Spatial modulation spectroscopy imaging of nano-objects of different sizes and shapes

Tuphan Devkota, Mary Sajini Devadas, Andrew Brown, Joseph Talghader, Gregory V. Hartland

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Spatial modulation spectroscopy (SMS) is a powerful method for interrogating single nanoparticles. In these experiments optical extinction is measured by moving the particle in and out of a tightly focused laser beam. SMS is typically used for particles that are much smaller than the laser spot size. In this paper, we extend the analysis of the SMS signal to particles with sizes comparable to or larger than the laser spot, where the shape of the particle matters. These results are important for the analysis of polydisperse samples that have a wide range of sizes. The presented example images and analysis of a carbon microparticle sample show the utility of the derived expressions. In particular, we show that SMS can be used to generate extinction cross-section information about micrometer-sized particles with complex shapes.

Original languageEnglish (US)
Pages (from-to)796-801
Number of pages6
JournalApplied Optics
Issue number4
StatePublished - Feb 1 2016

Bibliographical note

Publisher Copyright:
© 2016 Optical Society of America.


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