- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Wide-Spectrum Pulsed Fiber Laser based on Picosecond Pulse Generation Supercontinuum
摘要： We demonstrated a wide-spectrum pulsed fiber laser by using supercontinuum (SC) generate from a narrow pulse width fiber laser pump into high nonlinear fiber (HNLF). The pulse width of wide-spectrum pulsed fiber laser is 7.95ps and the repetition frequency is 4GHz with a 20nm bandwidth. It is found that the anomalous dispersion region near the zero dispersion wavelength has a better stability by observing the wide spectrum pulses in different bands.
关键词： different dispersion region,super-continuum,wide-spectrum pulsed fiber laser,narrow pulse width
更新于2025-11-28 14:24:03
-
Narrow linewidth DBR laser based on high order Bragg grating defined by i-line lithography
摘要： In order to obtain narrow linewidth semiconductor laser around 1564 nm, we design a distributed Bragg reflector (DBR) laser with high-order Bragg gratings (HOBGs) using butterfly encapsulation. The DBR laser is fabricated only by i-line lithography technology with grating period of 4.84 μm, groove width of 1.5 μm and grating length of 72 μm on a strip width of 4 μm. The 1mm-long devices achieved an output power of 9.9 mW and a side mode suppression ratio (SMSR) more than 30 dB without facet coating at an injection current of 80 mA. The lasers showed ultra-narrow Lorentz linewidth of 70 KHz. This paper provides a simple method for large-scale production of narrow linewidth semiconductor lasers.
关键词： narrow linewidth spectrum,Semiconductor laser,high-order grating,distributed Bragg reflector laser
更新于2025-11-28 14:23:57
-
Analysis of Fluorescence and Biodegradability of Wastewater
摘要： Three-dimensional fluorescence spectrometer was adopted for the content analysis of different types of organics in coking wastewater before biochemical treatment and through biochemical treatment, and the model of parallel factors was employed to analyze fluorescence components and contents. It was found that tryptophan-like components were the most easily degraded by biology, while humic-like components were the least easily degraded. Meanwhile, it had been seen that the change trends over time of total fluorescence densities of proteinoid fluorescence, and degradable organic fluorescence were highly consistent with that of parameter values of COD, NH3-N in this wastewater after analyzing the trends of the two indexes. It was proved that the three-dimensional fluorescence spectrum method was appropriate for the accurate degradation analysis of wastewater components.
关键词： Coking wastewater,Analysis and evaluation,Biodegradation,Parallel factors model,Three-dimensional fluorescence spectrum
更新于2025-11-14 15:23:50
-
The influence of particle size on the intensity and reproducibility of Raman spectra of compacted samples
摘要： Given the growing interest in the application of Raman spectroscopy for quantitative purposes in solid pharmaceutical preparations, a revision of the effect of particle size on Raman spectra of compacted samples is presented. For this purpose, a set of tablets of potassium hydrogen phthalate (KHP) of different particle size were prepared. KHP was used because of its purity and stability, which allow to consider that samples will not be altered during measurements; but also because of its chemical structure (aromatic ring and carboxylic groups), that are present in many active pharmaceutical ingredients (API). The latter makes possible to consider KHP as a model pseudo-API. As KHP tablets only contain a pure compound, the mapping strategy that was considered for measuring our samples will not be affected by subsampling issues. The spectra variance can be attributed to the intrinsically reproducibility in recording the spectra (which mainly depends on the instrument set-up) and the site-to-site differences in elastic scattering properties. Two different instrumental optics have been studied: a macro-Raman system and a Raman microscope (500 μm and 50 μm laser spot size, respectively). The effect of the spectra preprocessing is also evaluated. The overall results demonstrate raw Raman intensity increases with particle size up to a value that depends on tablet width and that the applied spectral preprocessing (baseline correction and a unit vector normalization), reduces the differences in Raman intensities due to the particle size, but does not completely eliminate it for the lower particle sizes (< 20 μm). For tablets containing particles with predefined sizes, it corrects the mapping site-to-site differences in elastic scattering.
关键词： Raman spectroscopy,Peak intensity,Reproducibility of a raman spectrum,Particle size
更新于2025-11-14 15:16:37
-
Design of an intermediate Bragg reflector within triple-junction solar cells for spectrum splitting applications
摘要： We investigate the use of distributed Bragg reflectors (DBRs) within triple-junction solar cells (TJSC) for spectrum splitting photovoltaics. An optical model of a lattice-matched (LM) GaInP/GaInAs/Ge TJSC with intermediate DBR is developed, in good agreement with measured reflectance. By modifying the DBR layer number, composition and thickness to broaden the reflectance band, we show that a DBR can provide suitable 900–1050 nm reflectance for spectrum splitting from the LM TJSC to a Si cell, resulting in a more efficient 4-junction receiver. For better practicality and cost effectiveness, we propose that the buffer layers in metamorphic (MM) TJSCs could additionally function as a DBR for spectrum splitting applications. We propose several DBR designs to achieve a suitable spectrum-splitting reflectance band from MM TJSCs to a Si cell, again resulting in a more efficient 4-junction receiver. Finally, we show that our intermediate DBR approach to spectrum splitting has the advantage of a greatly reduced angle-of-incidence dependence compared to a discrete dielectric filter.
关键词： Triple-junction solar cell,Spectrum splitting,Buffer layers,Distributed Bragg reflector
更新于2025-10-22 19:40:53
-
[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Design of Bragg Reflector in GaInP/GaInAs/Ge Triple-junction Solar Cells for Spectrum Splitting Applications
摘要： The use of intermediate distributed Bragg reflectors (DBRs) is investigated. Optical models for both commercial lattice-matched (LM) and metamorphic (MM) GaInP/GaInAs/Ge triple-junction solar cells (TJSCs) are developed, in good agreement with measured reflectance. Integrating a suitable DBR structure into a TJSC has the potential to provide the required IR reflectance for spectrum splitting from the LM and MM TJSC to a Si cell. We show that the intermediate DBR approach to spectrum splitting has the advantage of a greatly reduced angle-of-incidence dependence compared to a discrete dielectric filter.
关键词： Spectrum splitting,Buffer layers,Distributed Bragg reflector,Triple junction solar cell
更新于2025-10-22 19:40:53
-
[IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Investigation of the Structure and Optical Properties of Thin Copper Films
摘要： Copper nanolayers were formed using the vacuum magnetron-assisted sputtering in various technological modes (sedimentation speed, working pressure, discharge power). Results of microstructural study of the 1 nm to 65 nm thick copper nanofilms deposited on quartz, glass and silicon substrates are presented. Spectra of transmission and reflection coefficients of the copper nanofilms were studied in the wavelength range from 0.2 μm to 1.1 μm. The transmission and reflection spectra of films correspond well to the known spectra of bulk materials. The obtained results are of practical importance for development of nanostructural systems with the preset optical properties and for design of functional devices to be used in optoelectronics, information and energy-saving technologies.
关键词： transmission spectrum,microstructure,nanofilms,reflection spectrum
更新于2025-09-23 15:23:52
-
Image Color Conversion by Illumination
摘要： We developed a software program to imitate the color of an object within the range of sRGB on a PC display. The obtained colors were converted from the picture information taken under a white light source, such as D65. Other, arbitrary light sources such as natural sunlight or standard illuminants, could be used in addition to the test illumination. Judging from the sample of the converted pictures, the software functions quite well.
关键词： Simulation,Picture,Color conversion,Spectrum,Illumination,D65
更新于2025-09-23 15:23:52
-
A Full-Spectrum Metal-Free Porphyrin Supramolecular Photocatalyst for Dual Functions of Highly Efficient Hydrogen and Oxygen Evolution
摘要： A full-spectrum (300–700 nm) responsive porphyrin supramolecular photocatalyst with a theoretical solar spectrum efficiency of 44.4% is successfully constructed. For the first time, hydrogen and oxygen evolution (40.8 and 36.1 μmol g?1 h?1) is demonstrated by a porphyrin photocatalyst without the addition of any cocatalysts. The strong oxidizing performance also presents an efficient photodegradation activity that is more than ten times higher than that of g-C3N4 for the photodegradation of phenol. The high photocatalytic reduction and oxidation activity arises from a strong built-in electric field due to molecular dipoles of electron-trapping groups and the nanocrystalline structure of the supramolecular photocatalyst. The appropriate band structure of the supramolecular photocatalyst adjusted via the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of the porphyrin gives rise to thermodynamic driving potential for H2 and O2 evolution under visible light irradiation. Controlling the energy band structure of photocatalysts via the ordered assembly of structure-designed organic molecules could provide a novel approach for the design of organic photocatalysts in energy and environmental applications.
关键词： supramolecular photocatalysts,photocatalysis,full spectrum,dual functions,dipoles
更新于2025-09-23 15:23:52
-
Based on Spectrum Modeling and Optimization
摘要： Bistatic synthetic aperture radar (SAR) is able to break through the limitation of monostatic SAR on forward-looking area imaging with appropriate geometry configurations. Thanks to such an ability, bistatic forward-looking SAR (BFSAR) has extensive potential practical applications. For the focusing problem of conventional side-looking SAR, ω–k algorithm is accepted as the ideal solution. In this paper, the ω–k algorithm will be discussed in BFSAR geometry. As for the bistatic configuration, spatial domain linearization procedure should be carried out to extract a range variable from the point target reference spectrum (PTRS) in the existing ω–k algorithms. With respect to the BFSAR geometry, nevertheless, the linearization procedure reduces the accuracy of PTRS seriously. To cope with such a problem, a novel ω–k algorithm for BFSAR is proposed. In the proposed method, the range variable is modeled as a parameterized polynomial, and the corresponding PTRS with respect to two-dimensional frequencies is established. Then, the parameters are estimated by differential evolution to minimize the PTRS errors for each range coordinate and frequency point. Based on the estimated PTRS, the BFSAR data can be focused well by the proposed ω–k algorithm. Simulation results verify the effectiveness of the proposed method.
关键词： Bistatic forward-looking synthetic aperture radar (BFSAR),differential evolution (DE),ω–k,point target reference spectrum (PTRS)
更新于2025-09-23 15:23:52