Spectral inhomogeneities and spatially resolved dynamics in porphyrin J-aggregate studied in the near-field

Nagahara, Tetsuhiko; Imura, Kohei; Okamoto, Hiromi

doi:10.1016/j.cplett.2003.09.051

Cited by 33 publications

(47 citation statements)

References 14 publications

(16 reference statements)

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“…[15] For the microspheres, broad peaks ascribed to porphyrin J-aggregates were observed at 700 nm. [16] Fluorescence spectra of these architectures are shown in Figure 4 b. Red-shifted peaks were observed in the emission spectrum, again implying the formation of a J-aggregate. [16,17] To investigate their thermal stability, the self-assembled architectures on a substrate were heated by a hot plate at 120 8C for 2 minutes while under observation with a microscope ( Figure 5 a).…”

Section: Resultsmentioning

confidence: 88%

Fabrication of Microspheres from Phthalimide‐Substituted Porphyrin Derivatives

Ozawa

Kawao

Nagata

et al. 2010

Chemistry An Asian Journal

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Microspheres were fabricated from phthalimide-substituted porphyrin derivatives. Microscopic analysis showed that the structures of the supramolecular assemblies synthesized in the present study were spherical, with diameters in the sub-micrometer to micrometer range. The size of the microspheres could be controlled by changing the concentration of the casting solution. The spectroscopic properties of the microspheres were measured to determine the influence of their structural components. Thermal studies indicated that the temperature at which these structures became unstable was lower than the bulk melting point. During I-V measurements on devices composed of these microspheres, it was found that the current increased upon light irradiation, and the characteristic photoresponse properties of these devices were reproducible.

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Section: Resultsmentioning

confidence: 88%

Fabrication of Microspheres from Phthalimide‐Substituted Porphyrin Derivatives

Ozawa

Kawao

Nagata

et al. 2010

Chemistry An Asian Journal

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“…The principle of the near-field ultrafast measurement is basically the same as that of transient absorption correlation method 10,106,110 in the far-field experiment that is often used in ultrafast spectroscopy, except that the dispersion compensation is indispensable. 10,106,110 The optical beam from the pulsed laser source was divided into pump and probe beams with approximately the same intensity, and the two beams passed through respective optical delay lines to give a variable delay time between the pump and probe pulses.…”

Section: 11mentioning

confidence: 93%

“…To avoid that, the pulse is passed through a dispersion compensation device before coupling into the fiber to give a negative dispersion. 10,106,107 The dispersion compensation device is adjusted to yield the shortest possible pulse width at the exit of the aperture probe tip. A grating pair device is adopted typically as a dispersion compensation device.…”

Section: Time-resolved and Nonlinear Measurements In Near-field Micromentioning

confidence: 99%

“…10,106,110 The optical beam from the pulsed laser source was divided into pump and probe beams with approximately the same intensity, and the two beams passed through respective optical delay lines to give a variable delay time between the pump and probe pulses. The two beams were collinearly combined again into one beam, which was coupled into the fiber after the dispersion compensation device mentioned above.…”

Section: 11mentioning

confidence: 99%

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Nanooptical Studies on Physical and Chemical Characteristics of Noble Metal Nanostructures

Okamoto¹

2013

Bulletin of the Chemical Society of Japan

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Studies on physical and chemical properties of noble metal nanostructures, mainly by near-field optical microscopy and spectroscopy, are described. Near-field optical microscopy provides optical observation methodology with a spatial resolution in nanometer regime beyond the diffraction limit of light. We developed near-field imaging systems equipped with various light sources including ultrashort pulsed lasers, which enables advanced nonlinear and ultrafast near-field measurements as well as conventional near-field imaging. In particular, near-field two-photon excitation imaging was shown to provide a convenient tool to visualize the enhanced optical fields in the vicinities of metal nanostructures. With these methods we demonstrated that nanoscale optical field structures in metal nanostructures can be directly visualized. For single noble metal nanoparticles, such as gold nanorods as typical examples, plasmon standing wave functions were visualized. Ultrafast imaging revealed that sub-picosecond relaxation was reflected on the plasmon wave function images through thermally induced dielectric function changes of the metal. In some cases optical field distribution features arising from the lightning rod effects were observed, depending on the resonance conditions of the incident wavelengths with the plasmon modes. We also found anomalous near-field transmission phenomenon for nanoapertures blocked by nanodisks near the plasmon resonance wavelengths, which arise from the efficient near-field to propagating-field conversion ability of the nanodisks. In assembled nanoparticles, enhanced optical fields at the gap sites between the particles were visualized, which elucidates experimentally the mechanism of surface-enhanced Raman scattering. The characteristic field distributions in many particle assemblies were also observed and analyzed. Through these studies, we established a valuable methodology to investigate optical and spectroscopic properties of metal nanostructures, and the information obtained is available only by optical measurements with high spatial resolution.

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“…Moreover, in many other ultrafast dynamical researches on mesoscopic systems including coherent excitation spectroscopy [21] and coherent nonlinear response [22] of semiconductor quantum dots, transient absorption dynamics in organic nanocrystals [23] , optical gate actions of molecular films [24] , J aggregations [25] and so on [26][27][28][29][30][31][32][33] , the ultrahigh spatiotemporal resolved spectroscopy also has important applications.…”

Section: Figurementioning

confidence: 99%

Ultrahigh spatiotemporal resolved spectroscopy

Zhang

Yang

et al. 2007

Sci. China Ser. G-Phys. Mech. Astron.

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We review the technique and research of the ultrahigh spatiotemporal resolved spectroscopy and its applications in the field of the ultrafast dynamics of mesoscopic systems and nanomaterials. Combining femtosecond time-resolved spectroscopy and scanning near-field optical microscopy (SNOM), we can obtain the spectra with ultrahigh temporal and spatial resolutions simultaneously. Some problems in doing so are discussed. Then we show the important applications of the ultrahigh spatiotemporal resolved spectroscopy with a few typical examples.ultrahigh spatiotemporal resolved spectroscopy, femtosecond near-field spectroscopy, scanning near-field optical microscopy (SNOM), femtosecond time-resolved, nanomaterial Space and time resolved measurements are very fundamental methods in scientific research. With the development of modern nanotechnology and laser techniques, people now can characterize and study many basic physical processes on nanometer spatial scale [1] and femtosecond or picosecond time scale [2] . Examples include the carrier dynamics in metals and semiconductors, vibrational motion of molecules, energy relaxation in semiconductors and so on. Achieving optical spectroscopic information with ultrahigh spatial and temporal resolutions is a very important research method in such areas. For the widely concerned mesoscopic systems and nanomaterials, because of their small characteristic dimensions, a thorough study on their ultrafast dynamics needs ultrahigh resolutions in both space and time to be obtained simultaneously. The same conclusion is reached if one considers the research of real-space transport, since a transportation electron moves over a distance on the order of nanometer in one femtosecond [3] . Here, the small space-scale and the small time-scale are tightly related with each other. All these require the ultrahigh space and time resolved measurements to be implemented simultaneously.Limited by the responding speed, the temporal resolution using electronics and optoelectronics can only reach the picosecond range. As ultrafast laser progresses, femtosecond time-resolved spectroscopy gets to a temporal resolution of femtosecond scale. It is widely used in the research

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Spectral inhomogeneities and spatially resolved dynamics in porphyrin J-aggregate studied in the near-field

Cited by 33 publications

References 14 publications

Fabrication of Microspheres from Phthalimide‐Substituted Porphyrin Derivatives

Fabrication of Microspheres from Phthalimide‐Substituted Porphyrin Derivatives

Nanooptical Studies on Physical and Chemical Characteristics of Noble Metal Nanostructures

Ultrahigh spatiotemporal resolved spectroscopy

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