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ABSTRACT: The synthesis of hybrid nanostructures with controlled size, shape, composition and morphology has attracted increasing attention due to the fundamental and applicable interest. Here, we demonstrate the synthesis and optical properties of hierarchical CdSe-Au hybrid nanostructures with zinc blende (ZB) CdSe nanocrystals (NCs). For 3.5 nm ZB CdSe NCs, one Au cluster was deposited on each CdSe NC. Nevertheless, several Au clusters were selectively deposited on the apexes of 5 nm and 8 nm ZB CdSe NCs, resulting from the different reactivity of crystal facets. Furthermore, hierarchical CdSe-Au nanostructures with complex morphology were organized with the isolated CdSe-Au hybrid NCs by the coalescence of Au domains on the CdSe-Au hybrid NCs. UV-Vis spectra revealed a red tail upon the deposition of Au clusters. The chemical joint of Au on CdSe NCs was further confirmed by fluorescence quenching. The optical limiting performance of CdSe-Au hybrid NCs dispersed in toluene was investigated at 532 nm using a Nd:YAG laser with the pulse width of 8 ns.
Physical Chemistry Chemical Physics 08/2012; 14(38):13180-6. · 3.57 Impact Factor
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ABSTRACT: The authors have demonstrated the optimization of the active layer thickness on the threshold of organic solid-state dye-doped laser (SSDL), which was fabricated by three-dimensional polymeric opal photonic crystal and tert-butyl Rhodamine B (t-Bu-RhB) doped polymer film. Gain media were produced by incorporating t-Bu-RhB into polymer film at 3.0 wt %. The sandwiched laser resonator cavities with different active layer thickness displayed single-mode lasing oscillations in the reflection band gap of the resonator structure. The lasing threshold as low as 1.13 μJ/pulse was achieved. The optimization of active layer would provide an opportunity to accelerate the development of low threshold polymeric SSDLs.
Applied Physics Letters 03/2011; 98(9):093304-093304-3. · 3.84 Impact Factor
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ABSTRACT: Gold nanoparticles (AuNP's) prepared through a controllable synthesis and aggregation process are attractive for their unique properties that arise from their surface plasmon resonances (SPRs). However, aggregation-controlled AuNP's on amorphous surfaces have not been well explored. In this study, we present a simple in situ synthesis method for preparing AuNP's in which the AuNP's self-aggregate into microscale Candock-leaf-like structures on a polyelectrolyte film (PEF) surface. In this approach, the PEF plays an important role in adsorbing and storing AuCl(4)(-) as well as in controlling the release speed of AuCl(4)(-) in the preparation process. The mechanism for forming these Candock-leaf-like structures has been illustrated by both the growth process of gold nanoparticles and the Ostwald ripenning of the aggregations. AuNP's with a unique structure exhibited significantly enhanced surface Raman scattering and strong superhydrophobicity.
Langmuir 02/2011; 27(7):3249-53. · 4.19 Impact Factor
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ABSTRACT: The authors observed amplified spontaneous emission (ASE) action with an ultra-low threshold under optical excitation from
an active polymeric distributed-feedback (DFB) resonator which consists of sub-micrometer fiber grating. A dendrimer was used
to modify the laser dye and increased its concentration up to 4.95wt. % in the photocured resin. The DFB resonator was fabricated
by using two-photon induced polymerization (TPIP) technique. The ASE at 556nm was observed with a threshold of 0.30μJ/pulse
due to fourth-order diffraction feedback of the optical gain. This DFB could be expected to open a way for the fabrication
and application of microscale polymeric mirrorless laser.
Applied Physics A 09/2007; 89(1):145-148. · 1.63 Impact Factor
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ABSTRACT: The authors observed amplified spontaneous emission (ASE) from dye-doped polymer film sandwiched by two opal photonic crystals (PhCs). The ASE effect occurred at 599 nm with a full width at half maximum of about 5.1 nm, which corresponds to the L-point gap edge of the opal PhCs. Photoluminescence lifetimes of both dye-doped polymer films with and without opal PhCs were measured and corroborated that the ASE of the dye-doped polymer film emission is due to the presence of the photonic stop band.
Applied Physics Letters 07/2007; 91(3):031109-031109-3. · 3.84 Impact Factor
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ABSTRACT: The authors demonstrated the lasing emission of the cavity constructed by the allyl derivative of fluorescein doped dendrimer/polymer film and two opal photonic crystals. A dendrimer encapsulated the structure modified laser dye and increased its concentration up to 5.3 wt % in the polymer film with high optical gain. Laser emission of the cavity was observed, which is located at 589 nm with a full width at half maximum of 1.7 nm above the lasing threshold of 15 μJ/pulse. The lasing output was observed at an unordinary angle owing to the superprism effect of opal photonic crystals.
Applied Physics Letters 12/2006; 89(24):241101-241101-3. · 3.84 Impact Factor
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ABSTRACT: We have proposed an asymmetric bowtie 2-color controller and analyzed its resonance frequency spectra and temporal responses. The results show improved optical properties of the asymmetric bowtie 2-color controller as compared to symmetric bowties. The improved optical properties are a broad bandwidth of the plasmonic spectrum consisting of two resonant peaks, a high field enhancement in the gap of the bowtie structure, and a large effective enhancement volume. The system might have applications in the generation of XUV light via high-harmonic generation as well as in ultrabroadband sensors and multicolor optoelectronic filters.Highlights► Proposed an asymmetric bowtie 2-color controller. ► Support multiple resonances in the visible and NIR range. ► Lead to broad overall bandwidth and ultrafast responses. ► Show an intensity enhancement factor exceeding 103 with larger effective volume. ► Potential applications for HHG and ultrabroadband sensing.
Optics Communications 284(13):3474-3478. · 1.49 Impact Factor
