Digital Light Deflection and Electro-Optical Laser Scanning for STED Nanoscopy

Abstract

Electro-optical deflectors provide a very attractive means of laser scanning in coordinate-targeted super-resolution microscopy due to their high scanning precision and high scanning velocity. Setups equipped with electro-optical deflectors demonstrate especially high resolving powers, fast imaging and reduced photobleaching. Two major shortcomings limit a widespread application of such devices. Their polarizing properties prevent de-scanning causing either a loss in signal or an increased background signal and the restricted deflection angles severely narrow the field of view. Herein, I report solutions to both of these problems. The polarization issue is evaded via a passive polarization rectifier that allows unpolarized light to pass the laser scanner. The field of view is nearly doubled through a digital light deflector composed of a Pockels cell and a Wollaston prism. This principle could be extended by N stages of the same kind yielding a field of view enlargement by a factor of 2^N. Thus, the work at hand paves the way for ultrafast electro-optical laser scanning with a large field of view.