Complex photonics

The team deals with problems that are connected with the mechanical properties of the laser beam interacting with dielectric objects. An experimental setup enabling optical 3D trapping of microobjects and nanoobjects by means of the optical fields has been built up here as the only one in the Czech Republic. The system is being gradually modified to enable generation and independent positioning of several optical traps by use of a computer. An original method employing the Gaussian standing wave and objective with a low numerical aperture was suggested and experimentally tested for the optical trapping. This setup has been enriched by the possibility of laser microablation that is used for topology modification of optically trapped objects, perforation of inner and outer cell membranes and cell fusion. This system is used for our own experimental activities or for experiments on biological objects that are coordinated by our external colleagues. Precise detection of position of optically trapped objects is employed for the measurement of weak forces (in the range from pN to nN) acting on the optically trapped probe. It is the only method enabling estimation of forces comparable to intermolecular ones acting on the neutral objects. Original methods for the cooling and trapping of atoms using the Gaussian standing wave have also been developed.