Dynamic Ultrasound Projector Controlled by Light

Abstract

Dynamic acoustic wavefront control is essential for many acoustic applications, including biomedical imaging and particle manipulation. Conventional methods are either static or in the case of phased transducer arrays are limited to a few elements and hence limited control. Here, a dynamic acoustic wavefront control method based on light patterns that locally trigger the generation of microbubbles is introduced. As a small gas bubble can effectively stop ultrasound transmission in a liquid, the optical images are used to drive a short electrolysis and form microbubble patterns. The generation of microbubbles is controlled by structured light projection at a low intensity of 65 mW cm–2 and only requires about 100 ms. The bubble pattern is thus able to modify the wavefront of acoustic waves from a single transducer. The method is employed to realize an acoustic projector that can generate various acoustic images and patterns, including multiple foci and acoustic phase gradients. Hydrophone scans show that the acoustic field after the modulation by the microbubble pattern forms according to the prediction. It is believed that combining a versatile optical projector to realize an ultrasound projector is a general scheme, which can benefit a multitude of applications based on dynamic acoustic fields.

Biomechanical Sensing Using Gas Bubbles Oscillations in Liquids and Adjacent Technologies: Theory and Practical Applications

“…Each method has its own advantages and disadvantages in particular applications, which is often established via trial-and-error testing. However, microbubbles created as ultrasound contrast agents appear to be the main choice in many experiments that are, in general, unrelated to medical imaging [ 242 , 243 ]. The reasons for this are manifold.…”

“…Secondly, bubble clusters with controlled inter-bubble spacings can be generated using light [ 242 ] and acoustic pressure waves [ 243 ]. For instance, in [ 243 ] the secondary Bjerknes force discussed in the main text of the current review has been amplified to enable acoustic assembly and manipulation of centimetre-scale objects.…”

Soft-lithographically defined template for arbitrarily patterned acoustic bioassembly

“…To address this challenge, a few novel acoustic bioassembly techniques have been recently demonstrated using traveling wave-based acoustic techniques 24, 25 . Specifically, acoustic holography (AH) enables to generate arbitrarily spatial distribution of bioparticles on a specific assembly plane 26 .…”

Biomechanical Sensing using Gas Bubbles Oscillations in Liquids and Adjacent Technologies: Theory and Practical Applications

“…Secondly, bubble clusters with a controlled inter-bubble spacings can be generated 1031 using light [242] and acoustic pressure waves [243]. For instance, in [243] the secondary Thirdly, it is known that the surface of oscillating bubbles can exhibit wall 'shim-1038 mering' [244,245] that is visually detectable surface Faraday waves [246].…”