We observed rotational anisotropy of optical second harmonic generation (SHG) from V-shaped chromium nanohole arrays with 150 nm arm-length, 50 nm width, 360 nm periodicity, 120 o apex angle, and an area of 100 µm 2 , fabricated by electron beam lithography. Phenomenological analysis indicated that the effective nonlinear susceptibility element χ ଷଵଷ (ଶ) had a characteristic contribution to the observed anisotropic SHG intensity patterns. Here coordinate 1 is in the direction of the tip of V shapes in the substrate plane, and 3 indicates the direction perpendicular to the sample surface. The SHG intensity for the S-polarized output light was very weak, probably due to cancellation effect by the image dipoles created at the metal-air boundary. The possible origin of the observed nonlinearity was discussed according to the susceptibility elements obtained.2

We presented a green and simple method to synthesize carbon nanodots (C-dots) from millets using hydrothermal synthesis route for the first time. The obtained C-dots have average diameter ranging from 6 to 10 nm. Optical measurements showed the insight into the formation of functional groups on the particle surfaces, resulting in their good water solubility and bioconjugation. After treatment with C-dots, small subpopulation of the human cervical tumor cells became bright and exhibited multicolor fluorescence under different excitation wavelength. The achievement demonstrated potential applications of fluorescent C-dots in the field of biomedical application.

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This article describes a simple way to introduce nanomaterials using the presence of carbon nanodots (CNDs) in widely available food. Budweiser® beer and Coca-Cola®, commercial foods that are commonly accessible, were utilized to demonstrate the optical property of nanoparticles. Specifically, green and violet laser pointers were employed for the observation of excitation-dependent photoluminescence of CNDs. To represent the application of CNDs, we obtained multiple-color emissions in onion cells that were imaged by using Budweiser beer and Coca-Cola as a dye. The demonstration could offer a perspective on the use of food in teaching nanomaterials at the high school and undergraduate levels.

We investigated optical second harmonic generation (SHG) from the arrays of V‐shaped chromium nanoholes with the arm width of 50 nm. We systematically investigated the dependence of the SHG intensity on the designed parameters of Cr nanoholes, i.e. the arm length and apex angle. Several combinations of structural parameters of apex angles (A) and arm lengths (L) were examined. The SHG intensity in Pin/Pout configuration was enhanced when L was enlarged. We suggest that the nonlinear optical behavior was dictated by the bulk contribution of metallic electrons. Copyright © 2014 John Wiley & Sons, Ltd.