We propose a novel configuration for nonvolatile and reconfigurable tuning of surface lattice resonances (SLRs) based on thin films of phase-change material Ge2Sb2Te5 (GST). The configuration is composed of gold nanorod array embedded in a thin GST film. Results show that, an extremely wide SLR wavelength tuning range reaching 1600 nm, large tuning figure of merit of 21, and high SLR quality factors of 47 and 17 can be achieved in the mid-infrared regime when GST transits from the amorphous state into the crystalline state. The effects of the GST layer thicknesses on the SLR tuning performance are discussed, and the performances of several modified configurations are compared. We expect this work will advance the engineering of SLR tuning based on phase-change materials and promote its applications especially in nanolasing and narrowband filtering.

We report the design of broadband highly reflective subwavelength high-index-contrast gratings (HCGs) for both TE and TM polarizations in the visible regime. Results show that high reflectivity above 99% covering 544–726 nm or 510–666 nm can be achieved, corresponding to a fractional bandwidth of Δλ/λ0 = 28.7% or 26.5% for the TM or TE polarization, respectively. We reveal that these broad high-reflectivity bands originate from a blend of multiple leaky modes, similar to the counterparts operating in the near-infrared regime. By investigating the effects of the grating height, period, and width, we find that the broadband high reflectivity requires careful optimization. We expect that this work will advance the engineering of broadband HCG reflectors and promote their applications in the visible regime.

We report the design of ultra-broadband, highly reflective all-dielectric reflectors covering the entire visible regime based on two cascaded subwavelength high-index-contrast gratings (HCGs). We find that the spectral distance between the two gratings’ reflective bandwidths, which should be appropriately designed in order to extend the overall bandwidth for high reflectivity, is analogous to the well-known Rayleigh, Abbe and Sparrow criteria for resolution limits. Results illustrated with TM-polarized normal incidence show that high reflectivity above 98.5% covering 400–800 nm can be achieved for two cascaded HCGs with an appropriate spectral distance. The effects of key structural parameters on the bandwidth extension are discussed with physical insights. We expect this work will advance the engineering and applications of HCGs as ultra-thin, ultra-broadband and all-dielectric reflectors.

We propose a nonvolatile, reconfigurable, and narrowband mid-infrared bandpass filter based on surface lattice resonance in phase-change material Ge2Sb2Te5. The proposed filter is composed of a two-dimensional gold nanorod array embedded in a thick Ge2Sb2Te5 film. Results show that when Ge2Sb2Te5 transits from the amorphous state to the crystalline state, the narrowband reflection spectrum of the proposed filter is tuned from 3.197 μm to 4.795 μm, covering the majority of the mid-infrared regime, the peak reflectance decreases from 72.6% to 25.8%, and the corresponding quality factor decreases from 19.6 to 10.3. We show that the spectral tuning range can be adjusted by varying the incidence angle or the lattice period. By properly designing the gold nanorod sizes, we also show that the quality factor can be greatly increased to 70 at the cost of relatively smaller peak reflection efficiencies, and that the peak reflection efficiency can be further increased to 80% at the cost of relatively smaller quality factors. We expect that this work will advance the engineering of Ge2Sb2Te5-based nonvalatile tunable surface lattice resonances and will promote their applications especially in reconfigurable narrowband filters.

We report the design an ultra-broadband highly reflective subwavelength grating that covers almost the entire visible region. Results show that high reflectivity above 90% covering 450–700 nm can be achieved, corresponding to Δλ/λ=43%. We also provide intuitive physical insights into the broadband high reflection performance of reflector. We expect that this ultra-thin, ultra-broadband and highly reflective all-dielectric reflector can find applications in hyperspectral imaging based on tunable etalon filters.

Here we report a tunable polarization-independent broadband absorber in the terahertz regime. The proposed structure consists of periodic all-dielectric array on a gold substrate, sandwiched by a monolayer graphene and an epsilon-near-zero layer. Simulation results show that the absorption that is independent from the incident polarization remains above 90% over a broadband spectral range from 1.6 THz to 4.1 THz, corresponding to a bandwidth of 2.5 THz and a relative bandwidth of 87.7%. By varying the graphenes Fermi energy from 0.2 eV to 0.5 eV, the absorption bandwidth can be turned from 1.5 THz to 2.5 THz. We expect this polarization-independent absorber with dynamically tunable bandwidth can be used as filters in applications such as terahertz detectors.

The chirality of photons plays a fundamental role in light-matter interactions. However, a limiting factor in photonic integrated circuits is the lack of a miniaturized component, which can distinguish the chirality in a low cost and integrated manner. Herein we numerically demonstrate a chirality-distinguishing beamsplitter that can address this challenge. It consists of an integrated polarization rotator and a linear polarization beamsplitter, which together can fulfill the task of distinguishing and splitting left- and right-handed quasi-circularly polarized modes on a chip with an ultra-broadband operation range from 1.45 μm to 1.65 μm. Owning to the reciprocity, the device can emit photons with selectable spin angular momentum depending on the chosen feeding waveguide. The device is compatible with complementary metal-oxide semiconductor technology and it may open up new avenues in the fields of on-chip nano-photonics, bio-photonics and quantum information science.

Green nano probe with high sensitivity which is Mn2 + doped ZnS quantum dots (ZnS∶ Mn2 + · QDs) has been used in the quantitative analysis of trace substances.This article demonstrates progress in the implementing ZnS∶ Mn2 + · QDs in the detection of heavy metal,in biology,medicine and pharmacology.This study prospects for the future application of ZnS∶ Mn2 + · QDs.

The rapid development of near-infrared surface-enhanced Raman scattering (NIR SERS) imaging technology has attracted strong interest from scientists and clinicians due to its narrow spectral bandwidth, low background interference, and deep imaging depth. In this report, the graphene oxide (GO)-wrapped gold nanorods (GO@GNRs) were developed as a smart and robust nanoplatform for ultrafast NIR SERS bioimaging. The fabricated GO@ GNRs could efficiently load various NIR probes, and the in vitro evaluation indicated that the nanoplatform could exhibit a higher NIR SERS activity in comparison with traditional gold nanostructures. The GOs were prepared by directly pyrolyzing citric acid for greater convenience, and GO@GNRs were fabricated via a facile synthesis strategy. Higher NIR SERS activity, facile synthesis method, excellent biocompatibility, and superb stability make the GO@GNRs/probe complex promising nanoprobes for NIR SERS-based bioimaging applications.

Data storage with ultrahigh density, ultralow energy, high security, and long lifetime is highly desirable in the 21st century and optical data storage is considered as the most promising way to meet the challenge of storing big data. Plasmonic coupling in regularly arranged metallic nanoparticles has demonstrated its superior properties in various applications due to the generation of hot spots. Here, the discovery of the polarization and spectrum sensitivity of random hot spots generated in a volume gold nanorod assembly is reported. It is demonstrated that the two-photon-induced absorption and two-photon-induced luminescence of the gold nanorods adjacent to such hot spots are enhanced significantly because of plasmonic coupling. The polarization, wavelength, and spatial multiplexing of the hot spots can be realized by using an ultralow energy of only a few picojoule per pulse, which is two orders of magnitude lower than the value in the state-of-the-art technology that utilizes isolated gold nanorods. The ultralow recording energy reduces the cross-talk between different recording channels and makes it possible to realize rewriting function, improving significantly both the quality and capacity of optical data storage. It is anticipated that the demonstrated technology can facilitate the development of multidimensional optical data storage for a greener future.

Gears are rotating machines, meshing with each other by teeth to transmit torque. Interestingly, the rotating directions of two meshing gears are opposite, clockwise and counterclockwise. Although this opposite handedness motion has been widely investigated in machinery science, the analogue behavior of light remains undiscovered. Here, we present a simple nanophotonic directional coupler structure which can generate two light beams with opposite handedness of polarization states-optical gears. Due to the abrupt phase shift effect and birefringence effect, the angular momentum (AM) states of photons vary with the propagation distance in two adjacent waveguides of the coupler. Thus, by the choice of coupling length, it is able to obtain two light beams with opposite handedness of polarization, confirming the appearance of optical gears. The full control in the handedness of output beams is achieved via tuning the relative phase between two orthogonal modes at the input port. Optical gears thus offer the possibility of exploring light-matter interactions in nanoscale, opening up new avenues in fields of integrated quantum computing and nanoscale bio-sensing of chiral molecules.

Red light-emitting diodes (LED) were used to irradiate the isolated hypertension hemoglobin (Hb) and Raman spectra difference was recorded using confocal micro-Raman spectroscopy. Differences were observed between the controlled and irradiated Hb by comparing the spectra records. The Raman spectrum at the 1399 cm−1 band decreased following prolonged LED irradiation. The intensity of the 1639 cm−1 band decreased dramatically in the first five minutes and then gradually increased in a time-dependent manner. This observation indicated that LED irradiation increased the ability of oxygen binding in Hb. The appearance of the heme aggregation band at 1399 cm−1, in addition to the oxygen marker band at 1639 cm−1, indicated that, in our study, 30 min of irradiation with 15.0 mW was suitable for inhibiting heme aggregation and enhancing the oxygen-carrying capacity of Hb. Principal component analysis showed a one-to-one relationship between irradiated Hb at different time points and the corresponding Raman spectra. Our approach could be used to analyze the hemoglobin from patients with confocal micro-Raman spectroscopy and is helpful for developing new nondrug hypertension therapy.

A surface plasmon resonance sensor based on a U-shaped photonic crystal fiber with a rectangular lattice has been designed through finite element method. The U-shaped fiber exhibits not only stronger mechanical strength but also better sensor performance than our previous scheme. The upper detection limit extends to higher analyze refractive index, 1.384, for phase interrogation. We introduce a ratio to evaluate the impact of higher order plasmonic mode. For wavelength modulation scheme, the parameter to describe the performance of a sensor is chosen to be the figure of merit, which can be up to 533.8[RIU −1 ] around complete coupling condition.

Nanophotonic waveguides are the building blocks of integrated photonics. To date, while quarter-wave plates (QWPs) are widely used as common components for a wide range of applications in free space, there are almost no reports of Integratable QWPs being able to manipulate the angular momentum (AM) of photons inside nanophotonic waveguides. Here, we demonstrate two kinds of Integratable QWPs respectively based on the concept of abrupt phase change and birefringence effect. The orientation of the equivalent optical axis of an Integratable QWP is designable. Remarkably, a combination of two integratable QWPs with different equivalent optical axes leads to an integrated system that performances one-way AM conversion. Moreover, this system can be used as a point source that can excite different patterns on a metal surface via directional excitation of surface plasmon polaritons (SPP). These results allow for the control of AM of light in nanophotonic waveguides, which are crucial for various applications with limited physical space, such as on-chip bio-sensing and integrated quantum information processing.

利用多粒子非对称量子纠缠态,提出一种多体高维非对称量子信道的量子受控密集编码方案。采用量子测量的方法控制纠缠量子信道和密集编码经典信息的传送,通过构造幺正变换矩阵和正交量子测量,纯化量子信道,以一定的概率实现量子受控密集编码,解决了实际量子信道退相干影响下最大纠缠态提取的问题,实现了N方发送方和1方接收方之间密集编码传送信息量的控制,提高了密集编码可调控传送信息量,扩大了调控范围。

Optical vortices of physical eigenstates, generating and control technology and high-dimensional enco-ding QKD based on OAM ( Orbital Angular Momentum) are summarized and elaborated in this paper.The OAM and spin angular momentum ( SAM) preparation methods based on the preliminary study are summarized as fol-lows:using type-I phase matching BBO crystal with spontaneous parametric down-conversion process to obtain sig-nal and idle photon pairs entangling in OAM; using SAM and OAM freedom conversion device to transverse the SAM into OAM.How to use the spatial light modulator ( SLM) as a post-selection device of OAM entangled state to propose the improved BB84 QKD system based on OAM and the hybrid SAM-OAM entanglement QKD are dis-cussed and how to prepare W-state entangled photons is proposed.It shows that the amount of encoding information can achieve log2(m+2) bits (m is the number of possible values of l) and it is expected to achieve scalable secure communication with high dimension, strong entanglement properties and the ability of anti-bit loss.Furthermore, the experiments show that cell technology has a very important scientific significance for further increasing the quan-tum communication channel multiplexing capability and improving network security.

Confocal micro-Raman spectroscopy was used to distinguish human xanthelasma skin (HXS) from the human normal skin (HNS). Results showed that intensive Raman peaks at 1,269, 1,336, 1,448, and 1,656 cm(-1) increased obviously. Both 1,269 and 1,656 cm(-1) peaks showed that the proteins in HXS were mostly in the anti-parallel ß sheet conformation. While the intensities of bands at 1,032, 1,087, 1,300, and 1,448 cm(-1) belonged to lipids were enhanced in HXS spectrum compared to those in HNS spectrum. There were main intercellular lipids alkyl chains with minor proteins contribution at 1,087 cm(-1) and phenylalanine at 1,032 cm(-1) . To quantitative analysis of the difference, the ratio of I852/I829 was calculated, which was 1:1.04 ± 0.04 and 1:1.11 ± 0.02 for HNS and HXS (p < 0.01), respectively. The data indicated that some tyrosine residues, which form a hydrogen bond with H2 O prior to aggregation, were captured by strong hydrogen-bond acceptors in the aggregate. The decreased ratio of I852/I829 indicated more hydrophobic in HXS than HNS. Principal component analysis showed a one-to-one relationship between human xanthelasma skin and the corresponding Raman spectra. It could be given useful help for the diagnostication of xanthelasma.

This study aims to characterize and classify serum surface-enhanced Raman spectroscopy (SERS) spectra between bladder cancer patients and normal volunteers by genetic algorithms (GAs) combined with linear discriminate analysis (LDA). Two group serum SERS spectra excited with nanoparticles are collected from healthy volunteers (n = 36) and bladder cancer patients (n = 55). Six diagnostic Raman bands in the regions of 481–486, 682–687, 1018–1034, 1313–1323, 1450–1459 and 1582–1587 cm −1 related to proteins, nucleic acids and lipids are picked out with the GAs and LDA. By the diagnostic models built with the identified six Raman bands, the improved diagnostic sensitivity of 90.9% and specificity of 100% were acquired for classifying bladder cancer patients from normal serum SERS spectra. The results are superior to the sensitivity of 74.6% and specificity of 97.2% obtained with principal component analysis by the same serum SERS spectra dataset. Receiver operating characteristic (ROC) curves further confirmed the efficiency of diagnostic algorithm based on GA-LDA technique. This exploratory work demonstrates that the serum SERS associated with GA-LDA technique has enormous potential to characterize and non-invasively detect bladder cancer through peripheral blood.

Mid-infrared optical source and the detection technologies have numbers of important practical values and prospects in many fields such as remote sensing, medical, environmental protection and military. The main methods of producing Mid-infrared optical sources, at present, are optical parametric oscillator, quantum cascade and ceramic. Physi CAL theoretically got the transformation near 100%, from the near infrared light(~ 1064 nm) to the mid-infrared one(~ 3.53 um) utilizing LiNbO3 crystals which doped of MgO , based on the adiabatic difference frequency method. Then we used the three cascade different frequency KTP crystals, getting the 3.8 um wavelength light in the output, from the digital simulation, nearly 100% of the transformation was realized theoretically.It is a great task for us to achieve the integrate of the infrared sensor with silicon base, and the discovery of black silicon provides a novel way to achieve it. The external quantum efficiency is beyond 100%, on accounting of the extreme gain. We think that the combination of quantum confinement effect and doping of sulfur is responsible for the gain, based on the analyzing of massive works of other groups previous. We also tried to model the black silicon diode and already have built up the models of black silicon solar cell, in which three levels and four levels system is used.

Objective To explore the characteristics of light propagation along the Pericardium Meridian and its surrounding areas at human wrist by using optical experiment and Monte Carlo method. Methods An experiment was carried out to obtain the distribution of diffuse light on Pericardium Meridian line and its surrounding areas at the wrist, and then a simplified model based on the anatomical structure was proposed to simulate the light transportation within the same area by using Monte Carlo method. Results The experimental results showed strong accordance with the Monte Carlo simulation that the light propagation along the Pericardium Meridian had an advantage over its surrounding areas at the wrist. Conclusion The advantage of light transport along Pericardium Merdian line was related to components and structure of tissue, also the anatomical structure of the area that the Pericardium Meridian line runs.