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Temperature and Emissivity Inversion Accuracy of Spectral Parameter Changes and Noise of Hyperspectral Thermal Infrared Imaging Spectrometers
摘要： The emergence of hyperspectral thermal infrared imaging spectrometers makes it possible to retrieve both the land surface temperature (LST) and the land surface emissivity (LSE) simultaneously. However, few articles focus on the problem of how the instrument?s spectral parameters and instrument noise level affect the LST and LSE inversion errors. In terms of instrument development, this article simulated three groups of hyperspectral thermal infrared data with three common spectral parameters and each group of data includes tens of millions of simulated radiances of 1525 emissivity curves with 17 center wavelength shift ratios, 6 full width at half maximum (FWHM) change ratios and 6 noise equivalent differential temperatures (NEDTs) under 15 atmospheric conditions with 6 object temperatures, inverted them by two temperature and emissivity separation methods (ISSTES and ARTEMISS), and analyzed quantitatively the effects of the spectral parameters change and noise of an instrument on the LST and LSE inversion errors. The results show that: (1) center wavelength shifts and noise affect the inversion errors strongly, while FWHM changes affect them weakly; (2) the LST and LSE inversion errors increase with the center wavelength shift ratio in a quadratic function and increase with FWHM change ratio slowly and linearly for both the inversion methods, however they increase with NEDT in an S‐curve for ISSTES while they increase with NEDT slightly and linearly for ARTEMISS. During the design and development of a hyperspectral thermal infrared instrument, it is highly recommended to keep the potential center wavelength shift within 1 band and keep NEDT within 0.1K (corresponding LST error < 1K and LSE error < 0.015) for normal applications and within 0.03K (corresponding LST error < 0.5K and LSE error < 0.01) for better application effect and level.
关键词： inversion error,hyperspectral thermal infrared,FWHM change,instrument noise,center wavelength shift,temperature and emissivity separation
更新于2025-09-23 15:21:01
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SPR studies on optical fiber coated with different plasmonic metals for fabrication of efficient biosensors
摘要： In the recent years, there have been numerous reports on study of Surface Plasmon Resonance (SPR) in different Plasmonic metals. Optical – fiber based SPR sensors have gained much attention over the years because of their copious advantages over conventional Prism coupled SPR sensors, including miniaturization, ability to perform remote sensing etc. In the present work, Optical – fiber based Surface Plasmon studies are performed on metal – air interface with different Plasmonic metals. Four different metals chosen for the current work are as follows: Gold (Au), Silver (Ag), Aluminum (Al) and Copper (Cu). Thermal Evaporation technique is utilized to deposit the Au, Ag, Al and Cu metal thin films. XRD, AFM and UV–Visible spectroscopy are used for the determination of the structural, morphological and optical characteristics of the deposited metal thin films. SPR transmittance curve is obtained for different metals and their observed SPR wavelength (kspr) matches very well with the reported values. The performance of these metals for their application in SPR based biosensors, was assessed in terms of the Full Width at Half Maxima (FWHM) and minimum transmitted intensity (Tmin) of their SPR transmittance curves and it was found that Ag (50 nm thickness) possesses the least FWHM whereas Au (40 nm thickness) has the lowest Tmin. Suitability of both Ag and Au is discussed for sensing applications and it was concluded that Au (40 nm thickness) is a better candidate for the realization of efficient biosensors.
关键词： SPR,Plasmonic metal,FWHM,Optical fiber,Bio sensor
更新于2025-09-23 15:19:57
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European Microscopy Congress 2016: Proceedings || An in-situ Low Energy Argon Ion Source for Local Surface Modification
摘要： A new in-situ low energy ion source for surface modification of a sample surface has been designed. The source is based on the principle of low energy ion bombardment from a beam of ions such as Ar+, N+, or He+ can be used for a local modification of the sample surface. Typical energies are in the range 10 - 100 eV, covering the interaction types from chemical reaction to ion etching and to ion implantation. The source is based on the following principle: electrons from a filament are accelerated towards a grid by a potential difference between the filament and the grid. The electrons enter a gas-filled region between the grid and the sample, where they ionize the gas. The ions are then accelerated towards the sample by a potential difference between the grid and the sample. The source produces a static beam of ions with a selectable energy of 10-100 eV and a full width half maximum (FWHM) of 7.1 um. This corresponds to a central ion current density of 0.019 nA/um2 at 100 eV, which is very similar to the current density at 100 eV of a regular ICP source. In this way, the sample area that is affected by the low energy ions can be more or less defined by the applied bias voltage. The first application can be polishing the top surface of a TMD laminate produced by CVD, or improvement of and LPE surface prepared by ICP. An example of the interaction with the beam is shown in Figure 1, where a native oxide on Si has been removed in 25 seconds, using 100 eV Ar+ ions.
关键词： Ar+,surface modification,low energy ion source,chemical reaction,FWHM,native oxide removal,ion etching,ICP,current density,static beam,N+,ion bombardment,TMD,He+,LPE,ion implantation,in-situ,gas ionization,filament,grid,CVD
更新于2025-09-19 17:15:36
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[IEEE 2019 8th International Symposium on Next Generation Electronics (ISNE) - Zhengzhou, China (2019.10.9-2019.10.10)] 2019 8th International Symposium on Next Generation Electronics (ISNE) - Structural optimization of 273nm deep ultraviolet laser in wave guide
摘要： The full width at half maxima (FWHM) of the LDs is very narrow, with small threshold current and high luminous power. Through simulation, it can be seen that the radiation recombination rate and wave intensity of different lateral positions of LDs are different. The waveguide layer of the high Al composition has a lower refractive index and can reduce the divergence angle of light. In this paper, the device structure is optimized by gradually increasing the Al component toward the p-cladding layer and decreasing the Al component toward p-side. Compared with the original structure, the grading wave guide proves that it can have better electrical characteristics and the FWHM is smaller.
关键词： grading wave guide,wave intensity,radiation recombination,FWHM
更新于2025-09-16 10:30:52
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Simultaneous measurements of fuel concentration and temperature in gas jets by laser induced breakdown spectroscopy
摘要： Laser induced breakdown spectroscopy (LIBS) enables quantitative measurements of the equivalence ratio in flames, spray and gas jets. Although there are always considerable temperature differences between the calibrations and the LIBS measurements in flames and fuel jets, the temperature effects on LIBS were rarely mentioned and not corrected in the previous LIBS measurements. In this study, a novel method to simultaneously measure the equivalence ratio and the gas temperature by LIBS in a single laser shot is proposed. This method can correct the temperature effects based on the linear correlation between the peak intensity ratio (PIR) of atomic lines and the gas temperature. The PIR of H656/N746 and the full width at half maximum (FWHM) of H656 are employed to establish calibration curves with the equivalence ratio and the gas temperature, respectively, and both of calibrations show high coefficients of determination (R2). Then, the measurement accuracy and precision of the proposed method are discussed in detail. The total uncertainties in measurements of equivalence ratio and gas temperature are estimated by 5.6% and 5.8%, respectively. Finally, the simultaneous measurements of equivalence ratios and gas temperatures in methane jets at different positions and at different injection pressures are conducted. The comparison of equivalence ratios before and after correction of the temperature effects indicates that the accuracy of the fuel concentration measurements by LIBS would be remarkably degraded if the temperature variations were neglected.
关键词： Measurement uncertainties,Laser-induced breakdown spectroscopy (LIBS),Equivalence ratio,Gas temperature,Full width at the half maximum (FWHM)
更新于2025-09-12 10:27:22
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31.2: <i>Invited Paper:</i> Advanced Materials Development for Ink‐Jet Printed OLEDs
摘要： High-performance, ink-jet printable OLED materials have been successfully developed. Our wide libraries of platforms and small molecule hosts were effective for improving efficiency and lifetime of OLEDs. For wide color gamut, new emitters with deep in color and narrow full-width at half maximum were developed. Further, solvent systems having physical properties suitable for improving film uniformity in pixels were found.
关键词： Small molecule,FWHM,Viscosity,Red emitter,Surface tension,Platform,Film-uniformity,PLQY,Ink-jet,OLED
更新于2025-09-12 10:27:22
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Performance analysis of direct detection optical OFDM systems
摘要： Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation technique, in which the data information is carried over many lower rate subcarriers. This technique is started effectively using in both line communication and wireless communication systems. This modulation technique has been actively started in the field of light wave communication called optical OFDM (OOFDM) system. OOFDM is a multicarrier modulation technique; it is used to overcome the problem of inter-symbol interference due to the chromatic dispersion and polarization mode dispersion of the fiber channel. In this paper, we have done simulation on direct detection optical OFDM (DDOOFDM) system with data rate of 10Gbps and measuring performance analysis of DDOOFDM system with respect to the received optical power and various full width half maximum value of the continuous wave laser source. This analysis is simulated using RSOFT Design Group OptSim Version-5.2.
关键词： Mach-Zehnder Modulator (MZM),Coherent Detection Optical OFDM (COOFDM),Optical Band Pass Filter (OBPF),Optical Single Sideband (OSSB),Full Width Half Maximum (FWHM),Direct Detection Optical OFDM (DDOOFDM)
更新于2025-09-04 15:30:14