Upconversion Photoluminescence to Monitor Local Heat Release During Femtosecond Direct Laser Writing of Bioinks In Situ.

ABSTRACT: Exothermic photopolymerization releases heat into the sample environment. Using NaYF₄:Yb³⁺/Er³⁺ upconversion nanoparticle (UCNP) photoluminescence and a colinear lithography and thermometry laser configuration, we monitor thermal signatures in the focal spot during femtosecond direct laser writing in real time. A statistical short-pass filtering is introduced to reduce the standard error in temperature calibration compared to conventional Gaussian deconvolution. Thermometry performance of our set-up achieved a relative sensitivity of 0.89-1.58% K^-1 and a measurement uncertainty of 0.2-0.4 K for 2 Hz sample rates. With this, the effect of scan speed, laser power, and photoinitiator concentration on accompanying local heating could be followed. Non

SUBMITTER: Zeynali A 

PROVIDER: S-EPMC12929933 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature