Fig. 7
a Analogous model of a spring-mass oscillator. b Calculated deformation of the fiber surrounded by water in response to planar ultrasound waves. Left: (2,1) torsional-radial mode at 22 MHz. Right: (2, 2) torsional-radial mode at 39 MHz. SRS-based multiwavelength fiber laser source for functional PAM. (a): Schematic of the laser and PAM; (b): Laser output spectrum; (c): Schematic of the phase cancelation effect; and d: Effective interaction length with different source-to-fiber distances [50]