Local temperature measurement during ultrafast laser 3D nanolithography writing

Luminescence measurements of upconverting nanocrystals (UCNCs) dispersed in SZ2080 hybrid prepolymer being processed under different laser polymerization regimes are presented. Er3+ ions doped β-NaYbF4 UCNCs were prepared by a one-step thermal decomposition method. The ratio of the 2H11/2 → 4I15/2 and 4S3/2→ 4I15/2 emission intensities under λ= 980 nm excitation in the range from 24 to 70°C confirmed to follow Boltzmann type distribution and enabled a self-referenced optical readout of the sample temperature changes. Variation of thermally-coupled spectral bands intensity ratio was observed under typical laser writing conditions (1030 nm, 300 fs, 200 kHz, NA = 0.8) and E(pulse) varying from below threshold to the optical breakdown. Average fitted temperature changes around polymerized voxel calculated to be ΔT1