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

Daniel Choi,Sheng Song,Manpreet Singh,Yongkoo Kang,Jae Chang,Jong-In Hahm

doi:10.3390/photonics2020684

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.

Highlights

The optical properties of one-dimensional zinc oxide nanorods (1D ZnO NRs) have been extensively studied and engineered for better photonic [1–7], optoelectronic [8–14], and biosensing applications [15–18]
We study the optical responses of individual ZnO NRs upon illumination with a linearly polarized, monochromatic beam of light (642 nm in wavelength), while focusing on elucidating light polarization- and NR orientation-dependent, elastic scattering characteristics of single
As displayed in panel (i) of Figure 1, multiple components involved in the ZnO NR sample assembly are refractive index-matched throughout all existing interfaces, and this configuration allows for total internal reflection (TIR) of the incident laser beam after illuminating the sample

Summary

Introduction

The optical properties of one-dimensional zinc oxide nanorods (1D ZnO NRs) have been extensively studied and engineered for better photonic [1–7], optoelectronic [8–14], and biosensing applications [15–18]. Many studies have previously demonstrated that the incorporation of 1D ZnO materials in those applications can enable improvements in emission efficiency and/or detection sensitivity over their 2D and bulk counterparts [11,19–25]. From these efforts, beneficial optoelectronic characteristics of 1D. The optical signal-enhancing capability of ZnO NRs has been used in conjunction with dye-coupled DNA and proteins for fluorescence-based biomedical detection [15–18,25,31–33]. Both individual and ensembles of ZnO NRs have been exploited for the aforementioned applications

Methods

Results

Conclusion