Open AccessSingle-particle photothermal imaging via inverted excitation through high-Q all-glass toroidal microresonators
Author(s) -
Kassandra A. Knapper,
Feng Pan,
Morgan T. Rea,
Erik H. Horak,
Jeremy D. Rogers,
Randall H. Goldsmith
Publication year - 2018
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.025020
Subject(s) - whispering gallery wave , materials science , resonator , optics , wafer , photothermal therapy , toroid , fabrication , optoelectronics , nanotechnology , physics , plasma , quantum mechanics , medicine , alternative medicine , pathology
Whispering-gallery mode (WGM) microresonators have recently been employed as platforms for label-free single-molecule and single-particle detection, imaging, and spectroscopy. However, innovations in device geometry and integration are needed to make WGM microresonators more versatile for biological and chemical applications. Particularly, thick device substrates, originating from wafer-scale fabrication processing, prevent convenient optical interrogation. In this work, we fabricate all-glass toroidal microresonators on a coverslip thickness (~170 μm) substrate, enabling excitation delivery through the sample, simplifying optical integration. Further, we demonstrate the application of this new geometry for single-particle photothermal imaging. Finally, we discover and develop simulations to explain a non-trivial astigmatism in the point spread function (PSF) arising from the curvature of the resonator.