Vibrational spectroscopy is one of the key instrumentations that provide non-invasive investigation of structural and chemical composition for both organic and inorganic materials. However, diffraction of light funda-...Vibrational spectroscopy is one of the key instrumentations that provide non-invasive investigation of structural and chemical composition for both organic and inorganic materials. However, diffraction of light funda- mentally limits the spatial resolution of far-field vibrational spectroscopy to roughly half the wavelength. In this article, we thoroughly review the integration of atomic force microscopy （AFM） with vibrational spectroscopy to enable the nanoscale characterization of emerging energy materials, which has not been possible with far-field optical techniques. The discussed methods utilize the AFM tip as a nanoscopic tool to extract spatially resolved electronic or molecular vibrational resonance spectra of a sample illuminated by a visible or infrared （IR） light source. The absorption of light by electrons or individual functional groups within molecules leads to changes in the sample＇s thermal response, optical scattering, and atomic force interactions, all of which can be readily probed by an AFM tip. For example, photothermal induced resonance （PTIR） spectroscopy methods measure a sample＇s local thermal expansion or temperature rise. Therefore, they use the AFM tip as a thermal detector to directly relate absorbed IR light to the thermal response of a sample. Optical scattering methods based on scanning near-field optical microscopy （SNOM） correlate the spectrum of scattered near-field light with molecular vibrational modes. More recently, photo-induced force microscopy （PiFM） has been developed to measure the change of the optical force gradient due to the light absorption by molecular vibrational resonances using AFM＇s superb sensitivity in detecting tip-sample force interactions. Such recent efforts successfully breech the diffraction limit of light to provide nanoscale spatial resolution of vibrational spectroscopy,which will become a critical technique for characterizing novel energy materials.展开更多
The electromagnetic interaction of light with polar materials shows a sharp and well defined electromagnetic response in the infrared(IR)region that consists mainly of excitation of optical phonons.Similar to surface ...The electromagnetic interaction of light with polar materials shows a sharp and well defined electromagnetic response in the infrared(IR)region that consists mainly of excitation of optical phonons.Similar to surface plasmons in the visible region,surface phonons can couple efficiently to infrared light in micron-sized antennas made of polar materials.We applied the boundary element method to calculating the infrared electromagnetic response of single SiC disks acting as effective infrared antennas as a function of different parameters such as disk size and thickness.We also analyzed the effect of locating a probing metallic tip near the SiC disk to scatter light in the proximity of the SiC disk,thereby obtaining new spectral peaks connected with localized modes between the tip and the SiC disk.We then further investigated their application in IR scanning probe microscopy.A near-field map of the phononic resonances enhances the understanding of the nature of the IR extinction peaks.展开更多
In this article, we primarily review the time-resolved imaging of THz phonon polariton, which is generated by femtosecond laser in ferroelectric crystal. We pay more attention to the imaging in thin crystal, which can...In this article, we primarily review the time-resolved imaging of THz phonon polariton, which is generated by femtosecond laser in ferroelectric crystal. We pay more attention to the imaging in thin crystal, which can be used as an integration platform for terahertz-optics or terahertz-electrics. The imaging techniques, which can get quantitatively in-focus time-resolved images, are introduced in more detail. They have made enormous progress in recent years, and are powerful tools for the research of phonon polariton, optics, and THz wave. We also briefly introduce the generation principle and general propagation properties of THz phonon polariton.展开更多
The interface phonon-polaritons in quantum well systems consisting of polar ternary mixed crystals are investi-gated. The numerical results of the interface phonon-polariton frequencies in the GaAs/AlxGa1-xAs, ZnSxSe1...The interface phonon-polaritons in quantum well systems consisting of polar ternary mixed crystals are investi-gated. The numerical results of the interface phonon-polariton frequencies in the GaAs/AlxGa1-xAs, ZnSxSe1-x/ZnS, and ZnxCd1-xSe/ ZnSe quantum well systems are obtained and discussed. It is shown that there are six branches of interface phonon-polariton modes distributed in three bulk phonon-polariton forbidden bands in the systems. The electric fields of interface phonon polaritons are also presented and show the interface locality of the modes. The effects of the ＇two-mode＇ and ＇one-mode＇ behaviours of the ternary mixed crystals on the interface phonon-polariton modes are shown in the dispersion curves.展开更多
Surface phonon-polaritons in slabs of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, based on Maxwell＇s equations with the usual...Surface phonon-polaritons in slabs of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, based on Maxwell＇s equations with the usual boundary conditions. The numerical results of the surface phonon-polariton frequencies as functions of the wave-vector and thickness for slabs of ternary mixed crystals AlxGa1-xAs, Znx Cd1-x S,and Gax In1-x N are obtained and discussed. It is shown that there are four branches of surface phonon-polaritons in slab systems. The “two-mode” and “one-mode” behaviors of surface phonon-polaritons are also shown in their dispersion curves.展开更多
基金supported by the National Key Research and Development Program of China(2022YFA1203500)the National Natural Science Foundation of China(11874407,11721404,61888102,12204125,12074416,and 12222414)+5 种基金the National Key Basic Research Program of China(2019YFA0308500)the Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(XDB30000000 and XDB33030200)CAS Project for Young Scientists in Basic Research(YSBR-003)the CAS Youth Interdisciplinary Teamthe Youth Innovation Promotion Association of CAS(2018008)China Postdoctoral Science Foundation(2021M703173)。
文摘Vibrational spectroscopy is one of the key instrumentations that provide non-invasive investigation of structural and chemical composition for both organic and inorganic materials. However, diffraction of light funda- mentally limits the spatial resolution of far-field vibrational spectroscopy to roughly half the wavelength. In this article, we thoroughly review the integration of atomic force microscopy （AFM） with vibrational spectroscopy to enable the nanoscale characterization of emerging energy materials, which has not been possible with far-field optical techniques. The discussed methods utilize the AFM tip as a nanoscopic tool to extract spatially resolved electronic or molecular vibrational resonance spectra of a sample illuminated by a visible or infrared （IR） light source. The absorption of light by electrons or individual functional groups within molecules leads to changes in the sample＇s thermal response, optical scattering, and atomic force interactions, all of which can be readily probed by an AFM tip. For example, photothermal induced resonance （PTIR） spectroscopy methods measure a sample＇s local thermal expansion or temperature rise. Therefore, they use the AFM tip as a thermal detector to directly relate absorbed IR light to the thermal response of a sample. Optical scattering methods based on scanning near-field optical microscopy （SNOM） correlate the spectrum of scattered near-field light with molecular vibrational modes. More recently, photo-induced force microscopy （PiFM） has been developed to measure the change of the optical force gradient due to the light absorption by molecular vibrational resonances using AFM＇s superb sensitivity in detecting tip-sample force interactions. Such recent efforts successfully breech the diffraction limit of light to provide nanoscale spatial resolution of vibrational spectroscopy,which will become a critical technique for characterizing novel energy materials.
文摘The electromagnetic interaction of light with polar materials shows a sharp and well defined electromagnetic response in the infrared(IR)region that consists mainly of excitation of optical phonons.Similar to surface plasmons in the visible region,surface phonons can couple efficiently to infrared light in micron-sized antennas made of polar materials.We applied the boundary element method to calculating the infrared electromagnetic response of single SiC disks acting as effective infrared antennas as a function of different parameters such as disk size and thickness.We also analyzed the effect of locating a probing metallic tip near the SiC disk to scatter light in the proximity of the SiC disk,thereby obtaining new spectral peaks connected with localized modes between the tip and the SiC disk.We then further investigated their application in IR scanning probe microscopy.A near-field map of the phononic resonances enhances the understanding of the nature of the IR extinction peaks.
文摘In this article, we primarily review the time-resolved imaging of THz phonon polariton, which is generated by femtosecond laser in ferroelectric crystal. We pay more attention to the imaging in thin crystal, which can be used as an integration platform for terahertz-optics or terahertz-electrics. The imaging techniques, which can get quantitatively in-focus time-resolved images, are introduced in more detail. They have made enormous progress in recent years, and are powerful tools for the research of phonon polariton, optics, and THz wave. We also briefly introduce the generation principle and general propagation properties of THz phonon polariton.
基金supported partly by the National Natural Science Foundation of China (Grant Nos.10764003 and 10947179)
文摘The interface phonon-polaritons in quantum well systems consisting of polar ternary mixed crystals are investi-gated. The numerical results of the interface phonon-polariton frequencies in the GaAs/AlxGa1-xAs, ZnSxSe1-x/ZnS, and ZnxCd1-xSe/ ZnSe quantum well systems are obtained and discussed. It is shown that there are six branches of interface phonon-polariton modes distributed in three bulk phonon-polariton forbidden bands in the systems. The electric fields of interface phonon polaritons are also presented and show the interface locality of the modes. The effects of the ＇two-mode＇ and ＇one-mode＇ behaviours of the ternary mixed crystals on the interface phonon-polariton modes are shown in the dispersion curves.
文摘Surface phonon-polaritons in slabs of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, based on Maxwell＇s equations with the usual boundary conditions. The numerical results of the surface phonon-polariton frequencies as functions of the wave-vector and thickness for slabs of ternary mixed crystals AlxGa1-xAs, Znx Cd1-x S,and Gax In1-x N are obtained and discussed. It is shown that there are four branches of surface phonon-polaritons in slab systems. The “two-mode” and “one-mode” behaviors of surface phonon-polaritons are also shown in their dispersion curves.
