Abstract: The invention discloses a method and an apparatus for trapping and manipulating particles, relating to the field of acoustic manipulation. The invention discloses a photoacoustic tweezers, which use bimodal transducer generate a weak acoustic wave and a strong acoustic wave. The strong acoustic wave behaves as an effective gain medium to amplify the acoustic radiation force of this weak acoustic wave. After an interference of the strong acoustic wave and the weak acoustic wave, an amplified trapping force is produced for achieving the trapping and manipulation of particles. The invention can manipulate several particles simultaneously in high throughput and particles of various sizes ranging from 1 ?m to 1 mm. The invention can form reconfigurable acoustic fields which permits versatile and selective manipulation with no need of complicated acoustic arrays. The invention is a versatile, biocompatible, selective and high-throughput manipulation method.

Abstract: The invention discloses an apparatus and a method for capturing and manipulating particles, relating to the field of acoustic manipulation. In view of the problems in the prior art that can't achieve a contactless, versatile, selective, and universal manipulation method for particles, the present application provides photoacoustic tweezers, which uses a photoacoustic transducer unit and an electroacoustic transducer unit to form a bimodal transducer, generates a weak acoustic wave and strong acoustic wave respectively through signal excitation. The strong acoustic wave behaving as a gain medium, amplifies the acoustic radiation force of the weak acoustic wave. The invention enables contactless and label-free selective capture and manipulation of particles. Further, the amplified acoustic radiation force enhances biocompatibility by requiring lower optical powers than alternative optical methods.

Abstract: Electroacoustic device that includes a body, an electrode to be electrically powered, named hot electrode, and an electrode to be electrically grounded, named ground electrode. The body includes a piezoelectric part or the electroacoustic device further including a piezoelectric part different from the body. The hot electrode includes a hot track spiraling around a spiral axis. The radial step between two consecutive coils of the hot track decreasing radially from the spiral axis. The hot electrode and the ground electrode are arranged on the piezoelectric part such as to define a wave transducer configured to generate a focalised ultrasonic vortex propagating in the body and/or, when a fluid medium is acoustically coupled with the electroacoustic device, in the fluid medium.

Abstract: Electroacoustic device that includes a body, an electrode to be electrically powered, named hot electrode, and an electrode to be electrically grounded, named ground electrode. The body includes a piezoelectric part or the electroacoustic device further including a piezoelectric part different from the body. The hot electrode includes a hot track spiraling around a spiral axis. The radial step between two consecutive coils of the hot track decreasing radially from the spiral axis. The hot electrode and the ground electrode are arranged on the piezoelectric part such as to define a wave transducer configured to generate a focalised ultrasonic vortex propagating in the body and/or, when a fluid medium is acoustically coupled with the electroacoustic device, in the fluid medium.