- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Prospects for a polar-molecular-ion optical probe of varying proton-electron mass ratio
摘要： Molecules with deep vibrational potential wells provide optical intervals sensitive to variation in the proton-electron mass ratio (μ). On one hand, polar molecules are of interest since optical state preparation techniques have been demonstrated for such species. On the other hand, it might be assumed that polar species are unfavorable candidates, because typical molecule-frame dipole moments reduce vibrational state lifetimes and cause large polarizabilities and associated Stark shifts. Here, we consider single-photon spectroscopy on a vibrational overtone transition of the polar species TeH+, which is of practical interest because its diagonal Franck-Condon factors should allow rapid state preparation by optical pumping. We point out that all but the ground rotational state obtains a vanishing low-frequency scalar polarizability from coupling with adjacent rotational states, because of a fortuitous relationship between rigid rotor spacings and dipole matrix elements. We project that, for good choices of spectroscopy states, demonstrated levels of ?eld control should make possible uncertainties of order 1 × 10?18, similar to those of leading atomic ion clocks. If fast state preparation can be achieved, the moderately long-lived vibrational states of TeH+ make possible a frequency uncertainty approaching 1 × 10?17 with one day of averaging for a single trapped ion. Observation over one year could probe for variation of μ with a sensitivity approaching the 1 × 10?18/yr level.
关键词： Stark shifts,Zeeman shifts,optical probe,vibrational overtone transition,quadrupole shifts,proton-electron mass ratio,TeH+,polar-molecular-ion
更新于2025-09-09 09:28:46
-
in light filaments
摘要： We present our results on the emissions from N2+ pumped with ultrafast filaments using high-resolution pump probe. Our result shows the phase relation between transition lines at earlier delays. We show that the gain on transition lines extends beyond the time when coherence is lost.
关键词： stimulated emission,N2+,rotational wave packet,light filaments,ultrafast pump probe
更新于2025-09-09 09:28:46
-
A CD probe with a tailored cantilever for 3D-AFM measurement
摘要： A critical dimensional (CD) probe, such as a boot shaped probe, is widely used for measuring the sidewall profiles of nanostructures in atomic force microscopy (AFM). However, conventional CD probes usually have high spring constants that restrict their ability to operate in critical dimension scanning modes. Furthermore, the flexure spring constant of the tip is much smaller than the torsion spring constant of the cantilever, which probably makes the sidewall measurement unstable. Here, we proposed a method of tailoring the probe where the cantilever was trimmed to reduce the spring constant. The simulation results, using a finite element method (FEM), illustrated that both the flexure and torsion spring constants decreased nearly ten times. Meanwhile, the torsional resonant frequency decreased to below 1 MHz, which could benefit the torsional oscillation scanning. By using a focused ion beam (FIB), a CD probe with a rectangular cantilever was reprocessed. It was mounted to a home-built three-dimensional AFM system (3D-AFM), and had the flexure and torsion sensitivities precisely calibrated. The ratio of the flexure sensitivity to torsion sensitivity showed good accordance with the simulation results. Additionally, a grating standard sample was measured using the tailored probe under a modified step-in scanning mode, and the error due to torsional deformation of the tip was compensated. The measurement results demonstrated the validity of the tailored CD probe in 3D metrology.
关键词： deformation,3D-AFM,sidewall,tailored cantilever,CD probe
更新于2025-09-09 09:28:46
-
A cyclometalated iridium(III) complex-based fluorescence probe for hypochlorite detection and its application by test strips
摘要： A new cyclometalated iridium(III) complex-based fluorescence probe (IrCN) for hypochlorite (ClO?) has been synthesized and characterized. The probe displayed nonfluorescent around 577 nm, while a 54-fold enhancement in fluorescence emission intensity was observed after the addition of ClO? due to the removal of C=N isomerization effect. Such “turn-on” fluorescence probe worked excellently in wide pH range (5–12) with short response time (< 20 s) and the detection limit was as low as 0.11 μM. In addition, IrCN exhibited high selectivity even in the presence of other competing species. Furthermore, IrCN was successfully integrated in towards ClO? fluorescent test strips for real-time detection of ClO?.
关键词： Fluorescence probe,Iridium(III) complex,Test strips,Hypochlorite
更新于2025-09-09 09:28:46
-
[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Space Charges in Metal-Solid Electrolyte-Metal Structures
摘要： The influence of electrodes on the space charge distribution in solid polymer electrolytes has been investigated. Aluminum-poly(ethylene oxide)-aluminum sample structures with varying distance between the metal electrodes are considered. The charge distribution in the poly(ethylene oxide) is extracted by differentiating twice the surface potential measured by the Kelvin Probe Force Microscopy. With this approach, charge oscillations and charge packets have been detected for the first time in solid electrolytes under biased and unbiased conditions.
关键词： Kelvin probe force microscopy,interface effects,space charges,solid electrolyte,charge distribution
更新于2025-09-09 09:28:46
-
A water-soluble benzoxazole-based probe: real-time monitoring PPi via situ reaction by two-photon cells imaging
摘要： Pyrophosphate (PPi) played crucial roles in various fundamental physiological processes. Herein, a two-photon absorption (TPA) “On-Off-On” type benzoxazole-based fluorescence probe BN was designed and synthesized, which detected PPi through Cu2+ displacing method in situ system in aqueous medium. The on-off-on process of BN recognizing PPi was verified by mass spectra and theoretical calculations, which was successfully applied in TPA cells imaging.
关键词： Fluorescence probe,Benzoxazole,LLCT and MLCT,TPA imaging
更新于2025-09-09 09:28:46
-
Surface potential and thin film quality of low work function metals on epitaxial graphene
摘要： Metal films deposited on graphene are known to influence its electronic properties, but little is known about graphene’s interactions with very low work function rare earth metals. Here we report on the work functions of a wide range of metals deposited on n-type epitaxial graphene (EG) as measured by Kelvin Probe Force Microscopy (KPFM). We compare the behaviors of rare earth metals (Pr, Eu, Er, Yb, and Y) with commonly used noble metals (Cr, Cu, Rh, Ni, Au, and Pt). The rare earth films oxidize rapidly, and exhibit unique behaviors when on graphene. We find that the measured work function of the low work function group is consistently higher than predicted, unlike the noble metals, which is likely due to rapid oxidation during measurement. Some of the low work function metals interact with graphene; for example, Eu exhibits bonding anomalies along the metal-graphene perimeter. We observe no correlation between metal work function and photovoltage, implying the metal-graphene interface properties are a more determinant factor. Yb emerges as the best choice for future applications requiring a low-work function electrical contact on graphene. Yb films have the strongest photovoltage response and maintains a relatively low surface roughness, ~5 nm, despite sensitivity to oxidation.
关键词： work function,Kelvin Probe Force Microscopy,photovoltage,rare earth metals,graphene
更新于2025-09-09 09:28:46
-
Controlling the Phase Segregation in Mixed Halide Perovskite through Nanocrystal Size
摘要： Mixed halide perovskites are one of the promising candidates in developing solar cells and LEDs, among others applications due to their tunable optical properties. Nonetheless, photoinduced phase segregation, by forming segregated Br-rich and I-rich domains, limits the overall applicability. We tracked the phase segregation with increasing crystalline sizes of CsPbBr3-xIx and their photoluminescence under continuous-wave laser irradiation (405 nm, 10 mW cm-2), and observed the occurrence of the phase segregation from the threshold size of 46 ± 7 nm. This results have an outstanding agreement with the diffusion length (45.8 nm) calculated also experimentally from the emission lifetime, segregation rates. Furthermore, through Kelvin probe forced microscopy, we confirmed the correlation between the phase segregation and the reversible halide ion migration among grain center/boundaries. These results open a way to achieve segregation-free mixed halide perovskites and improve their performances in optoelectronic devices.
关键词： nanocrystal size,photoluminescence,phase segregation,Kelvin probe force microscopy,Mixed halide perovskites
更新于2025-09-09 09:28:46
-
Temperature-Dependent Refractive Index of Quartz at Terahertz Frequencies
摘要： Characterisation of materials often requires the use of a substrate to support the sample being investigated. For optical characterisation at terahertz frequencies, quartz is commonly used owing to its high transmission and low absorption at these frequencies. Knowledge of the complex refractive index of quartz is required for analysis of time-domain terahertz spectroscopy and optical pump terahertz probe spectroscopy for samples on a quartz substrate. Here, we present the refractive index and extinction coefficient for α-quartz between 0.5 THz and 5.5 THz (17–183 cm?1) taken at 10, 40, 80, 120, 160, 200 and 300 K. Quartz shows excellent transmission and is thus an ideal optical substrate over the THz band, apart from the region 3.9 ± 0.1 THz owing to a spectral feature originating from the lowest energy optical phonon modes. We also present the experimentally measured polariton dispersion of α-quartz over this frequency range.
关键词： Terahertz,Quartz,Refractive index,Dispersion,Silica,Optical pump terahertz probe OPTPS,Time-domain spectroscopy,Polariton,SiO2
更新于2025-09-09 09:28:46
-
Iridium(III) complex-based fluorescent probe for detection of thiophenols and its application in water samples
摘要： In consideration of the nucleophilic capacity of thiophenols, which could cleave sulfonamide under neutral conditions, a cyclometalated iridium(III) complex (probe 1) comprised 2,4-dinitrobenzenesulfonamide (DNBS) as the recognition unit was designed and synthesized to high selectivity and sensitivity detect thiophenols successfully based on internal charge transfer (ICT) mechanism. Upon addition with thiophenols to 20% DMSO/PBS solution of nearly non-fluorescent probe 1 (10 μM, pH = 7.4), fluorescent product (complex 2) was formed after cleavage of DNBS group and a significant emission enhancement at 470 nm was observed. In addition, it could be successfully applied to detect thiophenol in water samples with a high recovery, confirming its practical value in environment science.
关键词： Iridium(III) complex,2,4-dinitrobenzenesulfonamide,Thiophenol,Fluorescent probe
更新于2025-09-09 09:28:46