Investigation on improvement of lateral resolution of continuous wave STED microscopy by standing wave illumination

Won Sup Lee, Geon Lim, Wan Chin Kim, Guk Jong Choi, Han Wook Yi, No Cheol Park

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

In this paper, we report the enhancement of resolution of continuous wave (CW) stimulated emission depletion (STED) microscopy by a novel method of structured illumination of an excitation beam. Illumination by multiple excitation beams through the specific pupil apertures with high in-plane wave vectors leads to interference of diffracted light flux near the focal plane, resulting in the contraction of the point spread function (PSF) of the excitation. Light spot reduction by the suggested standing wave (SW) illumination method contributes to make up much lower depletion efficiency of the CW STED microscopy than that of the pulsed STED method. First, theoretical analysis showed that the full width at half maximum (FWHM) of the effective PSF on the detection plane is expected to be smaller than 25% of that of conventional CW STED. Second, through the simulation, it was elucidated that both the donut-shaped PSF of the depletion beam and the confocal optics suppress undesired contribution of sidelobes of the PSF by the SW illumination to the effective PSF of the STED system. Finally, through the imaging experiment on 40-nm fluorescent beads with the developed SW-CW STED microscopy system, we obtained the result which follows the overall tendency from the simulation in the aspects of resolution improvement and reduction of sidelobes. Based on the obtained result, we expect that the proposed method can become one of the strategies to enhance the resolution of the CW STED microscopy.

Original languageEnglish
Pages (from-to)9901-9919
Number of pages19
JournalOptics Express
Volume26
Issue number8
DOIs
Publication statusPublished - 2018 Apr 16

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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