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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

Scattering of a single ZnO NR (138 nm in diameter, 8.06 μm in length) measured by using two polarization directions of an incoming laser (E∥ and E⊥) on the NR oriented in the y direction (ZnO NR∥). Scattering intensity is measured with respect to the position along the length of the 1D nanomaterial as well as the analyzer angle. (A) The 3D contour plot summarizes scattering results from a ZnO NR∥ under the excitation of E∥ as a function of both the analyzer angle and the spatial position on the NR. The highest and lowest scattering is observed when the collection polarization angle is set parallel (0°) and perpendicular (90°) to the incoming polarization direction, respectively. The phenomenon is clearly seen in the 2D projection of the scattering intensity with respect to the analyzer angle at each position along the length of the ZnO NR∥. Color schemes used in the 2D plot are the same as the scattering intensity level profiled in the 3D contour graph. A series of grey-scale panels are the scattering images obtained from the ZnO NR measured at the analyzer angle of 0°, 30°, 60°, and 90°, presented from left to right, respectively. (B) The same set of scattering measurements was repeated by using the orthogonal excitation of E⊥ as functions of the analyzer angle and the spatial position on the same ZnO NR∥ shown in (A). Similar to what was observed under E∥, highest and lowest scattering from the NR occurred when the analyzer angle was set parallel and perpendicular to E⊥, respectively. In (B), those analyzer angles correspond to 90° for the former and 0° for the latter case.
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Figure 2: Scattering of a single ZnO NR (138 nm in diameter, 8.06 μm in length) measured by using two polarization directions of an incoming laser (E∥ and E⊥) on the NR oriented in the y direction (ZnO NR∥). Scattering intensity is measured with respect to the position along the length of the 1D nanomaterial as well as the analyzer angle. (A) The 3D contour plot summarizes scattering results from a ZnO NR∥ under the excitation of E∥ as a function of both the analyzer angle and the spatial position on the NR. The highest and lowest scattering is observed when the collection polarization angle is set parallel (0°) and perpendicular (90°) to the incoming polarization direction, respectively. The phenomenon is clearly seen in the 2D projection of the scattering intensity with respect to the analyzer angle at each position along the length of the ZnO NR∥. Color schemes used in the 2D plot are the same as the scattering intensity level profiled in the 3D contour graph. A series of grey-scale panels are the scattering images obtained from the ZnO NR measured at the analyzer angle of 0°, 30°, 60°, and 90°, presented from left to right, respectively. (B) The same set of scattering measurements was repeated by using the orthogonal excitation of E⊥ as functions of the analyzer angle and the spatial position on the same ZnO NR∥ shown in (A). Similar to what was observed under E∥, highest and lowest scattering from the NR occurred when the analyzer angle was set parallel and perpendicular to E⊥, respectively. In (B), those analyzer angles correspond to 90° for the former and 0° for the latter case.

Mentions: The typical scattering behavior of individual NRs was first characterized from the y axis-oriented NRs (NR∥) by employing the two cases of polarized illumination, E∥ and E⊥. Figure 2 summarizes the resulting data by showing 3-dimensional (3D) contour plots of the scattering intensity as a function of both the position along the ZnO NR long axis and the analyzer angle, 2-dimensional (2D) projection maps of the scattered signal with respect to the analyzer rotation along the spatial position of the NR, and DF images of the NR∥ at four representative analyzer angles of 0°, 30°, 60°, and 90°. Schematics showing the orientations of the key measurement components are also provided in Figure 2. The set of data in Figure 2A represents typical scattering responses of ZnO NRs lying along the y-axis when they are illuminated with an incoming light oriented parallel to the long axis of the NR, i.e., E∥. ZnO NRs used in our study are free of atomic defects and they do not absorb any visible light or show any defect emission in the visible wavelength range. Hence, the scattering signal from individual ZnO NRs collected at the same wavelength as the incident light is not associated with any type of inelastic scattering phenomena. The scattering intensity of the NR∥ decreases as the analyzer angle is changed from parallel (0°) to perpendicular (90°) with respect to the incident polarization direction and recovers back to its full scattering intensity when the analyzer rotation is increased from 90° to 180°. This trend in the NR∥ scattering intensity is quantitatively confirmed in the 3D contour plot in Figure 2A in which the highest intensities are observed at 0° and 180° while the lowest intensity is observed at 90°. These analyzer angle-dependent changes in NR scattering intensity are further evidenced quantitatively in the 2D projection map and qualitatively in the four representative DF images of the ZnO NR sampled at analyzer rotations of 0°, 30°, 60°, and 90°.


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)

Scattering of a single ZnO NR (138 nm in diameter, 8.06 μm in length) measured by using two polarization directions of an incoming laser (E∥ and E⊥) on the NR oriented in the y direction (ZnO NR∥). Scattering intensity is measured with respect to the position along the length of the 1D nanomaterial as well as the analyzer angle. (A) The 3D contour plot summarizes scattering results from a ZnO NR∥ under the excitation of E∥ as a function of both the analyzer angle and the spatial position on the NR. The highest and lowest scattering is observed when the collection polarization angle is set parallel (0°) and perpendicular (90°) to the incoming polarization direction, respectively. The phenomenon is clearly seen in the 2D projection of the scattering intensity with respect to the analyzer angle at each position along the length of the ZnO NR∥. Color schemes used in the 2D plot are the same as the scattering intensity level profiled in the 3D contour graph. A series of grey-scale panels are the scattering images obtained from the ZnO NR measured at the analyzer angle of 0°, 30°, 60°, and 90°, presented from left to right, respectively. (B) The same set of scattering measurements was repeated by using the orthogonal excitation of E⊥ as functions of the analyzer angle and the spatial position on the same ZnO NR∥ shown in (A). Similar to what was observed under E∥, highest and lowest scattering from the NR occurred when the analyzer angle was set parallel and perpendicular to E⊥, respectively. In (B), those analyzer angles correspond to 90° for the former and 0° for the latter case.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Scattering of a single ZnO NR (138 nm in diameter, 8.06 μm in length) measured by using two polarization directions of an incoming laser (E∥ and E⊥) on the NR oriented in the y direction (ZnO NR∥). Scattering intensity is measured with respect to the position along the length of the 1D nanomaterial as well as the analyzer angle. (A) The 3D contour plot summarizes scattering results from a ZnO NR∥ under the excitation of E∥ as a function of both the analyzer angle and the spatial position on the NR. The highest and lowest scattering is observed when the collection polarization angle is set parallel (0°) and perpendicular (90°) to the incoming polarization direction, respectively. The phenomenon is clearly seen in the 2D projection of the scattering intensity with respect to the analyzer angle at each position along the length of the ZnO NR∥. Color schemes used in the 2D plot are the same as the scattering intensity level profiled in the 3D contour graph. A series of grey-scale panels are the scattering images obtained from the ZnO NR measured at the analyzer angle of 0°, 30°, 60°, and 90°, presented from left to right, respectively. (B) The same set of scattering measurements was repeated by using the orthogonal excitation of E⊥ as functions of the analyzer angle and the spatial position on the same ZnO NR∥ shown in (A). Similar to what was observed under E∥, highest and lowest scattering from the NR occurred when the analyzer angle was set parallel and perpendicular to E⊥, respectively. In (B), those analyzer angles correspond to 90° for the former and 0° for the latter case.
Mentions: The typical scattering behavior of individual NRs was first characterized from the y axis-oriented NRs (NR∥) by employing the two cases of polarized illumination, E∥ and E⊥. Figure 2 summarizes the resulting data by showing 3-dimensional (3D) contour plots of the scattering intensity as a function of both the position along the ZnO NR long axis and the analyzer angle, 2-dimensional (2D) projection maps of the scattered signal with respect to the analyzer rotation along the spatial position of the NR, and DF images of the NR∥ at four representative analyzer angles of 0°, 30°, 60°, and 90°. Schematics showing the orientations of the key measurement components are also provided in Figure 2. The set of data in Figure 2A represents typical scattering responses of ZnO NRs lying along the y-axis when they are illuminated with an incoming light oriented parallel to the long axis of the NR, i.e., E∥. ZnO NRs used in our study are free of atomic defects and they do not absorb any visible light or show any defect emission in the visible wavelength range. Hence, the scattering signal from individual ZnO NRs collected at the same wavelength as the incident light is not associated with any type of inelastic scattering phenomena. The scattering intensity of the NR∥ decreases as the analyzer angle is changed from parallel (0°) to perpendicular (90°) with respect to the incident polarization direction and recovers back to its full scattering intensity when the analyzer rotation is increased from 90° to 180°. This trend in the NR∥ scattering intensity is quantitatively confirmed in the 3D contour plot in Figure 2A in which the highest intensities are observed at 0° and 180° while the lowest intensity is observed at 90°. These analyzer angle-dependent changes in NR scattering intensity are further evidenced quantitatively in the 2D projection map and qualitatively in the four representative DF images of the ZnO NR sampled at analyzer rotations of 0°, 30°, 60°, and 90°.

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