Fig. 9
From: Highly sensitive ultrasound detection using nanofabricated polymer micro-ring resonators
(Reproduced with permission from [34])
a A schematic illustration of potential contaminants attached to the waveguide. b A cross-sectional SEM image of the PS MRR in air. Scale bar 500 nm. c Optical resonance spectrum when unprotected MRR is exposed to whole blood for 2 h. d A schematic illustration of the MRR with the PDMS protection layer. e A cross-sectional SEM image of the PS MRR with the PDMS protection layer. Scale bar 500 nm. f Optical resonance spectrum when the MRR with the protection layer is exposed to whole blood for 2 h. g The quantitative comparison of the detection sensitivity in whole blood. h A schematic of the packaged MRR on the glass coverslip with the optical fibers. i The polymer MRR ultrasound detector for chronic cranial window mounted on the mouse’s forehead. j Illustration of optical scanning through the transparent polymer MRR. k Marginal reduction in the Q-factor of the MRR mounted on the mouse’s forehead for the 28-day-period. l–n Longitudinal PAM images of cortical vasculature of the mouse brain