Extended Data Fig. 1: Avalanche-shifting (7% Tm³⁺) ANP mechano-optics at the avalanching and saturation regimes.

a. Emission spectra as a function of applied force, for increasing excitation intensities, for single ANPs. At each excitation intensity, 100 force-dependent optical spectra are measured per 2.5 µN force ramp. The accessible force range (dashed line), and the relative brightness of the ANP (note different scales) for each excitation intensity correlate with avalanching behavior. b. Full compression cycles, each consisting of 100 emission intensity versus applied force data points, for single ANPs excited in their avalanching regime (27 kW cm⁻²) and saturation regime (85 kW cm⁻²). Each data point is derived from a single force-dependent optical spectrum (as in a and c). c. Two sequentially measured emission spectra (left) and their corresponding integrated intensities (right) as a function of applied force, for an ANP excited in its avalanching regime (18 kW cm⁻²). Error bars for integrated emission intensities are based on signal Poissonian statistics. The noise-defined resolution, retrieved from a full compression cycle (as in a and b), is depicted (P is photon counts (integrated intensity), F is force, P₀ is the photon count at F = 0). Integration time is 3 s for all measurements.