Generating ultrafast pulses with better spectrotemporal control is crucial for optimizing and characterizing nonlinear light–matter responses, yet it is limited by the gain bandwidth of laser media ...or the phase‐matching geometry of nonlinear processes. This work proposes a simple approach to independently manage a femtosecond source's spectral location and bandwidth. Self‐phase‐modulation‐enabled spectral broadening is first analyzed, which is potentially energy‐scalable using hollow‐core capillaries or multipass cells. It is demonstrated that the outmost lobes in the broadened spectrum show different dependencies on the initial pulse energy and duration. A simple yet effective toy model is introduced that successfully predicts broadband spectral tuning, and the impact of other nonlinear effects, dispersion, and input pulse asymmetry on the experimental scenario is also discussed. Thus a fiber‐based versatile source is demonstrated, which is compressible down to its transform‐limit duration, as short as 12.2 fs centered at 920 nm. In addition, bandwidth‐dependent third‐harmonic generation spectroscopy is performed from a dielectric metasurface with an optimized nonlinear response, and the dependency of laser bandwidth and pulse duration is investigated on the signal‐to‐background ratio of two‐photon images. It is believed that this demonstration will advance the investigation of bandwidth‐dependent nonlinear spectroscopy and microscopy.
Independent control of femtosecond sources’ spectral location and bandwidth is realized with a simple approach enabled by self‐phase modulation. This work thus demonstrates a fiber‐based versatile source, delivering pulses compressible down to few‐optical‐cycle regimes. These demonstrations pave the way for deeper insights into the spectral response of nonlinear resonances, further advancing the field of bandwidth‐dependent nonlinear spectroscopy and microscopy.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Plasma sputtering multi-principal element alloys (MPEAs) thin film is critical to functional multi-layer material design for a wide range of applications. To investigate its electrochemical ...stability, we established a multidisciplinary approach including in-situ optical microscope integrated EC-SPR coupled with ICPMS, and ex-situ XPS and XAS analysis. Compared to our previous work in bulk material, we observed a significant reactivity change of plasma sputtering thin film on gold. Based on XPS, XAS and SPR results, we propose that the formation of Cr(OH)3 at the edge and the interface between alloys and gold layers is responsible for weakening the corrosion resistance of an NiCoCr/Au system.
•Multidisciplinary investigation of plasma sputtering medium entropy alloy thin film corrosion.•Hard X-ray application in non-destructive thin film analysis.•Application of Surface Plasmon Resonance in study solid–solid interfacial interaction.•Addition of Fe in the studied alloys is crucial in stabilizing the Cr oxide passive layer.•EC-Microscope-ICPMS home-built setup for thin film corrosion study in real-time.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
By precisely managing fiber-optic nonlinearity with anomalous dispersion, we have demonstrated the control of generating plural few-optical-cycle pulses based on a 24-MHz Chromium:forsterite laser, ...allowing multicolor two-photon tissue imaging by wavelength mixing. The formation of high-order soliton and its efficient coupling to dispersive wave generation leads to phase-matched spectral broadening, and we have obtained a broadband continuum ranging from 830 nm to 1200 nm, delivering 5-nJ pulses with a pulse width of 10.5 fs using a piece of large-mode-area fiber. We locate the spectral enhancement at around 920 nm for the two-photon excitation of green fluorophores, and we can easily compress the resulting pulse close to its limited duration without the need for active pulse shaping. To optimize the wavelength mixing for sum-frequency excitation, we have realized the management of the power ratio and group delay between the soliton and dispersive wave by varying the initial pulse energy without additional delay control. We have thus demonstrated simultaneous three-color two-photon tissue imaging with contrast management between different signals. Our source optimization leads to efficient two-photon excitation reaching a 500-µm imaging depth under a low 14-mW illumination power. We believe our source development leads to an efficient and compact approach for driving multicolor two-photon fluorescence microscopy and other ultrafast investigations, such as strong-field-driven applications.
We have demonstrated widely tunable Yb:fiber-based laser sources, aiming to replace Ti:sapphire lasers for the nJ-level ultrafast applications, especially for the uses of nonlinear light microscopy. ...We investigated the influence of different input parameters to obtain an expansive spectral broadening, enabled by self-phase modulation and further reshaped by self-steepening, in the normal dispersion regime before the fiber damage. We also discussed the compressibility and intensity fluctuations of the demonstrated pulses, to reach the transform-limited duration with a very low intensity noise. Most importantly, we have demonstrated clear two-photon fluorescence images from UV-absorbing fluorophores to deep red dye stains.
Using a 24-MHz Cr:forsterite oscillator and the precisely controlled fiber-optic nonlinearity, we have simultaneously demonstrated sub-megawatt-peak-power femtosecond pulses at 1.3μm and compressible ...blue-shifted octave-spanning spectra.
碩士
國立中山大學
傳播管理研究所
100
The expansion of Internet promotes the rise of social media. The appeal of social marketing leads the enterprises start to set up fanpage on Facebook to interact with their ...members.This study discusses whether the messages’ emotion or the managers’ emotion result in members’ emotion in fanpage,and furthermore to find out the connection between members’ emotion and brand attitude. This research adopts experimental method and distributes on-line questionnaire, retrieving 384 samples and analyze the data with SPSS 17.0. The results shows that the display of messages and the menagers’emotional expression certainly affect menbers’ positive emotion, and directly affect the menbers’ brand attitude to the enterprises.This study points out the importance influence of emotion in marketing research,and provides some practical suggestions to enterprises to develop a new strategy.
In order to improve the performance of the robotic arm effectively, this study established a robotic arm velocity planning model developed by artificial intelligence in the simulation system. The ...model not only considered the dynamic factors of the robotic arm but was also able to set different customized conditions such as machining accuracy and rotation angle. The study could be divided into three parts. First, the simulation environment was constructed with the ABB IRB140 six axes multipurpose industrial robot. To be consistent with real-world situations, a Vortex physics engine was applied to the simulation supplying varying locomotion parameters. In this research, friction, kinematics, and inertia were considered. Second, artificial intelligence was imported into the robotic arm through the establishment of connecting V-rep and Python. The proposed model was developed in the Python environment by deep deterministic policy gradients. Eventually, a design of the appropriate reward function governing the ultimate results was presented. Compared with traditional velocity planning, the proposed method can decline moving error by 0.05 degrees under the considerations involving dynamic factors in a robotic arm. Besides, the proposed velocity planning strategy could be obtained after taking the training time of one hour which can meet the demand for the time cost of the industry.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An in-house developed full-vector finite-element imaginary-distance beam propagation method (FV-FE-ID-BPM) is employed to calculate the modes of a surface plasmon metal-stripe waveguide. Leaky modes, ...which possess less propagation losses compared with corresponding bound modes, are particularly studied. The calculated real and imaginary parts of the modal effective indices are shown to be with local-overshoot characteristics versus the stripe width when fine width steps are used. Using fine enough spatial mesh resolution, the field profile within the metal-stripe region is revealed and examined, and the local-overshoot characteristics could be correlated with the integer number of quasi-periods associated with the field variation along the interface between the metal stripe and the substrate.
This letter describes the design, analysis, and testing of a 28-GHz single-input differential-output (SIDO) low-noise amplifier (LNA) with a noise figure of 2.5 dB, compact size (0.25 mm 2 ), and ...high gain (22.3 dB). The proposed LNA was fabricated using the Taiwan Semiconductor Manufacturing Company (TSMC) 65-nm CMOS process. This amplifier contains a two-stage common-source (CS) buffer amplifier for a low-noise design and combines CS and common-gate transistors for converting single-ended signal into differential signal. A novel method of common-mode rejection ratio optimization is used to determine the optimal phase compensation transmission line and transistor size to reduce gain and phase imbalances simultaneously. The gain and phase imbalances were 0.042 dB and 2.6° at 28 GHz, respectively. Compared with published LNAs, this SIDO LNA achieved the high figure of merits (FoMs) of 7.17 and 2.27, respectively. Therefore, this LNA can be used for 5G NR band of n257 (26.5-29.5 GHz), n258 (24.25-27.5 GHz), and n261 (27.5-28.35 GHz).
Detecting bacteria in clinical samples without using time-consuming culture processes would allow rapid diagnoses. Such a culture-free detection method requires the capture and analysis of bacteria ...from a body fluid, which are usually of complicated composition. Here we show that coating Ag-nanoparticle arrays with vancomycin (Van) can provide label-free analysis of bacteria via surface-enhanced Raman spectroscopy (SERS), leading to a ~1,000-fold increase in bacteria capture, without introducing significant spectral interference. Bacteria from human blood can be concentrated onto a microscopic Van-coated area while blood cells are excluded. Furthermore, a Van-coated substrate provides distinctly different SERS spectra of Van-susceptible and Van-resistant Enterococcus, indicating its potential use for drug-resistance tests. Our results represent a critical step towards the creation of SERS-based multifunctional biochips for rapid culture- and label-free detection and drug-resistant testing of microorganisms in clinical samples.
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