Interferometric scattering microscopy(iSCAT) is the imaging technique based on interference between a scattered field from a weak scatterer (Escat) and a reflected field from a top surface of a substrate (Erefl). The iSCAT provides high detection sensitivity and temporal resolution for imaging and tracking of an individual nanoparticle (NP) and a single biomolecule. However, it is hard to the be applied to quantitative analysis or spectroscopy because interference signal (Re[Escat*Erefl]) of the iSCAT cannot provide separated amplitude and phase information on Escat. Here, we demonstrated a method to recover both the amplitude and phase spectra of an NP-scattered field (Escat) from iSCAT images using Gouy-phase interferometry. Vertical (z)-scanning of an objective lens around the focus adds a z-dependent Gouy-phase shift to the Escat, changing the iSCAT image contrast. We show that analysis of the z-dependent image contrasts allows us to recover the amplitude and phase of the Escat. The method was validated by showing that the recovered amplitude and phase spectra of a gold nanoparticle fully reproduce well-known spectral features of resonance of localized surface plasmons.

Recovery of the amplitude and phase of single nanoparticle scattering using Gouy-Phase nterferometry

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.