Dual-beam intracavity optical tweezers with all-optical independent axial and radial self-feedback control schemes.

The feedback control to optical tweezers is an obvious approach to improve the optical confinement. However, the electronic-based feedback controlling system in optical tweezers usually consists of complex software and hardware, and its performance is limited by the inevitable noise and time-delay from detecting and controlling devices. Here, we present and demonstrate the dual-beam intracavity optical tweezers enabling all-optical independent radial and axial self-feedback control of the trapped particle's radial and axial motions. We have achieved the highest optical confinement per unit intensity to date, to the best of our knowledge. Moreover, both the axial and radial confinements are adjustable in real-time, through tuning the foci offset of the clockwise and counter-clockwise beams. As a result, we realized three-dimensional self-feedback control of the trapped particle's motions with an equivalent level in the experiment. The dual-beam intracavity optical tweezers will significantly expand the range of optical manipulation in further studies of biology, physics and precise measurement, especially for the sample that is extremely sensitive to heat.