Direct measurement of multi-angle evanescent field by whispering gallery mode of the microsphere and fluorescent spots in an optical waveguide fluorescence microscopy

Evanescent field (EF) has been widely applied in various micro-imaging techniques for its ability to excite surfaces. However, measuring the multi-angle EF remains challenging. In this paper, the whispering gallery mode (WGM) is observed in an excited microsphere on an optical waveguide (OWG) with a...

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Bibliographic Details
Published in:Applied physics letters 2024-08, Vol.125 (8)
Main Authors: Hu, Yanjun, Dai, Xingang, Zhang, Hongru, Dai, Qun, Niu, Bowen, Jing, Gaoshan, Li, Yuan, Fan, Guofang
Format: Article
Language:English
Subjects:
Diameters
Fluorescence
Imaging techniques
Measurement methods
Nondestructive testing
Optical waveguides
Synchronism
Thickness
Online Access:Get full text
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Summary:Evanescent field (EF) has been widely applied in various micro-imaging techniques for its ability to excite surfaces. However, measuring the multi-angle EF remains challenging. In this paper, the whispering gallery mode (WGM) is observed in an excited microsphere on an optical waveguide (OWG) with a thickness of 0.6 mm, which is used to determine the diameter of the excited microsphere. A simple and nondestructive measurement method for multi-angle OWG-EF is proposed, which is based on the reliable diameter of the microsphere, determined by WGM and the TIRF spots. The measurement result for multi-angle OWG-EF shows a dynamic range between ∼180 and ∼2400 nm, which shows good agreement with the simulation results. The method synchronization possible for EF measurements and fluorescent experiments.
ISSN:0003-6951
1077-3118
DOI:10.1063/5.0218665