Fig. 5.

(a) SEM image of an MRR ultrasound detector; (b) high magnification view shows the square-shaped cross-section of the waveguide with a side length of 800 nm; (c) calculated electric field distribution of the TM mode when the waveguide is immersed in water. Reproduced with permission from [81]; (d) spectral profile of an ultrasound pulse generated by a 1-ns laser pulse from a 1.5-μm-thick carbon black thin film; (e) angular dependence of the frequency response of the MRR ultrasound detector was normalized with the maximum amplitude at each frequency. Reproduced with permission from [30].