Direct and quantitative photothermal absorption spectroscopy of individual particulates

Jonathan K. Tong, Wei-Chun Hsu, Sang Eon Han, Brian R. Burg, Ruiting Zheng, Sheng Shen, Gang Chen
2013 Applied Physics Letters  
Photonic structures can exhibit significant absorption enhancement when an object's length scale is comparable to or smaller than the wavelength of light. This property has enabled photonic structures to be an integral component in many applications such as solar cells, light emitting diodes, and photothermal therapy. To characterize this enhancement at the single particulate level, conventional methods have consisted of indirect or qualitative approaches which are often limited to certain
more » ... e types. To overcome these limitations, we used a bilayer cantilever to directly and quantitatively measure the spectral absorption efficiency of a single silicon microwire in the visible wavelength range. We demonstrate an absorption enhancement on a per unit volume basis compared to a thin film, which shows good agreement with Mie theory calculations. This approach offers a quantitative approach for broadband absorption measurements on a wide range of photonic structures of different geometric and material compositions. V C 2013 AIP Publishing LLC.
doi:10.1063/1.4858387 fatcat:dejwae5blbgfhcyu5dnmf36wgm