Single optical fiber based forward-viewing all-optical ultrasound self-transceiving probe

All-optical ultrasound probes with fully integrated ultra-sound generation and detection functions demonstrate some unique advantages over traditional electroacoustic counter-parts. However, due to the lack of an effective solution, the most commonly used method is to assemble two separate functional optical fibers together for ultrasound generation and detection, respectively. In this Letter, an innovative strat-egy, to the best of our knowledge, is developed to integrate the photoacoustic effect based ultrasound generation and the Fabry-Perot (FP) interference based ultrasound detection structures together at the end of a single double clad opti-cal fiber (DCF), so as to make a compact forward-viewing ultrasound self-transceiving probe (1-mm diameter). From the experiment results, the as-fabricated probe can gener-ate an ultrasound signal with an amplitude of 2.36 MPa at 2.25 mm in the transmitting mode, and its peak fre-quency and -6-dB bandwidth are measured to be 10.64 MHz and 22.93 MHz, respectively. When being operated under the receiving mode, the probe has a detection sensitivity of 208.4 mV/MPa for ultrasound signals with the peak fre-quency of 8.24 MHz, and the noise equivalent pressure (NEP) is 76.8 kPa. In addition, the forward-viewing format ultra-sound self-transceiving experiment is also performed and the pulse-echo signal varying with the transmission distance is successfully captured for the first time. (c) 2023 Optica Pub-lishing Group