Philip H. Jones, Onofrio M. Maragò & Giovanni Volpe
Fig. 8.14 — Trap steering
The position of an optical trap can be changed within the sample (a) along the vertical z-direction by displacing one of the lenses in a telescopic arrangement and (b) in the horizontal xy-plane by conjugating the plane of a steerable mirror to the objective back aperture (BA). (c) It is also possible to construct a dual optical tweezers where a beam is split into two and recombined using two polarising beam splitters (PBS1 and PBS2) in order to create two independently steerable optical traps; the choice of polarising beam splitters is to avoid losing optical power.