage that is soft on one and rigid on the other.

Holography is a technique which can reconstruct the three-dimensional (3D) features of the object, and the 3D holographic images can be viewed without the visual aids. The coding material/equipment is very important for the qualities of the final hologram, for example, the mini-mum pixel size of the spatial light modulator (SLM) or digital micro-mirror device (DMD) limits the realization of a big viewing/diffraction angle of the holographic im-age.

Wu’s research team from A*STAR proposed and designed a hemispherical hyperlens with sea urchin-shaped geometry, which can overcome optical diffraction limit by capturing high-resolution information held by evanescent waves hiding near a target's surface.

The refraction and reflection are basic phenomena in the propagation of all kinds of waves, such as light waves, electromagnetic waves and acoustic waves, when they encounter the interface between different kinds of materials. Recently, it is discovered that the traditional optical laws regarding refraction and reflection can be rewritten when artificially designed subwavelength arrays are fabricated on the interfaces. The revised laws provide promising alternatives to achieve imaging, multi-physics decoupling and holographic display. Here we review the recent progresses in this emerging topic, including the refraction and reflection behavior in various materials configurations, the fundamental theories and practical applications. Finally, based on our recent results, the shortcomings of current researches are analyzed with a look towards the future trends of the overall area.

Semiconductor lasers are widely used for applications in biology, information storage, photonics and medical therapeutics. With the development of the emerging area of nano-optics and nanophotonics, more compact lasers attract significant interest. As the cavity size is reduced with respect to the emission wavelength, interesting physical effects in electromagnetic cavities arise. To scale down the semiconductor lasers in all three dimensions plays an important role in the development of low-dimension, low-threshold, and ultrafast coherent light sources, as well as integrated nano-optoelectronic and plasmonic circuits. In this review, the overall formal-ism of mode gain and confinement factor in the metal-semiconductor plasmonic lasers was introduced firstly. In addition, an updated overview of the latest developments, particularly in plasmonic nanolasers using the met-al-insulator-semiconductor (MIS) configuration and another related metal-cladded semiconductor microlasers was presented. In particular, it has been experimentally demonstrated that the use of plasmonic cavities based on MIS nanostructures can indeed break the diffraction limit in three dimensions. We also present some perspec-tives on the challenges and development trend for the plasmonic nanolasers. This review can provide useful guide for the research of plasmonic nanolasers.

Tumor biomarker plays an important role in early diagnosis, treatment evaluation, and prognosis pre-diction for human medicine and cancers. At present, the human serum tumor biomarker detection methods mainly include radioimmunoassay (RIA), enzyme linked immunosorbent assay (ELISA), and chemilumines-cence immunoassay (CLEIA), which have disadvantages of radioactive contamination, complicated operation, and long detection time and high cost. Various issues exist in these methods which limit its widespread applica-tions in clinic screening. Recently, biosensors based on localized surface plasmon resonance (LSPR) have at-tracted much research attention for their remarkable superiority in the domain of biomedicine detection. The LSPR biosensor, a novel type of optical fiber-based biosensor, uses an optical fiber or optical fiber bundle to transform biological recognition information into analytically useful signals in the LSPR spectrum, which is suita-ble for clinical detection because of the advantages of high sensitivity, high specificity, label free, portable equipment and lower cost. However, up to now, there was little progress on the report of the detection of tumor biomarkers associated diseases and tumors by using this LSPR biosensor. In this paper, the principle and re-search progress of local surface plasmon resonance biosensor, as well as the main findings of our study in the detection of tumor markers are reviewed.

Active plasmonics, as an important branch of Plasmonics, is growing rapidly over the last decades. The main principle of active plasmonics is to combine surface plasmon polaritons (SPPs) with ‘active’ materials to compenstate intrinsic weak optical nonlinearities and short propagation lengths of SPPs, so that external ma-nipulation and coherent control of SPPs can be realized. Here, we give a brief review of the studies in the area of active plasmonics. In particular, we focus on hybrid J-aggregate/metal nanostructures consisting of J-aggregate excitons and surface plasmon polaritons supported by metallic nanostructures. Two experimental methods: chrip-compensated spectral interferometry and nonlinear pump-probe spectroscopy are introduced. The strong coupling between J-aggregate excitons and SPPs is studied in detail by probing both the static optical properties and ultrasfast dynamics of the strongly coupled X-SPP systems. The results reveal that two different energy transfer channels: a coherent resonant dipole-dipole interaction and an incoherent exchange of photons, are co-existing in the hybrid system. Coherent energy exchange, that is, Rabi oscillations between the excitonic and the SPP systems in real time are also investigated. It is found that coherent X-SPP population transfer induces tran-sient oscillations in exciton density, leading to a periodic modulation of the normal mode splitting and thus optical nonlinearity on a 10 fs timescale.

This paper mainly introduces the fabrication of nanoparticles by short pulsed laser ablation and its ap-plications in the field of non-linear optics. With the characteristics of high purity, simple operation and wide ap-plicability, the non-linear nanoparticles synthesized by short pulsed laser ablation show controllable size and size distribution, which has an unique role in non-linear optical materials. In order to further summarize this research area, this paper first introduces the optical non-linearity of the nanoparticles and the working principles of the pulsed lasers. The mechanism of interaction between pulsed laser and material is described, followed by ana-lyzing the advantages of as-synthesized nanoparticles. The effects of processing parameters are also reviewed in detail. The current research status of various laser ablated nanoparticles is established for preparing different nanoparticles by pulsed laser ablation. Synthesis of nanoparticles by pulsed laser ablation is significantly con-sidered as an environmental-friendly and versatile method.

Bowtie aperture has been widely applied in the realm of nanometer direct-writing lithography for obtaining focusing spots beyond the diffraction limit. However, the obtained spot is elliptic-shape for the Bowtie case, which impacts the applications of the Bowtie structure. Double Bowtie aperture, as a novel nano-lithography structure, is proposed to attain circle-symmetric focusing spots beyond diffraction limit. The results demonstrate that circle-symmetry spots can be obtained, and the electric field intensity of transmission light is 22 times of that of incidence. By combining the double Bowtie structure with metal-insulator-metal, the propagation length of the enhanced transmission light is obviously prolonged.

Plasmonic sensor based on metallic nanostructures is a promising platform for applications, such as biology, chemistry, materialogy, photonics and bioscience due to their attractive properties. However, the sensitivity of plasmonic sensors is usually limited by broad-spectral features due to large radiative loss of metallic nanostructures in visible region. in this paper, we introduce structural asymmetry to generate the Fano resonance in the metallic nanostructure composed of asymmetric ellipsoidal pair. The distinct Fano-like resonance around wavelength of 681 nm possesses sharp peak as narrow as 10.8 nm. And the Fano mode exhibits high refractive index sensitivity as large as 299 nm/RiU. Due to the excitation of sharp spectral features, high figure of merit of 27.8 at the Fano resonance is obtained in a wide refractive index range of 1.0~1.1. This device is promising for the applications of high sensitivity microchip sensor.

The one-dimensional metallic photonic crystal film is an anisotropic metamaterial with an equivalent and uniform metal-medium multilayered structure. Compared with the single-layer metal film, the one-dimensional metal photonic crystal film has a higher degree of freedom in terms of chromatic dispersion regulation and control. With the existing of surface plasmon polariton (SPP), directional transmission of evanescent waves can be achieved. The experimental results and the calculated results of the equivalent medium theory and the finite-difference time domain (FDTD) method show that the active control on the wavelength, bandwidth and strength of the evanescent waves during transmitting can be realized by regulating the metal photonic crystal structure. The smaller is the ratio of metal film thickness, the longer are the center of the transmission wavelength and the cutoff wavelength, and the wider is the frequency band. When the thickness of the metal film layer is smaller than the penetration depth of the SPP, wide frequency-band evanescent waves can be transmitted. This paper also studied the transmission performance in the microwave band of the metal photonic crystal, finding that at the microwave band, the equivalent dielectric constant of the metal photonic crystal is negative and the metallic photonic crystal has a good reflection property. Furthermore, the shielding effectiveness of the metal photonic crystal film is far better than the electromagnetic shielding effectiveness of the ITO film with the same thickness. Even at the thickness of a few hundred of nanometers, the metallic photonic crystal film can achieve good electromagnetic shielding effectiveness. Thus, by adopting the metallic photonic crystal film, light and visual electromagnetic shielding materials with thin films can be created.