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- 摘要
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- 实验方案
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Strain Mapping of CdTe Grains in Photovoltaic Devices
摘要： Strain within grains and at grain boundaries (GBs) in polycrystalline thin-film absorber layers limits the overall performance because of higher defect concentrations and band fluctuations. However, the nanoscale strain distribution in operational devices is not easily accessible using standard methods. X-ray nanodiffraction offers the unique possibility to evaluate the strain or lattice spacing at nanoscale resolution. Furthermore, the combination of nanodiffraction with additional techniques in the framework of multimodal scanning X-ray microscopy enables the direct correlation of the strain with material and device parameters such as the elemental distribution or local performance. This approach is applied for the investigation of the strain distribution in CdTe grains in fully operational photovoltaic solar cells. It is found that the lattice spacing in the (111) direction remains fairly constant in the grain cores but systematically decreases at the GBs. The lower strain at GBs is accompanied by an increase of the total tilt. These observations are both compatible with the inhomogeneous incorporation of smaller atoms into the lattice, and local stress induced by neighboring grains.
关键词： X-ray microscopy,nanodiffraction,X-ray diffraction (XRD),solar cells,multimodal,CdTe,X-ray,strain,X-ray fluorescence (XRF),photovoltaic,X-ray beam induced current (XBIC)
更新于2025-09-19 17:13:59
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Ultra high damage threshold optics for high power lasers
摘要： The output energies of lasers have increased year-by-year since their invention. Compared to this increase of laser energies, the damage threshold of optical components has not strongly changed. Therefore, the size of optics in high-energy laser system increases. This situation could change dramatically if optics with higher damage threshold were developed. Here, we propose a high damage threshold optics using a neutral gas as an active medium. More than 95% diffraction ef?ciency has been achieved. The damage threshold for a 6 ns laser pulse is measured to be 1.6 kJ/cm2. The aperture size of the present system is about 60 mm2. Based on this result, we anticipate that control of a 1 kJ laser beam may be achievable using 1 cm sized optics, driven by a < 50 mJ ultraviolet laser, making this scheme promising in high power laser applications.
关键词： damage threshold optics,ultraviolet laser,high power lasers,diffraction efficiency,neutral gas
更新于2025-09-19 17:13:59
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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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Quantum diffraction of position-momentum entangled photons from a sharp edge
摘要： In this paper, an experiment of quantum diffraction of position-momentum entangled photons from a straight sharp edge is presented. Path of a single photon of an entangled pair is partially blocked by a sharp edge whereas the other photon is detected at a stationary location without revealing the which-path information of the other photon. Quantum diffraction pattern of the sharp edge is revealed only in the correlated conditional detection of spatially separated photons and no diffraction pattern is formed in local detections of individual photons. Theoretical analysis of the quantum diffraction of position-momentum entangled photons from a sharp edge is also presented in this paper. Experimental measurements of the quantum diffraction pattern are compared with theoretically calculated quantum diffraction pattern of position-momentum entangled photons.
关键词： Photon entanglement,Quantum interference,Quantum diffraction,Position-momentum entanglement
更新于2025-09-19 17:13:59
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[IEEE 2019 Days on Diffraction (DD) - St. Petersburg, Russia (2019.6.3-2019.6.7)] 2019 Days on Diffraction (DD) - Normal mode coupling in a waveguide with a range-dependent sound speed profile in the bottom
摘要： In this paper, a novel graphene-based multiple-input multiple-output (MIMO) concept is proposed for high-rate nanoscale wireless communications between transceivers, which are nano/micrometers apart from each other. In particular, the proposed MIMO architecture considers exploiting a deep-subwavelength propagation channel made of graphene. This allows us to increase the number of transmitted symbol streams, while using a deep-subwavelength arrangement of individual plasmonic nanotransmit/receive elements in which the spacing between the transmitters and/or the receivers is tens of times smaller than the wavelength. This exclusive benefit is achieved with the aid of the phenomenon of graphene plasmons, where graphene offers the extremely confined and low-loss plasmon propagation. Hence, the proposed graphene-based MIMO system is capable of combating the fundamental limitations imposed on the classic MIMO configuration. We also present a novel graphene-specific channel adaptation technique, where the chemical potential of the graphene channel is varied to improve the power of the received signals.
关键词： MIMO,surface plasmon polariton,nanoscale communication,chemical potential,graphene,Correlation,diffraction limit,deep subwavelength
更新于2025-09-19 17:13:59
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Comment on “An effect of novel Nd3+ doping on physical properties of nebulizer spray pyrolysis fabricated ZnS thin films for optoelectronic technology" by A. Jesu Jebathew, M. Karunakaran, K. Deva Arun Kumar, S. Valanarasu, V. Ganesh, Mohd. Shkir, S. AlFaify, A. Kathalingam, in Physica B: Physics of Condensed Matter (2019)
摘要： The present commentary connected with the errors and mistakes made in the structural and morphological properties of Nd3+ doped ZnS thin films by nebulizer spray pyrolysis.
关键词： ZnS thin films,Microstrain,Structural properties,X-ray diffraction
更新于2025-09-19 17:13:59
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Implementation and assessment of a low-cost 3D laser platform controlled by open software for printing polymeric micro-structures
摘要： A low-cost 3D opto-mechatronic platform controlled by free-source software with optical and mechanical resolutions of 120 μm and 10 μm, respectively, was developed to fabricate micro-pedestals in grid presentation and diffractive optical elements such as micro-square and micro-slits. Direct laser writing (DLW) and low-one photon absorption (LOPA) were employed as the fabrication protocol and the physical phenomena involved in the platform control and development of the micrometric structures. A laser pointer, one of the lowest-cost lasers in the market, centered at 532 nm with an intensity of 65 mW, was used to polymerize the SU8-2050 photoresist through the DLW procedures. The printing process was carried out by using a 5X and 10X microscope objectives with numerical apertures of 0.13 and 0.25, respectively. The point spread function demonstrated the geometrical variations and the field intensity distribution about the focal plane, where the Debye-Wolf approximation is valid, which were used for comparison purposes. Ray tracing simulations were in addition presented demonstrating how light interacts with the SU8-film and how out of focus condition plays a fundamental role in the final size of the printed micro-pattern. Finally, two optical diffractive elements and their diffraction patterns in the Fraunhofer regime were presented.
关键词： low-one photon absorption,micro-fabrication,direct laser writing,optical diffraction
更新于2025-09-19 17:13:59
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Optical properties of 2D photonic structures fabricated by direct laser writing
摘要： This paper presents the results of fabrication and investigation of different 2D photonic structures with the square C4v, hexagonal C6v, and pentagonal local C5v symmetry. The samples were created using the direct laser writing technique. The number of submicron scatterers varied from 25 to 10,000, and the lattice parameters varied in different samples in the range of 0.5 μm ≤ a ≤ 8.0 μm. Our experimental and theoretical studies demonstrate that 2D photonic structures reveal many remarkable optical effects. Created ordered and disordered photonic structures demonstrate a great variety of optical phenomena observed on a far-field screen placed behind the sample. When the random fluctuations of the orientation for individual rods were introduced to the perfect fishnet photonic structure, a crossover from Laue diffraction to speckle patterns was observed and investigated.
关键词： Laue diffraction,Light scattering,Photonic structure,Direct laser writing,SEM images,Metasurface
更新于2025-09-19 17:13:59
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Structure Quality of LuFeO3 Epitaxial Layers Grown by Pulsed-Laser Deposition on Sapphire/Pt
摘要： Structural quality of LuFeO3 epitaxial layers grown by pulsed-laser deposition on sapphire substrates with and without platinum Pt interlayers has been investigated by in situ high-resolution X-ray diffraction (reciprocal-space mapping). The parameters of the structure such as size and misorientation of mosaic blocks have been determined as functions of the thickness of LuFeO3 during growth and for different thicknesses of platinum interlayers up to 40 nm. By means of fitting of the time-resolved X-ray reflectivity curves and by in situ X-ray diffraction measurement, we demonstrate that the LuFeO3 growth rate as well as the out-of-plane lattice parameter are almost independent from Pt interlayer thickness, while the in-plane LuFeO3 lattice parameter decreases. We reveal that, despite the different morphologies of the Pt interlayers with different thickness, LuFeO3 was growing as a continuous mosaic layer and the misorientation of the mosaic blocks decreases with increasing Pt thickness. The X-ray diffraction results combined with ex situ scanning electron microscopy and high-resolution transmission electron microscopy demonstrate that the Pt interlayer significantly improves the structure of LuFeO3 by reducing the misfit of the LuFeO3 lattice with respect to the material underneath.
关键词： in situ X-ray diffraction,multiferroics,electron microscopy,pulsed-laser deposition
更新于2025-09-19 17:13:59
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Analysis of Seasonal Aspects of Nebulosity on the Project of Fixed Photovoltaic Installations at the City of Bel??m, Brazil
摘要： In this paper, we adopt the coded aperture technique to the alignment process for industrial machinery. As a special setting for assembly and inspection, such machinery uses an illumination of narrow wavelength range for imaging with less aberration. This leads to significant influence of light diffraction on the image restoration. Although the diffraction was treated as negligible in most previous studies of coded aperture since they were carried out for natural images, the aperture patterns of them do not achieve enough accuracy for the alignment. We optimize the aperture pattern by performing a simulation of light diffraction, and we experimentally show that it achieves better performance in the alignment.
关键词： Alignment,industrial machinery,template matching,light diffraction,coded aperture,inspection,image restoration,factory automation
更新于2025-09-19 17:13:59