Figure 3.

Illustration of the laser feedback AO Tomography system including microchip laser (ML), beam splitter (BS), PD, lenses (L1, L2,), and US transducer (UT), for imaging microbubbles (MB) inside vessel wall (VW). A reflective and autocollimation configuration is used for the whole system. The ML is pumped by laser diodes, which modulate the output power by reflecting backscattered photons. Light reflected from the BS reaches the PD and incident light reaches the front surface of the phantom. UT is placed coaxially with the laser beam, where the US focus (UF) overlaps the laser focus (LF). A function generator produces sinusoidal bursts at a repetition rate of 100 Hz, and is then amplified. Light and US are focused in the tube simultaneously. During UT operation, measuring light is shifted (3 MHz), whereas background signal is not shifted. Reprinted from [75], Copyright (2022), with permission from Elsevier.