Dual-Modality All-Optical Ultrasound and Photoacoustic Imaging Using Permanent Marker Ink

A dual-modality all-optical ultrasound and photo to acoustic imaging probe was fabricated using a commercially available permanent marker ink. The permanent marker ink was dried and mixed with polydimethylsiloxane to form a composite coating on optical fiber tips. The coating exhibited wavelength-selective absorption, with absorption > 90% at 532 nm for ultrasound generation, and <; 10% at 1064 nm for photoacoustic light transmission. Ultrasound generated by the device had a peak-to-peak pressure in excess of 200 kPa and a corresponding -6 dB bandwidth of 17.3 MHz. The fabricated transmitter was combined with a plano-concave Fabry-Perot fiber optic hydrophone to create an imaging probe. The axial ultrasound resolution of the probe was <; 200 μm. Co-registered ultrasound and photoacoustic imaging was demonstrated with a wire phantom. This work demonstrates the feasibility for making low-cost dual-modality devices using all-optical ultrasound