**7. References**


**11** 

*1,4PR China 2Singapore 3USA* 

**Confocal White Light Reflection Imaging** 

*1College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 2Division of Physics and Applied Physics, School of Physical and Mathematical Sciences* 

The ability to image nanostructures with a high spatial resolution as well as spectral resolution is very important for a host of both fundamental and practical studies (Grigorenko et al., 2005; Dixon et al., 1991; Verveer et al., 2007; Yoshifumi et al., 2006; Singh et al., 2007; Patel & McGhee, 2007; Laurent et al., 2006). Recently, optical imaging and spectroscopic studies of metal nanoarrays, individual metal nanostructures, and graphene (one monolayer thick carbon atoms packed into a two-dimensional honeycomb lattice, which is the basic building block for other *sp2* carbon nanomaterials.) sheet have attracted much attention (Du et al., 2008, 2010; Laurent et al., 2005, 2006; Ni et al., 2007; Wang et al., 2010). As an example, scanning near-field optical microscope (SNOM) has provided high resolution and been widely used in nanostructure study. However, collecting an image by SNOM is very time-consuming and relies heavily on the equipment as well as the skill of the operator. SNOM is also ill-suited for spectroscopic measurements due to the weak signals. Comparatively, far-field techniques are simpler and generate much stronger signals, which have been successfully used to study localized surface plasmons (LSPs) of gold nanoparticle arrays (Laurent et al., 2005, 2006). Moreover, far-field white light scanning is a simple and low cost method, which also offers multiplewavelength advantage and is suitable to study spectral properties. White light confocal scanning microscopy has also been used to characterize material morphology, refractive index profile of fibers, etc (Ribes et al., 1995; Youk & Kim, 2006), where aperture or fiber were used as confocal pinhole. The best spatial resolution for normal confocal white light scanning optical microscope (not including that from a super continuum light source (Lindfors et al., 2004)) has been improved from 1.500 µm to about 0.800 µm (Youk & Kim, 2006). However, improvement of the spatial resolution is still much desired for the study

**1. Introduction**

of small-scale materials.

**for Characterization of Nanostructures** 

C. L. Du1, Y. M. You2, 3, Z. H. Ni4,J. Kasim2 and Z. X. Shen2

*Nanyang Technological University* 

*3Department of Chemistry, Yale University, CT* 

*4Department of Physics, Southeast University, Nanjing* 

