INO-CNR, National Institute of Optics-CNR, Largo E. Fermi 6, Florence, Italy.
Nanoscale. 2013 Oct 21;5(20):9645-50. doi: 10.1039/c3nr00726j.
In this paper we report on a new use for dark-field microscopy in order to retrieve two-dimensional maps of optical parameters of a thin sample such as a cryptograph, a histological section, or a cell monolayer. In particular, we discuss the construction of quantitative charts of light absorbance and scattering coefficients of a polyvinyl alcohol film that was embedded with gold nanorods and then etched using a focused mode-locked Ti:Sapphire oscillator. Individual pulses from this laser excite plasmonic oscillations of the gold nanorods, thus triggering plastic deformations of the particles and their environment, which are confined within a few hundred nm of the light focus. In turn, these deformations modify the light absorbance and scattering landscape, which can be measured with optical resolution in a dark-field microscope equipped with an objective of tuneable numerical aperture. This technique may prove to be valuable for various applications, such as the fast readout of optically encoded data or to model functional interactions between light and biological tissue at the level of cellular organelles, including the photothermolysis of cancer.
本文报告了暗场显微镜的一种新用途，用于获取薄样品（如密码、组织切片或单层细胞）的二维光学参数图谱。具体来说，我们讨论了构建嵌入金纳米棒的聚乙烯醇薄膜的光吸收和散射系数定量图的方法，然后使用聚焦锁模钛宝石振荡器对其进行刻蚀。该激光的单个脉冲会激发金纳米棒的等离子体振荡，从而引发粒子及其环境的塑性变形，这些变形被限制在离光焦点几百纳米的范围内。反过来，这些变形会改变光的吸收和散射特性，可以在配备可调数值孔径物镜的暗场显微镜中以光学分辨率进行测量。这项技术可能在各种应用中具有价值，例如快速读取光学编码数据，或模拟光与生物组织在细胞器水平上的功能相互作用，包括癌症的光热疗法。
