Extended Data Fig. 2: Mechano-optical response of single avalanche-shifting (7% Tm³⁺) ANPs.

a. Excitation power dependence of the mechano-optical response of a single ANP. Each compression cycle (measured at a different excitation intensity) consists of 100 data points, derived from 100 force-dependent optical spectra measured at 3 s acquisition times. Force increment step size is 25nN. Excitation intensities and fitted graph equations (where P is emission intensity and F is force) for each compression cycle are depicted within the legend. b. Mechano-optical response cyclability of a single ANP. Repeating compression cycles measured for a single ANP at a specific excitation power (27 kW cm⁻²), for different acquisition times. Each compression cycle consists of 20 data points, derived from 20 force-dependent optical spectra measured at 2 s (cycles 1, 2) and 5 s (cycles 10, 11, 12) acquisition times. The force-dependent optical response is repeatable, for the 2.5-µN-force cycles applied. No photodegradation or plastic deformation is measured under these excitation and mechanical conditions, for up to 25 measured cycles per particle. The difference in apparent ambient particle brightness, and hence emission-force graphs, derives from the different acquisition times (noted for each cycle in the figure legend). Normalization by the acquisition time yields similar noise-equivalent sensitivity (NES) values for all cycles.