Subwavelength resonator for acoustophoretic printing

A method of acoustophoretic printing, the method comprising:

• providing an apparatus including an acoustic emitter and a subwavelength resonator for enhancing an acoustic field, the subwavelength resonator comprising:
• a hollow resonator body;
• and
• a nozzle body integrated with the hollow resonator body, the nozzle body having a first end outside the hollow resonator body and a second end inside the hollow resonator body, the nozzle body comprising a fluid channel extending between a fluid inlet at the first end and a fluid outlet at the second end, the fluid channel passing through a side wall of the hollow resonator body and including at least one bend;
• activating the acoustic emitter to generate an acoustic field, the acoustic field being transmitted to the subwavelength resonator and being enhanced in the hollow resonator body, thereby forming a high intensity acoustic field at the fluid outlet;
• and
• delivering an ink through the fluid channel to the fluid outlet, a predetermined volume of the ink being detached from the nozzle body in the high intensity acoustic field.