- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Hydrogen peroxide detection with a silver nanoparticle grating chip fabricated by plasmonic plating
摘要： An optical detection of hydrogen peroxide (H2O2) is proposed, using grating structures of silver nanoparticles (AgNPs). Periodic line structures of AgNPs are deposited on a gold nanoparticle (AuNP)-decorated glass plate using an interference exposure with a green laser beam, based on the plasmonic plating method. This AgNP grating chip diffracts incident light, and the diffraction efficiency is dependent on the amount of AgNPs. By applying a drop of H2O2 solution onto the chip, the diffraction intensity declines due to the autocatalytic decomposition of AgNPs. A portable measurement system of the diffraction intensity change is constructed, and the H2O2 detection in the concentration range 6.7 – 668 μmol/L is performed in 2 min simply by dropping the H2O2 solution onto the substrate.
关键词： silver nanoparticles,plasmonic plating,optical sensor,hydrogen peroxide detection,diffraction grating
更新于2025-11-25 10:30:42
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Metrology of Nanostructures by Tomographic Mueller-Matrix Scatterometry
摘要： The development of necessary instrumentation and metrology at the nanoscale, especially fast, low-cost, and nondestructive metrology techniques, is of great significance for the realization of reliable and repeatable nanomanufacturing. In this work, we present the application of a homemade novel optical scatterometer called the tomographic Mueller-matrix scatterometer (TMS), for the measurement of photoresist gratings. The TMS adopts a dual rotating-compensator configuration and illuminates the nanostructure sequentially under test conditions by a plane wave, with varying illumination directions and records. For each illumination direction, the polarized scattered field along various directions of observation can be seen in the form of scattering Mueller matrices. That more scattering information is collected by TMS than conventional optical scatterometry ensures that it achieves better measurement sensitivity and accuracy. We also show the capability of TMS for determining both grating pitch and other structural parameters, which is incapable by current zeroth-order methods such as reflectometry- or ellipsometry-based scatterometry.
关键词： inverse scattering,ellipsometry,pitch measurement,diffraction grating,scatterometry,Mueller matrix
更新于2025-09-23 15:23:52
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Influence of defects on structural colours generated by laser-induced ripples
摘要： The colourisation of metallic surface which appears due to periodic surface patterns induced by ultrashort laser pulses is studied. Ripples due to the sub-micrometer size of their period act as a diffraction grating, generating structural colours. Carefully chosen strategy of the laser spot scanning allows us to mimic the nanostructures responsible for structural colours of some flowers on the metal substrate. We investigate the correlation between the colourising effects and the artificially-induced defects in the ripples structure and show that these defects can make the colours observable in a larger range of viewing angles. Further we address the influence of the processing parameters on the spectral profile of the reflected light.
关键词： structural colours,viewing angles,diffraction grating,defects,laser-induced ripples
更新于2025-09-23 15:19:57
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High resonance frequency in a coupled cavity DFB-LD with two phase-shifts
摘要： To realize a single-longitudinal-mode laser diode (LD) with high speed direct-modulation, a coupled cavity DFB-LD with two phase-shifts is proposed. From simulated results, it is expected that the resonance frequency of 71.3 GHz and the 3-dB down bandwidth of 95.9 GHz are obtained when the injected current is 3.075 times the threshold current. The resonance frequency for a main-mode is enhanced by an interaction between the main-mode and sub-mode. This interaction is called photon–photon resonance. The proposed coupled cavity DFB-LD is composed of two regions which are connected in series. Both regions have phase-shifted gratings. The phase-shift of the first region is ? π; the phase-shift of the second region is ? 0.9π. A phase-shift is not introduced at the interface of the two regions. The corrugation pitch of the second region is shorter than that of the first region by 1.6 nm; the grating coupling coefficient is 40 cm?1; each region length is 300 μm. These parameters are modest to fabricate DFB-LDs.
关键词： Longitudinal mode,Coupled cavity,Direct modulation,Semiconductor laser,Diffraction grating
更新于2025-09-23 15:19:57
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Analytical analysis of PT and quasi-PT symmetry in thick diffraction gratings using coupled-wave theory
摘要： The concept of parity-time (PT) symmetry in optics could potentially provide emerging solutions to exploit the benefits of optical gain in optical processing. With this regard, PT and quasi-PT symmetry were studied in thick optical diffraction gratings by derivation of explicit analytical expressions using the coupled-wave theory and verified by numerical calculations. The conditions to observe PT and quasi-PT symmetry were discussed in terms of the gain-loss ratio and the refractive index modulation amplitudes for both reflective and transmissive gratings. The results show that the criterion to attain quasi-PT symmetry for the reflective and transmissive gratings is in reverse in terms of the ratio of the modulation amplitude of the imaginary to that of the real part of the refractive index (|Γ|). According to the model, a grating with fringes parallel to the surface experiences broken PT symmetry for a wide range of gain-loss ratios. Furthermore, by varying the gain-loss ratio or |Γ|, some extrema could be observed in the normalized transmission power of the diffraction orders, while operating in the quasi-PT symmetry regime. The analytical solutions could predict and justify the positions of those extrema which could be advantageous to the design purposes.
关键词： diffraction,grating,quasi-PT symmetry,Parity-time symmetry
更新于2025-09-23 15:19:57
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Ultra-narrow band perfect metamaterial absorber based on dielectric-metal periodic configuration
摘要： The ultra-narrow band perfect metamaterial absorber (PMA) based on dielectric-metal periodic configuration for near infrared spectral region is proposed. The PMA consists of a dielectric resonant structure and a metal substrate. Two design examples show that the proposed PMAs are able to exhibit nonpolarizing absorption peaks at normal and oblique incidences respectively. Moreover, the absorption spectra of the PMA for oblique incidence are insensitive to the incident angle under TE polarized light illumination. But this PMA exhibits a large spectral shift by rotating the angle of incidence under TM polarized light illumination. Then a PMA sample for oblique incidence is fabricated through thin-film deposition and electron beam lithography patterning. Finally, the reflection spectra of the fabricated PMA sample are measured. The absorption spectra obtained by subtracting the measured reflection spectra from incident spectra are consistent with the theory. Thus the novel characteristics of the ultra-narrow band PMA based on dielectric-metal periodic configuration are experimentally demonstrated.
关键词： Ultra-narrow band,Nonpolarizing absorption,Perfect metamaterial absorber,Tunable spectrum,Diffraction grating
更新于2025-09-19 17:15:36
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Fabrication of integrated spectrometer module based on optical waveguide platform with planar nano diffraction grating using UV imprint lithography
摘要： We proposed a simple and attractive integrated polymeric spectrometer module based on a planar optical waveguide platform that can be easily manufactured at a low cost. The proposed integrated spectrometer module comprises a planar optical waveguide with a concave mirror, a planar nano diffraction grating with a non-uniform pitch, an optical fiber, and a photodiode array. The nano diffraction grating and optical waveguide platform were precisely fabricated using the UV imprint lithography suitable for mass production. To provide uniform diffraction efficiency in the wavelength range of 400–650 nm, the nano diffraction grating had a quasi-three-dimensional V-shaped groove with a blazing angle of 22.5° and non-uniform pitches, maximum of 0.406 μm and minimum of 0.393 μm. In addition, the optical waveguide platform focuses the optical source to the nano diffraction grating using the concave mirror. The alignment guide pattern is used to align the nano diffraction grating and optical fiber. Through the packaging process of nano grating device, photo diode array and fiber on the planar optical waveguide platform, we manufactured the polymeric integrated polymeric spectrometer module. We confirmed that the fabricated planar spectrometer module had a resolution of 5 nm or less for spectral bandwidth of 250 nm, and it can be used widely in portable spectrometer sensors.
关键词： Integrated spectrometer module,UV imprint lithography,Planar optical waveguide,Nano diffraction grating
更新于2025-09-19 17:13:59
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Quasi-statischer MOEMS-Gitterscanner zum spektralen Durchstimmen eines MIR-Quantenkaskadenlasers
摘要： Broadband tuning of MIR-infrared radiation from 3 to 10 μm (1000 to 3200 wavenumbers) is a very promising way for spectroscopic study of gaseous, liquid, or solid species or intermixtures. We report a new quasi-static micro-optical-electrical-mechanic (MOEMS) grating for spectral tuning of an IR light source based on a quantum cascade laser. This concept unites the advantages of broadband sources with the advantages of coherent laser sources in a miniaturized setup. In contrary to resonant MOEMS device, the quasi-static driving principle allows the scanning with arbitrary trajectories and velocity and thus with potential higher spectral resolution. To stabilize the trajectory the MOEMS device is controlled by integrated position sensors. We report the dynamical characteristics of MOEMS micro-mirror with integrated diffraction grating and experimental results of the tuning of a QCL in the wavelength range from 4150 to 4600 nm.
关键词： quantum cascade laser,IR spectroscopy,MOEMS scanner,diffraction grating,micro-mirror
更新于2025-09-16 10:30:52
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Tapping underwater wireless optical communication in pure water and natural Dead-Sea ultra-high-salinity water by diffraction grating
摘要： Although underwater wireless optical communication (UWOC) receives much interest lately, security issues associated with it get little attention. In this paper, we show how a message communicated using UWOC can be eavesdropped without a sender's or addressee's awareness, by employing a diffraction grating. We also analyze the propagation of multiple diffracted Gaussian beams in water, and show for the first time that UWOC is feasible even in natural ultra-salty water taken from the Dead-Sea. We evaluate how far from the addressee the message could be eavesdropped, and discuss different possibilities of tapping the channel – one from the air and one underwater.
关键词： diffraction grating,eavesdropping,underwater wireless optical communication,ultra-salty water,UWOC,Dead-Sea
更新于2025-09-12 10:27:22
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Self‐Powered UV–Vis–NIR Photodetector Based on Conjugated‐Polymer/CsPbBr <sub/>3</sub> Nanowire Array
摘要： Perovskite photodetectors have attracted intensive research interest due to promising applications in sensing, communication, and imaging. However, their performance is restricted by the narrow spectrum range, required power source, and instability in ambient environment. To address these issues, a self-powered photodetector based on the inorganic CsPbBr3 perovskite nanowire array/conjugated-polymer hybrid structure is designed. The spectra response range of the device can be extended to 950 nm, along with outstanding stability, fast response speed (111/306 μs), and large detectivity (1.2 × 1013 Jones). The performance parameters are comparable to or even better than most reported CsPbBr3 and conjugated-polymer photodetectors. The excellent performance is mainly attributed to the efficient carrier generation, separation, and transport resulting from array structure and favorable band structure.
关键词： CsPbBr3,photodetector,perovskite,diffraction grating,self-powered
更新于2025-09-11 14:15:04