Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry ...Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry metal nanostructure arrays. In this paper, a novel perforated silver nanocap array with high surface-enhanced Raman scattering （SERS） activity and fluorescence suppression is reported. The array is fabricated by electron beam evaporating Ag onto the perforated barrier layer side of a hard anodization （HA） anodic aluminum oxide （AAO） template. The morphology and optical property of the perforated silver nanocap array are characterized by an atomic force microscope （AFM）, a scanning electron microscope （SEM）, and absorption spectra. The results of SERS measurements reveal that the perforated silver nanocap array offers high SERS activity and fluorescence suppression compared with an imperforated silver nanocap array.展开更多
Starting from the wave normal tracing treatment in the Savart polariscope that relates the Jones matrix to its transmission performance, this paper establishes a simple and effective model for the Jones matrix at an a...Starting from the wave normal tracing treatment in the Savart polariscope that relates the Jones matrix to its transmission performance, this paper establishes a simple and effective model for the Jones matrix at an arbitrary incidence in the spatial domain. Analytical expressions of all the matrix components are determined with the consideration of all the main impact factors. This model needs only a few parameters hence it is convenient to be employed to evaluate the propagation performance of any birefringent optical system. The simulated results obtained with it demonstrate that this model gives a precise representation of the characteristic of light propagation in the Savart polariscope. This would provide useful suggestions for the design, calibration, and performance improvement of any other birefringent polarisation element and optical system.展开更多
The equivalent air gap method is a simple way to trace the ray propagation in an isotropic medium, but it cannot be applied to an anisotropic medium. We present the exact general expressions of the equivalent air gap ...The equivalent air gap method is a simple way to trace the ray propagation in an isotropic medium, but it cannot be applied to an anisotropic medium. We present the exact general expressions of the equivalent air gap thicknesses and the displacements for the plane-parallel uniaxial crystal plates. They are also suitable for the isotropie medium. This method is useful when one determines whether certain size plane-parallel plates can be fitted into the available air of an optical system, and also in the prism system design.展开更多
Colloidal quantum dots(QDs),the building blocks of modern displays and optoelectronic devices,have reached the highest level of size and shape control,and stability during the last 30 years.However,full utilization of...Colloidal quantum dots(QDs),the building blocks of modern displays and optoelectronic devices,have reached the highest level of size and shape control,and stability during the last 30 years.However,full utilization of their potential requires integration or assembly of more than one nanocrystal as in the case of coupled quantum dots molecules(CQDM),where two core–shell QDs are fused to form two emission centers in close proximity.These CQDMs were recently shown to switch color under an applied electric field at room temperature.Here we use cryogenic single particle spectroscopy of single CQDMs under an electric field to show that various mechanisms can contribute to the spectrum change under an applied electric field at cryogenic temperatures.The first mechanism is the control of the delocalized electron wave function when the electric field is applied along the dimer axis.The electric field bends the conduction band and forces the electron wave function to localize in one of the QDs yielding preferential emission of that particular center.In addition,we found that QDs and CQDMs could become sensitive to surface traps under an electric field.In the case of CQDMs,that can result in decreasing the intensity of one of the QDs while increasing the other QD’s intensity.Moreover,we show that there are surface charges which screen the applied electric field in some of the QDs.This as well can result in electric field-induced color-tuning of CQDMs.Understanding the underlying mechanisms responsible for spectral shifts under applied electric fields is critical for the development of color-tunable devices utilizing CQDMs,including efficient displays and single photon sources.展开更多
The fidelity of light with arbitrary polarizations stored in a warm STRb atomic vapor at different storage time is studied. The exponential decay of regeneration efficiency with the storage time is observed and a dete...The fidelity of light with arbitrary polarizations stored in a warm STRb atomic vapor at different storage time is studied. The exponential decay of regeneration efficiency with the storage time is observed and a detectable signal at 300-us storage time is still existed. The storage fidelity at different storage time is well maintained in our experiment.展开更多
基金Project supported by the Industry Key Technologies R & D Project in Shaanxi Province of China (Grant No. 2012K07-19)
文摘Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry metal nanostructure arrays. In this paper, a novel perforated silver nanocap array with high surface-enhanced Raman scattering （SERS） activity and fluorescence suppression is reported. The array is fabricated by electron beam evaporating Ag onto the perforated barrier layer side of a hard anodization （HA） anodic aluminum oxide （AAO） template. The morphology and optical property of the perforated silver nanocap array are characterized by an atomic force microscope （AFM）, a scanning electron microscope （SEM）, and absorption spectra. The results of SERS measurements reveal that the perforated silver nanocap array offers high SERS activity and fluorescence suppression compared with an imperforated silver nanocap array.
基金Project supported by the State Key Program of National Natural Science Foundation of China (Grant No. 40537031)the National Natural Science Foundation of China (Grant No. 40875013)+1 种基金the National Defense Basic Scientific Research Project,China (Grant No. A1420080187)the National High Technology Research and Development Program of China (Grant No. 2006AA12Z152)
文摘Starting from the wave normal tracing treatment in the Savart polariscope that relates the Jones matrix to its transmission performance, this paper establishes a simple and effective model for the Jones matrix at an arbitrary incidence in the spatial domain. Analytical expressions of all the matrix components are determined with the consideration of all the main impact factors. This model needs only a few parameters hence it is convenient to be employed to evaluate the propagation performance of any birefringent optical system. The simulated results obtained with it demonstrate that this model gives a precise representation of the characteristic of light propagation in the Savart polariscope. This would provide useful suggestions for the design, calibration, and performance improvement of any other birefringent polarisation element and optical system.
基金Supported by the State Key Program of National Natural Science Foundation of China under Grant No 40537031 the National Defense Basic Scientific Research Project under Grant No A1420080187, the National Natural Science Foundation of China under Grant No 40875013, the National High Technology Research and Development Program of China under Grant No 2006AA12Z152, the Key Program of Science and Technology of Shaanxi Province under Grant No 2005K04-G18.
文摘The equivalent air gap method is a simple way to trace the ray propagation in an isotropic medium, but it cannot be applied to an anisotropic medium. We present the exact general expressions of the equivalent air gap thicknesses and the displacements for the plane-parallel uniaxial crystal plates. They are also suitable for the isotropie medium. This method is useful when one determines whether certain size plane-parallel plates can be fitted into the available air of an optical system, and also in the prism system design.
基金support from the Israel Science Foundation(ISF,No.3415/21)support by the Ministry of Science and Technology&the National Foundation for Applied and Engineering Sciences and the council for higher education,Israel.U.B.thanks the Alfred&Erica Larisch memorial chair.
文摘Colloidal quantum dots(QDs),the building blocks of modern displays and optoelectronic devices,have reached the highest level of size and shape control,and stability during the last 30 years.However,full utilization of their potential requires integration or assembly of more than one nanocrystal as in the case of coupled quantum dots molecules(CQDM),where two core–shell QDs are fused to form two emission centers in close proximity.These CQDMs were recently shown to switch color under an applied electric field at room temperature.Here we use cryogenic single particle spectroscopy of single CQDMs under an electric field to show that various mechanisms can contribute to the spectrum change under an applied electric field at cryogenic temperatures.The first mechanism is the control of the delocalized electron wave function when the electric field is applied along the dimer axis.The electric field bends the conduction band and forces the electron wave function to localize in one of the QDs yielding preferential emission of that particular center.In addition,we found that QDs and CQDMs could become sensitive to surface traps under an electric field.In the case of CQDMs,that can result in decreasing the intensity of one of the QDs while increasing the other QD’s intensity.Moreover,we show that there are surface charges which screen the applied electric field in some of the QDs.This as well can result in electric field-induced color-tuning of CQDMs.Understanding the underlying mechanisms responsible for spectral shifts under applied electric fields is critical for the development of color-tunable devices utilizing CQDMs,including efficient displays and single photon sources.
基金supported by the National Natural Science Foundation of China(No.10834007)the Key Program of the Chinese Academy of Sciences(No. KJCX2-SW-T12)
文摘The fidelity of light with arbitrary polarizations stored in a warm STRb atomic vapor at different storage time is studied. The exponential decay of regeneration efficiency with the storage time is observed and a detectable signal at 300-us storage time is still existed. The storage fidelity at different storage time is well maintained in our experiment.
