Parallel and Real-time Trapping, Manipulating and Characterizing Microscopic Specimens

Abstract

In the mesoscopic regime, very small forces that result from light-matter interaction are strong enough to significantly influence the motion of tiny particles. Until just a few years ago, virtually all laser manipulation schemes were based on trapping particles inside a single strongly focused beam and moving them into a desired position by translating the laser focus. Now, two decades later, a great deal of progress has been achieved in optical trapping and manipulation, both in terms of applications and technical developments. Particularly, much more versatile and general manipulation of particles and cell colonies is now possible by using specially tailored structures of light. 1 Such light patterns have unprecedented potential for manipulating mesoscopic objects and have already been successfully used to organize small particles, including microorganisms, in desired patterns and to sort samples of particles according to their size. 2 Optical trapping and manipulation of a plurality of micro-particles is now viable using reconfigurable patterns of optical fields. 3 This opens up research possibilities for many interdisciplinary fields, particularly those with biomedical relevance. With the advent of computeraddressable spatial light modulators, the reconfigurability of light patterns that can act as confining optical potential landscapes is made even more feasible with a great degree of interactive usercontrol. 4 We invented the “all-optical biophotonics workstation” to trap, manipulate and characterize microscopic specimens in parallel. We used an optical mapping from a beam-modulation module to obtain reconfigurable intensity patterns, corresponding to two independently