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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • LED stage lighting
  • CRI
  • RGBW four-color mixing model
  • the blackbody locus fitting
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Communication University of China
416 条数据
?? 中文（中国） ▾

  • Ellipticity control of high-order harmonic generation with nearly orthogonal two-color laser fields

    摘要： Elliptically polarized high-order harmonics opens a path toward the study of ultrafast dynamics in circular dichroism of magnetic materials, chiral molecules, and electronic spin motion. Recently, efficient high-order harmonic generation with controllable ellipticity has attracted considerable attention in experiment and theory. Here, we experimentally demonstrate a scenario using cross-linearly-polarized two-color fields consisting of a fundamental field and its second harmonic (SH). Through adjusting the relative phase, crossing angle, and intensity ratio of the cross-linearly-polarized two-color field, we obtain ellipticity-tunable high-order harmonics, with ellipticity up to ε = 0.73. Meanwhile, the elliptically polarized high-order harmonics preserve high efficiency. Furthermore, when the intensity of the SH field is stronger than that of the fundamental field, the even order harmonics will become several times stronger than the odd order harmonics with opposite helicity.

    关键词： attosecond science,high-order harmonic generation,ellipticity control,strong-field physics,two-color laser fields

    更新于2025-09-23 15:21:01

  • Intense circularly polarized attosecond pulse generation from solid targets irradiated with a two-color linearly polarized laser

    摘要： A method for the production of intense circularly polarized (CP) attosecond pulses from relativistic laser-solid interactions is proposed, where a two-color linearly polarized (LP) laser is used. The polarization, photon frequency, and other properties of the obtained attosecond pulse can be controlled by adjusting the ratio of the dichromatic driving LP field in different harmonics, which is much easier and more efficient than those previously using CP driving lasers. Both one- and two-dimensional particle-in-cell simulations show that a CP attosecond extreme-ultraviolet pulse with an intensity of 1.4 × 1019 W/cm2 and a duration of about 120 as is obtained by a two-color LP laser at intensities in the fundamental and second harmonics of, respectively, 1.5 × 1022 and 6.4 × 1021 W/cm2, which can be applied for the detection of the magnetic and chiral properties of materials.

    关键词： relativistic laser-solid interactions,attosecond pulse,two-color linearly polarized laser,circularly polarized,extreme-ultraviolet pulse

    更新于2025-09-23 15:21:01

  • Structural, thermal and optical characteristics of laser-exposed Pd/PVA nanocomposite

    摘要： Nanocomposite of polyvinyl alcohol (PVA) and nanosize palladium (Pd) were fabricated by ex situ casting technique. The fabricated Pd/PVA nanocomposite film has been exposed to infrared pulsated laser with fluences in the range 2–20 J/cm2. The effect of the laser radiation on the structural, thermal and optical properties of Pd/PVA has been investigated using XRD, TGA and UV–Vis spectroscopy. Exposure of IR laser radiation raises the refractive index from 1.84 to 3.38 at 700 nm which confirms the predominance of crosslinking process in the Pd/PVA nanocomposite. Furthermore, the reduction in the optical energy gap from 1.87 to 1.72 eV could be attributed to the increase in the structural disorder resulting from the coordination reaction between OH of PVA and Pd nanoparticles. The attained results reveal that the IR laser radiation enhances the dispersion of Pd nanoparticles in the PVA matrix resulting in more compact structure of Pd/PVA nanocomposite. Consequently, the onset temperature of decomposition increased upon laser irradiation. Commission Internationale de E’Claire (CIE units x, y and z) methodology was employed to describe the color of the studied samples. The color difference between the exposed nanocomposite films and the non-exposed one was raised from 5.63 to 12.01 as the laser fluence increases up to 20 J/cm2. Thus, the present study suggests that the IR laser radiation affects the microstructure of the Pd/PVA nanocomposite which in turn assists in tailoring the thermal and optical properties of such nanocomposite for usage in optoelectronics applications.

    关键词： Nanocomposite,XRD,UV spectroscopy,Thermal analysis,Color

    更新于2025-09-23 15:21:01

  • [IEEE 2018 IEEE 3rd International Conference on Cloud Computing and Internet of Things (CCIOT) - Dalian, China (2018.10.20-2018.10.21)] 2018 IEEE 3rd International Conference on Cloud Computing and Internet of Things (CCIOT) - Study on LED Color Mixing for Stage Lighting Based on Locus Fitting of Blackbody

    摘要： Aiming at overcoming the defects of basic lighting color rendering for LED stage lighting, this paper establishes a new mixing light method with RGBW four-color mixing model. Compared with traditional tricolor light mixing model, it uses the mixing light of white as the fourth input, with the three-basic color of red, green and blue to obtain a new mixing method. Then the original coefficients of RGBW are optimized after adjusting the two parameters of relative spectral power distribution and illuminance of mixing light for locus fitting of blackbody. Finally, better color rendering of white light can be acquired. By the MATLAB simulation and field testing, experimental results have shown that the proposed method will achieve ideal LED lighting performance, which is convenient for color management of lighting control system in modern theatre.

    关键词： LED stage lighting,CRI,RGBW four-color mixing model,the blackbody locus fitting

    更新于2025-09-23 15:21:01

  • An Electrically Modulated Singlea??Color/Duala??Color Imaging Photodetector

    摘要： An electrically modulated single-/dual-color imaging photodetector with fast response speed is developed based on a small molecule (COi8DFIC)/perovskite (CH3NH3PbBr3) hybrid film. Owing to the type-I heterojunction, the device can facilely transform dual-color images to single-color images by applying a small bias voltage. The photodetector exhibits two distinct cut-off wavelengths at ≈544 nm (visible region) and ≈920 nm (near-infrared region), respectively, without any power supply. Its two peak responsivities are 0.16 A W?1 at ≈525 nm and 0.041 A W?1 at ≈860 nm with a fast response speed (≈102 ns). Under 0.6 V bias, the photodetector can operate in a single-color mode with a peak responsivity of 0.09 A W?1 at ≈475 nm, showing a fast response speed (≈102 ns). A physical model based on band energy theory is developed to illustrate the origin of the tunable single-/dual-color photodetection. This work will stimulate new approaches for developing solution-processed multifunctional photodetectors for imaging photodetection in complex circumstances.

    关键词： organic/perovskite photodetectors,response speed,dual-color imaging

    更新于2025-09-23 15:21:01

  • High-color-purity transmissive colors with high angular tolerance based on metal/dielectric stacks

    摘要： In this work, high-color-purity transmissive colors with high angular tolerance are proposed. The metal/dielectric film stacks, by means of induced transmission effect, are able to achieve ～60% peak transmission and ～60 nm transmission band, so as to cover a large color gamut. The filter presents good incident angle insensitivity up to 60 degrees, ascribed to the combined contribution of the constant total phase shift within the intermediate dielectric layer and the relatively high refractive index of the dielectric layers. And the matching of the optical admittances for metal/dielectric layers is responsible to the high transmission of the metal-based film stack. Moreover, the optical constants of silver film, affected by deposition technology have a great impact on the optical property of the color device including the bandwidth and peak transmission. And the thickness of the top dielectric layer as well as the metal/dielectric stack number can also alter the performance of the color filter.

    关键词： Metal/dielectric stacks,High angular tolerance,High-color-purity transmissive colors

    更新于2025-09-23 15:21:01

  • Interaction effect of LED color temperatures and light-protective additive packaging on photo-oxidation in milk displayed in retail dairy case

    摘要： Effect of varied LED color temperatures on photo-oxidation in 2 % fat milk and protection efficiency of packaging with and without light-protective additives (LPA) under different color temperatures was firstly evaluated. Riboflavin (Rb) is one of the critical photo-sensitizers in 2 % milk when exposed to LED light. Higher color temperature with higher relative intensity of Rb absorbance region resulted in lower Rb and vitamin A retention, lower dissolved oxygen content, and higher TBARS value in milk packaged with non-LPA packaging. Yellow pigmented packaging that completely blocked the Rb absorbance region of all three LED color temperatures successfully reduced the rate of degradation of milk nutrients and flavor. TiO2-added packaging partially block the destructive light wavelength; higher level of TiO2 provided a longer protection on milk freshness. Combination of appropriate LED color temperature and LPA-packaging provided a cost-effective solution for minimizing photo-oxidation in retail dairy case.

    关键词： color temperature,oxidation,freshness,milk,packaging,light wavelength,LED

    更新于2025-09-23 15:21:01

  • High color rendering index white light-emitting diode based on enviromental friendly carbon and AIZS nanoparticles

    摘要： Solid-state white light-emitting diodes (WLEDs) based on carbon dots (CDs) have attracted broad attention due to their high brightness and enviromental friendly. However, the poor performance including low efficiency and weak emission of red-emitting CDs further hindered its application on WLED devices. Herein, we constructed one outstanding WLEDs device by combining carbon dots (blue emission, green emission) and Ag-In-Zn-S (AIZS) nanoparticles with red emission. Moreover, by adjusting the volume ratio of the three materials, the WLED showed maximum color rendering index (CRI) of 97 and maintained CRI value above 90 during the correlated color temperature (CCT) tuned from 3387 to 8018 K. Meanwhile, the as-fabricated WLED devices showed excellent color rendering stability during the working voltages from 3.0V to 3.5V. This work may provide one new avenue for development of low-cost, environmental friendly and high-performance CDs phosphor-based WLEDs.

    关键词： AIZS nanoparticles,color rendering index,white light-emitting diode,carbon dots,environmental friendly

    更新于2025-09-23 15:21:01

  • Narrow Bandpass and Efficient Semitransparent Organic Solar Cells Based on Bioinspired Spectrally Selective Electrodes

    摘要： The visual aesthetic that involves color, brightness, and glossiness is of great importance for building-integrated photovoltaics. Semi-transparent organic solar cells (ST-OSCs) are thus considered as the most promising candidate due to their superiority in transparency and efficiency. However, the realization of high color purity with narrow bandpass transmitted light usually causes the severely suppressed transparency in ST-OSCs. Herein, we present a spectrally selective electrode (SSE) by imitating the integrating strategy of beetle cuticle for achieving narrow bandpass ST-OSCs with high efficiency and long-term stability. The proposed SSE allows for efficient light-selective passage, leading to tunable narrow bandpass transmitted light from violet to red. An optimized power conversion efficiency of 15.07% is achieved for colorful ST-OSCs, which exhibit color purity close to 100% and a peak transmittance approaching 30%. Long-term stability is also improved for ST-OSCs made with this SSE due to the light-rejecting and the moisture-blocking abilities. The realization of bright and colorful ST-OSCs also indicates the application potential of SSEs in light-emitting diodes, lasers, and photodetectors.

    关键词： beetle cuticle,visual aesthetic,color purity,semi-transparent organic solar cells,long-term stability

    更新于2025-09-23 15:21:01

  • Color tunable upconversion luminescence and optical thermometry properties of mixed Gd2O3:Yb3+/Ho3+/Er3+ nanoparticles prepared via laser ablation in liquid

    摘要： The mixtures of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles were successfully prepared via pulsed laser ablation in liquid followed by solution mixing. Under excitation of 980 nm diode laser, tunable color from green to red emission was achieved. Based on the thermal linked energy levels, the temperature sensitive upconversion emission was observed. The fluorescence intensity ratio (FIR) of I513–530 nm/I530–580 nm increased as the elevation of temperature. The absolute sensitivity and relative sensitivity were derived from temperature dependent FIR. The results show that the mixture of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles are not only potential candidates for multicolor upconversion luminescence but also promising optical materials for non-contact optical thermometry.

    关键词： Gd2O3 nanoparticles,Color tunable emission,Pulsed laser ablation in liquid,Optical thermometry,Upconversion luminescence

    更新于2025-09-23 15:21:01