(left) Schematic illustration of all-optical transducer; CNT-PDMS composite film for ultrasound generation and thin-film etalon (polymer resonator) incorporating two DBRs for ultrasound detection.

(bottom) Experimental setup for pulse-echo measurement (1064-nm pulsed laser for photoacoustic excitation of the CNT-PDMS transmitter and 1550-nm CW laser for interferometric detection of ultrasound).  

 

Figure from IEEE Photonics J. 7(6), 6803708 (2015)