Extended Data Fig. 8: Exemplary OA Imaging (n=1) with different geometries: 64-element array and single element scanning.

a, Tomography slice of tubings filled with blood or rsGCaMP with different Ca²⁺ concentrations. The sample is consecutively illuminated with 488 nm (1.8 mJ/s) and 420 nm (1.8 mJ/s) light to elicit photo-modulation. The raw data is shown (acquisition dynamic range adjusted to blood intensity) and unmixed based on the photo-modulation pattern. b, Normalized switching kinetics extracted by averaging over 10 switching cycles obtained from (a) (dots) together with linear regression (line). c, Normalized time constants from (b) vs. Ca²⁺ concentrations. d, Raster scanning optoacoustic (RSOM) images of tubings filled with blood or rsGCaMP with different Ca²⁺ concentrations. The sample was consecutively illuminated with either only 50 Hz pulsed 488 nm light (90 µJ at the sample) or 488 nm light together with different intensities of 405 nm light (max. 0.8 W at the sample) to switch rsGCaMP off or to maintain different mixed populations, respectively. The raw data is shown and unmixed based on differential images using the highest 405 nm intensity. e, Normalized unmixed signals obtained from (d) at different 405 nm intensities together with linear regressions. f, Normalized half-times obtained from (e) vs. Ca²⁺ concentrations. All scalebars 1 mm.