A Fabry–Perot Fiber-Optic Array for Photoacoustic Imaging

Abstract

Photoacoustic imaging is an emerging noninvasive and nonionizing imaging modality with high contrast and high resolution, which originates from the photoabsorption selectivity and the broadband response of the photoacoustic signals. However, sensing of the photoacoustic signal is currently limited by the bandwidth of piezoelectric ultrasound transducers. The optical ultrasound sensors based on Fabry–Perot (F–P) interference exhibit broader bandwidth than piezoelectric transducers, which is expected to be a promising alternative. At present, nevertheless, the parallel sensing and processing of ultrasound signals using the fiber-optic ultrasound sensor is still a challenge. Here, we propose a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times16$ </tex-math></inline-formula> fiber-optic array based on F–P interference, which enables parallel sensing for imaging with a volume rate of 10 Hz. We experimentally demonstrated that the fiber-optic array ultrasound sensor exhibited a pressure nonlinearity of <3.64%, and −6 dB bandwidth from ~0 to 18.3 MHz. High-definition imaging is achieved by this sensing array without mechanical scanning. As the ultrasound sensing realized by optics, the photoacoustic imaging system is potentially an all-optic system with broadband response.