All-optical microscope autofocus based on an electrically tunable lens and a totally internally reflected IR laser
Date
05/02/2018Metadata
Show full item recordAbstract
Microscopic imaging at high spatial-temporal resolution over long time scales (minutes to hours) requires rapid and precise stabilization of the microscope focus. Conventional and commercial autofocus systems are largely based on piezoelectric stages or mechanical objective actuators. Objective to sample distance is either measured by image analysis approaches or by hardware modules measuring the intensity of reflected infrared light. We propose here a truly all-optical microscope autofocus taking advantage of an electrically tunable lens and a totally internally reflected infrared probe beam. We implement a feedback-loop based on the lateral position of a totally internally reflected infrared laser on a quadrant photodetector, as an indicator of the relative defocus. We show here how to treat the combined contributions due to mechanical defocus and deformation of the tunable lens. As a result, the sample can be kept in focus without any mechanical movement, at rates up to hundreds of Hertz. The device requires only reflective optics and can be implemented at a fraction of the cost required for a comparable piezo-based actuator.
Citation
Bathe-Peters , M , Annibale , P & Lohse , M J 2018 , ' All-optical microscope autofocus based on an electrically tunable lens and a totally internally reflected IR laser ' , Optics Express , vol. 26 , no. 3 , pp. 2359-2368 . https://doi.org/10.1364/OE.26.002359
Publication
Optics Express
Status
Peer reviewed
ISSN
1094-4087Type
Journal article
Rights
Copyright © 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
Description
Funding Information: Deutsche Forschungsgemeinschaft (SFB 688); NIH (Prime Grant No. 5 R01 DA038882-02); University of Wuerzburg.Collections
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