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Scattering Intensity and Directionality Probed Along Individual Zinc Oxide Nanorods with Precisely Controlled Light Polarization and Nanorod Orientation.

Choi DS, Singh M, Song S, Chang JY, Kang Y, Hahm JI - Photonics (2015)

Bottom Line: We then discerned, for the first time, the effects of light polarization, analyzer angle, and NR orientation on the intensity and directionality of the optical responses both qualitatively and quantitatively along the length of the single ZnO NRs.The fundamental light interaction behavior of ZnO NRs is likely to govern their functional outcomes in photonics, optoelectronics, and sensor devices.Hence, our efforts provided much needed insight into unique optical responses from individual 1D ZnO nanomaterials, which could be highly beneficial in developing next-generation optoelectronic systems and optical biodetectors with improved device efficiency and sensitivity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, Georgetown University, 37th & O Sts. NW., Washington, DC 20057, USA.

ABSTRACT

We elucidated the light-matter interaction of individual ZnO NRs with a monochromatic beam of linearly polarized light that scatters elastically from the ZnO NRs by performing forward scattering and back-aperture imaging in a dark-field setting. We precisely controlled the electric field vector of the incident light and the NR orientation within the plane of light interaction during both modes of measurement, and spatially resolved the scattering response from different interaction points along the NR long axis. We then discerned, for the first time, the effects of light polarization, analyzer angle, and NR orientation on the intensity and directionality of the optical responses both qualitatively and quantitatively along the length of the single ZnO NRs. We identified distinctive scattering profiles from individual ZnO NRs subject to incident light polarization with controlled NR orientation from the forward dark-field scattering and back-aperture imaging modes. The fundamental light interaction behavior of ZnO NRs is likely to govern their functional outcomes in photonics, optoelectronics, and sensor devices. Hence, our efforts provided much needed insight into unique optical responses from individual 1D ZnO nanomaterials, which could be highly beneficial in developing next-generation optoelectronic systems and optical biodetectors with improved device efficiency and sensitivity.

No MeSH data available.


Related in: MedlinePlus

The NR position-dependent scattering signals under the two excitation conditions of E∥ and E⊥ are collected over the entire length of the ZnO NR⊥ and plotted against the analyzer rotation. Red and blue symbols in all graphs are experimental data when the excitation polarizations of E∥ and E⊥ are used, respectively. Lines represent curves fits for the corresponding set of data. (A) The position dependent scattering signal averaged over the entire length of the NR⊥ is plotted as a function of the analyzer angle. The overall scattering intensity from the same NR was much lower when E⊥ was used as excitation instead of E∥ while keeping the same exposure time of 10 ms. (B) The average scattering intensity was normalized with respect to the highest intensity values measured at each excitation condition and graphed as a function of analyzer rotation. (C) Polarization anisotropy values calculated from the data shown in (B) follow a cos2θ dependence on the analyzer angle, θ. (D and E) Polar plots of average scattering intensities of the ZnO NR⊥ under (D) E∥ and (E) E⊥ excitation are displayed.
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Figure 5: The NR position-dependent scattering signals under the two excitation conditions of E∥ and E⊥ are collected over the entire length of the ZnO NR⊥ and plotted against the analyzer rotation. Red and blue symbols in all graphs are experimental data when the excitation polarizations of E∥ and E⊥ are used, respectively. Lines represent curves fits for the corresponding set of data. (A) The position dependent scattering signal averaged over the entire length of the NR⊥ is plotted as a function of the analyzer angle. The overall scattering intensity from the same NR was much lower when E⊥ was used as excitation instead of E∥ while keeping the same exposure time of 10 ms. (B) The average scattering intensity was normalized with respect to the highest intensity values measured at each excitation condition and graphed as a function of analyzer rotation. (C) Polarization anisotropy values calculated from the data shown in (B) follow a cos2θ dependence on the analyzer angle, θ. (D and E) Polar plots of average scattering intensities of the ZnO NR⊥ under (D) E∥ and (E) E⊥ excitation are displayed.

Mentions: In order to substantiate the polarization-dependent scattering behavior of ZnO NR⊥ under the two cases of the incident laser, Figure 5 further displays the quantitative scattering data measured from the ZnO NR⊥ discussed in Figure 4. Figure 5A displays the scattering signal averaged over the entire length of the NR⊥ in response to E∥ (red points) and E⊥ (blue points) while systematically varying the analyzer angle. Red and blue lines in the graphs are the curve fits of the respective data. Figure 5B shows the scattering intensity as a function of analyzer rotation after normalizing the signals with respect to the highest and lowest intensity values measured at each excitation condition. The exposure time was kept constant at 10 ms between the two laser polarizations. The scattering intensity of the NR⊥ is approximately 2.5 times greater under E∥ irradiation than under E⊥, yielding a PA value of 0.428. When taking the different NR orientations into consideration, a larger difference between the average scattering intensity values from E∥ and E⊥ illumination is observed for NR∥ than for NR⊥. Figure 5C presents the calculated PA values at each analyzer angle for the NR⊥. Figure 5D,E provide polar intensity plots of the average scattering intensities from the ZnO NR⊥ under E∥ (red) and E⊥ (blue) radiation. Similar to the behavior observed in NR∥, the polar plots show a dipole-like pattern with a tightly closed center for E∥ excitation while the dipolar plot is slightly open at the center under E⊥.


Scattering Intensity and Directionality Probed Along Individual Zinc Oxide Nanorods with Precisely Controlled Light Polarization and Nanorod Orientation.

Choi DS, Singh M, Song S, Chang JY, Kang Y, Hahm JI - Photonics (2015)

The NR position-dependent scattering signals under the two excitation conditions of E∥ and E⊥ are collected over the entire length of the ZnO NR⊥ and plotted against the analyzer rotation. Red and blue symbols in all graphs are experimental data when the excitation polarizations of E∥ and E⊥ are used, respectively. Lines represent curves fits for the corresponding set of data. (A) The position dependent scattering signal averaged over the entire length of the NR⊥ is plotted as a function of the analyzer angle. The overall scattering intensity from the same NR was much lower when E⊥ was used as excitation instead of E∥ while keeping the same exposure time of 10 ms. (B) The average scattering intensity was normalized with respect to the highest intensity values measured at each excitation condition and graphed as a function of analyzer rotation. (C) Polarization anisotropy values calculated from the data shown in (B) follow a cos2θ dependence on the analyzer angle, θ. (D and E) Polar plots of average scattering intensities of the ZnO NR⊥ under (D) E∥ and (E) E⊥ excitation are displayed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643738&req=5

Figure 5: The NR position-dependent scattering signals under the two excitation conditions of E∥ and E⊥ are collected over the entire length of the ZnO NR⊥ and plotted against the analyzer rotation. Red and blue symbols in all graphs are experimental data when the excitation polarizations of E∥ and E⊥ are used, respectively. Lines represent curves fits for the corresponding set of data. (A) The position dependent scattering signal averaged over the entire length of the NR⊥ is plotted as a function of the analyzer angle. The overall scattering intensity from the same NR was much lower when E⊥ was used as excitation instead of E∥ while keeping the same exposure time of 10 ms. (B) The average scattering intensity was normalized with respect to the highest intensity values measured at each excitation condition and graphed as a function of analyzer rotation. (C) Polarization anisotropy values calculated from the data shown in (B) follow a cos2θ dependence on the analyzer angle, θ. (D and E) Polar plots of average scattering intensities of the ZnO NR⊥ under (D) E∥ and (E) E⊥ excitation are displayed.
Mentions: In order to substantiate the polarization-dependent scattering behavior of ZnO NR⊥ under the two cases of the incident laser, Figure 5 further displays the quantitative scattering data measured from the ZnO NR⊥ discussed in Figure 4. Figure 5A displays the scattering signal averaged over the entire length of the NR⊥ in response to E∥ (red points) and E⊥ (blue points) while systematically varying the analyzer angle. Red and blue lines in the graphs are the curve fits of the respective data. Figure 5B shows the scattering intensity as a function of analyzer rotation after normalizing the signals with respect to the highest and lowest intensity values measured at each excitation condition. The exposure time was kept constant at 10 ms between the two laser polarizations. The scattering intensity of the NR⊥ is approximately 2.5 times greater under E∥ irradiation than under E⊥, yielding a PA value of 0.428. When taking the different NR orientations into consideration, a larger difference between the average scattering intensity values from E∥ and E⊥ illumination is observed for NR∥ than for NR⊥. Figure 5C presents the calculated PA values at each analyzer angle for the NR⊥. Figure 5D,E provide polar intensity plots of the average scattering intensities from the ZnO NR⊥ under E∥ (red) and E⊥ (blue) radiation. Similar to the behavior observed in NR∥, the polar plots show a dipole-like pattern with a tightly closed center for E∥ excitation while the dipolar plot is slightly open at the center under E⊥.

Bottom Line: We then discerned, for the first time, the effects of light polarization, analyzer angle, and NR orientation on the intensity and directionality of the optical responses both qualitatively and quantitatively along the length of the single ZnO NRs.The fundamental light interaction behavior of ZnO NRs is likely to govern their functional outcomes in photonics, optoelectronics, and sensor devices.Hence, our efforts provided much needed insight into unique optical responses from individual 1D ZnO nanomaterials, which could be highly beneficial in developing next-generation optoelectronic systems and optical biodetectors with improved device efficiency and sensitivity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, Georgetown University, 37th & O Sts. NW., Washington, DC 20057, USA.

ABSTRACT

We elucidated the light-matter interaction of individual ZnO NRs with a monochromatic beam of linearly polarized light that scatters elastically from the ZnO NRs by performing forward scattering and back-aperture imaging in a dark-field setting. We precisely controlled the electric field vector of the incident light and the NR orientation within the plane of light interaction during both modes of measurement, and spatially resolved the scattering response from different interaction points along the NR long axis. We then discerned, for the first time, the effects of light polarization, analyzer angle, and NR orientation on the intensity and directionality of the optical responses both qualitatively and quantitatively along the length of the single ZnO NRs. We identified distinctive scattering profiles from individual ZnO NRs subject to incident light polarization with controlled NR orientation from the forward dark-field scattering and back-aperture imaging modes. The fundamental light interaction behavior of ZnO NRs is likely to govern their functional outcomes in photonics, optoelectronics, and sensor devices. Hence, our efforts provided much needed insight into unique optical responses from individual 1D ZnO nanomaterials, which could be highly beneficial in developing next-generation optoelectronic systems and optical biodetectors with improved device efficiency and sensitivity.

No MeSH data available.


Related in: MedlinePlus