Exploiting evanescent-wave amplification for subwavelength low-contrast particle detection

S. Roy, S. F. Pereira*, H. P. Urbach, Xukang Wei, O. El Gawhary

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

12 Citations (Scopus)
145 Downloads (Pure)


The classical problem of subwavelength particle detection on a flat surface is especially challenging when the refractive index of the particle is close to that of the substrate. We demonstrate a method to improve the detection ability several times for such a situation, by enhancing the "forbidden" evanescent waves in the substrate using the principle of super-resolution with evanescent waves amplification. The working mechanism of the system and experimental validation from a design with a thin single dielectric layer is presented. The resulting system is a simple but complete example of evanescent-wave generation, amplification, and the consequent modulation of the far field. This principle can have far reaching impact in the field of particle detection in several applications ranging from contamination control to interferometric scattering microscopy for biological samples.

Original languageEnglish
Article number013814
Number of pages5
JournalPhysical Review A (Atomic, Molecular and Optical Physics)
Issue number1
Publication statusPublished - 2017


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