Broadband all-optical ultrasound transducers

Abstract

A broadband all-optical ultrasound transducer has been designed, fabricated, and tested for high-resolution ultrasound imaging. It consists of a two-dimensional gold nanostructure on a glass substrate, followed by a 3μm polydimethylsiloxane layer and a 30nm gold layer. The signal to noise ratio of a pulse-echo signal is over 10dB in the far field of the transducer, where the center frequency is 40MHz with −6dB bandwidth of 57MHz. The potential for high-frequency ultrasound arrays using this technology is demonstrated using multiple measurements from the transducer to image a 25μm diameter wire.

Broadband miniature optical ultrasound probe for high resolution vascular tissue imaging

“…Whilst all-optical ultrasound images have previously been obtained [5][6][7][8], those in this study were significant in terms of the detail with which tissue microstructure was visualised, and the compactness of the probe with which they were acquired. The high performance of the probe in this study stemmed from a combination of the high ultrasound pressures transmitted by the optically absorbing film and the high sensitivity of the concave FP ultrasound sensor.…”

“…To achieve high optical-ultrasound transduction efficiency, a material with a high optical absorption coefficient and a high thermal expansion coefficient is desirable [9]. Recent studies have highlighted the efficacy of composite materials that comprise optical absorbers integrated within elastomers [5,10,11]. The authors recently demonstrated a method for creating ultrasound transmitters at the tip of an optical fiber using a composite material comprised of functionalised multi-walled carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS) [12].…”

“…Additionally, it can be challenging to achieve wide transmission bandwidths and adequate wideband reception sensitivity with small piezoelectric elements. Optical methods for transmitting and receiving ultrasound are emerging as alternatives to their electrical counterparts [5][6][7][8]. They offer several distinguishing advantages including the potential to generate and detect the broadband ultrasound fields (tens of MHz) required for high resolution endoscopic imaging.…”

“…Whilst all-optical ultrasound images have been demonstrated previously [5][6][7][8], there is a need to miniaturise the optical designs in order to make them compatible with interventional devices. In this paper, we describe a novel miniature fiber optic probe that is based on the two concepts outlined above: a fiber optic transmitter that employs a CNT based absorbing film [12] for generating broadband ultrasound and a fiber-optic FP polymer sensor [21] for receiving it.…”

All-optically integrated photoacoustic and optical coherence tomography: A review

“…[32][33][34][35] Next, we present the current development of multimodality imaging combined with all-optical PAI. At the end, an outlook about all-optical dual-mode imaging system is present.…”