A directional fibre optic ultrasound transmitter based on a reduced graphene oxide and polydimethylsiloxane composite

Abstract

Strongly directional ultrasound sources are desirable for many minimally invasive applications, as they enable high-quality imaging in the presence of positioning uncertainty. All-optical ultrasound is an emerging paradigm that exhibits high frequencies, large bandwidths, and a strong miniaturisation potential. Here, we report the design, modelling, and fabrication of a highly directional fibre-optic ultrasound transmitter that uses a composite of reduced graphene oxide and polydimethylsiloxane as the optical ultrasound generator. The ultrasound transmitter, which had an outer diameter of just 630 μm, generated ultrasound with a pressure exceeding 0.4 MPa for axial distances up to 16 mm, at a large bandwidth of 24.3 MHz. The ultrasound beam exhibited low divergence, with a beam diameter ranging between 0.6 and 2.1 mm for distances between 0 and 16 mm. The presented directional optical ultrasound source is hence well-suited to high-resolution interventional imaging.

CuInS2 Quantum Dot and Polydimethylsiloxane Nanocomposites for All‐Optical Ultrasound and Photoacoustic Imaging

“…[8,13,14,16,20] To compare the generation efficiency with previous results, the 2D pressure field measurements were numerically backpropagated to the coating surface to yield a transduction efficiency of 0.024 MPa mJ −1 cm −2 . While this efficiency was lower than those recently presented for carbon nanotube-based coatings [8,16] (0.13-0.65 MPa mJ −1 cm −2 ) and graphene-based coatings [69] (0.21 MPa mJ −1 cm −2 ), the high damage threshold of the CIS-PDMS coating allowed for comparable absolute pressures to be achieved. The generated pressure increased linearly with laser fluence, as expected from PA excitation.…”

Source Density Apodization: Image Artifact Suppression Through Source Pitch Nonuniformity

“…Recently, an all-optical alternative to electronic ultrasound transducers has been presented that uses light to both transmit and receive ultrasound. Using fibre optic technology, optical ultrasound sources [3][4][5][6][7][8] and detectors [9][10][11][12][13][14] are readily miniaturised, exhibit high bandwidths and sensitivities, and are immune to electromagnetic interference. Recently, a benchtop system has been demonstrated that used a single fibre optic ultrasound detector and a centimetre-scale monolithic photoacoustic ultrasound generator membrane to achieve video-rate two-dimensional imaging [15].…”

Large area all-optical ultrasound imaging using robotic control

“…Additionally, the OpUS probe can be optimised to provide improved lateral resolution. The divergence of the generated ultrasound beam could be reduced by using a concave ultrasound generating surface 13 or larger diameter planar surfaces, 14 to achieve a focus within tissue.…”