Ultrasonic Holographic Ghost Imaging

Abstract

Ghost imaging in terahertz range has proved that amplitude and phase holographic imaging could be realized by detecting time-resolved electromagnetic waves, which shows application potential in several areas, such as nondestructive evaluation, biological sample imaging, etc. Compared with terahertz electromagnetic waves, ultrasound is easier to emit, modulate, and detect, and its shorter wavelength can produce higher phase and spatial-imaging resolutions. Here, we investigate ultrasonic holographic ghost imaging (UHGI). A linear-array ultrasonic transducer is used to emit ultrasonic waves, which travel through the sample closely attached to the transducer, then propagate for a certain distance in water, and finally are received by a hydrophone. By encoding the ultrasonic waves emitted by the linear-array transducer and correlating the ultrasonic waves received by the hydrophone and prearranged sampling patterns, holographic imaging of transmittance and phase shift can be realized. Combined with near-field imaging, the spatial resolution (determined by the element size of the transducer) can reach 0.3 mm. The UHGI experiment is easy to carry out and can add more capabilities to ultrasonic medical imaging, nondestructive evaluations, and the imaging of acoustic metasurfaces.